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

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

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), www.vmm.be

PM10 Flanders +-50% due to emissions agricultural sector = NH3 PM10 Flanders : on average +- 25 % can be attributed to Flemish antropogenic emissions +-50% due to emissions agricultural sector = NH3

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

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

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)

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)

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

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 …

Thank you for your attention ! fierens@irceline.be