Evaluating Higher Temporal Observations in PM2.5 in Relationship with Lower Temporal Long-Term Trends--Initial Observations from the Baltimore Social-Environmental Collaboration

BENJAMIN A. NAULT, Lalitha Aiyar, Daniel C. Blomdahl, Jewel Grant, Ayreanna Pettijohn, Mina Tehrani, Benjamin Werden, Amira Yassine, Kirsten Koehler, Peter F. DeCarlo, James Hunter, Benjamin Zaitchik, Johns Hopkins University

     Abstract Number: 335
     Working Group: Aerosol Processes and Properties in Changing Environments in the Anthropocene

Abstract
Baltimore, MD, is located in a very atmospherically-dynamic location. It is a receptor site of emissions and aerosol produced during transport from Ohio River Valley and the forested and agricultural areas of Appalachia, from the Chesapeake Bay, from the agricultural area of the Eastern Shore, and from the Washington, D.C., area, depending on the synoptic and local wind patterns. The greater Baltimore-D.C. area is fortunate to have higher concentration of monitoring sites compared to many other regions in the U.S.; however, these monitoring sites operate at low temporal resolution (e.g., 24-hr averaged data once every 3 – 6 days for composition and organic aerosol precursors). This may lead to missing events that may impact aerosol concentration (e.g., wildfire transport, bay breeze) as well as diel cycle that better indicates sources and chemistry control aerosol concentrations in an urban environment. As part of the DOE Urban Integrated Field Laboratory experiment, the Baltimore Social-Environmental Collaboration (BSEC) Air Quality team set-up a long-term, higher temporal (1-sec to 10-min resolution) supersite to measure aerosol concentration and composition with the Aerodyne TOF-ACSM-X, along with a suite of other instruments, to evaluate the sources and chemistry of aerosol in Baltimore. Initial results from these observations have highlighted the importance of localized primary emissions from cooking, fireplaces, and traffic towards the total organic aerosol budget that monitoring sites may not capture. Furthermore, mobile measurements to different locations in Baltimore indicate that very localized, primary aerosol emissions from traffic are not well captured by current monitoring systems, where the aerosol concentrations are a factor of 2 – 3 higher than the monitoring sites. The combination of higher temporal and spatial measurements highlight the importance of understanding sources of aerosol in a complex urban environment.