Air Pollution and Health
Background and Summary on Air Quality and Health Issues
Population Health, Community Service, and Critical Thinking Unit (PHCSCT)
Placement: Clean Nova Scotia
Kimberley Creaser, Class 2005
Date: May 2, 2003
Table of Contents
Table of Contents
Objectives Provided By Clean Nova Scotia
Population Health Project Evaluation Guide
Search Strategy and results of Literature Search
Web Site Reference List
Useful & Interesting Scientific Reviews Studies
Introduction
Air Pollution
Table 1: Common Sources of Emissions
Issues in Nova Scotia
Health Effects
Table 3: Summary of Air Pollutants and know health effects
Ozone and Smog
Particulate Matter
Mercury
Populations at Risk
Asthma
Conclusions
Solutions
Summary
Appendix A – Additional Website Resources
Appendix b – Pub Med Search
References
Web Site Reference List
Air Pollution & Health Slide Show
http://www.health.uottawa.ca/hklab/APA4155/New%20Folder/Air%20Pollution%20and%20Health.pdf
Environment Canada – Atlantic Region – Air Pollution Topics & Resources
http://www.ns.ec.gc.ca/pollution/air.html
EPA Publication - Evaluating Exposures to Toxic Air Pollutants: A Citizen's Guide
http://www.epa.gov/oar/oaqps/air_risc/3_90_023.html
EPA Publication – Air Pollution and Health Risk
http://www.epa.gov/oar/oaqps/air_risc/3_90_022.html
UK Dept. of Health – Health Effects of Climate Change
http://www.doh.gov.uk/airpollution/climatechange02/index.htm
UK Dept of Health - THE HEALTH EFFECTS OF AIR POLLUTANTS: ADVICE FROM THE COMMITTEE ONTHE MEDICAL EFFECTS
OF AIR POLLUTANTS
http://www.doh.gov.uk/comeap/statementsreports/healtheffects.htm
UK Dept of Health – Asthma and Outdoor Air Pollution
http://www.doh.gov.uk/comeap/statementsreports/airpol2.htm
UK Dept of health – Air Pollution Statements & Reports
http://www.doh.gov.uk/comeap/state.htm
World Resources Institute – Health & Environment – The Health Effects of Air Pollution
http://www.wri.org/wr-98-99/airpoll.htm
Wildland forest fire smoke: health effects and intervention evaluation, Hoopa, California, 1999
http://www.ewjm.com/cgi/content/full/176/3/157
CBC News - Air pollution a significant health risk for Canadians
http://www.cbc.ca/stories/2002/06/07/Consumers/smog_020607
Canadian Public Health Association - Resource Development to Raise Public Awareness About the Health Effects of Air Pollution and
Actions to Improve Current Conditions
http://www.cpha.ca/english/natprog/airpollu/airpol_e.htm
Canadian Public Health Association – Climate Change and your child’s health
http://www.cich.ca/Climate_Change/English/AirPollution.htm#_Air_Pollution_1
Canadian Public Health Association - Air Pollution and Senior’s Health
http://www.cpha.ca/english/natprog/airpollu/Seniors.htm
Canadian Health Network – How Does Air Pollution Affect Our Health?
http://www.canadian-health-network.ca/faq-faq/environmental_health-sante_de_lenvironnement/7e.html
Environment Canada - Air Care: A parent's guide to air quality and health
http://www.ns.ec.gc.ca/udo/air.html
BEWARE THE AIR YOU BREATHE: ONTARIO'S DOCTORS CALL FOR CLEANER AIR
http://www.oma.org/pcomm/pressrel/1998/may12.htm
OMA Ground Level Ozone Position Paper
http://www.oma.org/phealth/ground.htm
Pollution Probe – Air Quality Publications
http://www.pollutionprobe.org/Publications/Air.htm
Environment Canada – Clean Air
http://www.ec.gc.ca/air/health_e.shtml
Environment Canada – Clean Air – Atlantic Canada and Clean Air
http://www.ec.gc.ca/air/fact_atlantic_e.html#a
Environment Canada – Mercury in Atlantic Canada: A Progress Report
http://www.ns.ec.gc.ca/reports/mercury_98-09-23.html
AIR POLLUTION AND ACTIVE TRANSPORTATION
http://www.hc-sc.gc.ca/hecs-sesc/air_quality/factsheet/transport.htm
AIR POLLUTION, CLIMATE CHANGE AND YOUR HEALTH
http://www.hc-sc.gc.ca/hecs-sesc/air_quality/factsheet/climate.htm
HEALTH EFFECTS OF AIR POLLUTION
http://www.hc-sc.gc.ca/hecs-sesc/air_quality/health_effects.htm
SMOG AND YOUR HEALTH
http://www.hc-sc.gc.ca/english/iyh/environment/smog.htm
Air Pollution and Asthma
http://www.asthma.ca/adults/lifestyle/outdoor.php
NB Lung Association - The Healthy Wood Stove
http://www.elements.nb.ca/theme/winter/woodstov/woodstov.htm
Canadian Lung Association – Outdoor Air Pollution
http://www.bc.lung.ca/airqualityfactsheets/outdoor_air_quality_factsheet.htm
Lung and Asthma Information Agency
http://www.sghms.ac.uk/depts/laia/laia.htm
Health and Clean Air Newsletter
http://healthandcleanair.org/newsletters/
Environment Canada - Major Pollutants
http://www.atl.ec.gc.ca/airquality/pollutants_e.html
Climate Change in Nova Scotia
http://www.climatechange.gc.ca/plan_for_canada/climate/pdf/ns.pdf
Useful & Interesting Scientific Reviews Studies
For a detailed list of reviews please refer to the references.
