Third Stage Review
and Assessment of
Air Quality in Hackney
Third Stage Review and Assessment of Air Quality in Hackney.......................... 4
1.0 Introduction........................................................................................................... 4
The National Air Quality Strategy ............................................................................ 4
DETR Guidance ................................................................................................... 6
Local Air Quality Management.............................................................................. 7
Central London Cluster Group................................................................................. 7
Selection of model for the study .............................................................................. 9
2.0 Sources and Health Effects of Air Pollution ........................................................ 10
Carbon Monoxide (CO).......................................................................................... 10
Nitrogen Dioxide (NO2) .......................................................................................... 10
Sulphur Dioxide (SO2) ........................................................................................... 11
Fine Particles (PM10) ............................................................................................ 11
Benzene ................................................................................................................ 12
1,3-butadiene......................................................................................................... 12
Lead ...................................................................................................................... 12
3.0 Air Quality Monitoring In Hackney ...................................................................... 14
Chemiluminescent Nitrogen Dioxide Analyser....................................................... 14
Non-dispersive infra-red carbon monoxide analyser ............................................. 14
Ultra Violet Photometric Ozone Analyser .............................................................. 14
Tapered Element Oscillating Microbalance (TEOM) fine particles –PM2.5 .......... 14
BS17457 Sulphur Dioxide and Black Smoke......................................................... 14
Passive Diffusion Tubes (Nitrogen Dioxide) .......................................................... 15
4.0 Stage 111 Review and Assessment of Air Quality............................................. 16
4.1 Introduction and overview................................................................................ 16
4.2 London Emissions Inventory............................................................................ 16
4.2.1 Inventory for ‘current’ emissions ................................................................... 18
NOx, PM10, VOC Emissions ................................................................................ 19
Road traffic sources............................................................................................ 19
Major Road ......................................................................................................... 19
Analysis of Major Road Data ................................................................................. 19
Replacement of LRC traffic data with DETR Traffic counts ................................... 20
Borough Data ........................................................................................................ 21
Minor Roads .......................................................................................................... 23
Cold starts and trip ends........................................................................................ 23
Industrial point sources.......................................................................................... 23
Aggregated grid sources........................................................................................ 23
Other Sources ....................................................................................................... 23
SO2 emissions ....................................................................................................... 23
Point source data................................................................................................... 24
Grid source data .................................................................................................... 24
Predicted 2005 Emissions Inventory ..................................................................... 24
Current NoX Emissions for London .................................................................... 27
Current PM10 emissions for London.................................................................... 28
Current NMVOC emissions for London. ............................................................. 29
Current SO2 emissions for London ..................................................................... 30
2005 NOX emissions........................................................................................... 31
2005 PM10 emissions.......................................................................................... 32
2005 NMVOC emissions .................................................................................... 33
2005 SO2 emissions ........................................................................................... 34
2005 NOx, PM10 and VOC emissions ................................................................. 35
2004 Major road emissions................................................................................. 35
Adjustment of 2004 road traffic emissions .......................................................... 35
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Calculation of the adjustment factor ................................................................... 36
Use of dispersion models for air quality predictions].............................................. 37
Overview of ADMS urban ...................................................................................... 39
Methodology – Model Input ................................................................................... 39
a) Emissions Inventory ....................................................................................... 39
Model Data and Assumptions................................................................................ 39
Meteorological data ............................................................................................ 39
Chemistry Scheme ............................................................................................. 40
Grid Sources....................................................................................................... 40
vehicle emissions ............................................................................................... 40
area emissions ................................................................................................... 41
point emissions................................................................................................... 41
Background Concentrations .................................................................................. 41
Base year background concentrations .................................................................. 41
NOx, NO2 and O3 ................................................................................................... 41
PM10 ................................................................................................................... 41
2005 background pollutant concentrations ............................................................ 45
PM10 ................................................................................................................... 45
NOx, NO2 and Ozone.......................................................................................... 45
Possible sources of error ....................................................................................... 46
Terrain ................................................................................................................ 46
Scenarios modelled using ADMS Urban................................................................ 47
Validation of model ................................................................................................ 47
Model Validation for Nitrogen dioxide and PM10 ................................................. 47
Model Validation of Sulphur Dioxide ................................................................... 48
Findings of Hackney's Stage 111 Review and Assessment .................................... 49
Baseline Runs ....................................................................................................... 49
1997 Meteorological Data...................................................................................... 49
(i) Annual Mean NO2 (Derwent-Middleton Scheme) (Figure 73)....................... 49
(ii) Annual Mean NO2 (GRS Scheme) (Figure 74).......................................... 49
(iii) Maximum NO2 (Derwent-Middleton Scheme) (Figure 75) ......................... 49
(iv) Maximum NO2 (GRS Scheme) (Figure 76)................................................ 50
(v) 99th percentile of running 24 hour mean PM10 concentrations (Figure 77). 50
(vi) Annual mean SO2 (Figure 78).................................................................... 50
(vii) 99.9th percentile of 15 minute mean SO2 concentrations (Figure 79) ........ 50
1996 Meteorological data ...................................................................................... 50
(i) Annual mean NO2 (Figure 80) ...................................................................... 50
(ii) Maximum NO2 (Figure 81) ......................................................................... 50
(iii) 99th percentile of running 24 hour mean PM10 concentration (Figure 82) .. 50
(iv) Annual mean SO2 (Figure 83).................................................................... 50
(v) 99.9th percentile of 15 minute mean SO2 concentrations (Figure 84) ........ 50
Future Scenario 2005 ............................................................................................ 51
1997 Meteorological Data...................................................................................... 51
(i) Annual Mean NO2 (Figure 85) ...................................................................... 51
(ii) Maximum NO2 (Figure 86) ......................................................................... 51
(iii) 99th percentile of running 24 hour mean PM10 concentrations (Figure 87). 51
(iv) Annual mean SO2 (Figure 88).................................................................... 51
(v) 99.9th percentile of 15 minute mean SO2 concentrations (Figure 89) ........ 51
1996 Meteorological data ...................................................................................... 52
(i) Annual mean NO2 (Figure 90) ...................................................................... 52
(ii) Maximum NO2 (Figure 91) ......................................................................... 52
(iii) 99th percentile of running 24 hour mean PM10 concentrations (Figure 92). 52
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(iv) Annual mean SO2 (Figure 93).................................................................... 52
(v) 99.9th percentile of 15 minute mean SO2 concentrations (Figure 94) ........ 52
Public Exposure.........................................................................................................
Future Developments ................................................................................................
Sulphur Dioxide .................................................................................................. 53
Nitrogen Dioxide ................................................................................................. 53
Particles (PM10) .................................................................................................. 54
Designation of proposed Air Quality Management Areas ...................................... 54
Methodology for selection of Air Quality Management Areas ....................................
Areas selected for proposed Air Quality Management Areas ....................................
Public Consultation....................................................................................................
Public consultation................................................................................................. 55
The next steps ....................................................................................................... 56
Appendix XXX ......................................................................................................... 57
Hackney's First Stage Air Quality Review & Assessment Executive Summary ..... 57
Air Pollution Monitoring in Hackney. ...................................................................... 57
Air Pollution in Hacknev......................................................................................... 57
Results of the First Stage Assessment. ................................................................. 57
APPENDIX X: CHEMISTRY SCHEMES USED IN ADMS URBAN ......................... 58
The Derwent-Middleton Correlation .................................................................... 58
Co-ordinates ............................................................................................................. 66
X
Y.............................................................................................................. 66
Co-ordinates ............................................................................................................. 67
Co-ordinates ............................................................................................................. 69
Appendix XXX .......................................................................................................... 72
LAQM. TG1(98) - Monitoring for Air Quality Reviews and Assessments.................. 72
References ............................................................................................................... 73
Additional references............................................................................................. 76
Table 1 NAQS Air Quality objectives ............................................................................
Table 2 Base year Greater London Emissions by source type .....................................
Table 3 Base year Greater London Emissions by source type %.................................
Table 4 AUN sites and selected roads for which LRC and Borough data were
compared................................................................................................................
Table 5 Base year SO2 emissions by source type ......................................................
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Third Stage Review and Assessment of Air Quality in
Hackney
1.0 Introduction
This report provides the final part of the three-stage review and assessment process
for the London Borough of Hackney, which forms part of the Local Air Quality
Management process, laid down by Part 1V of the Environment Act 1995.
The purpose of the Review and Assessment of air quality is to enable local
authorities to appraise current and future air quality for their geographical area,
against the current National Air Quality Strategy (NAQS) objectives, for the year
2005. These are set out in the Air Quality Regulations 1997. If the results of this
assessment are such that the objectives are unlikely to be met by the year 2005, the
local authority is then required to designate Air Quality Management Area (AQMA)
and prepare a written action plan.
The council has followed the phased approach required by the Government and has
undertaken the first stage of the review and assessment. The stage 1 review and
assessment report indicated the possibility of an exceedence of the NAQS objectives
for the following pollutants.
•
•
•
Nitrogen Dioxide
Fine Particulate Matter
Sulphur Dioxide
It was also concluded from the first stage review and assessment that a second
stage review and assessment of air quality in Hackney would not produce any useful
additional information. Hackney therefore, decided to proceed to a third stage review
and assessment for nitrogen dioxide, sulphur dioxide and particulate matter.
In the third stage review and assessment, local authorities are required to undertake
an accurate and detailed review and assessment of current and future air quality.
Department of the Environment Transport and the Regions (DETR) Statutory
Guidance advises that Local authorities will need to predict whether a failure to
achieve an air quality objective by the end of 2005 is likely. This will be a crucial
factor, which will trigger the designation of AQMAs.
The guidance further advises that a local authority should investigate the areas within
its boundaries where there is the likelihood of a failure to achieve air quality
objectives and the potential for exposure of individuals. The authority should also
estimate the magnitude and geographical extent of such exceedences.
The National Air Quality Strategy
In 1997 the Government published a National Air Quality Strategy for the UK with the
aim of creating a more strategic and integrated approach to air quality issues. The
Strategy attempts to embody the principles of sustainable development in formulating
the Government’s standards, objectives and targets for the improvement of air quality
in the UK.
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The Strategy highlighted eight main air pollutants: benzene, 1,3-butadiene, carbon
monoxide, lead, nitrogen dioxide, ozone, sulphur dioxide and fine particulates.
Standards are set for each of these pollutants based on health related
recommendations made by the Expert Panel on Air Quality Standards (EPAQS).
The Air Quality Regulations 2000 set Air Quality Objectives for seven of the eight
pollutants (summarised in Table 1) which are to be achieved at varying dates up to
31 December 2005.
The NAQS sets out a range of policy options for achieving the objectives, including a
combination of national and international policies as well as a nation-wide system of
local air quality management, in which local authorities are required to review and
assess the quality of air in their areas and to take action where health-based
objectives are unlikely to be met.
.
Local Authorities are required to carry out a comprehensive three-stage review and
assessment of air pollution levels in their borough, and to assess whether the air
quality targets set by the government will be met by 2005.This review and
assessment process involves;
•
Identifying major sources of pollution - either from roads or industry.
•
Collating information on traffic flows and speeds.
•
Monitoring levels of air pollution.
•
Identifying proposed developments, which may have an impact on future air
quality.
•
Using computer models to make future predictions about air pollution levels.
•
Identifying where air quality targets will not be met in 2005.
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5
Table 1 NAQS Air Quality objectives
Pollutant
Air Quality Objective Levels
5pbb or less, when expressed as a running annual mean by 31
Benzene
December 2003
1,3-Butadiene 1ppb or less, when expressed as a running 8 hour mean by 31
December 2003
Lead
0.5 μg.m-3, when expressed as an annual mean by 31 December
2004 and 0.25 μg.m-3or less, when expressed as an annual
mean by 31 December 2005
Nitrogen
200 μg.m-3 (105 ppb) not to be exceeded more than 18 times a
Dioxide
year, when expressed as an hourly mean by 31 December 2004
and 40 μg.m-3 (21 ppb) or less, when expressed as an annual
mean by 31 December 2005
PM10
50 μg.m-3or less as a 24 hour mean not to be exceeded more
than 35 times a year as expressed by 31 December 2004 and 40
μg.m-3or less, when exceeded as an annual mean
Sulphur
350 μg.m-3 (132ppb) not to be exceeded more than 24 times a
Dioxide
year when expressed as a 1 hour mean by 31 December 2004
and 125 μg.m-3 (47ppb) not to be exceeded more than 3 times a
year when expressed as a 24 hour mean by 31 December 2004
and 266 μg.m-3 (100ppb) not to be exceeded more than 35 times
a year when expressed as a 15 minute mean by 31 December
2005
Objectives for the protection of human health
ozone
100 μg.m-3 (50ppb) not to be exceeded more than 10 times a
year when expressed as a daily maximum of running 8 hour
mean to be achieved by 31 December 2005
Objectives for the protection of vegetation and ecosystems
Nitrogen
30 μg.m-3 (16 ppb) when expressed as an annual mean to be
oxides
achieved by 31 December 2000
Sulphur
20 μg.m-3 (8 ppb) when expressed as an annual mean to be
Dioxide
achieved by 31 December 2000 and 20 μg.m-33 (8 ppb) when
expressed as a winter average (1 October to 31 March) to be
achieved by 31 December 2000.
ppb = parts per billion, ppm = parts per million, μg.m-3= micrograms per cubic
metre
DETR Guidance
This study has been carried out accordingly, using the most appropriate data and
methodology within the time frame allowed. At each stage of the process, the
Council has had due regards to technical guidance issued by the Department of the
Environment, Transport and the Regions, as well as consulting with academics and
other expert groups in order to seek the latest advice. DETR technical guidance
notes which have been issued are listed in Appendix XXXX
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Local Air Quality Management
Local authorities are required by the Environment Act 1995 to carry out periodic
reviews of air quality in their area, and to review and assess present and likely future
quality against the health based standards/objectives set out in the NAQS and
prescribed by the Air Quality Regulations 2000.
