Ozone Production Efficiencies at Rural New York State Locations: Relationship to Oxides of Nitrogen Concentrations

This study examined the observed summertime ozone production efficiency (OPE) and background ozone ([O-3]) concentration at two rural sites in New York State, Pinnacle State Park (PSP) in Addison, NY, and Whiteface Mountain Summit (WFMS) in Wilmington, NY. Observed summertime OPEs and their relationship to oxides of nitrogen concentrations ([NOx]) were assessed during photochemically active periods at PSP and WFMS from 2000 to 2017 and 2015-2017, respectively. The summertime OPE increased in response to [NOx] reductions at PSP, consistent with a NOx-sensitive regime for O-3 production. At PSP, the summertime OPE increased from approximately 5-7 parts per billion per parts per billion (ppbppb(-1)) in 2000-2009 to approximately 13ppbppb(-1) in 2012-2017, and the median [NOx] concentration during photochemically productive periods decreased from about 0.60ppb in 2000-2005 to about 0.23ppb in 2012-2017. At WFMS, the summertime OPE was approximately 18ppbppb(-1) in 2015-2017, and the median [NOx] concentration during photochemically active periods from 2015 to 2017 was about 0.21ppb. The higher WFMS summertime OPE is consistent for a site characterized by lower [NOx] concentrations. The summertime background [O-3] concentration at PSP and WFMS was approximately 31-33ppb for the analysis period, indicating that both sites were likely affected by similar regional emission sources.