WG Teague. Outdoor air pollution - Asthma and other concerns. Pediatr Clin North Am 2001;1167-83.
Helen Suh, Tina Bahadori, Jose Vallarino, and John Spengler. Criteria Air Pollutants and Toxic Air Pollutants. Environ
Health Perspect 2000;625-33.
Bert Brunekreef, Stephen T Holgate. Air Pollution and Health. Lancet 2002;1233-42.
Abelsohn, Alan; Stieb, David; Sandborn, Margaret; Weir, Erica. Identifying and Managing adverse environmental health
effects: 2. Outdoor air pollution. CMAJ 2002; 166(9): 116-1167
MS f, KE P, L H. Impact of changes in transportation and commuting behaviors during the 1996 summer Olympic
games in Atlanta on air quality and childhood asthma. JAMA 2001;897-905.
Introduction
In April 2002 the Canadian Medical Association Journal published a paper on Outdoor air pollution as part of a series
addressing environmental health effects.1 There is a growing body of knowledge that has demonstrated that there are
health effects directly related to air pollution. As physicians we are in a position to educate patients about these effects and
recognize who is at higher risk for developing serious health illness due to air pollution. The goals of this paper are to
provide background information to physicians about air pollution and attempt to provide a review of some of the current
literature and encourage physicians to adopt strategies to reduce air pollution in response to a growing public health issue.
Since the seventies researchers have begun to link serious health effects to air pollution and during the nineties research
papers correlating health effects with levels of air pollution entered the primary literatures.2 We are now in a position where
we can say that air pollution does adversely affect health and it is a problem in Canada. The Canadian government has
estimated that air pollution is responsible for 5,000 premature deaths annually; this translates into 8% of all accidental
deaths being a direct consequence of air pollution from the combustion of fossil fuels. In Ontario 9,800 people are admitted
to hospitals and 13,000 visit emergency departments as a result of exposure to smog.3 Known adverse health effects of air
pollution include respiratory symptoms stemming from airway hyper-reactivity, lung inflammation, decreased lung function,
reduced exercise capacity, possible increased use of medications and increased visits to emergency departments and
physician offices, and possible increased mortality.
In order to educate our patients and act as advocates it is important for physicians to have an understanding of the issues
relevant to air pollution. Three conditions have been described as empowering people to make decisions with regard to
personal action; an understanding that there is a problem, an understanding that we are contributing to the problem, and
knowledge of solutions. The importance of these conditions holds true for the general population. The following article
highlights some of the reasons why physicians should care about climate change and specifically issues of air quality. This
background paper intends to provide some information for medical practitioners with some knowledge of air pollution issues
and health effects. The value of this information is not limited to the medical profession and can be used for educating any
member of the public about the health effects of air pollution. There are many reviews addressing the issue of health effects
of air pollution this paper will not repeat all information presented in the available reviews but will attempt to address some
the key issues.
Why Doctors Care About Climate Change
UPdate Fall 2002
While politicians dilly-dally about whether to make a concrete commitment to the Kyoto Protocol, agonizing over possible negative effects on the
economy, the Canadian Medical Association (CMA), official voice of Canadian physicians, has no such hesitations. "For our members, more than
53,000 physicians across Canada, this international accord is a commitment to improve health status of our citizens and people around the world. ...
CMA urge[s] the federal government to ratify the Kyoto Protocol and adopt a strategy that will reduce Canada's greenhouse gas emissions by at least
6% below 1990 levels by 2012."
Why would doctors care about climate change?
Consider these facts:
- close to 8% of all non-accidental deaths in Canada are caused by air pollution resulting from by-products from burning fossil fuels
- following smog days, hospital admissions for respiratory problems increase by 6%, admissions of infants with respiratory problems
increase by 15%
-forecasts show that without reductions in fossil fuel consumption, in 20 years there will be a 60% increase in particulate emissions
with a corresponding increase in respiratory illnesses, hospitalization and health care costs.
Air pollution is caused by the by-products of fossil fuel consumption, the same products which cause climate change. So cutting back on the
contributors to air pollution is also a step towards decreasing greenhouse gases and global warming.
Not cutting back means an increase in greenhouse gasses, which means an increase in hot, smoggy days. Increased heat and humidity lead to more heat
related deaths, as well as increases in smog and air pollution advisories and increases in pollens and mold spores in the air. People with heart problems,
respiratory diseases and allergies are all affected.
"Ralph Klein says the issue is greenhouse gasses, not air pollution, but you can't talk about one without talking about the other," says Ken Maybee,
President of the NB Lung Association. Maybee underlines the correlation between the use of fossil fuels, increasing greenhouse gasses and increasing
air pollution, which exacerbate health problems for those suffering from respiratory diseases including asthma, emphysema, and chronic obstructive
pulmonary disease. "It's essential that the general public understand that as greenhouse gases increase, so will the effects of
air pollution, low level ozone (smog) and particulate matter in the air," says Maybee.
Smog is not a problem restricted to major urban areas. Nova Scotia's agricultural Annapolis Valley is the site of the highest smog levels in Nova
Scotia, and smog advisories in the area were numerous this past summer.
Fifty health organizations and more than two thousand individual physicians and health scientists have signed the David Suzuki Foundation's
Physician's Statement on Climate Change, which calls for immediate and decisive action on Kyoto. They note that "reducing fossil fuel use will
improve air quality and protect the climate, both of which are key factors in public health."
