Analysis And Control Suggestion Of Near-surface Ozone Precursors And Meteorological Factors In Fujian Province

In recent years,the rapid development of China’s economy has led to serious air pollution.O₃ precursors undergo photochemical reactions under the ultraviolet radiation of the sun,causing the concentration of O₃ near the ground to rise significantly,causing photochemical pollution and affecting people’s lives.In recent years,near-surface O₃pollution has become one of the main pollutions of air in Fujian Province.Therefore,research on the characteristics of near-surface O₃ pollution and its influencing factors,to understand the O₃ pollution situation in Fujian Province,master the O₃ pollution law,and propose O₃ pollution.The control measures are of great significance for solving the atmospheric problems in Fujian Province and preventing and controlling air pollution.This study adopted nine places in Fujian Province（Fuzhou City,Ningde City,Xiamen City,Zhangzhou City,Quanzhou City,Putian City,Sanming City,Longyan City,Nanping City）from 2016 to 2018（focus on 2017-2018）.The near-surface O₃concentration,precursors（including VOCs,NOx,CO）and corresponding meteorological elements（temperature,relative humidity,wind speed）data of the city（province）control points were analyzed to understand the near-surface O₃ concentration in Fujian Province.The law of time and space changes,explore the effects of NO₂,CO and other atmospheric pollutants and corresponding meteorological factors on the variation of O₃concentration,and propose countermeasures for the control of near-surface O₃ pollution in Fujian Province.The specific research results are as follows:（1）The distribution of O₃concentration in the near-surface of Fujian Province is significantly different in the spatial region,which is reflected in the coastal cities（Fuzhou,Quanzhou,Xiamen,Putian,Zhangzhou,Ningde）.The concentration in O₃ is generally higher than that in inland cities（Nanping City,Sanming City,Longyan City）,and in addition to Xiamen City,the number of days exceeding the standard of the five coastal cities is much higher than that of the inland cities.The annual average maximum hourly concentration value and the maximum daily average concentration value of the near-surface O₃ concentration in the coastal areas are also higher than those in the inland areas.In addition,the coverage of vegetation in the suburbs is much higher than that in urban areas.The emission of VOCs from O₃precursors is higher than that in urban areas,resulting in a significantly higher concentration of O₃ in suburbs than in urban areas.The temporal variation of O₃ concentration in the near-surface of Fujian Province is obvious.In terms of seasonal changes,due to the large amount of summer precipitation in Fujian Province,the relatively high relative humidity absorbs a large amount of ultraviolet light,which affects the photochemical reaction of O₃.The concentration of O₃in the inland areas is lower in summer and winter,but the concentration of O₃ in spring and autumn is higher.The concentration of O₃ in coastal areas is autumn>spring>winter,while the concentration of O₃ in summer is variable.The change in O₃ month concentration is basically bimodal.Generally,it will reach the peak in May and September.In June and December,the valley will appear.This is due to the rainy season in Fujian Province in June,and the UV in December is The weakest period of the year.The change of O₃ concentration showed a unimodal type.At around 8:00,the ultraviolet intensity of the sun began to increase,and the photochemical reaction of O₃ gradually strengthened.The highest hour O₃concentration generally appeared in the afternoon（13:00～15:00）,and the winter was better than the summer.later.Since the O₃photochemical reaction stops at night,the average O₃ concentration is higher during the day than at night.Affected by human daily activities,the“weekend effect”of the near-surface O₃ concentration change in Fujian Province is obvious.（2）The photochemical reaction of the O₃ precursor is an important cause of O₃formation.In recent years,Fujian Province has been very effective in controlling NOx emissions.The province’s NOx emissions are in a low and stable range.The precursors affecting the formation of near-surface O₃ in Fujian Province are mainly VOCs.Therefore,this paper focuses on the emissions of VOCs in the province.In 2015,the total emission of VOCs in the province was 590,000 tons.The key emission industries were industrial processes,architectural coatings,motor vehicles,oil storage and transportation,etc.,accounting for 30%,26%,10%and 8%respectively.The province’s total NOx emissions are 670,000 tons.The key emission industries are electric power,non-metallic mineral products,ferrous metal smelting and rolling processing,chemical raw materials and chemical products manufacturing,paper and paper products.In addition,as the number of motor vehicles in Fujian Province has increased year by year,emissions have also increased.The VOCs emissions from mobile sources,industrial emissions and architectural coatings in Fujian Province are large,and the VOCs emissions from mobile sources,industrial emissions and architectural coatings should be controlled.（3）Combining the temporal and spatial variation characteristics of near-surface O₃concentration in Fujian Province,the correlation between O₃ and NO₂,CO,PM_2.5,PM₁₀and other atmospheric pollutants was analyzed.It was found that O₃ concentration was negatively correlated with NO₂ and CO and correlated.Preferably,when the concentration of NO₂ and CO is relatively high,the concentration of O₃ is low,especially in the morning,when the solar ultraviolet is strong,the correlation between O₃concentration and NO₂ and CO is better.However,the near-surface O₃ concentration has a significant hysteresis relative to the CO concentration.In addition,the study also found a close relationship between O₃ concentration and PM_2.5 and PM₁₀.Studies have shown that O₃ concentration is negatively correlated with PM_2.5 and PM₁₀ concentrations from November to March,and April-10 The month is positively correlated.（4）Meteorological conditions such as wind speed,temperature and humidity will affect the change of O₃ concentration in the near ground of Fujian Province.The local source emission of O₃ precursors in Fujian Province is relatively large.Under the same conditions,the wind speed is higher,the lower the O₃ precursor concentration,the smaller the O₃ concentration near the ground;in general,the solar ultraviolet radiation determines the temperature.High and low,and the photochemical reaction of O₃ is related to solar ultraviolet radiation.The stronger the solar ultraviolet light is,the higher the O₃concentration is.Therefore,under the same conditions,the temperature is positively correlated with the O₃ concentration trend.The higher the temperature,the higher the O₃concentration;O₃ The trend of concentration change is negatively correlated with relative humidity.The higher the humidity,the lower the O₃ concentration.（5）For the characteristics of VOCs controlled areas in most areas of Fujian Province,the control of O₃ concentration should be dominated by VOCs.The pollution pollution of VOCs in Fujian Province comes from inter-regional transmission.Joint prevention and control should be strengthened to strengthen regional coordination and leadership.Joint enforcement of regional environment.Strengthen law enforcement inspectors and implement the responsibilities of various departments.To strengthen source control,we should focus on the control measures of VOCs in industrial sources,living sources and mobile sources,promote enterprise upgrading,and develop clean production technologies.Strengthen source prevention,strictly control the recycling of VOCs,and strengthen end management.Strengthen the supervision of motor vehicles,improve the fuel quality of motor vehicles;accelerate the upgrading of environmentally-friendly and energy-saving vehicles.Strengthen social pollution control,carry out garbage collection and classification,strengthen the control of incineration pollution,and reduce pollution emissions.