In central and eastern China, regional heavy haze pollution occurs frequently in winter. The relationship between large-scale regional air pollution and urban haze has always been a key concern with respect to China’s air pollution. Dr. LU Miaomiao and Associate Professor TANG Xiao from Institute of Atmospheric Physics, Chinese Academy of Sciences analyzed a 30-day fine-particle (PM_2.5) pollution process that occurred in Wuhan, a megacity in central China, in a recently published study in Advances in Atmospheric Sciences.

They established a high-precision modeling system with an online source-tagged method to explore the impact of regional transport from surrounding city-clusters on the formation of severe PM_2.5 pollution in Wuhan. Furthermore, the paper reveals the relationship between the formation of continuous haze pollution in Wuhan and large-scale regional haze.

Wuhan is the largest city in central China and is situated at a crossroads where air pollutants from many neighboring and surrounding city clusters converge. For this reason, Wuhan’s geographic location has emerged as a key region for probing regional air pollution challenges in China. (Image by TAO Jin)

During the month of January 2014, the number of haze days was 18 in Beijing, while it was 30 in Wuhan. The team examined an unprecedented long period of persistent pollution over Wuhan that took place in January 2014, and compared the relationship between the haze episodes and meteorological conditions in Wuhan with Beijing. They found that the relationship between PM2.5 concentrations and meteorological factors over Wuhan was significantly different from that over Beijing.

"The sharp increases of PM_2.5 concentrations in Wuhan were often driven by strong northerly winds, while PM_2.5 pollution processes in Beijing mainly resulted from weak southerly winds and stable meteorological conditions. The high-precision simulation results showed that the formation of haze pollution in Wuhan was influenced by transport from the Wuhan megalopolis and surrounding city-clusters. In particular, long-range transport of polluted air masses from the North China Plain was the main factor leading to the sharp increases of PM_2.5 concentrations in Wuhan," says the lead author, LU Miaomiao.

Reference:

Lu, M. M., and Coauthors, 2019: Investigating the transport mechanism of PM2.5 pollution during January 2014 in Wuhan, Central China. Adv. Atmos. Sci., 36(11), https://doi.org/10.1007/s00376-019-8260-5 .

Media contact: Ms. LIN Zheng, jennylin@mail.iap.ac.cn