The NAQS and associated guidance sets out the manner in which the review and
assessment process should be carried out. It recommends a phased approach
undertaken in three stages. Pollutants where an initial review indicates there to be no
local problem will be excluded from the later stages. Pollutants where air quality
problems are anticipated in 2005 are likely to progress to the third and final stage of
the assessment which will detail both the level and the spatial distribution of noncompliance with the National Objectives.
Following the completion of the third stage review and assessment, the local
authority must declare Air Quality Management Areas in those locations where the
2005 objectives are unlikely to be met. Action Plans detailing the measures to be
taken by the local authority to reduce pollutant concentrations and achieve
compliance with the objectives must be drawn up within 12 months of declaration of
AQMA
Central London Cluster Group
The central London Cluster group is one of five cluster groups operating within
the London Air Quality Network. Each cluster group consists of adjacent London
Local Authorities with one of the boroughs being the lead borough. These
groups regularly meet to discuss matters concerning air quality initially set up to
ensure consistency in air quality monitoring. The Central London Group consist
of the following eight boroughs:
•
London Borough of Hackney
•
London Borough of Camden
•
City of Westminster
•
Corporation of London
•
London Borough of Islington
•
Royal Borough of Kensington & Chelsea
•
London Borough of Lambeth
•
London Borough of Southwark
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The Cluster Group have been working together on their Stage III modelling
assessment since May 1998, when a joint supplementary credit bid was made to the
Department of the Environment, Transport and the Regions to fund the development
of a complex computer model which would allow the local authorities to make
predictions about current and future air quality. This bid was successful, and
consultants were contracted to develop a pollution model specifically for the central
London boroughs.
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The local authorities are keen to continue to collaborate as much as possible on
future air quality management issues, since air pollution does not respect borough
boundaries. This is particularly important in the development of Action Plans, and the
local authorities are already beginning to discuss ideas for future joint initiatives.
Selection of model for the study
The central London cluster group used the ADMS-urban dispersion model provided
by Cambridge Environmental Research Consultants (CERC) for the third stage
review and assessment of air pollution. Five dispersion models initially appeared to
comply with the DETR guidance on choosing a dispersion model. After presentations
from the companies providing the models, it was clear that only two models; ADMS
and Indic Airviro fulfilled the essential criteria required by the cluster group. This was
as follows:
• An individual licence for each cluster group member to run the software in their
own offices
• Suitability for carrying out a third stage review and assessment
• Ability to predict oxides of Nitrogen, PM10 particles and Sulphur Dioxide to the
limits given in the National Air Quality Strategy and the required percentiles.
• Ability to produce a course receptor grid output (in other words to plot all eight
boroughs on an overview map).
• Ability to produce a fine receptor grid output (a fine scale map of each borough
or part of a borough).
• Ability to interface with Geographical Information System (a computer map
package)
• Ability to meet the specified timetable and budget.
• Provision of suitable training and technical support in use of the model.
Further more detailed criteria were looked at to separate ADMS-urban and Indic
Airviro, after adding up the scores, ADMS scored more highly on technical support
and training as CERC’s offices are based in Cambridge while Indic Airviro is run by
the Swedish Met Office. ADMS also gained a little over Indic on the user-friendliness
of the system, as it as based on a PC, while Indic runs from a more specialist Unix
Workstation. It was also felt that CERC had more experience of modelling UK cities.
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2.0 Sources and Health Effects of Air Pollution
Emissions from road traffic is the main source of air pollution in central London, and
accounts for around 80 - 90% of most of the key urban pollutants such as nitrogen
dioxide, carbon monoxide, benzene and particulates (PM10). Other less important
sources include industry, power stations, and domestic and commercial heating.
The sources and health effects of the main urban pollutants are summarised below:
Carbon Monoxide (CO)
Carbon monoxide gas is produced in the process of incomplete combustion, be it in a
motor car engine, domestic heating, a cigarette or a forest fire. In the indoor
environment individuals are exposed to carbon monoxide from sources such as
domestic fuel burning heaters and gas cooking appliances.
Outdoors, the main source of carbon monoxide in London is road transport, which
accounts for 75% of all emissions predominantly from petrol vehicles, diesel vehicles
contributing less than 5%. Improvements to vehicle performance and the introduction
of catalytic converters has resulted in reduced concentration of carbon monoxide in
inner cities. But there may be a slight and steady increase in carbon monoxide
concentration if traffic numbers increase as predicted.
Unlike many toxic gases, carbon monoxide is both colourless and odourless and lifethreatening concentrations can be breathed without giving any warning to the victim.
The first sign of severe poisoning is loss of consciousness and further inhalation of
high concentrations readily leads to death. These effects are due to the interference
of carbon monoxide with the processes whereby oxygen is taken up by the blood and
utilised in the cells in the body. It does this both by interfering with transport of
oxygen by red cells in the blood (by the formation of carboxyhaemoglobin, which
substantially reduces the ability of the red cell to carry oxygen) and also by blocking
essential biochemical reactions in cells. In those people who recover from accidental
or deliberate poisoning by carbon monoxide, brain damage of a greater or lesser
degree due to lack of oxygen.
The formation of carboxyhaemoglobin in the blood of people exposed to carbon
monoxide and the amount present depends on both the concentrations in the air and
duration of exposure, as well as on the rate and depth of breathing. Thus someone
exercising and breathing more rapidly and deeply, will have higher blood
concentration than someone resting but exposed to the same concentration.
Smokers may have levels of 4% to as high as 15% depending on the number of
cigarettes smoked. Uptake of carbon monoxide from multiple sources, such as
smoking and traffic, is not additive. It is likely that people who already have a disease
affecting delivery of oxygen to the heart or brain are likely to be at particular risk if
these delivery systems are further impaired by carbon monoxide. These will include
angina sufferers, others with severe heart and lung disease, or anaemia, as well as
young infants and the elderly.
Nitrogen Dioxide (NO2)
Nitrogen dioxide is a gas produced by reaction of nitrogen and oxygen in combustion
processes. The main source of nitrogen dioxide in urban areas is from motor
Review and Assessment of Air Quality in Hackney
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transport and fossil fuel combustion. Of the transport sources, petrol combustion in
cars is currently responsible for a greater proportion than diesel, though this
relationship is changing with the progressive introduction of the catalytic converters
on petrol vehicles.
It has been suggested that the gas may have both acute (short-term) and chronic
(longer-term) effects on health, particularly in people with asthma. Its properties as
an oxidising agent can damage cell membranes and proteins
The results showed that people with healthy lungs, whether at rest or exercising,
show little response to experimental inhalation of nitrogen dioxide at concentrations
well above those occurring in the ambient air, even during pollution episodes.
However, in people with asthma, some studies have shown changes in these tests of
lung function to have occurred at exposures of around 300ppb (parts per billion)
when subject have been exercising.
Sulphur Dioxide (SO2)
Sulphur dioxide is a gas at normal temperature and pressure. It dissolves in water to
produce an acidic solution which readily oxidises to sulphuric acid. The predominant
source of sulphur dioxide is from the combustion of sulphur containing fossil fuels,
principally coal and heavy oils. Road transport also accounts for a small percentage
with the combustion of diesel fuel contributing to background levels.
Sulphur dioxide is an irritant when it is inhaled because of its acidic nature. It causes
its irritant effects by stimulating nerves in the lining of the nose, throat and the lung's
airways. This causes a reflex cough, irritation, and a feeling of chest tightness, and
may lead to narrowing of the airways. This is often the case in asthmatics and people
suffering from chronic lung disease whose airways are often inflamed and easily
irritated. There is clear evidence that some asthmatics show reductions in breathing
capacity after short-term exposure to concentrations of about 400ppb. Healthy
individuals have exhibited measurable narrowing of the airways after exposure to
sulphur dioxide at concentrations above 1,000ppb.
Fine Particles (PM10)
Particles in the air may arise from a wide variety of sources, either natural or manmade. Man-made air borne particles result mostly from combustion processes, from
the working of soil and rock, from many other industrial processes and from the
attrition of road surfaces by motor vehicles
The largest single source of fine particles in urban areas is road traffic.
Unlike other gaseous pollutants, with which it has often been possible to carry out
controlled exposure of volunteers and of animals and thus reach reasonable
conclusions about concentrations at which harm is likely to occur, no similar studies
with mixtures of particulate pollutants characteristic of ambient PM10 (fine particles
less than 10 microns (μm) in diameter) have to date been technically possible.
There is evidence that long-term exposure to particulate pollution may increase the
risk of developing lung cancer as well as having an effect on mortality from heart and
lung diseases.
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Benzene
Motor vehicles are the most important single source of benzene accounting for over
70% of emissions, which is emitted in exhaust gases in both unburned form and also
that formed by combustion with other aromatic components of petrol.
The effect of long term exposure to benzene of most concern is leukaemia and in
particular several types of this disease known collectively as the non-lymphocytic
leukaemia. It acts on the genetic material of cells causing malignant effects.
At concentrations occurring in the ambient atmosphere, benzene does not have short
term or acute effects. The risks of leukaemia in individual workers, exposed to much
higher concentrations of benzene, has been related to their calculated lifetime
exposure- the more benzene they have been exposed to, the greater the risk.
1,3-butadiene
The motor vehicle is by far the largest source of 1,3 butadiene in urban areas. 1,3
butadiene is not present in diesel or petrol, either leaded or unleaded; the emissions
in the exhaust gases being produced by the combustion process itself. The
chemicals in petrol from which the 1,3-butadiene is derived, higher olefins, have been
present in increasing proportion in petrol over the last decade, and it is likely that the
amounts of 1,3-butadiene released into the atmosphere have therefore been rising.
However, 1,3-butadiene is removed efficiently by catalytic converters on motor cars
and levels of 1,3-butadiene are expected to fall.
There is evidence that workers exposed to 1,3 butadiene have a slightly higher than
expected risk of cancers to the bone marrow, lymphomas and leukaemia. Laboratory
studies have shown that 1,3 butadiene causes a variety of cancers in rodents and
damages the genetic structures of the cell. It is thus genotoxic carcinogen and, in
theory, it is not possible to determine an absolutely safe level for human exposure.
Lead
The single largest use globally is in the manufacture of batteries. As the compound
tetraethyl lead, it has been used as a petrol additive to enhance the octane rating.
With the recognition of the adverse effects of lead on human health and the
increasing use of catalytic converters, which are poisoned by lead, this use is
declining rapidly.
At the end of 1985 the maximum permitted lead content of petrol was reduced
significantly from 0.40g/l to 0.15g/l. This almost halved levels of lead in urban air in
the space of a few months. This improvement in urban lead levels continued with the
introduction of unleaded petrol in 1987.
Since 1993 all new petrol engined cars have been catalyst equipped and must run on
unleaded petrol Since 2000 no added lead in petrol.
Direct human exposure to lead occurs through food, water, dust, soil and air. Most
people receive the largest portion of their daily intake via food, although other
sources may be important in specific members of the population (e.g. water in areas
with lead pipes and a plumposolvent water supply, air in populations living near point
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sources of lead, soil, dust and paint flakes in young children living in houses with
leaded paint or contaminated soil).
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3.0 Air Quality Monitoring In Hackney
Hackney has given a high priority to air pollution in the borough since the introduction
of the clean air acts 1956 and 1968.In 1992, Hackney became part of the National
Diffussion tube survey monitoring nitrogen dioxide concentrations at various
throughout the borough. The techniques used to monitor the air quality in Hackney
are given in the following sections.
Chemiluminescent Nitrogen Dioxide Analyser
The determination of oxides of nitrogen is based on the chemiluminescent energy
emitted when nitric oxide is reacted with ozone to form chemiluminescent nitrogen
dioxide. The analysers are compliant with the international standard for this type of
equipment.
The quality control procedures as detailed in the National Technology Centre
(NETCEN) site operators manual are followed for the equipment. The analysers are
calibrated once every two weeks using gases traceable to national standards. All
data is scaled in line with fortnightly calibration checks. The analysers also perform
overnight span checks and are serviced every 6 months.
Non-dispersive infra-red carbon monoxide analyser
Carbon monoxide analyser works by transmitting an infra red beam of light through a
cell through which ambient air is pumped. The absorbency is related to the carbon
monoxide concentration.
The analyser is calibrated once every two weeks using gases traceable to national
standards. All data is scaled in line with fortnightly calibration checks. The analysers
also perform an internal overnight span check and are serviced every 6 months.
Ultra Violet Photometric Ozone Analyser
Ozone is measured using an ultra violet photometric ozone analyser. Ozone
concentration is calculated from the absorption of ultra violet light. The equipment
has its own internal analyser for routine zero/span checks. The analyser is serviced
every 6 months.
Tapered Element Oscillating Microbalance (TEOM) fine particles –PM2.5
The PM2.5 fraction is obtained through a separator and this air is passed through an
oscillating balance head, which traps the particulate matter. The weight of dust
landing on the balance slows down the speed of the oscillation. The energy needed
to regain the original frequency is equivalent to the weight of particulate matter;
giving an instantaneous concentration. Fifteen-minute average concentrations are
collected from the analyser. The inlet is heated to 50 degree Celsius to prevent
condensation problems.
