Investigating ground-level ozone pollution in semi-arid and arid regions of Arizona using WRF-Chem v4.4 modeling

• Published in: Geoscientific Model Development Vol. 17; no. 10; pp. 4331 - 4353
• Main Authors: Guo, Yafang, Roychoudhury, Chayan, Mirrezaei, Mohammad Amin, Kumar, Rajesh, Sorooshian, Armin, Arellano, Avelino F
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 24.05.2024; Copernicus Publications
• Subjects: Air pollution; Air quality; Air quality management; Air quality models; Arid regions; Arid zones; Atmospheric chemistry; Bias; Case studies; Chemistry; Climate change; Datasets; Deserts; Diurnal variations; Emissions; Emissions control; Environmental perception; Environmental protection; Meteorological research; Metropolitan areas; Nitrogen compounds; Nitrogen dioxide; North American monsoon; Numerical weather forecasting; Organic compounds; Outdoor air quality; Ozone; Pollutants; Pollution; Precipitation; Radiation; Regions; Semiarid zones; Temperature; Vegetation; VOCs; Volatile organic compounds; Weather; Weather forecasting; Arizona; Mexico; California; United States > US
• ISSN: 1991-9603; 1991-959X; 1991-962X; 1991-9603; 1991-962X
• DOI: 10.5194/gmd-17-4331-2024

Ground-level ozone (O.sub.3) pollution is a persistent environmental concern, even in regions that have made efforts to reduce emissions. This study focuses on the state of Arizona, which has experienced elevated O.sub.3 concentrations over past decades and contains two non-attainment areas as designated by the U.S. Environmental Protection Agency. Using the Weather Research and Forecasting with Chemistry (WRF-Chem) model, we examine O.sub.3 levels in the semi-arid and arid regions of Arizona. Our analysis focuses on the month of June between 2017 and 2021, a period characterized by high O.sub.3 levels before the onset of the North American Monsoon (NAM). Our evaluation of the WRF-Chem model against surface Air Quality System (AQS) observations reveals that the model adeptly captures the diurnal variation of hourly O.sub.3 levels and the episodes of O.sub.3 exceedance through the maximum daily 8 h average (MDA8) O.sub.3 concentrations. However, the model tends to overestimate surface NO.sub.2 concentrations, particularly during nighttime hours. Among the three cities studied, Phoenix (PHX) and Tucson (TUS) exhibit a negative bias in both hourly and MDA8 O.sub.3 levels, while Yuma demonstrates a relatively large positive bias. The simulated mean hourly and MDA8 O.sub.3 concentrations in Phoenix are 44.6 and 64.7 parts per billion (ppb), respectively, compared to observed values of 47.5 and 65.7 ppb, resulting in mean negative biases of -2.9 and -1.0 ppb, respectively.