wear particles from road traffic – the nordic experience€¦ · the nordic situation snowy and...
TRANSCRIPT
Non-exhaust particles
from road traffic – the
Nordic experience
Mats Gustafsson, Ph.D.
Photo: Göran Blomqvist
Outline
• The Nordic situation
• Main sources
• Factors influencing suspension from road surface
• Mitigation
• NORTRIP model
• Knowledge gaps
• Conclusions
The Nordic situation
Snowy and icy roads in winter (October-March)
• Studded winter tyres used in Norway, Sweden and Finland
• Winter road operation with sand and salt
MAIN PARTICLE SOURCES
Main PM10 emission sources
1. pavement wear affected by tyre and pavement properties
2. winter operation affected by use and properties of traction
sanding
3. brake and tyre wear minor sources during the problematic
season (late winter - early spring)
Influence of tyre type on direct PM10
emission
11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00Time [hh:mm]
Studded tyre
Friction tyre (non-studde winter tyre)
Summer tyre
0
1
2
3
4
5
6
PM
10 [m
g m
-3]
30
km/h
50
km/h
70
km/h
Studded winter
tyres
Non-studded
Nordic winter tyres
Summer tyres
11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00Time [hh:mm]
Studded tyre
Friction tyre (non-studde winter tyre)
Summer tyre
0
1
2
3
4
5
6
PM
10 [m
g m
-3]
Stud
ded
tyre share (%
)
Figure: Michael Norman, SLB-Analys, Stockholm
PM10 and studded tyre use in tunnel, Stockholm
Road pavement properties affecting direct PM10
emissions from studded tyre wear
Pavement property Influence on direct emission
Construction No comparable tests. Focus on the most
durable SMA type.
Maximum stone size (Dmax) Higher Dmax results in lower emissions
Rock wear resistance Higher wear resistance results in lower
emissions
Alt 1.: Rubber mixed asphalt Slightly lower emissions than reference
asphalt
Alt. 2.: Porous asphalt No effects yet assigned to the construction.
Low emission, but assigned to more
durable rock
Alt. 3.: Concrete Higher direct emissions than reference
asphalt, but lower total wear.
Lower total emission in reality?
Winter road sanding affects direct and
suspended PM10 emission
Kupiainen et al., 2011, KAPU-project
Uncertainties regarding sources
• The contribution from pavement wear and sand as
well as the interaction (sand wearing pavement)
and its variation in time and space.
• Results from NASTA project (Finland) show that
about 50 % comes from pavement and 25 % from
sand. One street and one sand material in one
season.
FACTORS INFLUENCING
SUSPENTION FROM ROAD
SURFACE
Road surface moisture rules PM10 emission from
road surface Hornsgatan v 12 2008
0
100
200
300
2008-03-13
00:00
2008-03-14
00:00
2008-03-15
00:00
2008-03-16
00:00
2008-03-17
00:00
2008-03-18
00:00
2008-03-19
00:00
Datum
PM
10,
µg
/m3
0
3
6
9
PM10
Vägfukt
Humid Humid Humid
Dry Dry Dry
Christer Johansson, SLB-analys
Winter road salting affects surface humidity
Pavement surface texture influences dust load
0
20
40
60
80
100
120
140
1 1.2 1.4 1.6 1.8 2
DL<
18
0 (
g/m
2)
MTD (mm)
Hjulspår
111021
111220
120302
120316
120413
120525
0
20
40
60
80
100
120
140
0.5 1 1.5 2 2.5
DL<
18
0 (
g/m
2)
MTD (mm)
Mellan hjulspår
111021
111220
120302
120316
120413
120525
Road dust in wheel track
Texture histograms of some Stockholm streets
Traffic?
