From Mountains to the Sea: Air Quality Measurements in the Grenoble Valley, Within the Mediterranean Basin, and Over the Equatorial Indian Ocean

Speaker: H. Langley DeWitt (View CV)
Research Associate, Laboratoire Chimie Environnement
Université Aix Marseille

Description: Particulate matter (PM) pollution was recently added to the World Health Organization’s list of known carcinogens and the radiative forcing of anthropogenic aerosol is one of the largest unknowns in climate change. Major issues in regulating PM emissions are the lack of a complete understanding of aerosol sources (both directly emitted as aerosol and formed from gas-phase and multi-phase reactions in the atmosphere), transformation processes during transport and aging, and the relationship between aerosol and convection. In this talk, I will present results from three different air quality field measurement campaigns, each site located at a different proximity to anthropogenic air pollution emission sources: 1) adjacent to a large highway in the Grenoble Valley, France, 2) in the Mediterranean basin on the islands of Corsica and Mallorca and 3) in the remote Indian Ocean during the passing of a major convective wave, the Madden Julien Oscillation. I will discuss the use of source apportionment modeling, back-trajectory calculations, and parallel measurements of volatile organic carbon and other gas-phase species to discriminate between origins of different air masses and air pollution sources. I will also discuss the potential aerosol-convection feedback above the Indian Ocean during the Madden Julien Oscillation. We found the majority of aerosol mass in all three locations to be secondary in nature, influenced by transport, aging processes, and gas-phase reactions. Even in remote clean marine environments, we observed transported anthropogenic influence.