Friday, November 10, 2023. 2:30 PM. Air Pollution Links to the Sources and Sinks of Greenhouse Gases in New York City. Roisin Commane, Columbia University. Sponsored by Rutgers Department of Environmental Sciences. More information here.
Abstract: Many city governments in the US have committed to reducing their emissions of GHGs based on inventories calculated for the city. However, few cities measure their carbon emissions to know if the enacted policies are having the desired effect. The New York Metro Area (pop. 20M) is the most populous urban area in the United States (US) and the largest urban source of CO2 in the US. The region also has some of the worst summertime air quality (NOx and ozone exceedances) outside of California, much of which is transported downwind to Connecticut. We have observed concentrations of methane, ethane, CO, CO2 and N2O over long periods at an observatory in Manhattan (starting in 2019) and at the Rutgers air quality site in New Brunswick since January 2023. We combine atmospheric transport models with our observations to evaluate various trace gas inventories for the city (for methane, CO and CO2). To interpret the CO2 observations, we built a model for biogenic CO2 photosynthesis and respiration for NYC that includes street and park trees and urban lawns and found that the large amounts of vegetation in the city absorbs much of the daytime CO2 emitted from traffic across the city. We also identified surprising N2O emissions from specific waste water treatment plants in the city. Our observations of many trace gases have allowed us to study the source characteristics of methane and understand the impact of co-emitted species on urban atmospheric chemistry.