Direct emission
• Traffic amount and composition
• Studded tyre frequency
• Speed – emission: linear relationship (studded
tyres)
Suspension
• Traffic amount and composition
• Speed
MITIGATION
Mitigation of PM10
1. Minimize the sources
a. Improve wear properties of materials
b. Reduce the wear potential of traffic
2. Minimize suspension to air
a. Remove dust from road surface (sweeping, vacuuming)
b. Bind dust to road surface (dust binding)
c. Adjust traffic (less traffic, lower speed, less heavy vehicles)
3. Optimized strategies combining 1 and 2
Used measures for PM10 mitigation
Measure Norway Sweden Finland
Reduce
studded tyres
Fees in cities
since 2000
Prohibition in
certain streets
since 2010
-
Improved
pavements
Improved since
the 90ies
Tested in
Norrköping
-
Improved sand
material
- - Tests in Helsinki
Dust binding MgCl2 MgCl2, CMA CaCl2
Sweeping/
vacuuming
In combination
with dust
binding
Tests in some
larger cities
Ambitious winter sand
removal. Tests within
KAPU and REDUST
projects
Speed
reductions
Environmental
speed limits
Tests -
Example: mitigation in Stockholm 2011-2012
• Two streets normal operation PLUS treated with
dust binder (CMA), an advanced street scrubber
(high pressure water cleaning, vacuuming and
sweeping) and water flushing.
• Two streets normal operation (references)
Accumulated number of days above 50 µg/m3 PM10
Treated street Hornsgatan
Treated street Sveavägen
Reference street
Folkungagatan
Reference street
Norrlandsgatan
2012
2012
}
} 2012 2009-2011 }
2012 2009-2011 }
Christer Johansson SLB-analys, Stockholm
Acc. num
ber
of
exceedances
2009-2011
2009-2011
Are the Nordic countries reaching limit values?
• Norway – yes, for the last 6 years
• Finland – yes (are using the possibility to subtract
winter sanding/salting events)
• Sweden – no. 2012 was first time ok in Stockholm,
but 2013 looks bad
Seasonal meteorology very important for the
possibilities not to exceed limit values.
Mitigation combination and strategies important for
success.
THE NORTRIP MODEL NON-EXHAUST ROAD TRAFFIC INDUCED PARTICLE
EMISSION MODELLING
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
Part II recently submitted
The NORTRIP model concept
Surface moisture conditions
Salting
Wearroad, brake and tyre
Sanding
Cle
anin
g
Freezing temperature
Meteorological conditionsParticles
TSPPM10
PM2.5
Deposition
Dra
inag
e
Sand abrasion
Retainedwear
Road surface
Dra
inag
e
Spra
ySp
ray
Plo
ugh
ing
Plo
ugh
ing
Pre
cip
itat
ion
Vapour pressure:
evaporation
Sand crushing
Wetting
Direct
emissions
Surface retention
Temperature, humidity and radiation
Energy balance
Evap
ora
tio
n
con
den
sati
on
Salt
Traf
fic
turb
ule
nce
an
d h
eat
flu
x
Tra
ffic
su
sp
en
sio
n
Win
d s
usp
en
sio
nBruce Denby & Ingrid Sundvor, NILU
Example: Hornsgatan, Stockholm
Bruce Denby & Ingrid Sundvor, NILU
KNOWLEDGE GAPS
Some important knowledge gaps
• How do the wear and winter sand sources
contribute, interact and vary over space and time?
• Interaction between road surface texture –
moisture – chemistry – dust load – dust emission
• Mitigation
• What are the optimal mitigation techniques and
strategies?
• How can winter road operation measures interact
with dust mitigation measures in strategies?
• Modelling: need for data supporting process
modelling including influence of road operation
measures
Conclusions
• Focus on road wear, road operation and
suspension processes
• Sources and processes rather well known but still
lack of data supporting relationships between
influencing factors and emissions
• Mitigation partly successful, but optimized
strategies are missing
• Model NORTRIP promising, but needs further
development
On-going activities
• 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)
• 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.
Thanks for your attention!
Contact: [email protected]
Thanks for your attention!
Contact: [email protected]
Sweeping technologies and strategies
• Street tests
• Controlled tests
• Techniques?
• Strategies – combine sweeping
with other abatement methods
• When, where and how?
EU limit values for PM10 in 2005
Choice of PM10 for the directive means:
• the coarser the particles (within PM10), the more
important for limit values and
• the more effective to mitigate to reach limit values
• Especially important where sources to coarse
fractions of PM10 are strong.
Evaluation of road dust measures in Stockholm
Texture (Sand patch)
RST
PM10 emission from and road dust on concrete
pavement
Asphalt Concrete
Health
• Toxicology show at least as high inflammatory
potential from road wear PM10 as from diesel
particles (Gustafsson et al., 2008)
• Epidemiology show that coarse fraction (PM10-2.5)
in Stockholm has a significant effect on daily
mortality (1.7% per 10 µg/m3) (Meister et al., 2012)
• No reasons NOT to abate the coarse fraction.
