Impact of Organic Aerosols on Air Quality and Climate

• Applicant: Dr. Alexandra Tsimpidi, Ph.D.
• Subject Area: Atmospheric Science
• Term: from 2015 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 283407833

Organic aerosol (OA) is an important constituent of atmospheric particulates. Depending on the region it contributes 20 to 90% of the total submicron particulate mass. However, OA sources, atmospheric processing, and removal are very uncertain. The principal goal of this proposal is to investigate the effects of OA on air quality and climate by improving the representation of OA formation and evolution in a global chemistry-climate model. The proposed work will be based on the computationally efficient module for the description of organic aerosol composition and evolution in the atmosphere (ORACLE) which is part of the ECHAM5/MESSy (EMAC) chemistry climate model. ORACLE will be updated to include all the recent findings and developments based on laboratory and field measurements in order to accurately represent the increasingly more oxidized, less volatile, and more hygroscopic character of OA during its atmospheric aging by tracking its two most important parameters: saturation concentration and oxygen content. This modeling framework will be used to reduce the uncertainty of the impact of OA on global air quality and radiative forcing by: i) quantifying the relative contributions of secondary organic aerosol (SOA) formation and primary organic aerosol (POA) emissions to the total OA focusing in different environments, ii) quantifying the contribution of biomass burning and fuel combustion emissions and their chemical aging and long-range transport to global OA budget iii) determining how SOA concentrations are affected by biogenic and anthropogenic emissions and by photochemical aging, iv) investigating the enhancement of SOA formation from natural sources due to their interaction with anthropogenic emissions, v) estimating the effect of photochemical aging on the physicochemical properties of OA (i.e., hygroscopicity, volatility), and vi) evaluating the indirect climatic effect of organic aerosols. Overall, the proposed work will provide to the next generation of chemistry-climate models a realistic description of the chemical evolution of organic aerosols in the atmosphere which is essential to reduce the aerosol related uncertainties in air quality and climate simulations. It will also expected to reveal valuable information about the sources and production of OA on a global scale that cannot be predicted from current CCMs and can be used from policy makers to effectively design future emission control strategies.

• DFG Programme: Research Grants
• International Connection: USA
• Co-Investigators: Dr. Vlasios Karydis, Ph.D.; Professor Dr. Johannes Lelieveld, Ph.D.
• Cooperation Partner: Professor Dr. Spyros Pandis, Ph.D.