The origin of atmospheric particles in Paris: a view through carbon and lead isotopes

The origin of particulate matter in the urban atmosphere and the impact of its various sources are still subject to debate. This uncertainty cannot be alleviated by the sole use of ‘classic’ chemical parameters, creating a need for complementary indexes. We show that the use of coupled carbon and lead isotopes allows the identification of aerosol sources in the atmosphere of Paris, permitting a semi-quantification of their respective contributions. The two study sites, representative of background pollution and the influence of heavy road traffic, both show the domination of diesel exhaust fumes to the level of carbon in aerosols (either PM 2.5 or PM 10), while industry is the main vector for lead, with a contribution generally superior to 50%. Within the last 10 years, the origin of the inorganic phase shifted from road traffic towards industrial activities.