Influence of urbanization on meteorological conditions and ozone pollution in the Central Plains Urban Agglomeration, China.

Changes in aerodynamic and thermal conditions caused by urbanization can impact regional meteorological conditions, subsequently affecting air quality. Updated Moderate-resolution Imaging Spectroradiometer (MODIS) land use data and coupled with the urban canopy models (UCMs) in the Weather Research and Forecasting (WRF) model. This enabled the impact of urban land expansion on meteorological conditions and ozone (O) concentrations to be evaluated. Urban expansion increased the temperature at 2 m (T) and the probability of precipitation in urban expansion areas, and enhanced the surface urban heat island at night. As the expansion areas became progressively larger, the increase in T became more pronounced. The proportions of urban surfaces in June 2016, 2018, and 2020 compared to 2001 increased by 0.69%, 0.83%, and 1.04%, respectively, while T increased by 0.12, 0.19, and 0.20 °C in urban areas, respectively. With urban expansion, the O concentration increased by 1.12, 1.37, and 0.76 μg/m (three-year averages) in urban, suburban, and rural areas, respectively. After coupling a multi-layer urban canopy model (building effect parameterization, BEP), or a multi-layer urban canopy model with a building energy model including anthropogenic heat due to air conditioning (BEP + BEM, abbreviated as BEM simulation), the O concentration changed significantly in the urban expansion area, compared to the results of a single-layer urban canopy model (UCM). O concentrations decreased most in the BEP simulation (-0.77 μg/m), while O concentrations increased most in the BEM simulation (+1.85 μg/m). The average observed O concentration was 108.35 μg/m (three-year average), while the simulated value was 75.65-83.72 μg/m (R = 0.69-0.77). The validation results in the BEM and Global Optimal Scenario (GOS) simulations were relatively good, with the GOS simulation producing slightly better results than the BEM. The simulation of O in urban agglomerations could be improved by integrating the results of the UCMs.