BS17457 Sulphur Dioxide and Black Smoke
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Hackney Council operates two sites; one at 205 Morning lane and one at Shoreditch
Town Hall (both are classified as background sites). They are used to assess the
European Union guidelines and limit values, which take account of both sulphur
dioxide and black smoke. During the smog of the 1950’s these two pollutants were
shown to act synergistically on the lungs; their combined effects on human health are
greater than the effects seen individually. The BS17457 monitors were used to
monitor the effects of the Clean Air Acts 1956 and 1968. AEA Technology operate a
quality control procedure for the sites used for the European Union Directive
Network. The Shoreditch Town Hall site is part of this Network, the other site is
operated to the same standard. This ensures that all pumps and gas meters are
operating satisfactorily and all chemicals used are made up to acceptable
concentrations. The pumps and gas meters have their flow rates checked weekly and
all pumps are serviced annually.
The monitors themselves work by Sampling ambient air so that smoke particles are
trapped onto a Whatman no. 1 filter and sulphur dioxide is removed from the air by
bubbling air through a 1% hydrogen peroxide solution. The concentrations are
determined by laboratory analysis. This equipment measures daily average
concentrations. The blackness of smoke is assumed to be correlated to
concentration and is measured with a reflectometer; these also have to be calibrated
annually.
Passive Diffusion Tubes (Nitrogen Dioxide)
Hackney Council has 12 sites within the borough and they were set up to estimate
whether any part of the borough exceeded the European Union Limit and guidelines.
Four of the sites were set in schools in the Hackney Wick area to monitor the impact
of the M11 link Road project. This is one of the cheapest methods available, but can
only give average concentrations over a relatively long time period.
The tubes absorb the gas onto an inert medium allowing the concentrations to be
determined later in a laboratory.
Review and Assessment of Air Quality in Hackney
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4.0 Stage 111 Review and Assessment of Air Quality
4.1 Introduction and overview
This section outlines the methodology used to undertake the stage III review and
assessment for nitrogen dioxide, sulphur dioxide and PM10, in order to assess
whether air quality objectives for these pollutants will be met by the 2005 deadline. It
describes the information and data that was collected for the review and assessment
process, and explains how the computer model was used to give predictions of air
quality in 2005.
For Stage III, the government expects local authorities to undertake an accurate and
detailed review and assessment of current and future air quality for particular
pollutants in question. An air quality management area can not be declared unless a
third stage review and assessment has indicated that air quality objectives are not
likely to be met by the end of 2005. Local authorities are required to investigate
locations within its boundaries, where both pollution levels may exceed the objective,
and where there is a potential for exposure to people. The authority must then
estimate the magnitude and geographical extent of such potential pollution problem
areas.
The government has indicated in their technical guidance that the level of detail
required for a third stage review and assessment will entail local authorities
constructing a detailed inventory of all possible sources of pollution. For example, in
the action of operating a factory, driving a car, or heating a house, a variety of
pollutants are released into the atmosphere and the amount of pollutant which is
released will need to be quantified. The authority will also need to use an appropriate
validated dispersion model in order to predict current and future air quality. The
dispersion model the local authorities decide to use should be from an approved list
as recommended by the Department of the Environment, Transport and the Regions.
The estimates of current air quality produced from the dispersion model will be
required to be validated against continuous automatic air quality monitoring. Where
such monitoring is undertaken, local authorities are required to demonstrate that the
monitoring data has been quality assured and controlled to an appropriate level and
that measurements are traceable to national reference standards.
4.2 London Emissions Inventory
The strategic approach in dealing with air pollution requires such details as the
sources of the emission, its concentration, rate of emission and a means of
determining or estimating future emission. It is also important to determine how the
emission will react with other pollutants, how their levels change with time and the
resultant effect on air quality
An emission inventory is the resultant database that collates all the information about
an emission that can be used to determine the above information. The construction
of an inventory is dependent on its intended use. The emission inventory used for
this stage 111 process was compiled by the London Research Centre (LRC). The
LRC was commissioned by DETR to produce an emission
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London road networ
20
0
20
40 Kilometers
N
Review and Assessment of Air Quality in Hackney
17
inventory for London, which was released in 1997. It contains information for eight
key pollutants that are contained in the NAQS and three additional pollutants. The
key pollutants are oxides of Nitrogen, Sulphur dioxide, Carbon monoxide, NonMethane volatile organic compounds, carbon dioxide, benzene, 1,3 butadiene and
particulate matter. The remaining pollutants are black smoke, methane, and total
suspended particulate.
The inventory was complied for and includes data obtained for all London Boroughs
and the City of London.
The data was collected and analsyed using 1x1 kilometre Ordnance Surveys’s
national grid. The sources were divided into three broad groups:
•
area emissions
The area emissions are mainly concerned with the emissions from residential areas
and large industrial estates, derived from the fuel consumption provided by the fuel
supply companies.
•
Line sources including roads and railways
• point emissions
These are the industrial processes that are regulated under the Environmental
Protection Act 1990 and are referred to as Part A and Part B processes.
4.2.1 Inventory for ‘current’ emissions
Atmospheric emissions inventories have been prepared for each of the pollutants of
interest and for each of the scenarios modelled which are as follows:
• a current or base year scenario has been modelled using a base year inventory,
representative of recent emissions, and 1996/1997 meteorological data.
A summary of emissions rates broken down by source type is shown in Table 2. The
total estimated emissions of NOx and PM10 from Greater London are dominated by
the contribution from road traffic in the base year, with SO2 and VOC emissions
arising primarily from non-road sources. Emissions of VOC’s have been included for
modelling of NO2 concentrations using the Generic Reaction Set (GRS), (Appendix
B).
Table 2 Base year Greater London Emissions by source type
Emission rate (T/Yr)
Source
NOx
PM10
VOC
Major road
96683
6616
55920
Minor road
12665
933
10659
Non-road
42365
2291
103789
Total
151713
9840
170368
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SO2
5051
519
18925
24495
Table 3 Base year Greater London Emissions by source type %
Percentage contribution
Source
PM10
VOC
SO2
NOx
Major road
63.73
67.22
32.82
20.62
Minor road
8.35
9.48
6.26
2.12
Non-road
27.92
23.28
60.92
77.26
NOx, PM10, VOC Emissions
The following sources have been considered in the
modelling of NO2 and PM10 concentrations:
Road traffic sources
Emissions arising from road traffic have been considered in three categories:
•
•
•
Emissions from major roads for which link-based traffic flow data are available,
Emissions from minor roads for which link-based traffic flow data are unavailable,
Emissions associated with cold starts and trip ends.
Major Road
The major roads emissions inventory is based primarily on that supplied by LRC.
The network (Figure 2) consists of a total of 9020 major road links derived from the
LTS transport-planning model. From this network approximately 1650 Central
London road links have been explicitly modelled, with the remainder considered as a
component of the aggregated grid source emissions (Section 2.1.1.3). The selection,
in accordance with the DETR’s Pollutant Specific Guidance (August 1998) for NOx,
represents all roads with an annual average daily traffic flow (AADT) of greater than
20000. Also included, are roads with an average speed of less than 10km/h,
additional roads specified by the London Cluster Group, and roads which when
included reconnect isolated network segments. A plot of these roads for Hackney is
shown in Figure XXX.
Analysis of Major Road Data
In order to validate and improve the inventory, the LRC traffic data have been
compared to more recent traffic flow information supplied by the Central London
boroughs. The additional data supplied include 1997 DETR annual average daily
traffic flow counts for all A roads within the eight Central London boroughs, and
1997/1998 hourly traffic flow counts for a number of roads within the London
boroughs of Camden, Southwark and the Corporation of London.
The DETR traffic counts formed the basis of a limited evaluation of the LRC traffic
data. In order to assess the consistency of the traffic flows between the DETR and
LRC data, common roads were compared using ArcView GIS. The comparison
focused on a selection of heavily trafficked roads within close proximity of the AUN
sites, with the additional aim of ensuring that the traffic data in the vicinity of those
AUN sites used for model validation were in good agreement with the DETR counts.
The results of the evaluation (Table 2) show some significant differences between
the two data sets, with a number of the DETR traffic counts being higher than the
LRC flows, there is however no consistent trend within the data considered.
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Replacement of LRC traffic data with DETR Traffic counts
Given the inconsistencies between the two data sets, DETR traffic data were used to
perform a limited adjustment to emissions from road sources. This adjustment was
performed during the validation study in order to assess the effect of incorporating
the measured traffic counts on the resultant concentrations. This is discussed further
in §4.2.1. In order to maintain consistency with the majority of the LRC major roads
inventory, the emission rates of the selected roads shown in Figure 4 and listed in
Table 2 were scaled according to the relative difference in the AADT, as follows:
Enew = E LRC
AADTboro
AADTLRC
(1)
where Enew is the new emission rate, ELRC is the LRC emission rate, AADTboro is the
DETR traffic data supplied by the Boroughs and AADTLRC is the traffic data supplied
by LRC.
Table 4 AUN sites and selected roads for which LRC and Borough data were
compared
Monitoring site
Comments
Road
LRC
Borough
name
AADT(7) AADT(7) 1997
Nearest to site
A420
29086
17902
Bloomsbury
Sections equivalent to A3213 11453
13042
Bridge Place
A202
3658
24880
A road N of site
A4
24500
60000*
Cromwell Road
A3220 19206
22332
Earls Court
AUN on road
A4
17774
74121
A road N of site
A107
35643
26400
Hackney
A road S of site
A104
29556
26213
A road on which site A501
41186
63740
Marylebone
lies
7837
No
road
to
North Kensington B road 50m E of site
compare
Sections equivalent to A2
19674
38561
Old Kent Road
Sections equivalent to A41
38442
51381
Swiss Cottage
A road on which site
38422
No
road
to
lies
compare
B road to E of site
24036
No
road
to
compare
B road to E of site
A41
29676
38891
B road to SE of site
A41
25117
45643
A road on which site A215
26716
23488
Walworth
lies
A road to E of site
A1
39212
18122
Islington
A road on which site A3211 22422
47280
Senator House
lies
*revised traffic flow for Cromwell Road as given by the NETCEN National Air Quality
website (DETR traffic count is 60865)
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Calculation and comparison of diurnal profiles
LRC data
In order to use the traffic data from the Emissions Inventory supplied by the LRC,
segmented roads had to be joined together, and two-way flow along roads added.
The following steps were then performed on the data, in order to calculate single
diurnal profiles from the LRC road traffic data.
1. From the data provided by the LRC the annual average hourly traffic counts
(AAHT) were calculated from the daily traffic flows, and then the total average
AAHT was calculated.
2. A diurnal profile was extracted from the data, using the variation in number of cars
through 24 hours.
3. From the above the diurnal variation in traffic, diurnal profiles for weekday,
Saturday and Sunday traffic were determined from data given in the LRC
inventory as:
Weekday counts=(variation in car numbers for a 24 hour)x1.04
Saturday counts=(variation in car numbers for a 24 hour)x0.94
Sunday counts=(variation in car numbers for a 24 hour)x0.85
Borough Data
The hourly traffic count data supplied by the London Boroughs of Camden,
Southwark and the Corporation of London, have been utilised in the derivation of a
diurnal emissions profile representative of the hourly patterns of traffic flow on
Weekdays, Saturdays and Sundays on roads across Central London. Each of the
three boroughs provided information on weekday flows, and in addition Southwark
and the Corporation of London provided weekend traffic flow data. These data were
analysed and then combined proportionally to create a single set of diurnal profiles
for Weekday, Saturday and Sunday traffic. Plots of the LRC and adjusted diurnal
profiles for weekdays, Saturdays and Sundays are shown in Figure 5. Comparison
of
the
profiles
supplied
by
LRC
and
the
borough
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0
4
8 Kilometers
Adjusted for DETR traffic data
LRC road network
Review and Assessment of Air Quality in Hackney
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N
profiles show that the weekday values are in reasonable agreement, but that the
Saturday and Sunday profiles are significantly different. Because the profiles derived
from the hourly traffic counts are based on actual traffic counts specific to Central
London, as opposed to modelled data generated for the whole of Greater London,
the borough diurnal profiles have been adopted in the model.
Minor Roads
Traffic emissions from the minor road network, have been considered as a
component of the total grid source emissions. The LRC minor road network
accounts for all roads for which link-based traffic flow data are unavailable, and is
based upon the difference between the DETR’s Rotating Traffic Census estimate of
total vehicle kilometres travelled in London in 1995 and the kilometrage accounted
for by the major road network.
Cold starts and trip ends
Cold start emissions (additional emissions associated with inefficient engine
performance at low operating temperatures) and trip end emissions (associated with
evaporative emissions of hydrocarbons from the hot engine and fuel system when
the engine is switched off) have been considered as a component of the total grid
source emissions.
Industrial point sources
For the purpose of modelling NOx and PM10 concentrations all industrial point
sources emissions with the exception of two sites (the South East London Combined
Heat and Power Plant, Lewisham and London Underground Power Station, Chelsea)
have been considered as a component of the aggregated grid source emissions.
The Lewisham and Kensington sources emit 960 T/a and 469 T/a of NOx
respectively, accounting for almost 1% of the total Greater London NOx emissions
and equivalent to over 3% of the total non-road source emissions. The majority of
industrial sources have not been modelled explicitly as it has been ascertained that
their individual contributions are unlikely to have a significant impact on exceedences
of the PM10 or NO2 objectives.
Aggregated grid sources
NOx and PM10 emissions from all other identifiable sources have been considered
within the 2466 1×1km total aggregated grid sources covering the whole of Greater
London. Figures 6,7 and 8 show the total grid source emissions of NOx, PM10 and
VOC for Greater London.
Other Sources
The inventory and hence the calculated pollutant concentrations do not allow for
intermittent sources such as those occurring during bonfire night or construction
activities.
