Differences in urban–rural gradient and driving factors of PM2.5 concentration in the Zhengzhou Metropolitan Area

The escalation of PM_2.5 pollution in the Zhengzhou Metropolitan Area (ZMA) underscores the pressing need for air pollution mitigation measures. We utilized high-resolution PM_2.5 data from 2020, with a 1 km spatial resolution, to identify and comprehend the factors influencing PM_2.5 concentration across the urban–rural continuum. This extensive dataset, inclusive of terrain, meteorological data, vegetation cover, population density, GDP, nighttime light data, and land use categories, facilitated our analysis of PM_2.5 trends across the urban–rural spectrum in nine ZMA cities. Our results demonstrate that there is no consistent correlation between city size and classification with PM_2.5 pollution levels. However, urban and suburban regions demonstrated higher pollution levels compared to rural areas. The PM_2.5 concentrations exhibited considerable variance along the urban–rural continuum. Spring and summer exhibited rising concentrations along the continuum, while autumn witnessed a decrease. Spatially, the PM_2.5 concentration demonstrated higher trends in the eastern and southern regions compared to the western and northern areas, indicating distinctive urban–rural gradient patterns. The influencing factors displayed a scale effect: metropolitan areas showed a stronger correlation with natural elements such as elevation and wind speed; suburban regions correlated with meteorological factors; urban areas were notably impacted by socio-economic factors. Effective collaboration among cities for emission reduction and pollution control is crucial, irrespective of meteorological conditions.