Understanding the Formation and Impacts of Fine particles (Invited Presentation)

Airborne particulate matter (PM) or aerosol (particles suspended in air) exerts profound impacts on the atmosphere-earth system, ranging from air quality, ecosystems, weather, to climate. In particular, fine aerosols interact directly and indirectly with the Earth's radiation budget, influencing weather and climate. Currently, the aerosol-radiation and aerosol-cloud interactions represent the greatest uncertainty in projection of future climate relevant to anthropogenic activities. A large fraction of the tropospheric aerosol populations is produced from new particle formation (NPF) under various environments. An understanding of the aerosol formation mechanism is critical in the development of efficient mitigation policies to minimize its local, regional, to global impacts. This talk will discuss the various aspects relevant to aerosol formation, including the fundamental chemistry and detection methodologies. I will present research that discovers a unique onset for the occurrence of NPF under urban conditions. Future research needs relevant to understanding the formation and impacts of fine aerosols will be discussed.