A March 2002 report from the US National Academies' National Research Council, Abrupt Climate Change:Inevitable Surprises, warns that people
can expect "climate surprises" in the form of "large, abrupt and unwelcome regional or global climatic events," including drought, floods, extreme heat,
hurricanes and rising sea levels.
Dr. Paul Epstein, associate director of the Center for Health and the Global Environment at Harvard Medical School, says the report indicates that
"we've underestimated the rate of this change, we've underestimated the sensitivity of biological systems, we've underestimated the cost of global
warming."
In a paper printed in the Canadian Medical Association Journal in September 2000, Epstein and co-authors Andrew Haines and Anthony J. McMichael
detail the widespread potential health impacts from climate change. Direct effects include illness and deaths from heat waves, drought, floods, storms
and the breakdown of systems in the aftermath of weather disasters. Indirect effects include decreased crop productivity owing to pests and climate
change, changing water availability, lower air quality, rising sea levels and animal-based diseases appearing in regions in which they had previously
been unheard of.
Global warming is already resulting in the spread of infectious diseases, as tropical insects which carry these diseases move north and south of their
traditional territory. Insect populations increase with warmer winters and better breeding conditions in summer. Projections show that malaria, dengue
fever and yellow fever could appear in Canada as insects carrying them migrate north. Epstein links drought intensified by climate change to the spread
of the West Nile virus.
Climate change can also threaten the quantiity and quality of drinking water. Water sources may be threatened by drought, as well as by increased
contamination from bacteria, viruses, protozoa and parasites.
Inaction on global warming is costly. Economists estimate that health benefits from improving ambient air quality in Canada would amount to $8
billion over 20 years. The CMA states, "While opponents are eager to argue that signing on will have a negative impact on Canadian industries, they
conveniently ignore the impact inaction will have on the health and well being of Canadians and others around the world. ... Reducing ... emissions
would provide significant health benefits, not only in terms of the number of adverse health effects that can be avoided but also the economic cost of
illnesses due to these health effects - an unhealthy workforce does not lead to a strong economy."
The bottom line is, there are many ways to run an economy, but there is no substitute for clean air, clean water and good health.
What you can do... While policy changes by government are important, individual action also helps cut greenhouse gasses. Driving less, and driving
fuel efficient vehicles, making your home more energy efficient, and only heating when you need to, and letting politicians know you support Kyoto
are valuable ways individuals can help. For more information on climate change and what you can do, check out www.davidsuzuki.org.
© http://www.environmentalhealth.ca/fall02doctors.html
Air Pollution
Air pollution is an umbrella term used to define air contamination with both primary and secondary pollutants. Primary
pollutants are those substances that directly affect the respiratory system such as carbon dioxide, carbon monoxide,
nitrogen dioxide, sulfur dioxide, and fine particles (dust, tobacco, sulfur containing fuels, pollen, bacteria, acidic aerosols).
Secondary pollutants are those substances that affect the respiratory system through interaction with primary pollutants
such as aerosols (smoke, fog, mist), ozone, and peroxyacetyl nitrate (an active component in smog). The Environmental
Protection Agency has identified six criteria air pollutants. These criteria include: Particulate Matter 10 •m (or PM10), PM2.5,
ozone, sulfur dioxide, nitrogen dioxide, carbon monoxide, and lead. In addition to the six criteria air pollutants there are an
identified one hundred eighty-nine potentially harmful air pollutants (or HAPs). The HAPs include metals, gases, other
particles and vapours. Most pollutants are created as a result of human activity; Table 1 illustrates the common sources of
air pollutants. Further discussion of some specific pollutants will occur later in this paper.
Sources of Green House Gas Emissions
Energy &
81%
transportation
Energy Industry
36%
Transportation
26%
Residential,
Commercial,
Institutional
Manufacturing
Industrial
Agriculture
Waste, Deforestation and Other
11%
8%
7%
8%
4%
Table 1: Common Sources of Emissions
Chronicle Herald July 24, 2001
Smog warning issued for Nova Scotians
HALIFAX (CP) -- Nova Scotians with lung problems should stay inside until pollution levels drop, Environment Canada warned
Monday. The federal department issued a smog advisory for most of Nova Scotia, saying the air quality forecast for Tuesday is even
worse. "The advisory has been issued for all of the province, except the Eastern Shore and Cape Breton," said Ted McIldoon, a
forecaster with Environment Canada. Health Department spokesman Morris Green said people with respiratory conditions -especially the young and seniors -- should stay indoors and avoid strenuous activity while the smog alert is in effect. Bill VanGorder,
president of the Nova Scotia Lung Association, said people with lung disease need to be concerned about the warning. "Smog irritates
the airways," he said. "When they become irritated they tighten, just like when you get something in your eye and your eye closes.
"When airways tighten, breathing becomes more difficult." One in four Nova Scotians has some form of lung disease. McIldoon said
even people without lung problems could be affected by the polluted air. "People without medical conditions can experience eye
irritation and shortness of breath," he said. Serge Desormeaux, meteorologist with the New Brunswick Weather Centre in Fredericton,
said the smog levels Monday were just above the advisory index. "It's just a borderline warning," he said. "But we are confident some
parts of Nova Scotia will experience high values." He said the smog, created by car exhaust fumes and industrial smoke, originally
drifted in from the Great Lakes region, but a shift in wind patterns is causing New England pollutants to gather here.