0
10
20
30
40
50
60
70
80
Kontroll PM 1 PM 2 PM 3 PM 4 PM 5 PM 6
TN
F-α
pg
/ml
x 1
04 c
ell
s
Inflam
mation p
ote
ntial
PM10 from
granite pavement
PM10 from
quartzite
pavement
PM10 from
Hornsgatan
PM10
from
subway
Diesel particles
Cell studies
Control
Road pavement properties affecting direct PM10
emissions from studded tyre wear
Pavement property Influence on direct emission
Construction No comparable tests. Focus on the most
durable SMA type.
Maximum stone size (Dmax) Lower Dmax results in higher emissions
Rock wear resistance Less wear resistance results in higher
emissions
Alt 1.: Rubber mixed asphalt Slightly lower emissions than reference
asphalt
Alt. 2.: Porous asphalt No effects yet assigned to the construction.
Low emission, but assigned to more
durable rock
Alt. 3.: Concrete Higher direct emissions than reference
asphalt, but lower total wear.
Lower total emission in reality?
Influence of rock material in same pavement construction
worn by studded tyres
Largest stone size (Dmax) and PM
600
500
400
300
200
100
Ef (m
g/f
km
) Rock material properties relates to PM10
emissions
Nordic ball mill value
(wear properties)
0
2
4
6
8
10
12
14
16
18
SMA pavementwith durable rock
Central EuropeanAC diorite
Central EuropeanAC limestone
No
rmal
ize
d c
Pavement type
Studded winter tyres
Studded tyres at 50 km/h on Nordic and C-
European pavements
Non-studded tyres at 50 km/h on Nordic and C-
European pavements
0
1
2
3
4
5
6
7
8
9
10
11
SMA pavementwith durable rock
Central EuropeanAC diorite
Central EuropeanAC limestone
No
rmal
ize
d c
Pavement type
Summer tyres
Nordic winter tyres
C-European winter tyres
Dust binding in Nordic cities
Trondheim
Oslo
Gothenburg Linköping
Norrköping
Stockholm Helsinki
MgCl2
CMA
Sugar
CMA/salt
CMA
MgCl2
CMA
CaCl2
+ Austria, the Netherlands, Germany, UK…
Aims:
Investigate what micro-textural properties within
stone material that affect formation of inhalable
particles and to
investigate the toxicity in airways of coarse and fine
pavement wear particles in relation to physical,
chemical and morphological particle properties.
RIVM finances the addition of brake wear particles
to the study
WearTox II
Influence of tyre type (limestone pavement)
Influence of tyre type (limestone pavement)
Influence of tyre type (diorite pavement)
Influence of tyre type (diorite pavement)
Evaluation of road dust measures in Stockholm
WDS
Effect of measures on PM10 on Hornsgatan
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
2009/2010 2010/2011 2011/2012 2011/2012 städning
2011/2012 spolning
2011/2012 CMA
Vägdammsdagar
Förhållande Ho/Fo
Road dust days (dry conditions)
Ratio treated/non-treated street
Sweeping Flushing Dust
binding
CMA
Previous seasons and non-
treated
Road dust (DL<180 µm) on streets
Ions on street surface (Hornsgatan)
0
2
4
6
8
10
12
14
16
18
2011-10-21 2011-12-20 2012-03-02 2012-03-02 2012-03-16 2012-03-16 2012-04-13 2012-05-25
Män
gd (
g/m
2)
Cl
NO3-N
SO4-S
Ca
Mg
Na
K
Fo
Ac
PM10 emission from and road dust on concrete
pavement
Asphalt Concrete
The NORTRIP model concept
Surface moisture conditions
Salting
Wear road, brake and tyre
Sanding
Cle
an
ing
Freezing
temperature
Meteorological conditions
Particles
TSP
PM10 PM2.
