Global Warming and Air Quality in China

Tuesday, 16 December 2014: 1:40 PM
Shaw Chen Liu, Academia Sinica, Taipei, Taiwan
The atmospheric lapse rate has been observed to decrease as a result of global warming. Reduced lapse rate is a result of a robust water vapor/lapse rate climate feedback simulated in coupled ocean–atmosphere models. The reduced lapse rate makes the atmosphere more stable, and in turn the more stable atmosphere can affect air quality in many aspects, most of them detrimental to the air quality. The largest effect of an increased vertical stability is an increased trapping of air pollutants in the boundary layer. A more stable atmosphere also makes it less likely to precipitate, especially for light and moderate precipitation that requires an unstable large–scale environment. Thus there is less scavenging of air pollutants by precipitation. Furthermore less precipitation implies less cloud cover or more clear days which can result in more nighttime inversions, again trapping more pollutants in the surface layer. Significant increase in clear days has been observed in China in the last 50 years, this can be a major contributor to more and worse fog/haze events in recent decades.