Pollution Characteristics,Health Risk And Economic Losses Of PM(2.5) In Zhengzhou

Zhengzhou,as the capital of Henan Province and a nationally important transportation hub city,has developed rapidly in recent years,but has also brought about serious PM_2.5pollution and health problems.The pollution characteristics and sources of PM_2.5and inorganic elements were comprehensively analyzed,the exposure-lag-response relationships of air pollutants and meteorological parameters with PM_2.5were analyzed by Distributed Lag Non-linear Model（DLNM）,the health risks and economic benefits of PM_2.5and the carcinogenic and non-carcinogenic risks of inorganic elements were assessed,and the regional transport of PM_2.5and inorganic elements health risks were analyzed,based on conventional air pollutants online observation data from nine stations in Zhengzhou City and inorganic elements online observation data.The study showed that the annual average PM_2.5concentration in Zhengzhou in 2022was 47.03±43.88μg/m³,which exceeded the national annual average secondary standard limit by 1.3 times.The PM_2.5concentration at each site was characterized by high in winter and low in summer,and the daily and hourly variations were characterized by"U"and bimodal distributions,respectively.PM_2.5showed significant positive correlations with PM₁₀,SO₂,NO₂and CO.As the characteristic ratio method and the characteristic radar chart showed,the atmosphere pollution in Zhengzhou was mainly fine particulate matter pollution,which was mainly influenced by secondary generation and motor vehicle emissions.PM_2.5showed significant positive correlation with air pressure and relative humidity,and significant negative correlation with wind speed and temperature.Air masses was mainly influenced by long-distance transport from northwest,medium-distance transport from northeast and local transport.Henan Province,Heze,Jining,and Liaocheng in Shandong Province,and Jingmen in Hubei Province were the potential source areas of PM_2.5.PM₁₀was more clearly contributed by coarse particles mainly transported from outside in spring,and the potential source areas in other seasons were better similar to PM_2.5.As DLNM showed,PM₁₀,SO₂,NO₂,O₃,CO and relative humidity had a positive effect on PM_2.5,while wind speed and temperature had a negative effect on PM_2.5,with PM₁₀and CO was the dominant factors affecting PM_2.5concentrations.The effects of PM₁₀,O₃,CO and meteorological parameters on PM_2.5concentrations were mostly most pronounced at lag 0 h,while the effects of SO₂and NO₂on PM_2.5were significantly weaker at lag 0 h than at other lag moments.The cumulative effects of high PM₁₀and CO concentrations were the dominant factors affecting PM_2.5.PM_2.5pollution was inhibited by high wind speed and high temperature and promoted by high relative humidity.Single-peaked trend showed in the cumulative effect of wind speed and temperature on PM_2.5,while changed in relative humidity caused an approximately linear increase in the cumulative effect suffered by PM_2.5.PM_2.5concentrations,various health effects and economic losses in Zhengzhou and surrounding cities（Pingdingshan,Xinxiang,Luoyang,Jiaozuo,Xuchang,and Kaifeng）showed a downward trend from 2019 to 2021,with the highest number of outpatient health effects and the highest economic losses recoverable from avoiding premature death.Zhengzhou and Luoyang had the highest total health effects and economic benefits.If the annual average PM_2.5concentration reached the national secondary annual average concentration limit（35μg/m³）,the total health effects in Zhengzhou for 2019-2021 were93016（42883,148357）,79,428（36515,127386）and 35386（16191,57092）people,respectively,and the total health economic benefits were 254.37（85.72,396.37）,19.949（67.55,321.10）and 9.418（31.71,15.590）billion yuan,respectively.The mass concentrations of elements such as Al,Si,Fe and Ca,which were mainly from natural emissions,were significantly higher in heating period than in summer.The main sources of inorganic elements were mixed combustion,dust,metal smelting,and motor vehicle emission in heating period,and motor vehicle emission,coal and waste combustion,metal smelting,dust,and industrial combustion in summer.Health risks in heating period significantly exceeded those in summer,with Mn contributed a significant non-carcinogenic risk.The health risk was mainly contributed by local transport within Henan Province,short-distance transport from neighboring cities in the west and medium-distance transport from the coastal area of Tangshan.