5
Deposition
Dra
ina
ge
Sand abrasion
Retained wear
Road surface
Dra
ina
ge
Sp
ray
Sp
ray
Plo
ugh
ing
Plo
ugh
ing
Pre
cip
ita
tio
n
Vapour
pressure:
evaporation
Sand
crushing
Wetting
Direct
emissions
Surface retention
Temperature, humidity
and radiation
Energy
balance
Eva
po
ratio
n
co
nd
ensation
Sa
lt
Tra
ffic
tu
rbu
lence
an
d h
ea
t flu
x
Tra
ffic
su
sp
en
sio
n
Win
d s
usp
en
sio
n
Bruce Denby & Ingrid Sundvor, NILU
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May0
200
400
600
Hornsgatan 2010-2011: Emissions and mass balance
Em
issio
n (
g/k
m/h
r)
Date
Total
Direct dust
Direct sand
Suspended
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May0
50
100
150
Mass lo
adin
g (
g/m
2 )
Date
Suspendable dust
Road salt(Na)
Dissolv ed salt(Na)
Suspendable sand
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May0
100
200
300
400
Mass lo
adin
g (
g/m
2 )Date
Non-suspendable sand
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May-2000
-1000
0
1000
2000
Rate
s (
g/k
m/h
r)
Date
Road dust production
Road dust sink
Production and sinks of road dust
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May0
200
400
600
Hornsgatan 2010-2011: Emissions and mass balanceE
mis
sio
n (
g/k
m/h
r)
Date
Total
Direct dust
Direct sand
Suspended
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May0
50
100
150
Mass lo
adin
g (
g/m
2)
Date
Suspendable dust
Road salt(Na)
Dissolv ed salt(Na)
Suspendable sand
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May0
100
200
300
400
Mass lo
adin
g (
g/m
2)
Date
Non-suspendable sand
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May-2000
-1000
0
1000
2000
Rate
s (
g/k
m/h
r)
Date
Road dust production
Road dust sink
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May0
500
1000
1500
Hornsgatan 2010-2011: Traffic
Traf
fic v
olum
e (v
eh/h
r)
Date
Total
Light
Heav y
Light studed
Light winter
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May25
30
35
40
45
50
Traf
fic s
peed
(km
/hr)
Date
Light
Heav y
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May0
0.5
1
1.5
2
2.5
Saltin
g/sa
nding
(g/m
2 )
Date
Sanding/10
Salting(Na)
Salting(Mg)
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May0
200
400
600
Hornsgatan 2010-2011: Emissions and mass balance
Em
issio
n (
g/k
m/h
r)
Date
Total
Direct dust
Direct sand
Suspended
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May0
50
100
150
Mass lo
adin
g (
g/m
2)
Date
Suspendable dust
Road salt(Na)
Dissolv ed salt(Na)
Suspendable sand
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May0
100
200
300
400
Mass lo
adin
g (
g/m
2)
Date
Non-suspendable sand
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May-2000
-1000
0
1000
2000
Rate
s (
g/k
m/h
r)
Date
Road dust production
Road dust sink
Example of NORTRIP model application Studded tyre season
Sanding and salting events
Wet surface retention
Road wear dust loading Suspendable
sand Salt
Dry surface suspension
Direct and suspended emission
Bruce Denby & Ingrid Sundvor, NILU
Examples: HCAB, Copenhagen
Bruce Denby & Ingrid Sundvor, NILU
Winter operation strategies for minimized PM
emissions
Normal winter operation, Southern Sweden
Winter
Studded tires
Salting NaCl
Gritting
AprilOctober November December January February March
Example of alternative strategy
Winter
Studded tires
Salting MgCl2 or CaCl2
Gritting
Dust binding
and anti-icing CMA
March AprilOctober November December January February
Relative differences at 50 km/h
1
10
100
1000
10000
100000
SMA pavementwith durable rock
AC diorite AC limestone
No
rmal
ize
d c
Pavement type
Summer
Nordic winter
C-European winter
Studded winter
Report on pavements and PM10
Available at www.trafikverket.se
Are the Nordic countries reaching limit values? N
um
ber
of
exceedances (
PM
10)
Year
Oslo
Strategies: REDUST (Finnish Life+ project)
2011-2014
• WP1 Demonstrating and finding the best practices to
mitigate PM10 road dust
• WP1.1 Winter time practices
• WP1.2 Dust binding practices
• WP1.3 Street cleaning practices
• WP1.4 Emission factor development and mitigation
potential of the practices
• WP2 Development of an optimized strategy to mitigate
urban PM10 road dust
• WP3 Dissemination of results
www.redust.fi