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Furthermore, the proportion of river and fishpond areas was positively correlated with the concentration of dissolved total phosphorus, dissolved organic carbon, and the permanganate index, while the proportion of the natural pond area was positively correlated with the concentration of particulate phosphorus and phytoplankton chlorophyll a. The influence of land-use types on water quality was also affected by distance from the river. This research indicates that the appropriate utilization of land and wetlands is key to controlling non-point nutrient loading in the river network, including Lake Taihu. Specifically, the self-purification capacity of wetland waters should be incorporated into nutrient control schemes, and special attention should be paid to the reduction of non-point source pollution in the drylands along the downstream riverbanks and urbanized areas.To explore the influence of human activities on the Yangtze River water chemistry, water samples were obtained from a representative section the main river stem/branch in wet and normal seasons in 2016. Ion ratio analysis, principal component analysis(PCA), and chemical ion balance calculations were performed, and carbonate rock dissolution rates were determined based on carbonate and exogenous acids. The result show that HCO3-Ca is the dominant hydrochemistry type, indicating that the dissolution of carbonate rocks in the basin is the main process affecting hydrochemistry, and carbonate acid is significant in the weathering of carbonate rocks. In addition, the proportion of carbonate acid dissolution in the wet and normal seasons accounted for 60.33% and 59.14% of the total dissolution, respectively. The dissolution ratio among the different sampling points was notable, which indicates that the carbon sink effect of exogenous acid cannot be ignored. In addition, cation exchange some influence on hydrochemistry but was not the main reaction process. Compared with hydrological monitoring data for the last few years, the weathering of rocks by sulfuric and nitrate acids has strengthened, and the negative effects of anthropogenic pollution in the Yangtze River have increased.The particulate matter emitted from coal-fired power plants includes condensable particulate matter(CPM) and filterable particulate matter(FPM). By analyzing the concentration of SO42-and NO3- components of CPM and FPM in the inlet/outlet of wet flue gas desulfurization(WFGD) and the outlet of wet electrostatic precipitator(WESP) from 7 ultra-low emission coal-fired power plants, the variation laws and transformation characteristics were investigated. The results showed that the concentration of SO42- and NO3- of CPM decreased after WFGD, with reduction rates of 43.12%-86.84% and 17.99%-91.58%, respectively, which were different from the conversion trend of FPM. The concentrations of SO42- and NO3- of CPM increased after WESP, with reduction rates of 21.05%-424.65% and 13.51%-298.37%, respectively, which were also different from that of FPM. In the WFGD system, CPM could be transformed into FPM due via condensation and aggregation under the decreasing temperature and increasing of humidity of the flue gas. In the WESP system, SO2 and NO2 in the flue gas combine with water vapor in a redox reaction, which promotes the generation of SO42- and NO3- in CPM through synergistic action.To understand the recent characteristics of atmospheric environmental changes in the Twain-Hu(Hunan-Hubei) Basin, including the middle reaches of the Yangtze River, this paper uses near-surface PM2.5 and PM10 observational data for the Twain-Hu Basin in the winters of 2015 to 2019, combined with wind-speed, topography, the normalized difference vegetation index(NDVI), and other datasets. The results show that① PM2.5 pollution occurred frequently in the winters of 2015-2019 in the Twain-Hu Basin, and Xiangyang and Jingmen in the western part of the basin, experience PM2.5 pollution on an average of 62 and 61 days in winter(PM2.5>75 μg·m-3). And the heavy pollution days in Xiangyang reached 19 more days(PM2.5>150 μg·m-3), indicating that the Twain-Hu Basin is an air pollution center in the middle reaches of the Yangtze River Basin; ② Spatially, pollution in the Twain-Hu Basin is heavier in the northwest than in the southeast, and in the urban agglomeration, which is mainly related to the regional transport of air pollutants by the winter monsoon and the high levels of emissions from urban areas; ③ A “U-shaped” nonlinear relationship was observed between near-surface wind speeds and PM2.5 and PM10 concentrations. The inflection points of PM2.5 and PM10 concentrations were 153 and 210 μg·m-3, respectively. This implies that the accumulation of local atmospheric particulate matter in the Twain-Hu Basin dominates light/medium pollution, while the regional transport of air pollutants dominates period of severe pollution; and ④ PM2.5 and PM10 in winter were significantly negatively correlated with terrain height and the NDVI, which reflects the atmospheric environmental effects of topography and urbanization.Under certain terrain and weather conditions, mountain-valley circulation is one of the main meteorological factors affecting aerosol pollution in plain-mountain area. Based on environmental monitoring data and multi-source meteorological data for the Beijing-Tianjin-Hebei region between 2015 and 2019, the characteristics, similarities, and differences of mountain-valley winds in the Beijing Plain and Yanhuai Basin regions were compared. The results show that the mountain-valley winds recorded at the Beijing Observatory are from southwest to northeast compared to from the southeast to northeast at Yanqing station. With the aggravation of pollution levels, the mountain-valley wind intensity decreased by 17.7%-32.4%. When the wind speed at Beijing Observatory was 2-6 m·s-1, the maximum PM2.5 concentration in southeast was 83 μg·m-3, which was higher than in the southwest. When the wind speed at the Yanqing station