Chemical Characteristics And Source Analysis Of Atmospheric Precipitation In Typical Regions Of My Country

In order to study the pollution characteristics and sources of atmospheric precipitation in different regions of China,this study is based on the wet deposition data from 2003 to 2018 of The Acid Deposition Monitoring Network in East Asia(EANET).This study selected conductivity,p H value and precipitation of water-soluble ion concentration and precipitation annual data,of Southwest China(Chongqing),Northwest China(Xi'an),East China(Xiamen)and South China(Zhuhai)in the precipitation,analyzed the temporal and spatial characteristics of atmospheric precipitation pollution in different regions,precipitation neutralization Capability and ion deposition characteristics,combined with PMF source analysis mode to analyze pollution sources.The results showed that the p H in the study area from low to high was:Southwest,East China,South China and Northwest China.It can be seen from the conductivity that the two most polluted areas are the Northwest China and Southwest China,and the precipitation in remote areas is cleaner than in urban areas.Except for the increase in southern China in recent years,the conductivity of each site has decreased over time.The p H value of precipitation in various places has also increased,and most areas with more serious acid rain problems have improved.Secondary sulfates,vehicle emission sources,and fossil fuel combustion sources are all local pollution sources.There are also dust sources and agricultural sources in the Southwest China and Northwest China.Biomass combustion sources and sea salt sources also have an impact on East China and South China.Acidic ion SO₄^2-and NO₃^-in the Northwest China and Southwest China are more thoroughly neutralized in the northwest and southwest regions,and weaker in the east and south regions.Ca²⁺is the alkaline particle that has the greatest neutralization effect in precipitation.Overall the total ion concentration of precipitation around gradually decreases with time,the degree of precipitation pollution better.Except for Southern China(Zhuhai)where the precipitation type is mainly mixed,the other areas are mainly sulfuric acid.The wet deposition flux is in the order of Southwest China>Northwest China>East China>South China,and the amount of wet deposition in Southwest,Northwest,and East China has a decreasing trend over time,while that in South China has increased after 2014.The sulfur deposition flux shows the characteristics of Southwest China>Northwest China>East China>South China,and the sulfur deposition flux is higher in urban areas due to emissions from human activities.In addition,the amount of sulfur deposition decreased significantly over time in both the Southwest and Northwest regions.In the research,the wet deposition of nitrogen is mainly NH₄⁺-N,and the total inorganic nitrogen deposition is characterized by Southwest China>Northwest China>East China?South China.