Atmospheric Organic Aerosols: Sources, Chemistry, and Health Impacts

Abstract

Organic aerosols constitute a significant fraction of submicron fine particulate matter (PM) in the atmosphere. Secondary organic aerosols (SOA) formed from condensation of low-volatility species produced by oxidation of gas-phase organic compounds often dominate the mass of atmospheric organic aerosols. Understanding the formation of SOA has proven to be a challenge owing to the difficulty in identifying and quantifying all the gas-phase precursors as well as the complex, multi-generation oxidative chemistry that leads to the aerosol formation. Laboratory chamber experiments provide the basic understanding needed for predicting SOA formation. Ambient field measurements provide important datasets for understanding the chemistry and life cycles of atmospheric aerosols. In this work, we employed an integrated laboratory and field measurement approach to investigate how emissions from human activities (e.g., SO2, NOx) interact with emissions from trees in the formation of SOA. We will also discuss oxidative stress induced by laboratory and ambient aerosols for understanding their impacts on human health upon exposure.