Study On Ozone Pollution Characteristic In Huangpu District Of Guangzhou

PM_2.5.5 and ozone are two major air quality problems in China.In recent years,PM_2.5.5 pollution in the pearl river delta region has improved.The concentration of PM_2.5.5 is decreasing year by year,and the rate of ozone exceeds the PM_2.5.5 level,which is even higher than PM_2.5.Ozone pollution near the ground is not only serious for human health,crop yield and vegetation growth,but also affects global climate change.Recent studies around the world have shown that ozone near the ground exhibits varying degrees of growth.The complex nonlinear relationship between VOC_S-NO_X-O₃ has brought great difficulties to the study of the formation mechanism of ozone and the prevention and control of pollution.In order to effectively control the growth of ozone concentration,it is necessary to explore the genetic mechanism of ozone and the regional difference of ozone sensitive type.To clarify the types of VOC_S and their contribution to ozone generation,the ozone control measures should be formulated according to local conditions.This study is based on the monitoring data of O₃ and NO_X of six atmospheric automatic monitoring stations in huangpu district,guangzhou in the last three years.Combined with VOC_S online monitoring data of a large residential area.The pollution characteristics of O₃ and its precursors in huangpu district of guangzhou,the sensitive type of ozone generation and the key types of VOC_S were studied.The main results are as follows.?1?The ozone concentration of 2015-2017 was analyzed by means of statistical analysis.The results show that,the number of days and hours in the air in huangpu district of guangzhou was not decreased.In 2017,the maximum 8-hour concentration of ozone day is 30 days and exceeded in 8.18%days.The daily variation of ozone concentration is unimodal.The highest value of O₃ appears around 15:00.There are obvious"weekend effects"in huangpu district,which is more influenced by human activities.?2?The annual mean of NO_X concentration increased year by year from 2015 to2017,andabovethenationalsecondarystandard.ExcessiveNO-NO₂-NO_X concentration in winter.The change of NO-NO₂-NO_X concentration day is the bimodal curve.Consistent with the peak hours,it can reflect that the nitrogen oxide concentration is mainly affected by vehicle exhaust pollution.?3?44 kind of VOC_S could be measured by SPIMS-1000 volatile organic compounds online monitoring instruments.The change in concentration of each species during observation was alkanes>olefin>halogenated hydrocarbon>aromatic hydrocarbon.The average hourly concentration of VOC_S was 75.75ppb.Accounted for alkanes was 50.9%.It's the main component of VOC_S.The characteristics of VOC_S day change showed that night concentration was higher than daytime.The tendency to increase at 20:00 in the evening is mainly due to the low height of the boundary layer.?4?To obtain the characteristic emission spectrum of automobile manufacturing industry.The VOC_S concentration trend in the industry was higher than that in the daytime.The changes in the concentration of each species were all the>alkene>halogenated>aromatic hydrocarbons.Alkanes are the largest amount of VOC_S in automotive industry.?5?The photochemical sensitivity of ozone in huangpu area was preliminarily determined by the VOC_S/NO_X ratio method.The formation of O₃ in huangpu district of guangzhou is VOC_S-limited.Therefore,the formulation of emission reduction measures against VOC_S can effectively reduce the effect of ozone concentration.?6?The reaction activity of VOC_S was studied by PEC and OFP method,the results show that,by PEC method,the proportion of olefins,alkanes and aromatic hydrocarbons is 58%,30%and 12%respectively.By OFP method,The proportion of olefins,aromatic hydrocarbons and alkanes is 62%,20%and 18%respectively.