Climatic Effects of Air Pollutants over China: A Review

Tropospheric ozone (O-3) and aerosols are major air pollutants in the atmosphere. They have also made significant contributions to radiative forcing of climate since preindustrial times. With its rapid economic development, concentrations of air pollutants are relatively high in China; hence, quantifying the role of air pollutants in China in regional climate change is especially important. This review summarizes existing knowledge with regard to impacts of air pollutants on climate change in China and defines critical gaps needed to reduce the associated uncertainties. Measured monthly, seasonal, and annual mean surface-layer concentrations of O-3 and aerosols over China are compiled in this work, with the aim to show the magnitude of concentrations of O-3 and aerosols over China and to provide datasets for evaluation of model results in future studies. Ground-based and satellite measurements of O-3 column burden and aerosol optical properties, as well as model estimates of radiative forcing by tropospheric O-3 and aerosols are summarized. We also review regional and global modeling studies that have investigated climate change driven by tropospheric O-3 and/or aerosols in China; the predicted sign and magnitude of the responses in temperature and precipitation to O-3/aerosol forcings are presented. Based on this review, key priorities for future research on the climatic effects of air pollutants in China are highlighted.