SO2 emissions
The SO2 emissions data have been split into two types: point source data and grid
sources. The point source data includes any significant emissions of SO2 mainly
from industrial sources, such as power stations and boilers. The grid source data
Review and Assessment of Air Quality in Hackney
23
includes the emissions from all the sources, including residential, roads and also all
the point source emissions previously mentioned.
Point source data
The LRC London atmospheric emissions inventory contains details of all Part A and
Part B processes within London. The data were used in conjunction with information
provided by the Environment Agency (Part A sources) and the individual London
borough councils (Part B sources) to form the inventory of point sources. A complete
listing of all Part A sources considered is given in Appendix C.
Sources which lie outside London and which emit significant amounts of SO2, were
also included in the modelling. Table 3 shows the distribution of emissions between
source types, while a map showing the location of all point sources considered is
shown in Figure 9.
Grid source data
The modelled grid source emissions data covers an area of approximately 60 by
50km, bounded by the M25. Each emission on the grid covers an area of 1km2. The
data used was supplied by LRC, and it is assumed that Part A and B point sources
have been aggregated onto the grid. Figure 10 shows the SO2 grid source emissions
throughout London.
Table 5 Base year SO2 emissions by source type
SO2 emissions (T/Yr)
Central
Whole
of Outside
Total
London
Greater
Greater
Study Area* London
London
Base year emissions
All sources
1550
24495
192366
216861
Explicitly modelled
327
13889
192366
206255
Part A processes
* The Central London Study Area emission rates shown are approximations, based
on the assumption that emissions from grid squares dissecting borough
boundaries are allocated in terms of the area in each borough.
Predicted 2005 Emissions Inventory
This section outlines the procedures undertaken in the preparation of the emissions
inventory for 2005. A summary of 2005 emissions rates by source type is given in
Tables 8a-d, and Figures 11-13 show the gridded emissions of NOx, PM10 and VOCs
for 2005.
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NMVOC (T/a)
0 - 25
25 - 50
50 - 100
100 - 250
> 250
N
0
20
Review and Assessment of Air Quality in Hackney
25
40 Kilometers
Location of SO2 point sources
Kodak Ltd
#
Didcot Power station
# Johnson Matthey plc
# Londonwaste Ltd
#
Guinness #
Nestle (UK) Ltd #
#
####
#
## #
#
# ## #
#
## # Mobil
ingsnorth Power station
Shell K
##
Rugby Group Plc # #
UCL SOAS
##
# # # Citigen Ltd
Birkbeck College
British Museum
#
Shell UK Ltd
Union Min-oxyde
#
#
Seabright Industries
Lots Road Power station
#
Grain Power station
Clinical waste (PTY)
# Ford
# Cohen & Co
Cargill
#
# Britannia ref-metals
#
#
Littlebrook Power station
# NP Tilbury
Blue Circle
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NOx (T/a)
0 - 50
50 - 100
100 - 250
250 - 100
> 1000
N
0
30
Current NoX Emissions for London
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60 Kilomete
PM10 (T/a)
0- 5
5 - 10
10 - 20
20 - 50
>50
N
0
20
Current PM10 emissions for London
Review and Assessment of Air Quality in Hackney
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40 Kilometers
Current NMVOC emissions for London.
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SO2 (T/a
0510
50
>25
N
0
30
Current SO2 emissions for London
Review and Assessment of Air Quality in Hackney
30
60 Kilometers
N
0
NOx (T/a)
0 - 50
50 - 100
100 - 250
250 - 1000
> 1000
30
2005 NOX emissions
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60 Kilometers
NOx (T/a)
0-5
5 - 10
10 - 20
20 - 50
> 50
N
0
20
2005 PM10 emissions
Review and Assessment of Air Quality in Hackney
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40
60 Kilometer
NMVOC (T/a)
0 - 25
25 - 50
50 - 100
100 - 250
> 250
N
0
30
2005 NMVOC emissions
Review and Assessment of Air Quality in Hackney
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60 Kilometer
SO2 (T/a)
0-5
5 - 10
10 - 5
50 - 2
> 250
N
0
30
2005 SO2 emissions
Review and Assessment of Air Quality in Hackney
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60 Kilometers
2005 NOx, PM10 and VOC emissions
With the exception of the London Underground industrial point source in Kensington
and Chelsea which will no longer be in operation in 2005, only emissions from road
transport have been calculated for 2005. Emissions from all other sources have
been assumed to remain constant. The calculated road emissions take into account
projected traffic growth, future UK fleet composition, new European vehicle emission
factors, and changes in fuel composition and vehicle speed.
2004 Major road emissions
Emissions rates for NOx, PM10 and VOC have been calculated on a link-by-link basis
using 2004 traffic data for Greater London supplied by LRC. The 2004 network has
been derived from the LTS traffic model output (courtesy of MVA and Government
Office for London (GOL)).
Adjustment of 2004 road traffic emissions
A comparison of the base year and 2004 traffic data identified an incompatibility
between the road networks used for the base year and for 2004. Initial processing
revealed a negative rate of growth in terms of annual vehicle kilometres travelled
between the base year and 2004 scenarios; although the 2004 scenario was
expected to exhibit some growth over the 1996 base case.
The discrepancy arises from the fact that the two road networks originate from
different versions of the LTS traffic model, with the 2005 road traffic forecast carried
out using a later and substantially updated version of the LTS model (version B1.10).
The updated LTS model has been found to predict significantly lower total vehicle
kilometrage than those predicted for the same year using the earlier model version,
version F3.3 (LTS technical note 25 “B1.10 Base Forecast Validation”).
This is illustrated in Table 4, which gives a comparison for the two versions of LTS of
the total vehicle kilometrage forecast for the 1991 morning peak traffic. As can be
seen, the total vehicle kilometrage forecast by the updated version of LTS was found
to be 27% lower than that forecast by the earlier version in Central London, 22%
lower in Inner London and 13% lower in Outer London. LRC regard this as a
confirmation of a suspected tendency in the base year major road network to overpredict traffic flows, compared to independent traffic counts (Charles Buckingham,
LRC private communication). The extent of this problem is not readily quantifiable,
although Technical Note 25 contains evidence to suggest that any overprediction is
within 5 percent on a London-wide basis. LRC still consider the existing inventory to
be a satisfactory representation of the situation in 1996.
Table 6 Comparison of the two versions of LTS 1991 total annual vehicle
kilometres-morning peak period.
F3.3
B1.10
Percentage
lower
787721
575394 27
Central London
3909070
3030336 22
Inner London
14052284 12190212 13
Outer London
Review and Assessment of Air Quality in Hackney
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(source: LTS technical note 25 “B1.10 Base Forecast Validation”)
The 2005 network is based on a more extensive and up to date road network
structure with a more appropriate traffic distribution, and as such it is preferable to
use this as a basis for the 2005 emissions inventory. It has however been found to
underpredict the total vehicle kilometrage. To account for this LRC have calculated
an adjustment factor based upon an acknowledged and quantified shortfall between
the modelled road traffic flows given by the updated LTS model and DETR counts for
1996. The methodology has been approved by DETR and GOL and is outlined
below.
Calculation of the adjustment factor
Comparison of road traffic flows from the updated LTS model with DETR counts for
1996, gives the following shortfalls:
7.92% shortfall
12.84% shortfall
6.84% shortfall
AM peak period (19.6% of notional day)
Inter peak period (60.8% of notional day)
Evening peak period (19.6% of notional day)
For the period 1996 – 2006, this corresponds to annual rates of change of:
AM peak period, shortfall per year =(1.0792)1/10
Inter peak period, shortfall per year =(1.1284)1/10
=1.012153 or 1.215% per year
Evening peak period, shortfall per year = 1.0672
1
10
= 1.006525 or 0.6523% per year
(2a)
(2c)
Thus, for the period 1996 to 2005, the adjustment factor is given by:
Adjustment factor = (1.00765 9/10 x 19.6% + 1.012153 9/10 x 60.8%
+1.006526 9/10 x 19.6%
Therefore, to account for the shortfall between the LTS road traffic flows and DETR
counts, 2005 traffic flows, and hence emissions, were increased by 9.57%.
Based on this network, emissions rates for NOx, PM10 and VOC have been
calculated for each of the major roads given that;
2005 emission rate = Emission factor (2005)
× Vehicle flow rate (2005 adjusted )
(3)
The emission rates for each road have then been aggregated to give the grid
emissions for major roads in 2005. 2005 minor road emissions were then calculated
based on the percentage reduction in major road grid emissions, after accounting for
differences between the two networks. Table 5 summarises the percentage
difference in total vehicle kilometres between 1991 (LTS version 3.3) and 2005 (LTS
version B.1.10 adjusted as above) (Charles Buckingham, private communication).
The changes are relatively modest in the central area, but there are significant
Review and Assessment of Air Quality in Hackney
36
differences in Hackney and Islington. Within Greater London there is an overall
increase in traffic flows of 14.3%.
Use of dispersion models for air quality predictions]
The prediction of pollutant concentrations within any local authority’s area for the
purposes of a Stage III Air Quality Review and Assessment must be “accurate and
detailed”1 so that dependable predictions may be made as to whether or not air
quality objectives are likely to be achieved by the end of the year 2005.
In a complex urban situation, there are many sources of different pollutants, and the
emissions of the pollutants will change over time, by reason of improving emission
control technologies, varying traffic flows, and varying energy demands to note but a
few of the factors. The varying emissions can be detailed by inventories assembled
from current data on installations and pollutant sources, and the temporal variations
applied to create forecast inventories.
The dispersion of pollutants is governed by atmospheric conditions, which in
themselves can vary widely, but which are all amenable to mathematical treatment.
Meteorological data for the area in question can be assembled to provide scenarios
of differing dispersion modes, and to provide results for “averaged” time periods, with
typical lengths of differing dispersion modes as found in the course of “typical” years.
The combination of all this information is best effected by a mathematical means that
will give reproducible results and takes into account all of the factors. Such
mathematical models can have the input information varied according to specific or
aggregated atmospheric conditions, all-source or contribution-only pollutant sourcing,
and other variations of the factors. The output information will show the pollutant
concentrations at specific receptor points or as contoured map outputs. The output
information can be expressed in the same terms as the air quality objectives, and the
results, subject to validation against measured pollutant concentrations, known
meteorological data and emission inventory, can be used as indicators for
determining the likelihood of attaining or failing the objectives.
Review and Assessment of Air Quality in Hackney
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Model set up and input data
Figure 1
Model set up
INPUT SECTION
AREA EMISSIONS
VEHICLE EMISSIONS
L.R.C Emission Inventory
for London and Local
authority Information
L.R.C Emission Inventory
for London and Local
Authority Information
POINT EMISSIONS
L.R.C Emission Inventory for
London and Local Authority
Information
METEOROLOGICAL
DATA
BACKGROUND
POLLUTANT
LEVELS
1996 & 1997
(London Heathrow)
DISPERSION
MODEL
UK ADMS - URBAN
INTERPRETATION AND ASSESSMENT
PREDICTED IMPACT
ASSESSMENT
Review and Assessment of Air Quality in Hackney
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Overview of ADMS urban
ADMS stands for Atmospheric Dispersion Modelling System. This model was
originally developed for modelling emissions from industrial chimney stacks, but has
been developed to include other sources of air pollution such as roads, railways and
domestic sources.
The model looks at pollution within the atmospheric boundary layer. This is the region
of the atmosphere that is affected by the earth’s surface. This layer can be up to 2.5
km thick. This layer is where dispersion of pollution occurs. The depth of the
boundary layer depends on the time of year and the weather. An emission factor is
put in to the model for each type of pollutant to allow concentrations to be predicted.
Concentrations will vary according to the weather, so for example, on a cold still
winter day a condition called a temperature inversion can occur, this effectively traps
pollution and does not allow it to move out of the area. Weather data for a particular
year or average weather data over several years are input into the model in order to
see what effect this has on the dispersion of pollution. Dispersion of pollution is also
affected where tall buildings stop the movement of air. Building heights were put in to
the model in order to take account of this effect.
Methodology – Model Input
a) Emissions Inventory
This contains all the raw data and information gathered for the assessment. The
format of the data was determined by the input requirements of the dispersion model.
Model Data and Assumptions
Meteorological data
The model runs were performed using hourly sequential meteorological data taken
from the London Heathrow meteorological monitoring site for 1997 and 1996, the two
years being used so that the effect of interannual variability could be considered.
The monitoring site is surrounded by flat terrain and therefore recorded wind fields
are unaffected by local obstructions. For 1997, there were 6161 valid met hours
which could be used for this study out of a total 8760. For 1996, there were 8726
valid met hours available. The use of meteorological data from other sites was
considered to supplement the missing 1997 data from Heathrow, however this
proved impractical because of differences in site characteristics (surface roughness)
The pattern of surface heat fluxes and boundary layer height as calculated by ADMS
from raw meteorological data at the Heathrow monitoring site in each year are shown
below in Figures 17 and 18. These show similar patterns except for the greater
number of deep boundary layers in 1996, which may have enhanced dispersion of
ground level sources.