Issues in Nova Scotia
Reports like the one above have become more common over the past few years. Air Quality has become and issue in Nova
Scotia, and Nova Scotia has had air quality events with levels of ozone (smog) and PM2.5 exceeding the national
standards.4 One of the objectives of this paper is to provide information that is relevant to Nova Scotia, this section will
highlight some of the issues specific to Nova Scotia. Environment Canada has identified smog, acid rain, mercury, and
pesticides to be specific air quality issues in Atlantic Canada. The levels of these pollutants are higher than the national
standard. The contributors to the high levels of these substances are both long-range transport from central Canada and the
eastern United States and human activity within our region. It is important to recognize the contribution of human activity in
Nova Scotia, as this is the area where individuals can implement change. According to a 1995 emissions study Nova Scotia
is the third highest producer of particulate matter due to wood burning in Canada.5 Also, Nova Scotia was the highest
producer of sulfur oxides due to non- industrial fuel combustion. Wood is very common in Nova Scotia as a method of
heating homes. The burning of wood produces particulate matter such as soot and ash, carbon monoxide, nitrogen oxides,
and hydrocarbons. The amount of these substances produced depends on the amount of burning and the efficiency of the
stove. An older uncertified wood stove can produce as much as 80 grams of smoke per hour, where as the new EPA
certified stoves produce less than 5 grams of smoke per hour.6 Automobile emissions are also a significant source of
pollution in Nova Scotia. Table 2 provides a brief summary of the Air Quality Forecast in Nova Scotia from the 2002
summer. There were 4 days in Nova Scotia from July - September with a poor air quality forecast. Southwestern Nova
Scotia, represented in part by the Alyesford Mountain monitoring station had the most fair à poor air quality forecasts in the
summer of 2002. Southwestern Nova Scotia, is upwind of major provincial emission sources thought to be the major source
of the poor air quality.4 Southwestern Nova Scotia routinely has the highest ozone levels in the province, which includes
elevations in particulate matter as well. Ironically the region with the poorest air quality is also the region home to Kejimkujik
National Park. In Halifax, the major pollutant tends to be particulate matter. In a 2001 report it was estimated that the levels
of PM2.5 needed to be decreased by 10% to reach the national standards. The major source of particulate matter in the
Halifax area is from the burning of oil for power generation, the refinery and institutions.4 Particulate and ozone levels in
industrial Cape Breton rarely exceed the national standards. It is important to note from this sample of data that air quality is
a growing issue in Nova Scotia. Little data is published on the effects of air pollution in Nova Scotia, however recognizing
that the same constituents of pollution are present in Nova Scotia as are in other areas of Canada and the US one can draw
conclusions from studies in other geographic areas to understand the health effects associated with pollution.
Table 2: Summary of Air Quality Forecast during July – September 2002 at Nova Scotia Air Monitoring Stations.
Categories of predicted levels of ground-level ozone (smog); good (0-25), fair (26-50), poor (51-100), very poor (>100). The
recommended standard for ozone in Canada is 65ppb.7 Only forecasts predicting air quality lower than good are shown.
Location
Very Poor Poor
Fair
Halifax
Aylesford
Pictou
Dayton
Sydney
Totals
0
0
0
0
0
0
0
4
0
0
0
4
13
25
16
14
2
70
Health Effects
It is important to understand what the definition of an adverse health effect is. The American Thoracic society has discussed
what defines an adverse health effect: “Where one draws the line to categorize it as an adverse health effect or an action
level between pathophysiologic or physiologic change is probably best left to the individual or the community.” 8 Figure 1
illustrates the varying severity of adverse health effects and the various end points that we can measure. It is important to
note and understand that severe adverse health effects such as mortality and hospital admissions are the tip of the ice burg
and air pollution can cause many health effects that are subtle enough to not warrant seeking medical attention. The ATS
has further described a more scientific definition for adverse health effects as a medically significant physiologic or
pathologic activity as interfering with the normal activity of a person, and episodic respiratory illness, incapacitating illness,
permanent respiratory injury or progressive respiratory dysfunction.
Figure 1: Pyramid of Health Effects of Air Pollution
© Health Canada (http://www.hc-sc.gc.ca/hecs -sesc/air_quality/definitions.htm)
Adapted from Source: Stieb, DM; Pengelly LD,Arron N, Taylor SM, Raizenne M.
Health effects of air pollution in Canada: Expert findings for the Canadian Smog
Advisory Program. Can Respir J 1995;2(3):155-60.
When discussing the adverse health effects of substances it is important to note both those effects that present acutely and
those that are associated with chronic exposure. Often it is difficult to accurately assess the effect of chronic or long-term
exposure on the health of individuals, despite the fact that the data may not always be available, one must remember that
chronic exposure to low level concentrations of potentially damaging and toxic substances can be significant. The degree of
health effect will depend on the duration of exposure and the concentration of the pollution.9 The type of long term health
effect will depend on what the exposure to pollution is and the quantity of exposure.9 There is a wide range of health effects.
Acute effects include symptoms resulting from irritation of the mucous membranes in the eyes, nose and throat; cough,
wheezing and chest tightness; airway hyper-responsiveness; tracheobronchitis; exacerbations of asthma; death in those
with significant cardiopulmonary disease. Chronic effects include long term decreases in lung function, chronic
tracheobronchitis, airway remodeling, and increased susceptibility to chronic lung diseases.10 The common effect of air
pollution is on the respiratory system, and each pollutant carries of risk of adverse health effects due to exposure. In general
air pollution at high levels has been shown to increase the risk of premature death, the results are summarized in Table 3.
