AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Changes in Organic Aerosol in the United States over the Last Quarter-Century
KELSEY BOULANGER, Jesse Kroll, MIT
Abstract Number: 253 Working Group: Remote and Regional Atmospheric Aerosols
Abstract Recently-developed analytical techniques have provided new insight into atmospheric organic aerosol (OA) chemistry and their impacts on climate forcing and human health, but our understanding of these impacts is hindered by the uncertainties in how OA has changed over the past few decades. This analysis uses existing aerosol data from the U.S. Interagency Monitoring of Protected Visual Environments (IMPROVE) Network to examine recent trends in aerosol species concentrations. Using data from as early as 1988 in many locations, monthly and yearly trends of aerosol concentrations are considered to provide insight into the long-term OA evolution across dozens of rural sites in the U.S. Changes in OA are characterized both on an absolute scale and relative to other key atmospheric constituents, including sulfate, nitrate, and ammonium. These are interpreted in terms of historic changes to a number of factors that may affect relative and absolute loadings: emissions of primary organic aerosol (POA), changes in emissions of precursors to both secondary organic aerosol (SOA) and secondary inorganic aerosol, and other factors that may affect aerosol formation (e.g., NOx levels and aerosol acidity).