Percentage frequency of hours in each surface heat flux class for 199 7
30
30
25
25
20
20
Frequency (%)
Frequency (%)
Percentage frequency of hours in each surface heat flux class for 1996
15
10
15
10
Review and Assessment of Air5Quality in Hackney
39 0
5
0
< -100
-100 - -50
-50 - -10
-10 - 10
10 - 50
Surface heat flux (Watts/m2)
50 - 100
> 100
< -100
-100 - -50
-50 - -10
-10 - 10
10 - 50
Surface heat flux (Watts/m2)
50 - 100
> 100
Figure 17. Frequency distribution of surface heat flux for valid met hours at the
Heathrow monitoring site in 1996 and 1997
Percentage frequency of hours in each boundary layer height class for 1997
30
25
25
20
20
Frequency (%)
Frequency (%)
Percentage frequency of hours in each boundary layer height class for 1996
30
15
10
5
15
10
5
0
100 - 150
150 - 250
250 - 500
500 - 750
750 - 1000
1000 - 1500
> 1500
0
100 - 150
150 - 250
250 - 500
Boundary Layer height (m)
500 - 750
750 - 1000
1000 - 1500
> 1500
Boundary Layer height (m)
Figure 18. Frequency distribution of boundary layer heights for valid met
hours at the Heathrow monitoring site in 1996 and 1997
The Heathrow data were adjusted to take account of the high surface roughness
and urban heating in the city area. For London, the surface roughness (z0) was set
at 2m, whilst in order to take account of urban heating a minimum value of the
Monin-Obukhov length (LMO), for stable conditions, was set to 100m. (Appendix A).
Chemistry Scheme
Concentrations of NO2 can be calculated using the two methods available in ADMSUrban, namely the Derwent-Middleton function relating NOX and NO2 based on data
measured at one site, and the GRS chemistry scheme (Appendix B). For model
validation (§4) both schemes were run to verify the best option. For the contour
maps (§5) all runs were run using the GRS scheme; in addition the correlation
method was used with 1997 meteorology and baseline emissions.
Grid Sources
Grid sources (volume sources arranged on a regular Cartesian grid) were used to
model dispersion from aggregated emissions. It was assumed that the pollutant is
uniformly mixed in the horizontal plane over the grid square and has a Gaussian
distribution in the vertical with the maximum concentration at half the height of the
grid square. The depth of all grid sources was set at 100m to account for the
distribution in the height of emitters.
vehicle emissions
The network of roads in London used is the same network as used in strategic
transport network within the M25 area. The emissions factor for the different vehicles
is obtained from national databases. Further information on the construction of the
various databases used can be obtained from the LRC
Review and Assessment of Air Quality in Hackney
40
area emissions
The area emissions are mainly concerned with the emissions from residential areas
and large industrial estates, derived from the fuel consumption provided by the fuel
supply companies.
point emissions
These are the industrial processes that are regulated under the Environmental
Protection Act 1990 and are referred to as Part A and Part B processes.
Background Concentrations
Base year background concentrations
NOx, NO2 and O3
For the GRS chemistry scheme rural background concentrations of NOx, NO2 and O3
representing pollutants advected into London from outside the region covered by the
emission inventory were estimated using monitored concentrations from a series of
rural monitoring sites around London. For each hour, the background site used was
dependent on the prevailing wind direction, as observed at Heathrow, with the
selected site being the one closest to directly upwind of the study area, as illustrated
in Figures 19 and 20. A series of pollution roses for the Central London composite
background files are presented in Figures 21-23. Figure 21 (NOX) illustrates the
contribution of background NOX concentrations to the calculated concentration and
how this depends on wind direction and speed. Average background concentrations
for each of PM10 (secondary particulates), NOX, NO2 and O3 for both 1996 and 1997
are shown in Table 9. For the Derwent Middleton correlation a constant background
NO2 of concentrations of 6ppb was assumed.
PM10
Background PM10 concentrations, representative of transport of PM10 into the London
area from non-local sources, have been calculated empirically using daily average
sulphate concentrations measured at the Bridge Place urban background monitoring
site during 1997 (Figure 24). The factors relating the measured sulphate (SO4)
concentration to total secondary contribution of PM10 were estimated using the
method of Stedman (1998) and comparisons between measurements of sulphate at
Bridge Place and rural monitoring sites. Background secondary PM10 concentrations
are given as:
Secondary PM10 = fs × SO4 concentration
(15)
The factor fs was calculated as 2.3 for 1996 and 2.0 for 1997. Only daily average
sulphate concentrations were available, and so the hourly average was assumed to
be constant over the whole day. A constant coarse component of 8 μg m-3 was then
added to each hourly secondary concentration to give the total PM10 background.
Review and Assessment of Air Quality in Hackney
41
This value is similar to London background levels estimated by APEG (Source
Apportionment of Airborne Particulate Matter in the United Kingdom).
Review and Assessment of Air Quality in Hackney
42
Wind sectors used for the calculation of background
NOx concentration within London
Wicken fen
#
Harwell #
#
#
London
Rochester
#
Lullington Heath
0
100
200 Kilometers
Rochester (60-135 degrees)
Lullington Heath (135 - 220)
Harwell (220 - 330 degrees)
Wicken fen (330 - 60 degrees)
Review and Assessment of Air Quality in Hackney
43
Wind sectors used for the calculation of background
Ozone concentrations within London
#
Bottesford
Sibton #
Harwell
#
#
London
#
Rochester
#
Lullington Heath
0
100
200 Kilometers
Sibton (20 - 78 degrees)
Rochester (78 - 135 degrees)
Lullington Heath (135 - 220 degrees)
Harwell (220 - 310 degrees)
Bottesford (310 - 20 degrees)
Review and Assessment of Air Quality in Hackney
44
Table 9. Annual Mean of Background Concentrations of Pollutants (ppb)
Pollutant
O3
NOX
NO2
Particulates
(μg/m3)
Meteorological Year
1996
1997
25.1
25.5
12.7
14.1
9.7
9.6
17.8
15.2
2005 background pollutant concentrations
PM10
2005 background PM10 concentrations have been based on the assumption that
there will be a 30% reduction in secondary PM10 concentrations between 1996 and
2010 (DETR Pollutant Specific Guidance, 1998). For 1997 data, this corresponds to
a reduction of 17.1% between and 1997-2005. For 1996 data, the relevant reduction
factor is 19.3%. The coarse component has been assumed to remain unchanged,
having a constant concentration of 8μg/m3.
NOx, NO2 and Ozone
Background NOx concentrations for 2005 have been estimated from a projected 50%
reduction in background NOx between 1996 and 2005 and a 40% reduction between
1998 and 2005 (DETR Pollutant Specific Guidance (August 1998). This corresponds
to an assumed reduction of 45% between 1997 and 2005. 2005 background NO2
concentrations have then been calculated from the correlation between base year
NOx and NO2 monitored background concentrations, and also the 2005 background
NOx concentrations (Figures 25a,b). Base year NO2 concentrations were used
where the correlation method resulted in hourly 2005 NO2 concentrations being
greater than base year concentrations. To conserve the potential for ozone
production, 2005 background ozone concentrations were taken as the sum of base
year ozone concentrations and the difference between base year and 2005
background NO2 concentrations.
Source Properties
In order to accurately model pollutant concentrations near major road sources, data
were provided by the boroughs on the width of the modelled roads. If no data were
available a default of 20m was used.
Street Canyon Height
In order to account for the effects of street canyons on pollutant dispersions, Central
London street canyons were identified and then modelled using building height data
compiled from a number of source3s. For the initial model validation, street canyon
heights were derived from building spot height measurements surveyed by University
College London along roads within a 250m radius of each monitoring sites within
street canyons. Subsequent validation and contour runs made use of extensive
building height data supplied by Geo-Information and MSI. The data supplied
contained highly detailed information giving both the height and precise shape of
each building in Central London. The methodology developed to simplify these data
and calculate the street canyon height in metres for each road modelled explicitly is
described in Appendix
Review and Assessment of Air Quality in Hackney
45
Possible sources of error
The mean canyon height calculated is very dependent on the canyon width used. For
roads with canyon widths greater than that specified, no buildings may be selected
and a canyon height of zero would be returned. Conversely, if the canyon width is
significantly narrower than that specified, then buildings outside the canyon may be
selected, which may or may not introduce errors into the calculation. This is further
compounded by the introduction of errors due to spatial inaccuracies of the LRC road
network. For quality assurance the heights of all major roads with an annual average
daily traffic flow of greater than 50,000 were manually checked, and updated where
necessary. Each of the London boroughs were also sent maps of the street canyon
heights, and the results deemed acceptable.
Terrain
It was assumed in this study that the area of Greater London was uniformly flat and
that no significant, large-scale, terrain features existed within the modelled domain.
This assumption was made so that the model would operate in its fastest mode, and
model runs would be completed within a realistic time period. The impact of omitting
the local effects of terrain in London are unlikely to be significant except in the most
stable conditions which are very unusual in Central London because of local
anthropogenic heating.
Review and Assessment of Air Quality in Hackney
46
Scenarios modelled using ADMS Urban
All of the above information was input into the dispersion model, ADMS Urban, in
order to produce the predictions of current and future air quality required for the
purposes of the review and assessment. Several runs of the model were made and
the results of those runs were validated against the data obtained from DETR
Automated Urban Network (AUN) sites in the study area. The results of the validation
exercise are show in section x.
After the data had being validated against the monitoring stations, the following
scenarios were modelled.
•
a current or base year scenario using a base inventory, representative of recent
emissions , and 1996 / 1997 meteorological data; and
•
a future scenario, corresponding to the NAQS objectives for 2005 using projected
2005 emissions and 1996 / 1997 meteorological data
The results from the scenarios were presented on maps depicting the concentration
and distribution of the pollutants.
Validation of model
A computer dispersion model is a computer programme used in calculating air
pollution concentrations using the information from pollutant emissions and the
nature of the atmosphere. The purpose of a model is to assess whether pollutant
emissions are likely to result in an exceedance of a prescribed objective; therefore it
is necessary to know the ground level concentrations which may arise at distances
from the source.
The Atmospheric Dispersion Modelling System (ADMS) Urban model was used to
calculate and predict the concentrations of Pollutants in the air up to the year 2005.
The model was used to predict the concentrations by using the 1996/ 1997
Meteorological data. The modelled results were compared with the monitored
concentrations from the National Air Quality monitoring sites in London.
Model validation is important in order to assess the accuracy of the model in
calculating and predicting air pollution concentrations. Validation runs were carried
out to assess the performance of the model. The modelled results were compared
with the concentrations from the monitoring sites in Central London, which was part
of the London Network.
The model validation focused on Nitrogen Dioxide (NO2), Sulphur Dioxide (SO2) and
PM10 (Fine particles less than 10microns in diameter) therefore the sites where
these pollutants were monitored in London were important to the validation study.
Model Validation for Nitrogen dioxide and PM10
Weather Conditions, atmospheric chemistry functions, road topography, vehicle
movements along selected major roads within 250m radius of the monitoring sites,
were used for the model runs for NO2 and PM10.
Review and Assessment of Air Quality in Hackney
47
The same set of data input used for modelling NO2 was also used to model PM10
except atmospheric chemistry functions.
The modelled concentrations were
compared with the monitored concentrations and the NO2 and PM10 concentrations
were well predicted by the model. The comparison between modelled and monitored
PM10 data shown in the table below shows that the model predicted the mean(s)
accurately. The NO2 data was accurately predicted by the model as well for example
at the Bloomsbury site the modelled data was 34.6ppb and monitored data was 36.2
ppb.
VALIDATION RESULTS FOR PM10 USING 1997 METROLOGICAL DATA
Monitoring Sites (Modelled/Monitored )
Mean PM10 Concentrations in μg/m3
BLOOMSBURY
Modelled
Monitored
MARYLEBON
Modelled
Monitored
NORTH KENSINGTON
Modelled
Monitored
37.3
41.2
44.8
36.5
27.2
24
Model Validation of Sulphur Dioxide
Sulphur Dioxide was modelled using 1996 and 1997 meteorological data. Nine
monitoring sites were modelled and used for the validation. The main sources of SO2
are major point sources outside central London. The major point sources were used
for validating the model. The validation was extended to cover much of the London
conurbation. The results of the monitored and modelled results were also compared
and the modelled results were reasonably accurate.
The slight differences between the modelled and monitored figures for the validated
pollutants could be due temporal variations in major point sources which were not
taken into consideration, emissions from major point sources may have been overestimated for 1997, etc. Although neither the modelled nor the monitored results
exceeded the National Air Quality Standards for So2.
The mean of the modelled N02 was well predicted in 1996 but overestimated in 1997.
The mean of the modelled PM10 were reasonably accurate but the mean of the
modelled SO2 results were overestimated using the ADMS Urban model to predict
concentrations of air pollutants in London has been accurate. According to
Department Of Environment Transport and Regions report on dispersion models, if
the modelled results lies above +/- 50% of the monitored concentrations the model is
considered to be poor.
Review and Assessment of Air Quality in Hackney
48
Findings of Hackney’s Stage 111 Review and Assessment
This section presents calculated contour maps of concentration for current and future
emissions.
Baseline Runs
Contour plots are shown for annual mean concentrations of NO2, the maximum 1
hour average NO2 concentration and the 99th percentile of the running 24-hour mean
PM10 concentration for base year emissions and meteorological data from 1996 and
1997. Areas calculated to be below the relevant NAQS objective are coloured blue or
green, and those exceeding the objective are shown in yellow, orange, red or purple
depending on the magnitude of modelled pollution levels. Tables 19a,b show the
percentage of the total area exceeding NAQS objectives in each borough for 1996
and 1997 meteorology. The network of explicitly modelled roads is overlaid on the
contour plots.
In the case of 1997 meteorological data NO2 concentrations have been calculated
using the two different chemistry schemes available in ADMS Urban: the DerwentMiddleton correlation and the GRS scheme.
Contour plots of annual mean SO2 concentrations and the 99.9th percentile of 15
minute mean SO2 concentrations are also shown for the eight London boroughs as a
whole. Borough specific maps for SO2 have not been included because of the low
gradients in SO2 concentrations across Central London.
