Extreme air pollution meteorology, such as heat waves, temperature inversions, and atmospheric stagnation episodes, can significantly affect air quality. In this study, we analyze their long-term trends and the potential impacts on air quality. The significant increasing trends for the occurrences of extreme meteorological events in 1951-2010 are identified with the reanalysis data, especially over the continental regions. A statistical analysis combining air quality data and meteorological data indicates strong sensitivities of air quality, including both average air pollutant concentrations and high pollution episodes, to extreme meteorological events. Results also show significant seasonal and spatial variations in the sensitivity of air quality to extreme air pollution meteorology.

Based on the sensitivity studies of air quality to air pollution meteorology, statistical models are constructed to predict the likelihood of extreme air pollution episodes with the status of extreme air pollution meteorology in two consecutive days. Our statistical models present reasonable estimation of air pollution days validated with observations. Our method is more computational efficiency and user-friendly than the complicated atmospheric chemistry models. It could be a useful tool for air quality forecast, in particular for projecting the risk of extreme air pollution episodes.

Extreme meteorological events related to precipitation, such as drought or heavy precipitation, are also important for air quality. To get a better understanding of the relationship between precipitation features and air quality, we examine the sensitivities of air pollutants to the changes of various precipitation characteristics in the context of climate change. Perturbation studies are tested with GEOS-Chem model to isolate the roles of precipitation frequency, precipitation intensity, and total precipitation amount in the lifetime of black carbon (BC). We find that the atmospheric lifetimes of BC are more sensitive to precipitation frequency than precipitation intensity. The relationship between the lifetime of aerosols and the change of precipitation characteristics offer a simple tool to examine the effects of long-term changes of precipitation characteristics on atmospheric aerosols in various regions.