Temporal And Spatial Characteristics Of Air Pollution Of Hohhot,2013-2017

Hohhot is located in the North China region and belongs to the Beijing-Tianjin-Hebei region.In recent years,air pollution has been gradually transformed from coal-smoke pollution to compound pollution influenced by industrial,coal-burning and motor vehicle exhaust emissions and other pollution factors,which has negative effects on the harmonious development of social economy,ecological environment and public health.In this paper,the spatial and temporal variation characteristics of PM₁₀,PM_2.5,SO₂,NO₂,CO and O₃ were systematically analyzed using the monitoring data of environmental air quality in Hohhot from2013 to 2017 and the enhanced monitoring data during heavy pollution.At the same time,mobile monitoring,lidar navigation observation and other means are introduced to monitor and evaluate the situation of coal burning in Hohhot and its influence,which is of practical guiding significance to understand the causes of spatial and temporal characteristics of air pollution in Hohhot,and to control and improve the quality of atmospheric environment.The paper concludes the following conclusion:1.From 2013 to 2017,the overall environmental air quality in Hohhot has been improved.The decrease sequence of pollutant concentration,which is dominated by soot air pollution,is:SO₂>CO>PM₁₀>PM_2.5.However,only SO₂ and CO in the city's ambient air meet the level 2 standard of environmental air quality standard?GB3095-2012?.The remaining four pollutants are still exceeding the standards,especially PM10 and PM_2.5,which are the primary pollutants that affect environmental air quality.2.The diurnal and seasonal variation characteristics of air pollution in Hohhot are obvious,showing the diurnal variation characteristics of"double-peak type"and the characteristics of serious pollution in heating period.3.In 2017,the concentration of O₃ in Hohhot reached 166g/m3,higher than the national level 2 standards and the 90th percentile increased year by year,which was the main reason for the excessive AQI on the ambient air quality day in summer.It may mean that the air pollution in Hohhot has changed from soot type to compound type.4.In terms of spatial distribution,Hohhot's air pollution presents the basic distribution characteristics of high in the north and west,low in the south and east.The high pollution area is obviously concentrated in the densely populated urban center of the built-up area.5.The lidar observation results show that the non-point source pollution in the urban area is dispersed,and the most serious pollution is in the villages of the city,which tends to diffuse and migrate to the city.