Non-exhaust particles
Mats Gustafsson, PhD
VTI
Swedish National Road and
Transport Research Institute
VTI is an independent and
internationally prominent research
institute within the transport sector
Head office in Linköping
Non-exhaust particles…
B. Denby, NILU, 2011
R&D focus regarding non-exhaust PM at VTI
• Wear particles from interaction pavement/tire
• Road dust (suspension/re-suspension)
• Studded tires, winter operation
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Processes and emissions
Particle properties
Abatement techniques and strategies
Toxicology
Road dust sampling techniques
• Wear particles from rail traffic
The VTI road simulator (”TRWP generator”)
4 wheels with electric
motors
exchangable pavement
Temperature controlled hall
The VTI road simulator (”TRWP generator”)
• Effects of tyre and pavement properties on particle
generation and properties
• PM concentrations (relative comparison)
• Size distributions
• Bulk or size fractionated sampling for analyses of
chemical and physical properties
• Sampling for toxicological studies
0
Influence of tyre type on direct PM10
emission
6
Studded tyre
Friction tyre (non-studde winter tyre)
Summer tyre
5
Studded winter
tyres
PM10 [mg m-3]
4
30
km/h
3
50
km/h
70
km/h
Non-studded
Nordic winter tyres
2
Summer tyres
1
0
12:00
11:00
12:00
13:00
13:00
14:00
15:00 15:00
16:00
17:00 16:00
18:00
14:00
Time [hh:mm]
Time [hh:mm]
19:00
17:00
18:00
Influence of rock material in same pavement construction
worn by studded tyres
Particle size distributions
2.5
Bridegstone Noranza
Michelin X-Ice North
Nokian Hakkapeliitta 4
2
70 km h
50 km h-1
30 km h-1
-1
60000
1.5
40000
1
20000
0.5
0
0
0.01
0.1
1
Size distribution (µm)
10
Mass concentration (dM/dlogDp [mg m-3])
Number conscentration (dN/dlogDp [# cm-3])
80000
Particle size distributions
0.014
Michelin Energy
AGI Proline
Nokian NRHi ecosport
Bridgestone Turanza
1200
-1
70 km h
50 km h-1
30 km h-1
0.012
1000
0.01
800
0.008
600
0.006
400
0.004
200
0.002
0
0
0.01
0.1
1
Size distribution (µm)
10
Mass concentration (dM/dlogDp [mg m-3])
Number concentration (dN/dlogDp [# cm-3])
1400
PM10 from summer tires - elemental composition
10 000
10 000
Si
S
1 000
Cl
K
100
Ca
10
Ti
Fe
1
Concentration (ng/m3)
Concentration (ng/m3)
Si
S
1 000
Cl
K
100
Ca
10
Ti
Fe
1
Cu
Cu
0
0,01
Zn
0,1
1
0
0,01
10
Zn
1
0,1
10
Particle size (µm)
Particle size (µm)
100%
100%
Zn
Zn
Cu
Fe
Ti
60%
Ca
40%
K
Cl
20%
Fe
Ca
40%
K
Cl
20%
S
Si
Si
0%
0,04 0,08 0,14 0,21 0,32 0,51 0,81 1,26 2,00 3,32 5,47 8,25
0,04 0,08 0,14 0,21 0,32 0,51 0,81 1,26 2,00 3,32 5,47 8,25
Particle size (µm)
Particle size (µm)
100%
100%
Zn
Zn
Cu
80%
ution
on
Ti
60%
S
0%
80%
Cu
80%
Relative contribution
Relative contribution
80%
Cu
Fe
Measurements of road dust load with wet dust
sampler (WDS)
Road dust load (<180µm) over 2 winter seasons
in some Stockholm streets
Aims:
investigate how rock
properties affect particle
emissions
investigate toxicity of
particles from pavement and
brake wear PM in relation to
particle properties
The NORTRIP model
Aim:
to gather all relevant information
on non-exhaust emission
processes into a tool for air quality
prediction, planning and
understanding
Denby et al. Atmospheric
Environment 77 (2013) 283-300
Denby et al. Atmospheric
Environment 81 (2013) 485-503
Example: Hornsgatan, Stockholm
Bruce Denby & Ingrid Sundvor, NILU
Some on-going activities on non-exhaust PM in
Scandinavia
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NRG – Nordic Road dust Group (authorities and researchers)
NORTRIP II planning
Finnish REDUST project (Life+) “best practises for road dust mitigation”
Railroad and road tunnel particle emissions
Sweeping technologies and strategies
Stockholm mitigation trials
Alternative pavement projects (concrete, cinder/slag)
Pavement grinding project
Modelling residual salt (MORS I & II) – road moisture modelling input!
