The Characteristics Of Ozone Pollution And Analysis Of Ozone Formation Potential Of Its Precursors VOCs In Chibi City

In recent years,the problem of ozone（O₃）pollution has become increasingly prominent in China,which has become one of the main pollutants affecting the continuous improvement of ambient air quality.The same is true for Chibi City,which is located in Wuhan"1+8"urban circle.Based on the typical pollutants O₃,PM_2.5and meteorological data of Chibi City from 2017 to 2019,this study analyzed the pollution characteristics of O₃,studied the correlation between O₃and other pollutants and meteorological factors by using the method of Person correlation coefficient,and studied the backward trajectory of air mass in the process of typical O₃pollution by using HYSPLIT model.Based on the field sampling results,the Ozone Formation Potential（OFP）of volatile organic compounds（VOCs）was calculated.The main research conclusions are as follows:（1）According to the statistical analysis,O₃has become the main pollutant that affects the air quality of Chibi City.The annual evaluation value of O₃in Chibi City increased from 141μg/m³to 169μg/m³from 2017 to 2019,and the proportion of O₃concentration exceeding the standard days increased from 35.1%to 77.8%.The daily change of O₃concentration was single peak,and it appeared peak at 17:00,which was later than that in Wuhan and other typical cities.At the same time,O₃concentration showed a significant working day higher than the weekend of the anti"weekend effect".（2）The results of Person correlation coefficient analysis showed that there was a significant linear correlation between O₃concentration and meteorological parameters such as air temperature and relative humidity.The correlation coefficient between O₃concentration and daily maximum temperature is 0.39,and that between O₃concentration and daily temperature difference is 0.58;the correlation coefficient between O₃concentration and daily average relative humidity is-0.59,and that between O₃concentration and daily minimum relative humidity is-0.66.（3）Based on the statistical analysis of meteorological conditions in Chibi City,the area near the monitoring station of Lushui Lake environment is obviously affected by the Lake-land breeze.It is speculated that the wind direction switching of the Lake-land breeze can promote the accumulation of O₃and its precursors near the monitoring station,and the photochemical reaction will occur,thus affecting the O₃concentration.（4）Using HYSPLIT model analysis,it is found that the typical ozone pollution air mass in Chibi City mainly comes from Wuhan,Xiaogan,Huangshi,Xianning and other cities in the province,and Anhui,Jiangxi and other places outside the province.（5）Based on the results of field sampling and GC-MS detection,the concentration level and species distribution characteristics of VOCs in different areas of Chibi City were analyzed.The results showed that the concentration of VOCs in the central urban area was the highest,and that in the suburban area was the lowest.Combined with the calculation results of OFP,the chemical activities of VOCs in different areas of Chibi City were analyzed.It was found that aromatic hydrocarbons and olefins contributed more than 80%of the total amount of OFP,which were the key VOCs affecting the formation of O₃in Chibi City.