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Aerosol Physics & Climate Research at ASRC

Researchers:  Fangqun Yu

The past decade has seen the growing importance of atmospheric aerosols (both from natural and anthropogenic sources) in a range of real-word problems. Atmospheric particles influence Earth´s climate directly by scattering and absorption of solar radiation, and indirectly by affecting cloud properties, precipitation, and the hydrologic cycle. The aerosol indirect radiative forcing is poorly constrained in climate models and this represents the single greatest uncertainty in assessing climate change. Aerosol particles are the carriers of a number of hazardous air pollutants, are known to have adverse health effects, are associated with acid deposition, and can cause regional haze that obscures scenic vistas. Atmospheric aerosols also act as sites for chemical reactions (i.e., heterogeneous chemistry). The effects of atmospheric aerosols depend strongly on the particle size distribution, composition, hygroscopic properties, and mixing state that are determined by a number of microphysical and chemical processes. Key aerosol properties exhibit significant spatial and temporal variability at both regional and global scales due to their short residence times and the non-linear dependence of production rates on atmospheric conditions.

Because of the important role of aerosols in modifying the climate, future climate changes and emission regulatory actions may significantly affect the aerosol properties leading to important climate feedback processes. In addition, various natural processes (such as volcanic eruptions, variations in solar activity and fluxes of galactic cosmic rays, oceanic emissions of precursors and primary particles, biogenic emissions, etc.) may affect aerosol abundances and thus serve as important external or natural forcings of Earth´s climate. In recent years, a number of conceptual ideas have been proposed to compensate for "greenhouse" warming (i.e., geo-engineering), and most of these ideas are associated with modifying aerosols in the atmosphere. In order to address various environmental issues associated with aerosols and to more accurately predict current and future climate, it is essential to improve fundamental process-level understanding of aerosol lifecycles, and adequately represent processes controlling key aerosol properties in regional and global models.

Our primary research interests include: (1) Mechanisms and fundamentals of new particle formation in the atmosphere: Quantum calculation, kinetic modeling, and data analysis; (2) Regional (WRF-Chem) and global (GEOS-Chem, CESM-CAM5) modeling of particle size distribution and cloud condensation nuclei (CCN) abundance; (3) Aerosol-cloud-Climate interactions; (4) Aerosol direct and indirect radiative forcing, climate change, and climate feedback mechanisms involving aerosol formation; (5) Formation and growth of volatile nanoparticles in various plumes (engine exhaust, power plant, volcano, etc.); (6) Soot particle formation and evolution inside engine; and other aerosol-related topics.

More detailed and updated information about our research (including publications) can be found at