Ambient Ammonia Concentrations Across New York State

Ammonia (NH 3 ) was monitored at four locations (two urban and two rural) across New York State from April 2016 to October 2017 using active and passive systems. The two rural sites were Pinnacle State Park (PIN) and the Village of Potsdam, and the two urban sites were the City of Rochester and Queens College in New York City. Active and passive concentrations were well correlated across all sites ( r 2 = 0.866), but the active systems measured 6.2% higher NH 3 concentrations. The mean (±SD) NH 3 concentrations measured using active systems in Queens College, City of Rochester, Village of Potsdam, and PIN were 3.22 ± 2.23, 2.84 ± 1.91, 1.29 ± 1.12, and 0.82 ± 0.64 ppb, respectively. Ambient NH 3 concentrations varied with diel vehicular and seasonal agricultural activities. NH 3 concentrations at the urban sites had lower seasonal variability than the rural sites. NH 3 concentrations were generally related to regional and in‐state NH 3 emissions although less regional influence was observed at the urban sites. Local NH 3 source directions were identified using conditional bivariate probability function. The urban sites were affected by local NH 3 sources such as vehicular emissions and urban population centers. Likely distant NH 3 source locations affecting the four sites were identified using simplified quantitative transport bias analysis model. Rural sites were more highly affected by transported NH 3 . Midwestern and Atlantic were major NH 3 source areas. NH 3 emissions from the south of PIN were probably due to the use of diesel trucks and other diesel engines in the hydraulic fracturing industry in Pennsylvania near the New York State border.