Abstract. Impacts of global climate change on the occurrence and development of air pollution have attracted more attentions. This study investigates impacts of the warming Tibetan Plateau on air quality in the Sichuan Basin. Meteorological observations and ERA-interim reanalysis data reveal that the Tibetan Plateau has been rapidly warming during the last 40 years (1979–2017), particularly in winter when the warming rate is approximately twice as much as the annual warming rate. Since 2013, the winter temperature over the plateau has even risen by 2 °C. Here, we use the WRF-CHEM model to assess the impact of the 2 °C warming on air quality in the Sichuan Basin. The model results show that the 2 °C warming causes an increase in the Planetary Boundary Layer (PBL) height and a decrease in the relative humidity (RH) in the basin. The elevated PBL height strengthens vertical diffusion of PM2.5, while the decreased RH significantly reduces secondary aerosol formation. Overall, PM2.5 concentration is reduced by 17.5 % (~ 25.1 μg m−3), of which the reduction in primary and secondary aerosols is 5.4 μg m−3 and 19.7 μg m−3, respectively. These results reveal that the recent warming plateau has improved air quality in the basin, to some certain extent, mitigating the air pollution therein. Nevertheless, climate system is particularly complicated, and more studies are needed to demonstrate the impact of climate change on air quality in the downstream regions as the plateau is likely to continue warming.
The Warming Tibetan Plateau improves winter air quality in the Sichuan Basin, China
