Changes in source specific PM2.5 from 2010 to 2019 in New York and New Jersey identified by dispersion normalized PMF

Abstract

Since the Clean Air Act amendments of 1970, various efforts have been made in the United States to control ambient particulate matter and improve air quality. Although substantial progress had been made by the end of the 1990s, further reductions were needed to meet the National Ambient Air Quality Standards. To assess the effectiveness of the regulations and the impacts of economic drivers, we investigated the PM2.5 source trends at 11 sites in New York and New Jersey for the 2010–2019 period. Dispersion-normalized positive matrix factorization (DN-PMF) was used to reduce the meteorological impacts on the source apportionment. The Theil-Sen nonparametric estimator and piecewise linear regression were applied to the resolved source contributions to quantify the trends. While there is a consistent overall decrease of PM2.5 at all sites, increases were observed for some specific PM sources. Secondary Sulfate increased after 2017 at most sites based on the piecewise analysis. Similarly, recent-year increases were resolved for Diesel concentrations likely due to increasing vehicle miles traveled for heavy-duty vehicles. Back trajectory analysis of the OP-Rich source identified southeastern U.S. as a likely major source area, while Biomass Burning has a mixed source from local domestic heating as well as transported from proscribed and wildfires in the southeastern U.S.