Evaluating chemical mechanisms with recent field data to account for the contributions of volatile chemical product emissions to urban ozone pollution

EPA Grant Number: R840010
Title: Evaluating chemical mechanisms with recent field data to account for the contributions of volatile chemical product emissions to urban ozone pollution
Investigators: Coggon, Matthew , Gkatzelis, Georgios , Schwantes, Rebecca , Li, Meng , McDonald, Brian
Institution: University of Colorado at Boulder , NOAA Earth System Research Laboratories
EPA Project Officer: Chung, Serena
Project Period: August 1, 2020 through July 31, 2023
Project Amount: $396,135
RFA: Chemical Mechanisms to Address New Challenges in Air Quality Modeling (2019) RFA Text |  Recipients Lists
Research Category: Early Career Awards , Air , Air Quality and Air Toxics


Urban emissions of volatile organic compounds (VOCs) in the United States are no longer solely dominated by tailpipe emissions. Research by McDonald et al. 2018 first showed that emissions from "volatile chemical products", or VCPs - including personal care products, cleaning agents, coatings, adhesives, and pesticides - may significantly contribute to VOC emissions, ozone formation, and SOA in urban areas. VCP sources emit a wide variety of saturated, unsaturated, and oxygenated VOCs; however, current chemical mechanisms may not adequately represent the atmospheric chemistry of VCP emissions in urban environments. We will use recent ambient measurements of VCP compounds in New York City and other U.S. urban areas to evaluate and update chemical mechanisms in the nearly-explicit Master Chemical Mechanism (MCM) and the condensed Regional Atmospheric Chemistry Mechanism, version 2 (RACM2).


Our objective is to add VCP compounds to current chemical mechanisms, validated by recent field measurements and assessed by 3D Eulerian modeling using WRF-Chem, to better represent the chemistry of modern urban air pollution in the United States.



We will use VOC measurements taken in New York City during the winter and summer of 2018 to identify VOCs whose OH reactivity is currently missing, or misrepresented, in chemical mechanisms. We will incorporate the known chemistry of measured VOCs, including those from VCP emissions, into the MCM and RACM2, and evaluate the performance of these mechanisms in predicting ozone and secondary VOC formation using observationally constrained box models. We will incorporate RACM2 updates into the Weather Research and Forecasting with Chemistry (WRF-Chem) model, a regional chemical transport model currently set up to simulate the 2018 summer ozone season in NYC, and evaluate the performance of the mechanism in quantitatively reproducing observed mixing ratios of ozone and secondary VOCs.

Expected Results:

We will produce an updated condensed chemical mechanism verified by field measurements, and use box and WRF-Chem modeling to develop ozone isopleths and identify the key VOCs contributing to ozone formation in U.S. urban areas.

Supplemental Keywords:

tropospheric, atmosphere, nitrogen oxides, ambient air, solvents mobile sources, environmental chemistry, modeling, consumer products, industrial products