WearTox II (toxicity of wear dust from pavements and brakes)
…and more.
Research needs
Recent workshops
Workshop in Amsterdam in 2011
van der Gon et al., 2011
Workshop in Barcelona in 2013
Amato et al., 2014 (in progress)
Health effects (van der Gon et al. 2013 +…)
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More toxicological and epidemiological evidence is needed to identify the urgency of tackling
wear emissions and guide policymakers. Proper toxicity comparison expressed in comparable units
between exhaust and non-exhaust (different sources) is crucial information but currently lacking.
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A standardized approach to assess hazard of, and exposure to, wear emissions in Europe is
needed to compare results from the various studies.
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To be able to define effective and necessary future policies we need to create (research)
opportunities to assess the health impact of wear particles so as to put this in the perspective
of cost effective abatement measures.
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Analytical methods to properly disentangle the PM of wear sources from other PM fractions
are warranted, for example, by use of appropriate markers to allow source apportionment.
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Within the mixture of wear PM, different fractions can be identified for which the hazard is not clear.
Simple measures such as chemical reactivity (redox or oxidative potential) may provide insights
into both the chemical composition as well as the hazard of various (sources of) wear particles.
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Need for both ”clean” sources and controlled mixed sources as well as real world aerosols in
toxicological studies
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Need for more endpoints in advanced cell exposure techniques and human inhalation studies
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Understanding of mechanisms
Sources
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Little data on all aspects of road wear PM Large differences in properties of suitable rocks
and pavement constructions across Europe as well as wear conditions (climate, traffic,
road operation).
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Tire wear particle probably the most variable in physical and chemical properties
depending on driving conditions, climate, type of tire etc. More data needed.
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Brake wear higher percentage of fine PM. Large variability in content. Generally high
content of metals. More data needed.
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Suspension/resuspension of road dust important and complicated process. More data
needed on:
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road dust source contribution and geographical/climatological differences
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Interaction between road surface texture – moisture – chemistry – dust load
– dust emission
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effects on suspension/resuspension of road surface properties, state, road
operation and traffic
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parameters needed for better emission modelling
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Road dust measurements – techniques and how to use results in modelling
Modelling: need for data supporting process modelling including influence of road
operation measures (NORTRIP model)
Mitigation
• Materials
• Tires – ongoing work with reducing wear and
particle emissions form studded tires
• Brake wear?
• Road wear – Nordic countries. Europe?
• Road operation – techniques, strategies and optimization
• What are the optimal mitigation techniques and strategies?
• How can winter road operation measures interact with dust
mitigation measures in strategies?
• Mitigation policies and health effects
“Work plan and structure of an expert group”
Aim of expert group?
Work plan
• Compile working groups, e.g.
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Primary sources (direct emissions) – emissions,
contribution to road dust, variability, properties,
toxicology
Road dust (suspension/resuspension) – amount and
composition variability in space and time, factors
influencing emissions, toxicology
Health effects
Measurements – sampling techniques, tracers
Abatement
Etc…
“Work plan and structure of an expert group”
Structure
Working groups with participants from all diciplines
and different geographical/climatological situations.
• Network of non-exhaust particle scientists have
met in two European workshops.
• Nordic network in NORTRIP projects and NRG
(Nordic Road dust Group)
• Work is on-going on research application NorDust
for the NordFoU (Nordic Road Authorities
research collaboration)
• Large research needs identified
• Horizon 2020 possibilities?
Contact:
[email protected]
Reports and info at:
www.vti.se