Pearl River Delta (PRD) is a region in China with severe aerosol pollution and is the focus of early research on haze weather. These studies on haze weather include haze references, scientific concepts, long-term trends, fine-particle pollution, horizontal transfer and vertical diffusion ability, aerosol physical, chemical characteristics, and aerosol optical properties. The results of this research have indicated that the pollution by aerosols over the PRD has worsened in recent years. Aerosol clouds occur all year round, with an area of heavy pollution located at the western side of the Pearl River Estuary. The haze weather mainly occurs from October to the following April, resulting in visibility deterioration. Since the beginning of the 1980s, the frequency of haze weather over the PRD has obviously increased and visibility has deteriorated dramatically. Three major fluctuations in visibility deterioration have been accompanied by development of the economy, which has caused dust pollution, sulfate and dust pollution, and dust, sulfate, and automobile exhaust pollution caused by photochemical processes, respectively. No indication has been made that the long-term tendency of fog and light fog days is affected by human activities or economical development, and its fluctuation was governed by the intrinsic inter-annual and inter-decadal variations of climate. The deterioration of visibility over the PRD is strongly associated with fine-particle pollution. Half of the monthly mean PM10 observations exceeded the mean critical value of the national second graded standard (70 μg m-3), and all of the mean PM2.5 values exceeded the mean critical value of the U.S. national standard (35 μg m-3). Some mean values of PM2.5 reached nearly twice the standard value, indicating high concentrations of fine particles. The ratio of PM2.5 to PM10 was also very high at approximately 51%－79%. The monthly mean of black carbon concentration was 5.0 μg m-3－9.1 μg m-3. Compared with observations data recorded 20 years ago, the ratio of fine particles has obviously increased. The ratios of organic carbon, nitrate, and ammonium have increased, while that of sulfate slightly decreased and that of calcium obviously decreased. The formation of an airflow stagnation area is the main meteorological condition causing this severe haze weather, which is aggravated by weak vertical transport.
吴兑,廖碧婷,陈慧忠,吴晟.2014.珠江三角洲地区的灰霾天气研究进展[J].气候与环境研究,19(2):248-264. WU Dui, LIAO Biting, CHEN Huizhong, WU Cheng.2014. Advances in Studies of Haze Weather over Pearl River Delta[J]. Climatic and Environmental Research (in Chinese],19(2):248-264.Copy