1997 Meteorological Data
(i)
Annual Mean NO2 (Derwent-Middleton Scheme) (Figure 73)
The majority of the borough falls within the 21 to 24ppb range for mean annual NO2,
exceeding the 21ppb objective, though significant sections along the north-eastern
boundary fall below it. To the east of the A10, south of the A104 intersection there
are extensive areas where concentrations are greater than 24ppb.
Mean
concentrations peak between 30 and 33ppb at the junction of Old Street and Great
Eastern Street, the junctions of these two roads with the A10, the junction of the A10
and A104 and the two ends of Graham Road.
(ii)
Annual Mean NO2 (GRS Scheme) (Figure 74)
Under the GRS chemistry scheme with 1997 meteorological data, concentrations are
higher and the 21ppb target is exceeded throughout the borough. The highest
concentrations, in excess of 36ppb, occur on the border with Islington in the vicinity
of St Agnes’ Well, along Great Eastern Street, the sections of Hackney Road and
Bethnall Green Road near their junction with the A10, the junction of the A10 and
A104, parts of the A104 and the two ends of Graham Road.
(iii)
Maximum NO2 (Derwent-Middleton Scheme) (Figure 75)
Maximum concentrations are below 90ppb for the majority of the borough, well
beneath the target of 150ppb. Higher values, greater than 150ppb, are predicted at
the junction of Great Eastern and Old Streets, and at their junctions with the A10, at
the intersection of the A10 and A104, the junction of the A104 with Graham Road
and along Eastway Ruckholt road before it becomes the A102(M).
Review and Assessment of Air Quality in Hackney
49
(iv)
Maximum NO2 (GRS Scheme) (Figure 76)
Maximum concentrations for the majority of the borough remain under the 150ppb
objective using the GRS scheme. However, along all of the explicitly modelled roads
and in the south west corner of the borough concentrations peak above the target
between 150 and 210ppb.
(v)
99th percentile of running 24 hour mean PM10 concentrations (Figure 77)
th
99 percentiles of the running 24 hour mean concentrations of PM10 lie above the
50μg/m3 objective for the entire borough. Concentrations in the majority of the
borough are between 60μg/m3 and 70μg/m3. A small fraction, in the 70μg/m3 –
80μg/m3 band, is located around roadsides throughout the borough.
(vi)
Annual mean SO2 (Figure 78)
Mean SO2 concentrations vary between 2 and 5ppb over the Central London
Boroughs. . In the southern half of Lambeth, Southwark and Kensington and, the
northern part of Camden, mean concentrations lie below 3ppb. They rise to a
maximum of between 4 and 5ppb in the south of Camden.
(vii) 99.9th percentile of 15 minute mean SO2 concentrations (Figure 79)
Values for the 99.9th percentile of running 24 hour mean SO2 concentrations are
below the 100ppb objective for the majority of Central London. They exceed the
objective, however, in the south of Hackney and in the north east of the City.
1996 Meteorological data
(i)
Annual mean NO2 (Figure 80)
Mean concentrations of NO2 lie above the 21ppb objective over the entire borough.
Along many of the explicitly modelled roads concentrations average more than
27ppb. Mean concentrations peak between 33 and 36ppb near St Agnes’ Well and
at the junctions of Great Eastern Street with Old Street and Shoreditch High Street.
(ii)
Maximum NO2 (Figure 81)
Maximum NO2 concentrations are above the 150ppb objective for the entire borough.
They are generally higher in the western half of the borough and peak above 240ppb
along many of the explicitly modelled roads and in much of the south western corner
of the borough.
(iii) 99th percentile of running 24 hour mean PM10 concentration (Figure 82)
99th percentiles of the running 24 hour mean concentrations of PM10 lie at least
10μg/m3 above the 50μg/m3 objective for the majority of the borough. Isolated areas
away from A roads in the east and north east sections of the borough lie in the
50μg/m3 – 60μg/m3 band.
(iv)
Annual mean SO2 (Figure 83)
Mean SO2 concentrations vary between 1 and 4ppb over the central London
boroughs. Concentrations over the majority of all the boroughs lie in the 2ppb – 3ppb
band, with the exception of the north of Camden and south of Southwark and
Lambeth.
(v)
99.9th percentile of 15 minute mean SO2 concentrations (Figure 84)
Values for the 99.9th percentile of 15 minute mean SO2 concentrations are below the
100ppb target throughout Central London. They are below 75ppb in most of
Review and Assessment of Air Quality in Hackney
50
Camden, Islington, Hackney, Lambeth, Southwark, Kensington and Westminster.
The majority of the City lies in the 75ppb – 100ppb band.
Future Scenario 2005
Contour plots for 2005 emissions are shown for annual mean concentrations of NO2,
the maximum 1 hour average NO2 concentration and the 99th percentile of the
running 24-hour mean PM10 concentration. Areas calculated to be below the relevant
NAQS objective are coloured blue or green, and those exceeding the objective are
shown in yellow, orange, red or purple depending on the magnitude of modelled
pollution levels. Tables 19a,b show the percentage of the total area exceeding
NAQS objectives in each borough for 1996 and 1997 meteorology. The network of
explicitly modelled roads is overlaid on the contour plots. All NO2 concentrations for
this scenario have been calculated using the GRS chemistry scheme.
Contour plots of annual mean SO2 concentrations and the 99.9th percentile of 15
minute mean SO2 concentrations are shown for the eight London boroughs as a
whole.
1997 Meteorological Data
(i)
Annual Mean NO2 (Figure 85)
Mean NO2 concentrations fall below the 21ppb objective for the majority of the
borough. Concentrations exceed the target, peaking between 21 and 24ppb,. along
a number of explicitly modelled roads. These include the A104 between its junctions
with Southgate and Graham Roads, Mare Street between its junctions with Graham
Road and Well Street, Whiston Road, the junction of Downs and Lower Clapton
Roads, the junction of Wick Road and the A102(M) and all the explicitly modelled
roads in the southern corner of the borough around Old Street.
(ii)
Maximum NO2 (Figure 86)
Maximum concentrations of NO2 lie between 90 and 120ppb throughout most of the
borough. Concentrations only exceed the 150ppb objective at the junction of Great
Eastern Street and Shoreditch High Street.
(iii) 99th percentile of running 24 hour mean PM10 concentrations (Figure 87)
99th percentiles of the running 24 hour mean concentrations of PM10 lie above the
50μg/m3 objective for the whole borough, falling largely in the 50μg/m3 – 51μg/m3
band. A small fraction, in the 51μg/m3 – 60μg/m3 band, is located around roadsides
throughout the borough.
(iv)
Annual mean SO2 (Figure 88)
Mean SO2 concentrations vary between 2 and 5ppb over the central London
boroughs. Concentrations over the majority of all the boroughs except City lie in the
2ppb – 3ppb band. Concentrations over City are mainly in the 3ppb – 4ppb band.
An area of concentration in the 4ppb – 5ppb band is located in the far south of
Camden.
(v)
99.9th percentile of 15 minute mean SO2 concentrations (Figure 89)
Values for the 99.9th percentile of 15 minute mean SO2 concentrations are below the
100ppb target throughout Central London. They are below 50ppb in northern parts of
Review and Assessment of Air Quality in Hackney
51
Camden, Islington and Hackney, as well as in most of Lambeth and Southwark and
southern parts of Kensington and Westminster. The 99.9th percentile does not
exceed 75ppb anywhere in the study area using 2005 emissions and 1997
meteorological data.
1996 Meteorological data
(i)
Annual mean NO2 (Figure 90)
Annual mean NO2 concentrations for 2005 lie below the target objective of 21ppb for
the majority of the borough with just one exceedence at the junction of Great Eastern
Street and Shoreditch High Street. The northern two thirds of the borough lie below
15ppb, except for some roadside areas which are generally in the 15ppb – 18ppb
band.
(ii)
Maximum NO2 (Figure 91)
Maximum concentrations of NO2 are below the 150ppb objective for all of the
borough except at the Old Street/Great Eastern Street Junction. Away from
roadsides, the northern two thirds of the borough are in the 90ppb –120ppb band,
whilst the majority of the southern third is in the 120ppb – 150ppb band.
(iii) 99th percentile of running 24 hour mean PM10 concentrations (Figure 92)
99th percentiles of the running 24 hour mean concentrations of PM10 lie above the
50μg/m3 objective for the entire borough. Concentrations in the eastern half of the
borough are generally between 50μg/m3 and 57μg/m3, except around main
roadsides. In the majority of the western half of the borough concentrations are in
the 57μg/m3 - 60μg/m3 band.
(iv)
Annual mean SO2 (Figure 93)
Mean SO2 concentrations vary between 1 and 3ppb over the central London
boroughs. Concentrations over the majority of all the boroughs except City lie in the
1ppb – 2ppb band. Concentrations over the whole of City are in the 2ppb – 3ppb
band.
(v)
99.9th percentile of 15 minute mean SO2 concentrations (Figure 94)
Values for the 99th percentile of mean SO2 concentrations are below the 100ppb
throughout Central London. They are below 50ppb in northern parts of Camden,
Islington and Hackney, as well as in most of Lambeth, Southwark and southern parts
of Kensington and Westminster. The 99.9th percentile does not exceed 75ppb
anywhere in the study area using 2005 emissions and 1996 meteorological data.
Table 19(a) Percentage areas of exceedence using the GRS scheme and
1996 meteorological data
Base year emissions
2005 emissions
th
th
Mean Max
99 % 99.9
Mean Max
99th% 99.9th
NO2
NO2
PM10
%
NO2
NO2
PM10
%
SO2
SO2
100.0
100.0
100.0
0.0
0.1
0.1
100.0
0.0
Camden
100.0
100.0
100.0
0.0
1.0
1.6
100.0
0.0
City
100.0
100.0
100.0
0.0
0.0
0.1
100.0
0.0
Hackney
100.0
100.0
100.0
0.0
0.0
0.4
100.0
0.0
Islington
Review and Assessment of Air Quality in Hackney
52
Kensingto
n
Lambeth
Southwark
Westminst
er
100.0
100.0
100.0
0.0
0.0
0.2
100.0
0.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
0.0
0.0
0.0
0.0
0.0
0.3
0.0
0.0
0.1
100.0
100.0
100.0
0.0
0.0
0.0
Table 19(b) Percentage areas of exceedence using the GRS scheme and
1997 meteorological data
Base year emissions
2005 emissions
th
th
99th % 99.9th
Mean Max
99 % 99.9
Mean Max
%
%
NO2
NO2
PM10
NO2
NO2
PM10
SO2
SO2
100.0
74.5
100.0
0.0
8.0
0.0
97.8
0.0
Camden
100.0
94.2
100.0
13.5
58.9
0.9
100.0
0.0
City
100.0
46.6
100.0
3.5
1.6
0.0
100.0
0.0
Hackney
100.0
73.7
100.0
0.2
5.4
0.1
100.0
0.0
Islington
90.0
100.0
0.0
4.2
0.0
100.0
0.0
Kensingto 100.0
n
100.0
100.0
100.0
0.0
3.4
0.3
66.9
0.0
Lambeth
69.4
100.0
0.0
1.9
0.1
69.0
0.0
Southwark 100.0
94.9
100.0
0.0
25.2
0.6
100.0
0.0
Westminst 100.0
er
Sulphur Dioxide
Sulphur dioxide emissions have been dropping for many years, due to the reduction
of domestic coal-and oil-heating, the closure of coal-fired power stations, reduction in
sulphur content of heating and fuel oils, and European legislation. Point sources,
such as coal- and oil-fired power stations, are the dominant sources in Europe, in the
UK and in London.
The European Commission is proposing a National Emissions Ceiling Directive which
will set limits for total sulphur dioxide and other pollutant emissions. The forthcoming
Directive on the Sulphur Content of Certain Liquid Fuels sets maximum levels for
heavy fuel oil and gas oil. Amendments to existing Directives on large combustion
plant are expected to further reduce EU emissions by 1 million tonnes over 20002010.
In England and Wales the government predicts that sulphur dioxide emissions from
the electricity supply industry will fall from 1.5 million tonnes in 1998 to 365,000
tonnes in 2005 – a fall of 75%.
Nitrogen Dioxide
The amendments to existing Directives on large combustion plant will reduce
nitrogen oxide emissions by 4 million tonnes over 2000-2010. The Auto-Oil
Programme will result in three Directives applying stringent new emission standards
to all new cars and light vans applying in two stages from 1 January +2000 and 1
Review and Assessment of Air Quality in Hackney
53
January 2006. A further proposed Directive will reduce permitted emissions from new
heavy goods vehicles by 30% from 1 October 2001, with further reductions from
2005 and 2008.
The reduction in sulphur content of vehicle fuel is also expected to have a secondary
effect on nitrogen dioxide levels.
Total annual emissions of NOx have fallen by 25% between 1990 and 1996, with a
similar fall in vehicle emissions. The government believes that further reductions of
56% of urban traffic emissions of NOx will occur by 2005.
Particles (PM10)
The Auto-Oil agreements mentioned above will also require a reduction in the direct
emissions of particles from road vehicles. The amendments to the Directive on Large
Combustion Plant will also reduce particle emissions. The reduction in sulphur
dioxide and NOx emissions from vehicles and stationary sources referred to above
will also have an effect on particle emissions by reducing the formation of secondary
particles.
Designation of proposed Air Quality Management Areas
The proposed extent of the Air Quality Management Area (AQMA) in Hackney
Review and Assessment of Air Quality in Hackney
54
Public consultation
Local authorities are required to consult at each stage of their air quality review and
assessment and the Environment Act specifies the statutory bodies to be included in
the consultation. This includes the Environment Agency, the Secretary of State, and
public bodies who have an interest in the authority’s area. In London this typically
includes the Traffic Director for London, the Government Office for London and the
Highways Agency.
