Carbon and lead isotope compositions of particulate matter in the atmosphere of Paris
Abstract
The impact of the various sources of particulate matter in urban atmosphere is still subject to debate. This uncertainty cannot be lifted by the sole use of chemical parameters, and thus the need of complementary indexes may arise. In this study we show that the use of coupled carbon and lead isotopes not only allows a precise identification of the sources of PM10 in the atmosphere of Paris, but also permits the quantification of their respective contributions. The first step of the study consisted in the isotopic (C and Pb)characterisation of PM10 emitted by the main sources of pollution in the city (mainly road traffic and heating sources). Results show that carbon isotopes distinguish PM10 from diesel and natural gas from the other sources, while lead isotopes discriminates road traffic from industrial lead. Atmospheric PM10 samples were then taken and analysed for 2 sites in Paris, one located near the south-east of the city background pollution) and another on the ring (heavy road traffic influence). Results show that the pollution is quite homogeneous from one site to the other in terms of carbon and lead concentrations and isotope compositions. A clear distinction between the organic and inorganic phases of the particles is observed. While more than 90 % of the organic phase is originating from diesel traffic (more than 50 % of the car sold in France are using this type of fuel), lead isotopes show that the majority of the inorganic phase is produced by the industry. This duality clearly reflects both particle interactions and coagulation during their transport in the atmosphere, and the effect of the lead reduction policy in fuel during the last twenty years that resulted in a migration from a prevalent traffic origin towards a complete industrial contribution. This study paves the way to a wide area of research regarding the use of coupled stable and radiogenic isotope systematic in the field of air pollution.
- Publication:
-
EGS - AGU - EUG Joint Assembly
- Pub Date:
- April 2003
- Bibcode:
- 2003EAEJA....14863W