AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Characterizing Aerosols Near Major Highways Using the US EPA’s National Near-road Monitoring Network
BRETT GANTT, U.S. EPA
Abstract Number: 757 Working Group: Urban Aerosols
Abstract As part of the United States Environmental Protection Agency’s 2010 NO2 National Ambient Air Quality Standards (NAAQS) revision, a national network of monitors was established to determine compliance, better understand human exposure on and near roads, and improve the characterization of pollutant behavior, interaction, and dispersion in the near-road environment. Sites for these monitors were required to be placed “as near as practicable” to major highways within CBSAs having a population greater than 1 million people. In addition to monitoring NO2, both CO and PM2.5 were required to be monitored by January 1, 2015 and January 1, 2017 for CBSAs greater than 2.5 million and 1 million people, respectively. Optional measurements at these sites include black carbon, ultrafine PM, air toxics, ozone, meteorology, and traffic counts.
Although most of the near-road sites do not yet have the 3 years of data required for determining regulatory compliance for PM2.5, many have a sufficient data record to characterize aerosols in the near-road environment. Analyses that have been performed include quantifying the seasonal and diurnal cycles of PM2.5 mass concentration, chemical composition of PM2.5, and increment of PM2.5 mass concentration relative to other sites within the CBSA. Data from this network are compared to that of existing sites close to major highways to estimate the long-term trends in PM2.5 mass and chemical composition relative to non-near-road sites. Finally, the annual average and 98th percentile PM2.5 mass concentrations at near-road sites across the US for 2016 are summarized to determine their potential regulatory impact in the future.