Contributions to aerosol production from human activities

Molecules from plant and human activity mix and mingle in the atmosphere. Credit: NOAA Digital Coast

Plants emit molecules into the air during growth, reproduction, and defense processes. These compounds undergo chemical reactions in the atmosphere, forming fine particles known as biogenic secondary organic aerosols (SOA) worldwide. These aerosols are minute and inhalable, impacting air quality, human health and Earth’s climate system. Human-made emissions, such as nitrogen and sulfur oxides, also result in a significant amount of SOA. While the SOA from plant sources in the atmosphere is relatively well understood, we do not yet have a full understanding of how human activities contribute to the total amount of biogenic SOA in the atmosphere and how they interact chemically with plant emissions. To address this gap, the Climate Program Office’s Atmospheric Chemistry, Carbon Cycle and Climate (AC4) Program partially funded a new study that investigates the role of anthropogenic sources in biogenic SOA production in the southeastern United States using a combination of observational datasets and the GFDL Global Atmospheric Chemistry-Climate Model.