Table 3: Summary of Air Pollutants and know health effects
Pollutant
Source
Particulate Matter
Primary Particulate Matter: Natural sources –
fog, dust, smoke
Human activities – Combustion of fossil fuels,
mining & milling, road dust, gaseous emissions
Secondary Particulate Matter:
Results from chemical reactions in the air with
gases and volatile heavy metals
Ground level ozone (O3) Interaction of nitrogen dioxides and volatile organic
compounds in the presence of light.
Formed by the combination of 3 oxygen molecules
SMOG
Nitrogen oxides (eg.
NO2)
Volatile Organic
Compounds
Carbon Monoxide
Sulfur Dioxide
Carbon Dioxide
Effect
Inspirable particulate mater < 10 microns, remains
in air for minutes to hours, and can travel a few
hundred meters to as much as 50km
Respirable Particulate matter < 2.5 microns,
remains in the air for days to weeks and can travel
as far as 800km.
Symptoms of chest tightness, shortness of breath,
cough, wheeze, pulmonary inflammation, declines
in lung function, increases in bronchial hyper
reactivity, exacerbations of allergen induced
asthma. Development of asthma, increased
emergency room visits, increased hospitalizations,
and increased mortality rates.
Effects of ozone exposure last up to 18hrs following
exposure.
1.4% increase in premature death
Chest tightness, difficulty breathing, exacerbations
fumes from cars, trucks, lawnmowers, boat
engines, ATVs and other fuel powered engines, as of asthma (see ground level ozone)
well as, the emissions from manufacturing plants,
dry cleaners and coal or gas-fired power plants.
Combustion of fossil fuel, vehicle emissions, power
generation, oil refineries, wood burning
NO2 can combine with water for form nitric acid
which contributes to acid rain
Natural vegetation (main source) – plants and trees
Human activities: combustion of gasoline, diesel
and fossil fuels; solvents and dry cleaning
chemicals
Causes irritation to the respiratory system results in
coughing, wheezing and shortness of breath.
5.35% increase in premature death
Energy generation, combustion of hydrocarbons
(gasoline)
Combustion of fossil fuels
2.5% increase in premature death
Natural Sources and Human activity
Headache, drowsiness, arrhythmias, coma, death
Combustion and burning of fossil fuels
Carbon Monoxide
*Increases in premature death from
Contribute to the formation of smog and secondary
particulate matter
Eye irritation, shortness of breath, decreased lung
function, inflammatory changes precipitating asthma
1.8% increase in premature death
Drowsiness, coma, death
Ozone and Smog
Smog is a composition of pollutants and particulate matter; the term historically was used to describe a mixture of smoke
and fog. What smog now refers to is a combination of toxic vapors, gases and particles. Ground level ozone is the primary
component of Smog. Ground level ozone is what is measured to provide air quality forecasts. Smog is formed through a
reaction involving nitrogen dioxides and volatile organic acids in the present of heat and sun. Volatile organic acids are
gases and vapours that evaporate easily and quickly. Sulfur dioxide is one of the smog pollutants and is important because
it can persist in the environment when it combines with water to form sulfuric acid, a major constituent of acid rain. The
reaction producing smog depends on weather, time of year, topography, wind speed and direction to urban and industrial
centers. Air quality indexes measure both the levels of ground level ozone and smog and then report days of high risk of
health effects.
Ozone is an unstable gas that can act as an oxidant and causes irritation of mucous membranes and lung tissues.10,11
Acutely, ozone causes decreased respiratory function, cough and chest tightness.11 It is not surprising that most effects can
be noted in individuals who are more physically active outdoors, thus having increased exposure time. It has been
suggested that decreased inspiratory capacity in relation to ozone exposure could be a protective effect and not an adverse
health effect at all, however we know that there is significant inflammation in response to increased ozone levels. Ozone is
the only pollutant that was found to have a significant effect on lung growth measured by changes in FEV1 in a 3 year
cohort study of children.10 Studies have indicated that there is a dose dependent effect of ozone on acute events in children
requiring medical attention. In one study in Atlanta during the Olympics a 42% decrease in asthma acute events in children
was associated with a 28% reduction in ground level ozone attributed to increased public transportation.12. Airway
inflammation is a known result of ozone exposure. At the molecular level it appears that neutrophillic infiltration is the main
cause of the inflammation. A consequence of the airway inflammation is airway remodeling, which can result in the ultimate
effect of decreased in lung growth. Despite this knowledge there doesn’t seem to be a consensus among researchers about
the overall effect of ozone on lung function and health. One of the reasons for this uncertainty is the variable effects that can
result from equal ozone exposure to different groups of individuals, this variation is thought to be due to the differing
sensitivity of individuals to ozone.11 More information is needed to determine the pathophysiology of lung damage due to
ozone exposure.13 What we do know is that the ground level ozone present in smog is associated with adverse health
effects.
