Simulation of Neighborhood‐Scale Air Quality With Two‐Way Coupled WRF‐CMAQ Over Southern Lake Michigan‐Chicago Region

Abstract The southern Lake Michigan region of the United States, home to Chicago, Milwaukee, and other densely populated Midwestern cities, frequently experiences high pollutant episodes with unevenly distributed exposure health burdens. Using two‐way coupled Weather Research Forecast Community Multiscale Air Quality Model (WRF‐CMAQ), we investigate criteria pollutants over a domain using 1.3 4 km resolution hindcast simulations. We assess WRF‐CMAQ's performance data from National Climatic Data Center Environmental Protection Agency System. Our simulation slightly improves on simulation's meteorological chemical while also resolving key details in areas impact, that is, urban environments. At km, find most air quality‐relevant components WRF‐CMAQ perform at or above community benchmarks. largely meets standards, substantial nuance depending metric component assessed. For example, hourly simulated NO 2 O 3 are highly correlated observations ( r > 0.6) PM 2.5 is less so = 0.4). Similarly, have low biases (<10%), whereas larger (>30%). Simulated spatial patterns show distinct urban‐rural footprints, 20%–60% higher than rural, 6% lower. use our simulations resolve high‐pollution within individual neighborhoods characterize seasonal changes regimes across tight gradients. findings demonstrate both benefits limitations high‐resolution simulations, particularly settings.