Seasonal Variability of Volatile Organic Compound (VOC) Concentrations at a Suburban Site on Long Island, New York

Volatile organic compounds (VOCs) play a significant role in air quality, particularly through ozone (O3) and secondary organic aerosol (SOA) formation, leading to increased air pollution and thus negative health impacts for local populations. New York City is the most densely populated large city in the United States and continues to suffer from poor air quality resulting from emissions of primary air pollutants (e.g., anthropogenic and biogenic VOCs) which can undergo chemical reactions and form secondary pollutants (e.g., ozone). Air pollutants from NYC can be advected to other regions of the northeastern United States, affecting regional air quality for millions of people. One of these affected areas is Long Island, NY, which is home to the Flax Pond Marine Laboratory operated by Stony Brook University and the New York State Department of Environmental Conservation (NYSDEC). Flax Pond Marine Laboratory is located about 60 miles downwind from NYC and is considered a suburban area surrounded by vegetation and a pond that feeds into the Long Island Sound. At Flax Pond, we deployed our proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) and the Campbell Scientific 3-D Sonic Anemometer (CSAT3) simultaneously to collect continuous data used for eddy covariance flux calculations. The CSAT3 was deployed on an eddy-flux tower, at about 21-m height and the PTR-ToF-MS had three sample lines on the tower at about 17-m, 21-m, and 26-m. Using selected VOCs detected by our PTR-ToF-MS, we present concentration measurements and calculated eddy covariance fluxes from the deployment at Flax Pond. Here we also present diurnal and seasonal trends of VOCs at Flax Pond and the relationships between selected VOCs and various meteorological parameters. For example, we have seen that VOCs with known biogenic sources, such as isoprene and monoterpenes, are driven by high temperatures and solar radiation, thus having higher concentrations in the summer season. We have also seen that on days with high temperatures, concentrations of some short-lived species (e.g., methacrolein [MACR] + MVK) will accumulate during the night, which can have implications on ozone production once photochemical reactions begin the following morning. The seasonality at Flax Pond can influence the concentrations and emissions of VOCs, which has implications on secondary pollutant formation (e.g. O3, SOA) over Long Island, NY. The eddy covariance flux measurements at Flax Pond will help better constrain VOC emission inventories, thus improving our knowledge of biosphere-atmosphere interactions and regional air quality.