Particulate Matter
Particulate matter originates from various sources depending on whether it is fine or coarse. Fine particulate matter refers to
particles that are less than 2.5 •m designated PM2.5 and can be composed of carbon material, nitrates or sulfates, other
compounds or water.14 Coarse particulate matter refers to particles that are 10•m in size designated PM10 and often arises
from mechanical manipulation of hard surfaces and substances. The effect of particles on the respiratory system depends
on the size of the particulate matter. Inspired particulate mater < 10 microns, remains in air for minutes to hours, and can
travel a few hundred meters to as much as 50km. Respirable Particulate matter < 2.5 microns, remains in the air for days to
weeks and can travel as far as 800km. PM2.5 are labeled respirable particles and can penetrate deep in the respiratory
system reaching the alveoli. PM10 are labeled inhallable are taken into the respiratory system but don’t penetrate deep
within the lungs. Particles from a direct source are referred to as primary particles, where as those that form from chemical
reactions with gases is referred to as secondary particulate matter. Particulate Matter has been associated with increased
mortality and morbidity in a variety of studies. A relative risk of 1.015 –1.085 for mortality has been found in studies where
particulate concentrations are 50 •g/m3.11 The interpretation of the health effects associated with particulate matter has
been somewhat controversial due to the fact that particulate matter is composed of a number of pollutants and has a
variable composition in different geographic settings and at different times. However, exposure to some specific substances
can cause significant effects, an example is diesel exhaust, which is known to cause airway leukocyte inflammation and can
precipitate asthma. Increased particulate matter has been associated with respiratory irritation, acute asthma events,
asthma like symptoms and cardiovascular disease. From an analysis of reviews in the literature there does not seem to be a
threshold for PM10 exposure below which there are no adverse effects.13 Adverse outcome associated with PM10 tend to
be more severe in individuals who have pre-existing cardiac or respiratory pathology.15 Additional studies have shown direct
effects of particulate matter PM10 cause a reduction in peak expiratory flow rates in children.16 All cause daily mortality (the
total number of deaths per day) increased by 0·6% (95% CI 0·4–0·8) for each 10 •g/m3 increase in PM10. In some
experiments using concentrated airborne particles no changes in lung function have been associated with exposure.17
Exposure to the PM2.5 is known to bronchospasm, congestions and bronchitis. It has been difficult for studies to identify the
effects of particulate matter on lung function and the health of individuals due to the heterogeneity of particulate matter in
the air and the tendency for smog (and ambient air) to contain a number of different particles at any given time. However,
the literature does show that increases in particulate matter are associated with mortality, exacerbations of asthma and
COPD and admissions of cardiovascular disease.18
Mercury
While the intent of this paper is not to review the literature regarding health effects of mercury a summary of information will
be provided because of its recognized contribution as an air pollutant in Atlantic Canada. Mercury is predominately emitted
into the air from coal-fired power plants. Mercury is an important pollutant, as it can remain suspended in the environment
for more than 30 days. Mercury can be transformed into methylmercury in acidified lakes and during times of elevated
ozone generally in the summer. One particular danger with mercury is that it can bioaccumulate, which is a concern with
populations who are reliant on fish consumption in high mercury level areas. Although mercury is transported through the air
most mercury exposure occurs via absorption from foods. Inhalation of mercury can occur in cases of spills. Mercury is
neurotoxin and can produce central nervous system lesions that can result in paresthesias. Further information on mercury
in air pollution was difficult to find, and levels specific for Nova Scotia were not available.
Populations at Risk
Although the entire population will be exposed to varying levels of air pollution there are groups within the population that
are at a higher risk for serious health effects. It is important to recognize the high-risk groups and direct appropriate
education and interventions at these groups. The groups identified include, children, elderly, and groups with existing
respiratory and cardiovascular diseases. Seniors seem to be at a higher risk for adverse health effects because of increased
prevalence of existing medical conditions such as heart conditions, chronic obstructive pulmonary disease to name a few.
The presence of many medical conditions can affect the capacity of an individual to deal with increased exposure to
pollutants and as a result have a higher likelihood to develop and adverse outcome.
Children are at a higher risk for serious health effects of pollution due to a number of factors. Children’s lungs are not fully
developed and during the time they are continuing to grow they are more susceptible to toxins. Children tend to breath more
rapidly, and exchange more air per kilogram than adults, thus are exposed to higher levels of pollutants. Children tend to
spend more time outside and are more active when they are outside than adults. One of the important risks to children is
precipitation of pre-existing asthma and development of asthma like symptoms.19 Studies have documented dose
dependent adverse health effects in response to ambient air quality in children. In a paper from California a greater effect
was found with PM2.5 than other components of air pollution. However, Gauderman reported that between two different
cohorts differences in effects were noted. Acid vapour was identified as the pollutant that had the most consistent effect on
lung function.20 Consensus agreements state that children in areas of high air pollution will have more adverse health
effects. It is not known if this is due to more frequent and severe acute events or chronic exposure. Particulate air pollution
has been associated with reduced lung function and growth in children.18 In studies comparing school absenteeism due to
respiratory illness to levels of air pollution, significant association have been found, increased absences from school due to
sore throats, coughs and acute asthma events paralleled rises in ozone, or smog, levels.20 For an increase in concentration
of 20 parts per billion, a common day-to-day variation in highly-polluted Southern California, absenteeism for respiratory
causes jumped 83 percent.
For the individuals at a higher risk for developing adverse health effects, minimizing exposure to air pollution on days where
levels are high is recommended.
Asthma
Example of time-series study demonstrating a relationship between ozone and acute asthma
events
Asthma is one of the most common outcomes of air pollution, it is important to understand the relationship between
pollutants and acute asthma events. The study discussed here was chosen because of it new data and unique
demonstration of the effects of variations of air quality within one region on events related to asthma exacerbations.
