1. Traffic related air pollution : total mass PM10 or Black Carbon (BC) as indicator ?
Frans Fierens Scientific staff member of the Flemish Environment Agency (VMM) at the Belgian Interregional Environment Agency (IRCEL)
Brussels, Stakeholder expert meeting on future air quality legislation, 6 and 7 june 2011

2. Location of PM10 monitoring sites in BE
Exceedances PM10 limit : Mostly at Industrial monitoring sites / AQ zones
Black Carbon:
12 sites (recently)

3. Chemical composition of PM10 (period september 2006 – september 2007)
Small difference total mass PM10 concentrations
Mineral dust
SIA = 41%
Sea salt
Large difference for specific components : 400% more ‘EC’ (Elementary Carbon, dieselsoot) in urban areas (Antwerp) than on rural sites (Coast)
Most “efficient” way to reduce total “mass” PM = reduction of SIA
Bron : ‘CHEMKAR’ rapport Vlaamse Milieumaatschappij (2009),

4. PM10 Flanders +-50% due to emissions agricultural sector = NH3
PM10 Flanders : on average % can be attributed to Flemish antropogenic emissions
+-50% due to emissions agricultural sector = NH3

5. Contribution Flemish Emissions (%)
Contribution of Flemish emissions in PM10 and BC : Urban area (Antwerp)
PM10 (average ~ 35 %)
BC (average ~ 75 %)
Contribution Flemish Emissions (%)
Bron : Felix Deutsch (VITO), BelEUROS model

6. Reduction of PM10 : which (local) measures ?
Ammonia (NH3) reductions : largest impact on the reduction of “total” mass PM = compliance with limit values
But … (small ?) impact on health effects ?
Traffic measures = reduction of Black Carbon (and NOx) probably more effective to reduce impact on health But … (very) small impact on the reduction of total mass PM

7. Impact of speed limits on highways during PM smog episodes
Difference (%) in PM10 concentrations during the SMOG episode in December 2007)
PM10
Difference for total mass PM10 (and PM2.5) is rather small (only a few %) ... but
Source : VITO - Lefebvre et al. (2009)

8. Results : EC (diesel soot)
Impact speed limit (EC)
Results : EC (diesel soot) EC
... EC (Elementary Carbon, diesel soot) reductions up till 30 % !!
Source : VITO - Lefebvre et al. (2009)

9. Car Free Sunday, Brussels 20 September 2009
Source : Peter Vanderstraeten (Leefmilieu Brussel, 2009)
10000
120
Car Free period
Black Carbon
9000
PM10
100
8000
7000 80
6000
Black Carbon (ng/m³)
PM10 (µg/m³)
5000 60
4000 40
3000
2000 20
1000
PM10 : high secundary fraction -> precursors yesterday/outside BRU …
BC : local (traffic ) emissions much more important : immediate effect !
2:30
4:00
5:30
7:00
8:30
10:00
11:30
13:00
14:30
16:00
17:30
19:00
20:30
22:00
23:30
1:00

10. Conclusions
(Local) primary traffic emission reductions : small impact on total mass PM, important to reduce impact on health
Total mass PM = not the best indicator for traffic related air pollution.
Support for measures that have only little effects on the current PM indicators = not easy
Black Carbon :
probably one of the most toxic components but not regulated (yet ?)
Direct effect of local (traffic) measures
Needs more attention …

11. Thank you for your attention ! fierens@irceline.be