The current study probed the spatial distribution and temporal variation of precipitation extremes over the Pearl River Delta region (PRD) depended on meteorological observation data for 1960-2019. The daily precipitation for the major 7 synoptic stations in the Guangdong province of China was analyzed. It is found that the spatiotemporal heterogeneity were the distribution characteristics of PRD precipitation. In terms of spatial distribution, more precipitation value in the eastern coastal areas of Guangdong province. In general, the average annual precipitation presented an increasing trend form 1960 to 2019. At the same time, the probability and intensity of extreme precipitation with increasing tendency were analyzed in this time period. It was indicated the continuing situation of climate fluctuation that adjusted the precipitation regime of Guangzhou. Summer became the season with the largest number of statistically significant trends of extreme precipitation, mostly increasing ones.

In this study, the water-soluble inorganic ions (WSIIs) composition of fine particulate matter (PM2.5) was measured in the northern Nanjing city from 2015 to 2021. NH4+, NO3− and SO42− concentrations dominated in total WSIIs (Na+, NH4+, K+, Mg2+, Ca2+, Cl−, NO3− and SO42−), accounting for 87.8%. The nitrate with highest average concentration among all ions was 11.0 μg·m−3. Total WSIIs concentrations were higher in winter and lower in summer, with the highest levels in December (45.6 μg·m−3) and the lowest levels in August (15.1 μg·m−3). NO3−/SO42− was higher than 1, indicating the important contribution of mobile sources. The aerosols exhibited a weak acidic by the molar ratio of water-soluble anions and cations. Positive matrix factorization (PMF) analysis results showed that secondary nitrate and sulfate were the major pollution sources in December 2016 and 2020. The contribution of secondary nitrate in 2020 increased by 47.6% compared to 2016, while that of secondary sulfate decreased by 42.4%. The potential source contribution results demonstrated that for secondary aerosol concentrations, the contribution of regional transport from north of Anhui increased, while the contribution of local emissions decreased. The results from this study could contribute to the better prevention and control of regional air pollution in the future.

Since the reform and opening up in China, the occurrence frequency of hazy phenomena have yearly increased, particularly in the urban agglomeration such as the Yangtze River Delta (YRD), Beijing-Tianjin Area, and the Pearl River Delta Area. The exposure to extremely poor ambient air quality might result in harmful influence on human health, such as respiratory system and cardiovascular diseases and deterioration in lung function. Here, we selected a typical area of the Yangtze River Delta (Nanjing city for case). We statistically analyze 45-year historical surface observations data of haze in Nangjing city, Southeastern China to study the relationship between lung cancer mortality and haze. The results showed that the dramatic increasing trend of annual occurrence of hazy days between 1961 and 2005, and then the relative incidence of lung cancer increased.