Disproportionate increases in emissions have occurred in the past few decades due to increased combustion of fossil fuels
in automobiles. Atlanta Georgia routinely has ozone levels higher than air quality standards during the summer months. A
study published in JAMA in 2001 measured changes in air pollution, metrological conditions and the amount of vehicular
traffic in addition to adverse health effects outcomes such as hospitalizations, emergency department visits, and urgent care
center visits for asthma during time various time frames. The study concluded that the alternative transportation plan in
Atlanta during the Olympic Games reduced ozone and other air pollutants and was associated with a significant, but
temporary, decrease in the acute events of asthma among Atlanta’s children.21 The study looked at the differences in the
two time frames and assumed that the Olympics occurred during a time point when there would be dramatic changes in
population and vehicular traffic. This study took advantage of the unique opportunity to study the changes in health
outcomes that occurred during the changes in emissions. Data on air quality was collected on primary pollutants: PM10,
carbon monoxide, nitrogen dioxide, sulfur dioxide, and secondary pollutants: ozone. Information was collected on
meteorological data (temperature, wind speed, relative humidity, barometric pressure and solar radiation), hourly traffic
counts, Public transportation usage, and gasoline use. Univariate and multivariate methods were used to analyze the data
and the Olympic period was compared to the baseline period. There was a reduction in gasoline use, peak traffic counts by
22.5%, and a greater than 200% increase in the use of public transportation. A reduction of 28% in ozone levels was
measured and was correlated with a drop in asthma events ranging from 11% - 44%. This study demonstrated that
reductions in ozone and PM10 below air quality standards could reduce adverse health effects when using the example of
asthma morbidity in children. It did not seem that there were significant changes in the population of children in Atlanta
during the time of this study to account for the reduction in asthma events. A weakness of the study design was the in
ability to determine the role of other pollutants in the reduction of asthma events. This study supports recommendations for
reductions in automobile emissions through changes in commuting habits.
Conclusions
Nearly 8% of non-accidental deaths in Canada can be attributed to pollution produced from the burning of fossil fuels. During times of
poor air quality hospital admissions for respiratory illnesses are increased by nearly 6%. Air quality does have a direct effect on human
health. Populations identified at a higher risk are children, elderly persons and individuals with pre-existing medical condition. The effects
of Air Pollution on health is a huge topic, the information provided in this paper only scratches the surface of the wealth of
knowledge available. I hope that the information presented here can be used to educate the public and professionals about
air quality issues in Nova Scotia and provide some direction to get more information when needed. Data collection specific
for Nova Scotia was difficult to accomplish. There is a need for published yearly reports of air quality monitoring. These
reports should focus on trends in the air quality and trend in health of the people in Nova Scotia, hospital admissions, acute
respiratory events and deaths should be reported on when there appears to be a link. There is a abundance of primary
literature focusing on the health effects of air pollution, it seems that now the next step would be to find dose relationships
between the health effects and the levels of pollutants. It would also be useful to have more information investigating the
pathophysiology of the effects of many of the common pollutants, so that the biological cause of health effects can be
understood and agreed upon. There have been many papers published that study the Epidemiology of air pollution and
health, the gap in the knowledge now seems to be a clear understanding of the underlying Pathophysiology. Another issue
with the scientific knowledge is the differences between using ambient air quality instead of levels of specific toxins. Both
methodologies have advantages and disadvantages. Mounting epidemiological data has shown that air pollution causes
adverse health effects, but this has not yet been supported by laboratory or other efforts to understand the underlying
pathophysiology.18 There have not been uniformly accepted threshold levels below which exists no effect on health for
many of the air pollutants. There have been some threshold levels set but these have not been agreed upon. Threshold
levels for safe levels of exposure need to be determined to enable us to institute changes at the government levels. There
needs to be investigation and documentation of attempts and successes to decrease air pollution and emissions with an
associated impact on the health of individuals where this is possible. We need data to support the recommendations for
reductions in emissions as having a positive impact on individual’s health.
Solutions
It has been well recognized that while individuals can to little to reduce air pollution generated that enters Nova Scotia via
long range transport it is important that every person do there part in terms of reducing emissions. There are many things
that an individual can do to limit their exposure pollution. Simple strategies include limiting time spent outdoors on days with
warnings and limiting strenuous exercise on days with known increases in pollution. Individuals with known lung disease
aggravated by increase in pollution may be able adjust the levels of medications that prevent or relieve acute events.
Environment Canada has suggested a list of activities that individuals can do to decrease emission levels. The suggestions
include:
●
●
●
●
●
●
●
●
●
Reduce air conditioning demands in summer by installing window blinds, using ceiling fans and shading your house
with trees or awnings.
Keep your oil or gas furnace properly tuned. A well-maintained unit uses 10 to 15 per cent less energy. Consider
replacing old furnaces with a high-efficiency model.
When shopping for new appliances, compare EnerGuide consumption rates and choose the one that is most
efficient. Even if it's more expensive initially, it will cost less in the long run.
Wood stoves are available with anti-pollution devices. Choose one of these if you are buying a new wood stove.
When shopping for a new home, keep energy efficiency in mind. What are the levels of insulation? How efficient is
the heating system? Are the windows the best available for reducing heat loss?
Remember there can be pollution from lawn mowers, snow blowers and outboard motors. Look for low-emission
engines.
Buying new lights? Consider using energy-efficient lighting. Fluorescent bulbs for use in standard incandescent
sockets are now available and are more than four times as efficient, and last eight to fifteen times longer than the
equivalent incandescent bulb.
Don't idle your car engine. Turn it off, even if it's just for a few minutes.
Try walking, biking or in-line skating rather than taking your car.
Summary
In recent years there has been intense study into the effects of air pollution on human health. Studies documenting
exposure to pollutants such as particulate matter and ozone (smog) have demonstrated increases in mortality and hospital
admissions due to respiratory and cardiovascular disease. Adverse health effects have been documented for day-to-day
variations and in long-term studies that have followed cohorts of exposed individuals over time. A threshold for levels of
exposure has not been adequately documented.
●
●
●
●
Air pollution is composed of ground-level ozone, particulate matter in varying sizes, carbon monoxide, nitrogen
oxides, and sulfur dioxides. Smog is a composition of pollutants and particulate matter and is often used
interchangeably with air pollution.