Local authorities are also required to consult with a
representative sample of local business, community groups and local action groups,
as they think appropriate. Local authorities must also consult their neighbouring
authorities who they share boundaries with.
Guidance from DETR specifies the particularly information which should be included
in the review. This includes a named person within the authority to whom enquires
can be addressed; the size and boundaries of the local authority; the start date and
completion of the review and assessment; the arrangements for consultation; any
details of inter-borough collaboration and, details of consultees.
It is important that the council’s methodology and subsequent conclusions are clearly
explained, and the public can understand the rationale behind the councils
conclusions. Also that that where requested interested parties can view the full data
in a clear and comprehensible format. A final report incorporating points raised in the
consultation should be included.
While DETR guidance has mentioned the compulsory consultees, the central London
cluster group wish to consult effectively with as wide a range of people and
organisations as possible. These local consultees will include local campaigning
groups, environmental forums, neighbourhood and residents associations, and
Agenda 21 participants in their consultation. While some people may be well
informed about air quality, the central London cluster group recognise the importance
of presenting information in an easily understood format. The use of summary
leaflets, maps, and press releases will all help the public in understanding the
implications of the review. Large public meetings may not be the most useful way of
publishing the results. Many of the individual cluster group members will use focus
groups and consumer panels to help us achieve a truly representative sample of our
commuters.
Given that many of the public most easily understand air quality issues in the context
of traffic, several authorities will combine the consultation exercise with a wider
discussion on local transport strategies.
The minimum time for consultation recommended by DETR is six weeks but it is
intended to extend this period by several months to ensure that all groups within the
community have an opportunity to usefully comment on the results of the air quality
review. While the consultation is focused on the local and London wide area, we
also intend to consult with national interest groups, who are looking with interest at
the exciting work carried out by the London cluster group. It is intended that
consultees concerns and views will be reflected in the final report.
Review and Assessment of Air Quality in Hackney
55
The next steps
1. Take into account comments received during consultation process.
2. Accuracy of predictions - sensitivity analysis
3. Further assessment - monitoring
4. Possible revised Amass
5. Action Plans
Review and Assessment of Air Quality in Hackney
56
Appendix XXX
Hackney's First Stage Air Quality Review & Assessment Executive Summary
Public and government concerns about air quality in the UK have resulted in a
comprehensive national strategy and statutory measures aimed at bringing about a
marked improvement in air quality.
Under Part IV of the 1995 Environment Act, local authorities are required to make a
review and assessment of air quality in their areas. The process will identify areas
where air quality is unlikely to meet the National Objectives prescribed in the Air
Quality Regulations 1997, by 2005. Where the National Objectives are not met, a
local authority must declare an Air Quality Management Area (AQMA). In an AQMA,
a local authority must produce action plans to secure the necessary improvements in
air quality to meet the National Objectives. This summary outlines the first stage of
the review and assessment process. A leaflet from the Department of the
Environment, Transport and the Regions with a further explanation of the process is
enclosed.
In its National Air Quality Strategy, the government has identified eight key pollutants
that present a risk to health. These are benzene, 1,3-butadiene, carbon monoxide,
lead, nitrogen dioxide, fine particles (also known as PM1O - particulate mailer less
than 0.0001 mm), sulphur dioxide and ozone. Of these, ozone is a secondary
pollutant produced by chemical reactions in the air. As this cannot be controlled
directly, it has been excluded form assessment.
Air Pollution Monitoring in Hackney.
Hackney Council is concerned about the high levels of air pollution in the borough.
The Pollution Group currently monitors nitrogen dioxide, carbon monoxide, ozone,
fine particles, acid gases and smoke. These are sampled using a variety of
techniques at several locations in the borough. Information on current levels of air
pollution
is
available
on
the
internet
at
http://www.aeat.co.uk/netcen/airqual/bulletins/..
Air Pollution in Hackney
The main source of air pollution in Hackney is from motor vehicles. Vehicles produce
the majority of fine particles and nitrogen dioxide. sulphur dioxide is blown in from the
large power stations along the Thames estuary when the wind is in the east.
Results of the First Stage Assessment.
Levels of benzene, 1,3-butadiene, carbon monoxide and lead in Hackney's air are
likely to be similar across London. Monitoring of these pollutants, carried out by other
local authorities and the government have shown the National Objectives are not
being breached. Levels of these pollutants are expected to reduce further. These
reductions are due to national control measures such as the phasing out of lead in
petrol and better pollution control measures on vehicles with petrol engines for
carbon monoxide. No further action is needed on these pollutants.
Review and Assessment of Air Quality in Hackney
57
The position for nitrogen dioxide, fine particles and sulphur dioxide is different.
Nitrogen dioxide and fine particles are produced from motor vehicle exhausts
although particles do have other origins as well. As such, these are the principle
sources of in Hackney. Whilst levels of these pollutants are due to fall, they may not
fall sufficiently to ensure that the National Objectives are met. Sulphur dioxide is a
different case. As explained above, most of the sulphur dioxide comes from outside
Hackney. Sulphur dioxide has an acute effect and exposures for as short a time as
15 minutes can have an effect. Occasionally, when the wind is in the east, sulphur
dioxide can descend to ground level in Hackney.
APPENDIX X: CHEMISTRY SCHEMES USED IN ADMS URBAN
The Derwent-Middleton Correlation
When this option is selected, output concentrations of NO2 are calculated from NOX
concentrations using the following function, where concentrations are hourly average
values in ppb.
[NO2] = 2.166 – [NOx(1.236 – 3.348A + 1.933A2 – 0.326A3)]
and where A = log10 (NOX) and the equation is valid in the range 9ppb to 1141.5ppb.
The method is described in Derwent and Middleton (1996) and has been derived
from monitored data at a roadside site.
The Generic Reaction Set
Vehicles and industrial sources emit a complex mixture of chemicals including many
organic compounds e.g. VOCs (Volatile Organic Compounds) and oxides of nitrogen
which are involved in reactions with Ozone. It is beyond the scope of a fast practical
model to model all the chemical reactions; a scheme is used in ADMS Urban which
models the important reactions involving nitrogen, VOCs and ozone (O3). The
Generic Reaction Set (GRS) of equations (Venkatram et al., 1994) is a
semi-empirical photochemical model which reduces the complicated series of
chemical reactions involving NO, NO2, Ozone and many hydrocarbons to just seven:
(1)
ROC + hυ
→
RP + ROC
(2)
RP + NO
→
NO2
(3)
NO2 + hυ
→
NO + O3
(4)
NO + O3
→
NO2
(5)
RP + RP
→
RP
(6)
RP + NO2
→
SGN
→
SNGN
(7)
RP + NO2
where:
ROC = Reactive Organic Compounds (assumed to be equivalent to VOCs)
RP
= Radical Pool
Review and Assessment of Air Quality in Hackney
58
SGN = Stable Gaseous Nitrogen products
SNGN = Stable Non-Gaseous Nitrogen products
Equations (3) and (4) represent exact chemical reactions, which take place very
quickly. The other equations are approximations.
The GRS chemistry scheme in ADMS-Urban can be used in two ways. The simplest
approach models chemical reactions that occur only in the main model domain,
which contains all individually defined sources, receptor points and output grid. A
weighted mean age of each pollutant is calculated for each output point in the plume
down wind of each source in the main model domain. At each output point, the
minimum (non-zero) value is used to determine the time period over which the GRS
scheme of chemical reactions is applied. The scheme is only applied to points that
are affected by source emissions within the main model domain to provide a receptor
specific value of pollutant concentration
In addition, the GRS scheme can also be used in conjunction with another model
(known as a Box Model). This scheme allows the ADMS output grid to be nested
within a larger domain such as a large urban conurbation, where the effects of NOX
and VOC emissions over the whole area need to be considered:
Box model domain
Main model domain
First source
Backgound monitoring site
U
Figure B1 Schematic showing the main model nested within large area-wide
box model
Computational time is a major restriction on the complexity of the Box Model, as it is
used for a large number of sequential meteorological datasets. For this reason a
single layer ‘Box’ model with a regular grid is used. Meteorological parameters and
emissions are assumed to be constant over the grid square. Removal of pollutants
from the atmosphere is by way of dry deposition at the surface.
Review and Assessment of Air Quality in Hackney
59
The governing equation for the box model is
Fe
V C (t )
dC (t )
=
- d
dt
Hmix
H mix
where C(t) is the concentration of the chemical species at time t, Hmix is the depth of
the atmospheric boundary layer, Vd is the applied deposition velocity and Fe is the
emission flux of the species.
The solution of this equation for a time period Λt (assuming steady state conditions)
is given by
C(t0 + Λt) = C(t0)*exp {-
Δt *Vd
}+
H mix
Fe
Δt *Vd
*[1 - exp{}]
Vd
H mix
The Box model is employed in the following way. For each prevailing weather
condition, a number of receptor points are defined, which lie on a regular grid in the
Box Model domain. For each receptor point, a back trajectory is calculated from the
receptor point to the edge of the Box Model domain. The Box Model is initialised
using concentrations from automatic monitoring sites or values specified by the user.
The Box Model is then run along the current trajectory from the edge of the domain to
the receptor point, grid square by grid square. This process is repeated for each of
the receptor points in the Box Model. Pollutant concentrations at the receptor points
are then used as background values in the main ADMS model domain.
Review and Assessment of Air Quality in Hackney
60
MapInfo Format to Shapefile conversion
The Geo-Information and MSI data sets were supplied in MapInfo format (MIF) and
converted into shapefiles for use with ArcView. All subsequent processing was
carried out in ArcView.
ii. Selection of Buildings
The buildings forming a street canyon were identified by selecting all buildings within
a user-defined distance of road centre-line using ArcView. For the purpose of this
study a distance of 25m was chosen (ie canyon width equal to 50m). Figure 26a
shows an example of such a selection, as can be seen this results in the inclusion of
buildings, or sections of buildings, which do not form part of the street canyon.
In order to select the relevant parts of buildings, i.e. those near the roads, the
selection is updated by converting all building shapes to a set of points, and then
discarding any points outside the specified canyon area (Figure 26b). Buildings
located within other buildings were discarded since the inclusion of such buildings
would have resulted in an overestimate of the length of building parallel to the road.
Review and Assessment of Air Quality in Hackney
61
Figure 26a. Example selection used to identify buildings forming street
canyons
Road links
Road links
Buildings
Figure 26b. Revised selection used to identify buildings forming street
canyons
Road links
Road links
Buildings
Review and Assessment of Air Quality in Hackney
62
No Page 63?
Draft 1 17/05/1117:09
allbuildings
B
∑H
× LB
(16)
1.
Calculation of Street Canyon Height from selected buildings
The contribution of each building to the overall street canyon height has been considered in terms of the total cross sectional area
of building parallel to the road (CSATotal), given by,
CSATotal =
Where, HB is the building height (m), and LB the length of building parallel to the road (m).
y
Length parallel to road, LB (m)
x
∑L
B
allBiuldings
HCanyon = 0
LTotal =
(18)
(17)
The mean street canyon height (HCanyon) is then calculated from the total cross sectional area of building forming the canyon
(CSATotal). The method used depends on the ratio of road length (LRoad) to total building length (LTotal),
if (LTotal) < (LRoad), then
64
Draft 1 17/05/1117:09
if (LTotal) < 2 x (LRoad), then
if (LTotal) > 2 x (LRoad), then
HCanyon =
HCanyon =
CSATotal
LTotal
CSATotal
2 × LRoad
(20)
(19)
Figure 27 shows the street canyon heights used during this study. For areas outside the Geo-Information and MSI data coverage
the relevant local authorities have supplied additional street canyon information.
2.
Possible sources of error
The mean canyon height calculated is very dependent on the canyon width used. For roads with canyon widths greater than that
specified, no buildings may be selected and a canyon height of zero would be returned. Conversely, if the canyon width is
significantly narrower than that specified, then buildings outside the canyon may be selected, which may or may not introduce
errors into the calculation. This is further compounded by the introduction of errors due to spatial inaccuracies of the LRC road
network. For quality assurance the heights of all major roads with an annual average daily traffic flow of greater than 50,000 were
manually checked, and updated where necessary. Each of the London boroughs were also sent maps of the street canyon
heights, and the results deemed acceptable.
