Gasoline cars produce more carbonaceous particulate matter than modern filter-equipped diesel cars

S. Platt (1) , I. El Haddad (1) , S. Pieber (1) , A. A. Zardini (2, 3) , R. Suarez-Bertoa (3) , M. Clairotte (3) , K. R. Daellenbach (1) , R.-J. Huang (4) , J. Slowik (1) , S. Hellebust (5) , B. Temime-Roussel (5) , Nicolas Marchand (5) , J. de Gouw (6) , J. L. Jimenez (7) , P. L. Hayes (8) , A. L. Robinson (9) , U. Baltensperger (10) , C. Astorga (11, 3) , A. S. H. Prévôt (10)

1 PSI - Paul Scherrer Institute
2 IAC - Institute for Atmospheric and Climate Science [Zürich]
3 JRC - European Commission - Joint Research Centre [Ispra]
4 Institute of Earth Environment [Xi’an]
5 LCE - Laboratoire Chimie de l'environnement
6 ESRL - NOAA Earth System Research Laboratory
7 Department of Chemistry and Biochemistry [Boulder]
8 UdeM - Université de Montréal
9 CAPS - Center for Atmospheric Particle Studies [Pittsburgh]
10 LAC - Laboratory of Atmospheric Chemistry [Paul Scherrer Institute]
11 IET - JRC Institute for Energy and Transport

Carbonaceous particulate matter (PM), comprising black carbon (BC), primary organic aerosol (POA) and secondary organic aerosol (SOA, from atmospheric aging of precursors), is a highly toxic vehicle exhaust component. Therefore, understanding vehicle pollution requires knowledge of both primary emissions, and how these emissions age in the atmosphere. We provide a systematic examination of carbonaceous PM emissions and parameterisation of SOA formation from modern diesel and gasoline cars at different temperatures (22, −7 °C) during controlled laboratory experiments. Carbonaceous PM emission and SOA formation is markedly higher from gasoline than diesel particle filter (DPF) and catalyst-equipped diesel cars, more so at −7 °C, contrasting with nitrogen oxides (NO X). Higher SOA formation from gasoline cars and primary emission reductions for diesels implies gasoline cars will increasingly dominate vehicular total carbonaceous PM, though older non-DPF-equipped diesels will continue to dominate the primary fraction for some time. Supported by state-of-the-art source apportionment of ambient fossil fuel derived PM, our results show that whether gasoline or diesel cars are more polluting depends on the pollutant in question, i.e. that diesel cars are not necessarily worse polluters than gasoline cars.

Domaines: Océan, Atmosphère; Autre; Milieux et Changements globaux

S. Platt, I. El Haddad, S. Pieber, A. A. Zardini, R. Suarez-Bertoa, et al.. Gasoline cars produce more carbonaceous particulate matter than modern filter-equipped diesel cars. Scientific Reports, 2017, 7, pp.4926. ⟨10.1038/s41598-017-03714-9⟩. ⟨hal-01656074⟩