was 2-6 m·s-1, the PM2.5 concentrations in SE-SSE area was 20-40 μg·m-3 higher than in other direccal circulation may be related to the bidirectional feedback mechanism of the boundary layer and high concentrations of aerosols.Air pollutant concentrations in the Xiamen Bay cities during the period before and after COVID-19 lockdown(from January 11 to February 21, 2020) were studied to determine the influence of human activities on air quality in this region. During the Chinese Spring Festival holiday and the lockdown period, the concentrations of SO2, NO2, CO, PM10, and PM2.5 decreased by 6%-22%, 53%-70%, 34%-48%, 47%-64%, and 53%-60%, respectively. However, the changes in O3 concentrations were not consistent with the variations of human activities. The reduction rates for PM2.5, PM10, CO, and NO2 during the Spring Festival were greater than in previous years(2018 and 2019), but the reduction rates for SO2 were comparable. The concentrations of NO2 increased sharply(38%-138%), and much higher those of SO2(2%-42%), after the resumption of socioeconomic activities, indicating the importance of traffic reductions due to the lockdown measures on NO2. Higher wind speeds and rainfall after the Spring Festival were also favorable for the decline of SO2, NO2, and PM. The spatio-temporal distributions of the six criterial pollutants in the Xiamen Bay city cluster were obtained based on the Inverse Distance Weight method. The variability in regions with high NO2 concentrations was strongly linked to traffic emissions, while spatial patterns for CO and SO2 changed little over the six-week study period. The concentrations of PM2.5 and PM10 increased notably in the region, linked to more construction activity, but changed comparatively little in regions with dense populations and traffic networks. O3 remained relatively stable but low-value regions corresponded to those regions with high NO2 concentrations, indicating the significant titration effect of NO2 on O3. Noradrenalinebitartratemonohydrate These results provide valuable information that can inform O3 pollution reduction measures.To determine the differences in emissions among different types of coatings, such as solvent-based, water-based, solvent-based ultra-violet(UV), water-based UV, and powder coatings, representative furniture manufacturing companies were selected for analysis. The emission concentrations and compositional characteristics of volatile organic compounds(VOCs) in different types of coatings were compared and studied. The ozone formation potential(OFP) and secondary organic aerosol formation potential(SOAFP) of the different types of coatings were also analyzed. Solvent-based coatings has higher TVOC concentrations, OFPs, and SOAFPs than water-based, solvent-based UV, water-based UV, and powder coatings. The concentrations and composition of VOCs emitted from the different types of coatings were also different. The main VOC groups of the solvent-based and solvent-based UV coatings were aromatic hydrocarbons and oxygenated volatile organic compounds(OVOCs). Specifically, the proportions of aromatic hydrocarbons are 4carbons(43.46%), OVOCs(28.06%), and olefins(25.24%) were the main factors affecting the OFP of the powder coatings. Aromatic hydrocarbons dominate the SOAFP of solvent-based, water-based, solvent-based UV, water-based UV, and powder coatings, accounting for more than 99%.A total of 99 volatile organic compound(VOC) species were detected the Langfang development zones based on continuous monitoring using a ZF-PKU-1007 between August 25 and September 30, 2018. The concentrations, reactivity, and sources of VOCs were studied under different O3 concentrations using compositional analysis. The results showed that the average VOCs concentration during the research period was(75.17±38.67)×10-9, and was(112.33±30.96)×10-9, (66.25±34.84)×10-9 on pollution days and cleaning days, respectively(VOCs concentrations were 69.6% higher on pollution days). The contribution of VOCs species to the ozone formation potential(OFP) were ranked in the order aldehydes > aromatics > alkenes > alkanes. In the case of L·OH, the main contributions were from aromatics(30.0%) and alkenes(25.8%) on pollution days, while the contribution from aromatic alkenes(29.8%) was a slightly higher than aromatics(28.0%) on cleaning days. By applying the positive matrix factorization(PMF) model, five major VOCs sources were extracted, namely vehicle emissions(34.4%), solvent usage and evaporation(31.7%), the petrochemical industry(15.7%), combustion(11.1%), and plant emissions(7.9%). The contributions of solvent usage and evaporation and plant emission sources on pollution days were 13.1% and 1.2% higher than on cleaning days, respectively, which was likely due to relatively higher temperatures on these days. Therefore, vehicle emissions and solvent usage and evaporation should be priorities in VOCs control strategies for the Langfang development zones between August to September.To study the characteristics of ozone sources in a petrochemical industrial park in Shanghai, O3 and its precursors were synchronously and continuously measured for 3 months(June-August 2020) alongside meteorological parameters using an online monitoring system. The Texas Commission on Environmental Quality(TCEQ) method and principal component analysis(PCA) were used to study the contribution of regional background and local O3 concentrations in the industrial zone, the results of which were compared. The results indicated that① During the observation period, the dominant wind directions in the park were southeast and east, and the average temperature was 27.12℃. The daily average ρ(VOCs-36), ρ(NOx), and ρ(O3) was 32.05-240.51, 10.15-47.51, and 31.81-144.43μg·m-3, respectively. Alkanes are the most abundant of 36 VOCs; ② The regional background concentrations based on the TCEQ method ranged from 32.63 to 191.13μg·m-3, and the local concentrations ranged from 16.08 to 134.25 μg·m-3. The percentage contribution of the regional background ranged from 32.