Investigating the Relationship Between Reactive Nitrogen Species and Ozone in the Wintertime Atmosphere

Wintertime air pollutant emission trends are poorly understood in comparison to emission trends in the summer mostly due to a lack of available and analyzed data on precursor air pollutants in the wintertime. This creates uncertainty in current atmospheric chemistry models. “WINTER 2015” was an aircraft research campaign launched in February 2015 that was executed to measure pollutant concentrations in addition to other data. All of which were relevant to the transportation, distribution, and chemical kinetics of pollutants and aerosols across the northeastern United States. The colder temperatures as well as lack of available sunlight have significant effects on chemical kinetics in the atmosphere. During the daytime, nitrogen oxides tend to produce ozone (O₃), a criteria pollutant regulated by the U.S. EPA, but nitrogen oxides destroy ozone at night. Longer nights, and lower sunlight during the day may mean that nitrogen oxides net destroy ozone for much of the winter. Current air quality models do not accurately simulate the nighttime chemistry of nitrogen oxides. This project examines the wintertime relationship between nitrogen oxides (NO_x (NO+NO₂), NO₃, N₂O₅, ClNO₂, acyl peroxy nitrates, alkyl nitrates, and HNO₃) and O₃ using data taken in the WINTER 2015 campaign to gain insights into the extent to which wintertime nitrogen oxide emissions produce or destroy ozone.