The Response of Summertime Organic Aerosol Composition to Emission Controls in the Northeastern United States

JIE ZHANG, Junfeng Wang, Yele Sun, Shan Zhou, ManishKumar Shrivastava, Alexandra Catena, Nga Lee Ng, Qi Zhang, James Schwab, Atmospheric Sciences Research Center, University at Albany

     Abstract Number: 171
     Working Group: Aerosol Chemistry

Abstract
The responses of secondary organic aerosols (SOA) to emission controls remain uncertain due to the limited continuous long-term measurements. Measurements of detailed carbonaceous aerosol composition in the New York City metropolitan region during the summers of 2001, 2009, 2011, 2018 provide a look at the changes in summertime SOA over the past two decades when significant pollution reduction and emission controls occurred in the northeastern United States. Here, we show that the averaged nighttime SOA, especially the fresh local SOA, extreme mass concentrations resulted from anthropogenic volatile organic compounds (VOCs) reductions, while there is a little trend for the regional aged SOA. Meanwhile, these fresh SOA extremes occurred most often under conditions of high relative humidity during nighttime. The analysis presented here provides a comprehensive evaluation of the evolution of the increasingly important organic component of the submicron ambient aerosols in this major metropolitan area.