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Volatile chemical product emissions and criteria pollutant enhancements in the United States
Citation:
Seltzer, K., B. Murphy, E. Pennington, V. Rao, K. Isaacs, AND H. Pye. Volatile chemical product emissions and criteria pollutant enhancements in the United States. 16th IGAC Scientific Conference, virtual, Virtual, September 12 - 18, 2021.
Impact/Purpose:
We show that emissions from volatile chemical products contribute to ozone and fine particle pollution across the United States using the VCPy inventory and CMAQ.
Description:
Volatile chemical products (VCPs) are a broad assortment of sources that emit reactive organic carbon (ROC) to the atmosphere. Among these sources are personal care products, general cleaners, architectural coatings, pesticides, adhesives, and printing inks. Here, we present VCPy, a new framework to model ROC emissions from VCPs throughout the United States. Evaporation of a species from a VCP mixture is a function of the compound-specific physiochemical properties that govern volatilization and the timescale relevant for product evaporation. For 2016, VCPy predicts emissions from VCPs to be 3.1 Tg nationwide, making VCPs a significant source of anthropogenic ROC in the United States. We then incorporate this inventory, which will serve as the EPA-based solvent sector estimates for the 2020 National Emissions Inventory, into the Community Multiscale Air Quality (CMAQ) model, with VCP-specific updates to better model air quality impacts. These updates include a refined mapping of explicit inventory compounds to new model species that better represent secondary air pollutant formation pathways from non-oxygenated intermediate volatility organic compounds (IVOCs), oxygenated IVOCs, and siloxanes. The model configuration implemented here yields predictions of particulate organic carbon and ozone that often meet the highest standards of regional air quality modeling performance metrics. Results suggest VCPs enhance the nationwide annual-average, population weighted secondary organic aerosol (SOA) concentration by ~0.15 µg m-3, which is ~11% of the modeled, population weighted SOA mass. Daily SOA enhancements attributable to VCPs can fluctuate substantially, with some urban areas often featuring noontime enhancements > 1.0 µg m-3. While the ozone enhancements from VCP emissions are more modest on average, their influence can cause a several ppb increase on select days in populated cities. In addition, we assess contributions from various VCP categories (e.g. Personal Care Products) on SOA and ozone.
