Wintertime aerosol chemical composition and source apportionment of the organic fraction in the metropolitan area of Paris

TLDR

A month‑long winter 2010 field campaign in the Paris metropolitan area used three aerosol mass spectrometers, two aethalometers, and positive matrix factorization to apportion organic sources, while black carbon was assigned to traffic and wood‑burning sources via a wavelength‑dependent absorption model. Source apportionment revealed that submicron aerosols were dominated by organic matter (30–36 %) and nitrate (28–29 %), with secondary organic aerosol contributing over 50 % of the organic mass, primary sources including traffic (11–15 %), biomass burning (13–15 %) and cooking (up to 35 % during meal hours), and the similarity of composition and temporal patterns across three sites indicating regional dominance and a limited local impact from Paris emissions. Abstract.

Abstract

Abstract. The effect of a post-industrial megacity on local and regional air quality was assessed via a month-long field measurement campaign in the Paris metropolitan area during winter 2010. Here we present source apportionment results from three aerosol mass spectrometers and two aethalometers deployed at three measurement stations within the Paris region. Submicron aerosol composition is dominated by the organic fraction (30–36%) and nitrate (28–29%), with lower contributions from sulfate (14–16%), ammonium (12–14%) and black carbon (7–13%). Organic source apportionment was performed using positive matrix factorization, resulting in a set of organic factors corresponding both to primary emission sources and secondary production. The dominant primary sources are traffic (11–15% of organic mass), biomass burning (13–15%) and cooking (up to 35% during meal hours). Secondary organic aerosol contributes more than 50% to the total organic mass and includes a highly oxidized factor from indeterminate and/or diverse sources and a less oxidized factor related to wood burning emissions. Black carbon was apportioned to traffic and wood burning sources using a model based on wavelength-dependent light absorption of these two combustion sources. The time series of organic and black carbon factors from related sources were strongly correlated. The similarities in aerosol composition, total mass and temporal variation between the three sites suggest that particulate pollution in Paris is dominated by regional factors, and that the emissions from Paris itself have a relatively low impact on its surroundings.