Black Carbon as the metric to assess the efficiency of traffic restrictions in urban and non-urban environments

Transcription

1 Black Carbon as the metric to assess the efficiency of traffic restrictions in urban and non-urban environments AIRUSE final conference Barcelona, 18 Apr 2016 A. Gregorič, L. Drinovec, I. Ježek, I. Iskra, G. Invernizzi, A. Ruprecht, D. Westerdahl, G. Močnik

2 Aerosol Black Carbon BC is a primary product of incomplete combustion BC not automatically related to CO 2 emission BC emissions can not be predicted: must be measured BC particles from different sources can have different characteristics that produce different effects in the atmosphere: (Coal/Diesel/Biomass, USA/Asia/Europe) relevance: climate change, health Note change in scale d pp =20 nm d m =472 nm 2 d pp =46 nm

3 BC and CM two sides of the same coin Black Carbon BC Primary, sources Carbonaceous matter CM Primary and secondary, contribution to PM2.5 3

4 LOCAL air pollution regulation of sources simplest - traffic 4

5 Aerosol Black Carbon covers large regions Approx m above New Delhi region, India: late afternoon. 5

6 Aerosol Black Carbon: understanding heterogeneity and effects BC emissions vary by orders of magnitude Need to measure emission factors Ambient concentrations show exteme heterogenity Local effects: health Regional effects: transport of pollutants Global effects: climate Need to measure local, regional and global: determine zero state plan abatement measures validation of models effectiveness of abatement measures 6

7 Ljubljana, Slovenia Source: Environmental agency largest city in Slovenia, in a basin inhabitants one of the most polluted cities in Europe traffic, domestic heating traffic: vehicles to the city every day traffic restrictions!

8 Ljubljana (winter 2014) background Center - bypass Center - closure 500 m H-2 H-1 5 km 8

9 Ljubljana (August October 2013) BC (ng/m 3 ) B) Vošnjakova Pred zaporo Med zaporo Center - bypass After closure Before closure BC (ng/m 3 ) C) Vojkova Pred zaporo Med zaporo Before closure Background After closure Ura (h) Ura (h) Before closure Background BC (ng/m 3 ) After closure Center - bypass Center - closure 2000 A) Slovenska Pred zaporo Med zaporo Ura (h) Center - closure Titos, 2015

10 Ljubljana (BC traffic city background) 8000 BC traffic BC traffic (backgroud) (ng/m 3 ) % Before closure After closure Center - closure Center - bypass Titos,

11 Milano, Italy largest city in N Italy, in a valley 1.3 M inhabitants one of the most polluted cities in Europe major traffic in the Po valley traffic: 89,000 vehicles in the city center every day traffic restriction in place since Jan 2008

12 Radial measurements Each site: PM10, PM2.5, PM1 Black Carbon RH, T 08:30 19:30 Summer: July km T = 30 C

13 Results No difference! PM Big difference! BC/PM Invernizzi, 2011

14 Ljubljana (winter 2014) Center - bypass BC BC BB BC TR Center - closure BC BC BB BC TR BC (ng/m 3 ) BC (ng/m 3 ) Hour Traffic Wood combustion BC (ng/m 3 ) BC BC BB BC TR Hour Background Hour 14

15 Ljubljana (winter 2014) Decrease of BC traffic to the background level. Traffic Wood combustion H-2 H BC BC BB BC TR H-1 H BC BC BB BC TR BC (ng/m 3 ) BC (ng/m 3 ) Hour Hour 15

16 Influence of meteorological conditions on BC (Ljubljana winter 2014) KIS 9000 R 2 =0,55 R 2 =0,67 k= 28,6% Pošta R 2 =0,55 R 2 =0,67 k= 28,6% Vošnjakova R 2 =0,55 R 2 =0,67 k= 28,6% Background Center - closure Center - bypass BC (ng/m 3 ) v w (m/s) Barje - skedenj R 2 =0,55 R 2 =0,67 k= 28,6% H v w (m/s) v w (m/s) Wind speed v w (m/s) 16

17 Background Center - closure Center - bypass z i after Stull, 1988 H-2

18 Conclusions Radical local abatement works Softer abatement needed off-center in cities Traffic is local, wood smoke regional Meteorology plays a part! Regional abatement requires regional consensus To-Do: individual source characerization, predictive restrictions 18

19 Super emitters contributions to total fleet emissions 25% of diesel cars contributed: 63% of BC 47% of NO x 61% of PN Ježek et al., ACP 2015

20 Thank you for your attention! Questions? 20