Study On Influencing Factors And Source Simulation Of Atmospheric Hydrogen Peroxide Concentration In Urban Area

The research on hydrogen peroxide has been started in foreign countries in the 19th century,but in China,there is still little research on hydrogen peroxide.The study of hydrogen peroxide in the atmosphere is not only of great significance to human health and the normal growth of animals and plants,but also to the study of atmospheric environmental quality and global climate.Hydrogen peroxide has the same strong oxidizing properties as ozone,so it will also affect the plant,which will damage the roots,stems and leaves of the plant and affect the normal growth of the plant.For crops,it will reduce the yield of crops,Causing severe losses to the peasant economy.Therefore,the research on hydrogen peroxide and its impact on plants and the impact on climate change have important research significance.At the same time,hydrogen peroxide is a storage material for free radicals in the atmosphere.Research is of great significance.During the period of 2018-2019,the hydrogen peroxide was sampled and analyzed in the urban area of Beijing,the factors affecting the concentration of hydrogen peroxide in the atmosphere and the qualitative simulation analysis of the source of its air mass were discussed.The main findings are as follows:（1）During the experimental observation period of 2018-2019,the measured minimum value of hydrogen peroxide is 0.17 ppbv,the maximum value is 6.85 ppbv,the concentration range is 0.17⁶.85 ppbv,and the average concentration is 1.46±1.56 ppbv.The hydrogen peroxide in the atmosphere shows a"single peak"daily change every day.Since the daily experimental observations start at 7:00 and end at 19:00,and show different diurnal changes on sunny days and cloudy days,The maximum concentration of hydrogen oxide on a cloudy day（July 27,2018）is much smaller than that on a sunny day（July 31,2018）.To analyze the seasonal changes,the seasonal change of atmospheric hydrogen peroxide concentration during the observation period is summer>autumn>spring.（2）The concentration of hydrogen peroxide in the atmosphere shows a significant positive correlation with temperature,and the concentration of hydrogen peroxide in the atmosphere increases with increasing temperature.In the three seasons of summer,spring and autumn,the hydrogen peroxide and ozone in the atmosphere showed a significant positive correlation.The hydrogen peroxide in the atmosphere showed a significant negative correlation with NO2 and NO concentrations.The correlation coefficient R with NO concentration was 0.378,and the correlation coefficient R with NO₂ concentration was 0.6954.The concentration of hydrogen peroxide in the atmosphere increases as the PM_2.5 concentration decreases,and the PM_2.5concentration is generally higher in the morning and evening every day,and the hydrogen peroxide concentration is the lowest at this time.In summer,hydrogen peroxide in the atmosphere has a relatively negative correlation with relative humidity.（3）During the observation period,it was found that the hydrogen peroxide in the atmosphere will increase on the evening of July 27,28,2018,and July 30,2018.The phenomenon was explained using backward trajectory simulation.It was observed at the simulation point in the evening The increase in the concentration of hydrogen peroxide in the atmosphere is mainly due to the fact that the air masses from the southeast and southwest of Beijing carry more hydrogen peroxide precursors.Under the conditions of atmospheric transport,reaching the simulation point makes the atmosphere in the simulation point area Peroxide concentration increased.At 7:00 and 8:00 on July 27,2018,the air mass originated from the coastal area of Tianjin.It passed through the Ninghe District at the junction of Tianjin and Tangshan,and then entered the Beijing area from the southeast of Beijing to the simulation point.The high concentration of hydrogen peroxide in the atmosphere was observed in the morning at the simulation point,mainly because the air mass in the southeast of Beijing carried more hydrogen peroxide precursors,and finally reached the simulation point through the air mass transport,so that A higher hydrogen peroxide concentration was observed in the morning.（4）According to the trajectory of the polluted air mass during the sampling period and the qualitative analysis of the source of the air mass,the results are as follows:There are three transmission paths for the generation of hydrogen peroxide at the observation point,which are the air masses from northern Beijing,which account for the smallest proportion（17%）,and the air masses from the east,mainly from Tangshan and Chaoyang City（33%）,and the air masses from southeast Hebei Langfang and Tianjin,accounting for the largest proportion（50%）.（5）Potential sources of pollution are mainly distributed in Langfang,Hebei and Tianjin,which belong to relatively short-distance transmission.The population density of Langfang and Tianjin is relatively large,and there are more hydrogen peroxide precursors in automobile exhaust and industrial exhaust gas,which reach the observation point through the transmission process,resulting in an increase in the concentration of hydrogen peroxide at the observation point.The high concentration of hydrogen peroxide during the summer observation period mainly comes from Langfang and Tianjin in the southeast.It shows that in summer,the hydrogen peroxide concentration in Beijing will be affected by the transmission,and the transmission in Hebei Langfang and Tianjin will be the most affected.The results simulated by the above potential source analysis（PSCF）and concentration weighted trajectory analysis（CWT）are more consistent.