The air quality index is a measure of 6 common pollutants (Particulate Matter 10 •m (or PM10), PM2.5, ozone, sulfur
dioxide, nitrogen dioxide, carbon monoxide, and lead), but often tends to be a major reflection of smog
Air pollution causes a significant number of deaths and adverse health effects in Canada each year.
Acute effects of air pollution include: irritation of eyes, nose and throat; exacerbations of existing lung and heart
diseases, wheezing, coughing and difficulty breathing. Particulate matter has been associated with increased risk of
heart disease.
●
Chronic effects include increased mortality, chronic bronchitis, lung cancer, prevalence of asthma,
●
The health effects of chronic long-term exposure to low levels of pollution is controversial
It is important for each individual to reduce emission in their own life as this can help to decrease the effects of air
pollution on their health and the health of their community.
In Nova Scotia
●
•
•
•
Nova Scotia has had levels of ozone and PM2.5 that exceed the National Standards.
Air Quality Issues in Nova Scotia are: smog, acid rain, mercury, and pesticides.
Nova Scotia is the third highest producer of particulate matter due to wood burning in Canada. Wood burning
Summary of Air Pollutants and know health effects
Pollutant
Particulate Matter
Ground level ozone (O3)
Source
Primary Particulate Matter: Natural sources
– fog, dust, smoke
Human activities – Combustion of fossil
fuels, mining & milling, road dust, gaseous
emissions
Secondary Particulate Matter:
Results from chemical reactions in the air
with gases and volatile heavy metals
Interaction of nitrogen dioxides and volatile
organic compounds in the presence of light.
Formed by the combination of 3 oxygen
molecules
Effect
Inspirable particulate mater < 10 microns, remains in
air for minutes to hours, and can travel a few
hundred meters to as much as 50km
Respirable Particulate matter < 2.5 microns, remains
in the air for days to weeks and can travel as far as
800km.
Symptoms of chest tightness, shortness of breath,
cough, wheeze, pulmonary inflammation, declines in
lung function, increases in bronchial hyper reactivity,
exacerbations of allergen induced asthma.
Development of asthma, increased emergency room
visits, increased hospitalizations, and increased
mortality rates.
Effects of ozone exposure last up to 18hrs following
exposure.
1.4% increase in premature death
SMOG
fumes from cars, trucks, lawnmowers, boat See ground level ozone
engines, ATVs and other fuel powered
engines, as well as, the emissions from
manufacturing plants, dry cleaners and coal
or gas-fired power plants.
Nitrogen oxides (eg. NO2) Combustion of fossil fuel, vehicle emissions, Causes irritation to the respiratory system results in
power generation, oil refineries, wood burning coughing, wheezing and shortness of breath.
NO2 can combine with water for form nitric
5.35% increase in premature death
acid which contributes to acid rain
Volatile Organic Compounds Natural vegetation (main source) – plants
Contribute to the formation of smog and secondary
and trees
particulate matter
Human activities: combustion of gasoline,
diesel and fossil fuels; solvents and dry
cleaning chemicals
Carbon Monoxide
Sulfur Dioxide
Carbon Dioxide
Carbon Monoxide
Energy generation, combustion of
hydrocarbons (gasoline)
Combustion of fossil fuels
Natural Sources and Human activity
Combustion and burning of fossil fuels
*Increases in premature death from
2.5% increase in premature death
Eye irritation, shortness of breath, decreased lung
function, inflammatory changes precipitating asthma
1.8% increase in premature death
Headache, drowsiness, arrhythmias, coma, death
Drowsiness, coma, death
Appendix A – Additional Website Resources
Appendix b – Pub Med Search
Search
Most Recent Queries
#35 Related Articles for PubMed (Select 12512164)
Time
Result
114
20:05:23
#33 Related Articles for PubMed (Select 12000251)
20:03:55
1016
#30 Search #26 AND Management
20:00:30
23
#27 Search #26 AND #2
19:58:18
14
#26 Search Outdoor Air Pollution
19:56:59
795
#25 Search #24 AND #2
19:56:31
1
#24 Search Effect of outdoor air pollution
19:56:08
120
#23 Search Effect of out door air pollution
19:55:56
0
#12 Search #2 AND #3 AND #4
19:54:20
33
#22 Search #5 AND #2 AND #4
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2078
#21 Search #5 AND #2
19:53:52
31567
#20 Search #5 AND #2 AND #3
19:53:44
551
#18 Search #5 AND #1 AND #3
19:53:24
6
#10 Search #1 AND #3
19:53:05
6
#19 Search #4 AND #1 AND #3
19:52:45
0
#17 Search #5 AND #1
19:52:14
689
#16 Search #6 AND #1
19:52:06
3
#15 Search #3 AND #6 AND #1
19:51:57
0
#14 Search #3 AND #6 AND #2
19:51:38
23
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19:49:45
1145
#11 Search #2 AND #3
19:49:08
551
#9 Search #1 AND #2
19:48:35
1223
#6 Search "Environmental Health"[MESH]
19:45:37
12743
#5 Search "Environment and Public Health"[MESH]
19:45:10 2869488
#4 Search "Health"[MESH]
19:44:46 114950
#3 Search "Air Pollution"[MESH]
19:44:30
35972
#2 Search Canada
19:44:19
70461
#1 Search Nova Scotia
19:44:13
1335
Sample of search results
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Exposure and respiratory health in farming in temperate zones--a review of the
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Vincent R, Radon K.
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