Emissions and oxidative aging of non-traditional gas-phase organic compounds in the Greater New York City Metropolitan Area

Non-traditional sources of volatile organic compounds (VOCs), intermediate-volatility and semi-volatile organic compounds (I/SVOCs)and oxygenated VOCs (OVOCs), including volatile chemical products, have become the largest anthropogenic emitters of reactive gas-phase organic compounds in urban areas. With ongoing reductions in emissions from combustion-related sources, this mix of highly under-constrained sources has a larger impact on urban air quality as primary pollutants and as precursors to secondary organic aerosol (SOA) and ozone. However, the full spectrum of sources and the chemical composition of non-traditional emissions remains understudied, especially for I/SVOCs and OVOCs. Knowledge gaps on emission rates, chemical composition, and oxidative aging inhibit air quality models and management plans, thereby necessitating top-down emissions studies with flux measurements and detailed chemical characterization. Our proposal brings a unique combination of expertise and a synergistic suite of novel analytical capabilities that overcome historical limitations to address these gaps.
We will investigate the emission rates and oxidative aging of VOCs, I/SVOCs, OVOCs, and greenhouse gases (GHGs) at an elevated near-source site in Manhattan, NY. Intensive measurements will be conducted during winter and summer periods and will enable a more comprehensive assessment of the impacts of these emissions on local and regional air quality. Our objectives are to: (1) Quantify the magnitude, temperature dependence, and seasona variability in ambient concentrations and emissions via fluxes of GHGs and the speciated complex mixture of VOCs, I/SVOCs, and primary OVOCs with comparison to past concentration measurements in NYC and other cities. (2) Investigate the downwind oxidative aging and sinks of VOCs, I/SVOCs, and primary OVOCs by (a) sampling through an oxidation flow reactor (OFR) at the NYC site, and (b) comparing NYC measurements and OFR oxidation products with measurements obtained at a downwind CT receptor site. (3) Identify sources of GHGs, VOCs, I/SVOCs, and OVOCs emitted from non-vehicular and vehicular sources at both sites via source apportionment. (4) Conduct select, follow-up laboratory OFR studies of the oxidation of key nontraditional sources.
We will accomplish these objectives with 2 sites that capture the composition and dynamics
of non-traditional urban emissions and their downwind evolution via an unprecedented
combination of state-of-the-art spectroscopy-, chromatography-, and mass spectrometry-based techniques that are sensitive to a wide range of gas- and particle-phase compounds. Results from flux measurements and source apportionment will be compared to existing emissions inventories.