High-resolution WRF-LES-Chem simulations to investigate ozone formation regimes in Houston
Folorunsho, A., Dudhia, J., Sullivan, J., Walter, P., Flynn, J., et al. (2025). High-resolution WRF-LES-Chem simulations to investigate ozone formation regimes in Houston. ACS ES&T Air, doi:https://doi.org/10.1021/acsestair.5c00109
| Title | High-resolution WRF-LES-Chem simulations to investigate ozone formation regimes in Houston |
|---|---|
| Genre | Article |
| Author(s) | A. Folorunsho, Jimy Dudhia, J. Sullivan, P. Walter, J. Flynn, T. Griggs, R. Sheesley, S. Usenko, G. Gronoff, M. Estes, Y. Li |
| Abstract | Despite decades of ongoing mitigation efforts, ozone (O3) levels remain persistently high in Houston, TX. For a high O3 episode observed during the NASA Tracking Aerosol Convection Interactions ExpeRiment-Air Quality (TRACER-AQ) campaign, we use a high-resolution large-eddy simulation (LES) within the Weather Research and Forecasting model coupled with Chemistry (WRF-LES-Chem) to investigate temporal and spatial variations in O3 formation regimes over the region. By leveraging improved simulations of O3 and its precursors by LES, compared to the mesoscale WRF model, we derive and compare two O3 sensitivity indicators: the formaldehyde-to-nitrogen dioxide ratio (FNR) and the ratio of radical loss via NOX reactions to total primary radical production (LN/Q). Specifically, we use LN/Q to inform the threshold for FNR, the latter being a more commonly used and accessible indicator, although it is subject to significant uncertainties. We demonstrate that O3 production in the Houston urban area transitions from a nearly homogeneous early morning VOC-limited regime to a NOX-limited regime by midday. Using the LN/Q indicator, we identify that a range of 0.6 < FNR < 1.8 falls in the transition zone of O3 formation regime. The high-resolution modeling of O3 formation and the FNR range developed in this LES study offers valuable insight for assessing future air quality and improving the understanding of atmospheric chemistry that underpins pollution control in Houston. |
| Publication Title | ACS ES&T Air |
| Publication Date | Aug 8, 2025 |
| Publisher's Version of Record | https://doi.org/10.1021/acsestair.5c00109 |
| OpenSky Citable URL | https://n2t.net/ark:/85065/d7805746 |
| OpenSky Listing | View on OpenSky |
| MMM Affiliations | WMR |