65
Draft 1 17/05/1117:09
92.3
199
199
199
199
41.2
1.1
1.1
7.0
7.0
7.0
7.0
2.0
11
11
11
673
705
614
631
13
13
12
12
20
21
19
19
27
153
153
193
193
130
130
130
130
2.2
20.2
23.1
2.6
3.5
316.9
350.5
331.4
369.3
2.2
20.2
23.1
2.6
3.5
316.9
350.5
331.4
369.3
APPENDIX XX: STATUS OF EXPLICITLY MODELLED SO2 POINT SOURCES BASE YEAR AND 2005
Name
Sta Co-ordinates Heigh Diamet Volum Vertic Temperat Current Emissio Comment
ck
X
Y
t (m)
er (m)
e flow al
ure (0C)
emissio n rate in
rate
velocit
n
rate 2005
(m3/s)
y (m/s)
(g/s)
(g/s)
29
18
27
3.4
3.4
1796
10
1917
40
1917
40
1917
40
1917
40
1827
00
92.3
1.0
11
8
Cohen & 2
Co
Didcot A
1
5460
40
4512
63
4512
63
4512
63
4512
63
5193
90
1827
00
92.3
1.0
40
1
2
5193
90
1827
00
92.3
2.6
Didcot A
2
5193
90
1827
00
76
3
3
5193
90
1966
80
Didcot A
4
5366
20
4
3
Didcot A
Guinness
Brewing
Ltd
Guinness
Brewing
Ltd
Guinness
Brewing
Ltd
Guinness
Brewing
Ltd
Johnson
Matthey
Plc
66
5367
40
1965
80
15
0.8
4
9
77
77
6.9
6.9
6.9
6.9
Draft 1 17/05/1117:09
6
9
13.1
4
13.1
83.2
0.8
160
207.9
15
8
541
1965
80
6
23
5367
40
1.3
165
2.5
7
50
5.0
6.3
1
Johnson
Matthey
Plc
Johnson
Matthey
Plc
Kodak Ltd
215
228
1896
70
1765
00
18
5146
40
5557
00
19
1
1.5
8.5
Littlebrook
Power
Station
75
8.5
7.9
2
230
7.9
1765
00
17
234
5557
10
48
5
Littlebrook
Power
Station
2.7
11
2.5%
to
1%
Sulphur
fuel
2.5%
to
1%
Sulphur
fuel
100
1.4
7.9
43
2
7.9
1.4
234
43
Sta
ck
25
5
Heigh Diamet
t (m)
er (m)
Volum
e flow
rate
(m3/s)
2
10
3
0.5
1
11
1
Londonwa
ste Ltd
Nestle
(UK)
Nestle
(UK)
Name
10
0.3
Emissio Comment
n rate in
2005
(g/s)
3.0
1816
90
5
Current
emissio
n
rate
(g/s)
3.0
5458
20
1816
90
Vertic Temperat
al
ure (0C)
velocit
y (m/s)
10
25
1
5458
20
3.0
2
3.0
5357 1926
10
10
5101 1792
50
50
5101 1792
50
50
Co-ordinates
X
Y
Seabright
Industries
Ltd
Seabright
Industries
Ltd
67
5746
00
5619
00
5619
00
5619
00
5746
00
5850
00
5624
00
5624
00
5614
00
5455
00
1825
00
1825
00
1768
00
1768
00
1768
00
1825
00
1760
00
1746
00
1746
00
1756
00
1823
50
106.7
106.7
45.7
45.7
45
45
61
198
36.5
168
168
19
1.0
1.0
1.0
1.0
0.9
0.9
1.4
6.1
1.1
6.1
6.1
1.0
13
13
13
13
8
8
21
592
19
351
263
8
10
10
10
10
13
13
14
20
19
12
9
27
120
120
120
120
130
130
130
130
15
167
167
465
49.3
49.3
49.3
560
3.8
3.8
12.1
1398
101.3
56
56
70.1
19.7
19.7
19.7
224
3.8
3.8
12.1
1398
101.3
0
0
70.1
Closing
Closing
Draft 1 17/05/1117:09
2
5746
00
1825
Union
2
Miniere
Oxyde Ltd
Blue Circle 1
3
5746
Cargill
Cargill
1
3
2
Mobil
Mobil
Britannia
1
Refined
Metals Ltd
Kingsnorth 1
Power
Station
Cargill
1
Blue Circle 2
Mobil
4
2.5%
1%
Sulphur
fuel
2.5%
1%
Sulphur
fuel
2.5%
1%
Sulphur
fuel
2.5%
Mobil
68
to
to
to
to
Shell
Shell
Shell
Shell
Name
Shell
Shell
Shell
Shell
NP Tilbury
Mobil
J2
J1
E
D3
D2
Sta
ck
D1
C1
A2
A1
1
5
5662 1756
00
00
5718 1819
10
10
5717 1819
80
00
5717 1817
90
20
5717 1820
50
70
Co-ordinates
X
Y
5746
00
00
1825
00
00
Draft 1 17/05/1117:09
Shell
1820
70
1821
40
1818
90
1820
20
1820
30
1819
K2
5717
90
5718
00
5716
30
5713
40
5713
50
5718
Shell
35
35
61
110
61
110
61
61
164
106.7
0.8
0.8
2.7
2.4
2.8
Heigh Diamet
t (m)
er (m)
61
1.2
2.8
2.5
2.0
2.6
8.9
1.0
14
2
2
16
46
Volum
e flow
rate
(m3/s)
12
12
27
24
36
420
13
13
3
3
3
10
6
8
7
7
10
250
250
300
150
Vertic Temperat
al
ure (0C)
velocit
y (m/s)
2
150
2
180
150
200
290
290
130
120
19.1
2.1
2.1
10.4
51.6
Current
emissio
n
rate
(g/s)
19.1
19.1
30
28
31.9
1826
49.3
0
0
0
0
0
0
0
0
1826
19.7
Closing
Closing
Closing
Closing
Emissio Comment
n rate in
2005
(g/s)
0
Closing
0
Closing
Closing
Closing
Closing
Closing
1%
Sulphur
fuel
2.5%
to
1%
Sulphur
fuel
75
69
Shell
O/P
L/M
Draft 1 17/05/1117:09
Shell
British
Museum
Ford
Birkbeck
College
UCL
2
1
1
Rugby
1
Group Plc
Shell UK 1
Ltd
SOAS
1
Ford
3
1
Ford
4
1
Ford
Citigen Ltd 1
Lots Road
2
1
Citigen Ltd 2
Lots Road
70
5711
60
5721
20
5691
00
5750
00
5299
72
5296
29
5298
28
5302
68
5499
00
5499
00
5499
00
5499
00
5316
30
5316
30
5263
68
5263
10
1816
70
1818
10
1644
00
1620
00
1821
46
1815
29
1822
22
1815
39
1819
00
1819
00
1819
00
1819
00
1817
40
1817
40
1770
17
1770
83.5
83.5
42
42
80
80
80
80
30
30
25.6
48
50
114
107
92
5.2
5.2
1.3
1.3
1.5
1.5
1.5
1.5
1.0
1.0
0.8
0.6
1.0
3.0
0.9
0.9
146
146
26
26
11
13
12
10
4
4
4
4
10
155
22
2
7
7
32
32
10
11
10
8
5
5
8
14
13
22
37
3
120
120
157
157
149
146
139
141
330
330
340
325
100
130
8000
260
1.1
1.7
0.7
0.7
9.2
7.9
8.4
7.6
2
2
2
2
154.1
3.2
24.2
45.2
0
0
0.7
0.7
9.2
7.9
8.4
7.6
2
2
2
2
154.1
0
0
0
Closing
Closing
Closing
Closing
Closing
70
Draft 1 17/05/1117:09
Grain
1
Power
Station
Clinical
1
waste
(PTY) Ltd
Kings
college
hospital
5325
00
68
5885
00
1760
00
17
1756
00
17
251
1.0
19.0
6
521
8
23
55
91
0.005
77.4
0.005
77.4
71
Draft 1 17/05/1117:09
Appendix XXX
LAQM. G1(97) - Framework for review and assessment of air quality
This guidance outlines;
the general framework of reviewing and assessing air quality,
the information local authorities should collect to complete a review and assessment
of air quality and
the role of reviewing and assessing air quality in local air quality management.
LAQM. G2(97) - Developing local air quality action plans and
principal considerations
strategies:
the
This guidance gives local authorities general advice on the principal considerations,
which should underpin the development of a local air quality strategy, and, where
necessary, an action plans.
LAQM. G3(97) - Air quality and traffic management
This guidance assist local authority to determine the role that traffic management
might play in a balanced consideration of local options for the delivery of
improvements in air quality and achievement of National Air Quality Objectives.
LAQM. G4(97) - Air quality and land use planning
This guidance principal objectives are
to ensure that the land use planning system makes an appropriate contribution to the
achievement of National Air Quality Objectives and
air quality considerations are properly considered along with other material
considerations in the planning process.
LAQM. TG1(98) - Monitoring for Air Quality Reviews and Assessments
This guidance includes advice on monitoring strategy, quality assurance and quality
control, automatic monitoring methodologies and non- - automatic monitoring
methodologies where these may be used.
LAQM. TG2(98) - Preparation and Use of Atmospheric Emissions Inventories
This guidance focuses on the consideration of pollutant emissions and the
construction of an atmospheric emissions inventory
LAQM. TG3(98) - Selection and use of Dispersion Models
This guidance provides practical advice on the selection and use of dispersion
models for the review and assessment of air quality
72
Draft 1 17/05/1117:09
LAQM. TG4(98) - Review and assessment: pollutant specific guidance
This guidance provides advice to local authorities on approaches for all the
pollutants prescribed in the Air Quality Regulations 1997. The information will be
used to identify areas at risk of exceeding the National Air Quality Objectives within
their locality. The methodologies presented in the guidance are considered sufficient
to demonstrate that the Authority has met the requirements of section 82 of the
Environment Act 1995.
References
1.
DETR, (1997): Framework for Review and Assessment of Air Quality; LAQM
G1(97); ISBN 0-11-753426-9 (97); The Stationary Office.
2.
Buckingham, Clewley, Hutchinson, Sadler, Shah: London Atmospheric
Emissions Inventory; London Research Centre; (February 1998) ISBN 1 85261 267
3.
3.
Expert Panel on Air Quality Standards, (1994): 1,3-Butadiene, Department of
the Environment.
4.
Expert Panel on Air Quality Standards, (1994): Benzene, Department of the
Environment
5.
Expert Panel on Air Quality Standards, (1994): Carbon monoxide ,
Department of the Environment.
6.
Expert Panel on Air Quality Standards, (1994): Ozone, Department of the
Environment
7.
Expert Panel on Air Quality Standards, (1995): Particles, Department of the
Environment
8.
Expert Panel on Air Quality Standards, (1995): Sulphur dioxide, Department
of the Environment
9.
Expert Panel on Air Quality Standards, (1996): Nitrogen dioxide, Department
of the Environment
10.
AEA Technology, (1994): Air Pollution in the UK: 1992/93, Department of the
Environment
11.
AEA Technology, (1995): Air Pollution in the UK: 1993/4, Department of the
Environment
12.
AEA Technology, (1996): Air Pollution in the UK: 1994, Department of the
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Urban Air Review Group.
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Appendix III Glossary of Terms and Abbreviations
Term Description
1,3, butadiene
petrol
Accuracy
value.
A volatile aliphatic compound produced by the combustion of
A statistical method for measuring how well a set of data fits the true
ADMS Atmospheric dispersion modelling system
AEA
Atomic Energy Authority
AEI
Atmospheric emissions inventory
AEOLIUS
Office
An atmospheric dispersion model developed by the Meteorological
Air Quality Objective
the concentrations and averaging periods set out in the
Air Quality Regulations 1997
Air Quality Standard (AQS)
Derived from the EPAQS recommendations, set
out in the National Strategy standards
AQMA Air Quality Management Area
AQR&A
Air Quality Review and assessment
Atmospheric dispersion model
A mathematical method for calculating levels of
pollutants under a set of known variables
AUN Automatic Urban Network
Benzene
B.S.
A volatile aromatic compound which is a component of petrol
British Standard
Carbon monoxide (CO)
A gaseous pollution formed during
combustion of a hydrocarbon fuel. Lethal at high concentrations
Concentration
air)
incomplete
A method of defining an amount of a substance in a volume (of
DETR Department of the Environment, Transport and the Regions (formerly DoE)
Diffusion tube
dioxide
dl
an adsorption tube used to measure benzene or nitrogen
Decilitre
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DMRB Design Manual for Roads and Bridges
DOAS Differential Optical Absorption spectroscopy
DoE
Department of the Environment (now DETR)
EPAQS
Expert Panel on Air Quality Standards
Fine particulate
Particles less than 10 microns
Hydrocarbon Compound that contains both carbon and hydrogen and is usually
derived from oil.
LAQN London Air Quality Network
Lead A toxic metal element and also used as an organometallic compound
(tetraethyl lead) in 4 star petrol as an anti-knock additive.
LRC
London Research Centre
Mean the average of a data set.
mg/m3
Milligrams per cubic metre
NAEI National Atmospheric Emissions Inventory
NAMAS
National Auditing Service
NETCEN
National Environmental Technical Centre
Nitric oxide (NO)
The main oxide of nitrogen which is created during high
temperature combustion
Pollutant which is created during high temperature
Nitrogen dioxide (NO2)
combustion and as the result of oxidation of nitric oxide in the presence of ozone.
NOx Generic name for all oxides of nitrogen
NPL
National Physical Laboratory
NRTF National Road Traffic Forecast
OPSIS
A technique for measuring pollution using UV/Visible light adsorption of
specific pollutants (Uses DOAS).
Ozone
Irritant secondary pollutant created by the reaction of VOCs and other
pollutants in the presence of sunlight.
PM1
Particulate matter with a mean effective aerodynamic diameter of 1 micron.
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PM2.5 Particulate matter with a mean effective aerodynamic diameter of 2.5 microns.
Can penetrate even further into the lungs than PM10.
PM10 Particulate matter with a mean effective aerodynamic diameter of 10 micron.
Are of concern because of the depth to which they penetrate the lungs.
ppb
parts per billion
ppm
parts per million
Precision
A statistical definition of how closely a range of readings are to one
another (not the same as accuracy).
QUARG
Quality of Urban Air Review Group
Rolling/running average An average set for a consecutive time period where the
average moves in a continuous step.
SEIPH
South East Institute of Public Health
A gas, mainly produced from the burning of coal and oil
Sulphur dioxide (SO2)
with a small contribution from diesel.
TEOM Tapered Element Oscillating Microbalance
TSP
Total suspended particulate
μg/m3 Micrograms per cubic metre
USEPA
United States Environmental Protection Agency
VOC Volatile organic compounds, (like benzene and other hydrocarbons that
evaporate readily.)
WHO
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