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Volatile Chemical Product Enhancements to Criteria Pollutants in the United States (CMAS)
Citation:
Seltzer, K., B. Murphy, E. Pennington, C. Allen, K. Talgo, AND H. Pye. Volatile Chemical Product Enhancements to Criteria Pollutants in the United States (CMAS). CMAS, Durham, North Carolina, November 01 - 05, 2021.
Impact/Purpose:
Volatile chemical product use results in emissions of volatile organic compounds (VOCs) to air. In air, these VOCs form fine particles (PM2.5), ozone, and formaldehyde. This work connects the recent ORD-developed VCPy inventory framework to criteria pollutant concentrations over the U.S. using the CMAQ model.
Description:
Volatile chemical products (VCPs) are a broad assortment of residential, commercial, institutional, and industrial sources of reactive organic carbon (ROC) emissions. Collectively, these sources currently contribute ~3.1 Tg of ROC emissions in the United States, with a substantial fraction of the sector (>20% by mass) serving as secondary organic aerosol (SOA) precursors. Here, we incorporate a new nationwide VCP inventory into the Community Multiscale Air Quality (CMAQ) model, with VCP-specific updates to better model air quality impacts. These CMAQ updates include representation of secondary air pollutant formation pathways for alkane-like intermediate volatility organic compounds (IVOCs), oxygenated IVOCs, and siloxanes. VCPs most enhance anthropogenic SOA formation in densely populated areas, with modeled, population-weighted annual average SOA increasing by 15 – 30% in Southern California and New York City due to VCP emissions (contribution of 0.2 - 0.5 µg m-3). Annually, VCP emissions enhance total population-weighted PM2.5 by up to 10% and generally ~5% in California, ~3% in New York, New Jersey, and Connecticut, and 1 – 2% in most other states. While the ozone enhancements from VCP emissions are more modest on average, their influence can cause a several ppb increase on select days in major cities and can account for up to 8.9% of annual-average maximum daily 8-hour ozone. Emissions from printing inks, cleaning products, paints and coatings contribute ~75% to the modeled VCP-derived SOA, and emissions from cleaning products, paints, coatings, and personal care products contribute ~81% to the modeled VCP-derived ozone. Overall, improved VCP emissions enhance modeled formation of multiple criteria pollutants throughout the United States, with the largest impacts in urban cores.