Analyses Of Characteristics And Causes Of Ozone Pollution In Suzhou City,Anhui Province

Tropospheric ozone,which is harmful to health,ecology,agriculture and so on,is mainly generated by photochemical reactions of VOCs,NO_x.At present,the situation of fine particulate pollution has been greatly improved due to the promotion of air pollution action,but the number of days with ozone as the primary pollutant is gradually increasing,and the situation of ozone pollution is serious in summer,so ozone pollution is attracting more and more attention.The boundary area of Jiangsu,Anhui,Shandong and Henan（JJLY）is located in the middle of Beijing-Tianjin-Hebei region and the Yangtze River Delta region（YRD）where air pollution control is relatively weak.The air pollution situation of JJLY is affected by industrial transfer and regional transmission in BTH and YRD.Suzhou is located in the north of Anhui and is a key city at the junction of JJLY.This paper compared the ozone pollution situation and association in the JJLY region by the analysis of characteristics of ozone pollution.Through the sensitive analysis of ozone,precursor and pollution characteristics analysis and parsing,ozone and the correlation analysis of meteorological factors,backward trajectory cluster analyses and so on,this paper explained the ozone causes and source of Suzhou from the point of view of chemistry and meteorology.In order to provide scientific ozone pollution prevention and control countermeasures for Suzhou.The characteristics of ozone pollution in Suzhou from 2017 to 2020 showed that ozone is gradually replacing PM_2.5 as the primary pollutant,and regional transport has an important contribution to the ozone concentration.Alkanes contribute the most to VOCs concentration in Suzhou from April to September in 2020,while the chemical activity of olefin and aromatic hydrocarbon is the highest,and the chemical activity of formaldehyde,acetaldehyde and hexaldehyde in OVOCs is the highest.The results of sensitivity analysis showed that NO_x and VOCs coordinated emission reduction is an effective means of ozone pollution control in Suzhou.The analytical results of PMF sources showed that exhaust gas from gasoline vehicles,industrial processes and gasoline volatilization contributed significantly to ozone generation.The correlation analysis of meteorological factors showed that ozone concentration has a great correlation with surface radiation,relative humidity and precipitation from April to September in 2020.Ozone pollution phenomenon mainly occurred when tempreture was between 25℃and 28℃,and relative humidity was below 75%.Different wind speed had different effects on ozone:when wind speed was lower than 4.5m/s,ozone concentration increased;When wind speed was 4.5-5.5 m/s,the increase of wind speed has a dilution effect on ozone concentration.The results of potential source analysis showed that the ozone pollution air mass in Suzhou mainly came from the border area of Hubei,Henan and Anhui provinces in southwest in April,and from the NYD region in southeast in May and June.From the perspective of chemical generation and meteorology,Suzhou should strengthen the collaborative control of VOCs and NO_x,focus on the monitoring of alkanes,olefin and OVOCs species in VOCs,focus on the investigation of exhaust gas from gasoline vehicles,industrial processes,gasoline volatilizes and other emission sources;In addition,the cooperation degree of ozone control in JJLY region should be improved,and the early warning and prevention and control of ozone transport should be strengthened.