西宁近地面臭氧特征及其影响因素

Study on Surface Ozone Characteristics and Its Influencing Factors in Xining

利用青藏高原东北部城市西宁2015—2017年O_3质量浓度和各气象要素数据(紫外辐射、最高气温等),分析近地面O_3变化特征及其影响因素,结果表明:该地区臭氧平均质量浓度呈现单峰型日变化规律。每年6—8月O_3质量浓度最大,12月至翌年2月最小。依据环境空气质量指数AQI统计分析,6—8月污染天气O_3占首要污染物总天数的72%。O_3与NO_2、CO呈极显著负相关,臭氧日最大1 h平均质量浓度与紫外辐射、日最高气温呈极显著正相关,与日平均气压、日最高气压、日最低气压呈极显著负相关,与日平均相对湿度相关性不显著。不同季节不同高度风速大小和风向频率对O_3质量浓度影响不同,500 h Pa盛行风向以WNW为主时有利于扩散。2017年青海省大部地区O_3月平均质量浓度总体呈先增加后减小变化趋势。纬度越低,海拔越高的地区,O_3质量浓度升高越早。降水量的差异对O_3质量浓度影响较小。

Based on the data of surface ozone mass concentrations and various meteorological elements(ultraviolet,maximum temperature,etc.)during 2015-2017,the characteristics and influencing factors of ozone near surface were analyzed.The results show that diurnal variation of surface ozone average mass concentration showed a single peak.There was a high surface ozone mass concentration from June to August and a low value from December to February.According to the statistical analysis of ambient air quality index(AQI)from June to August,the days of O 3 becoming primary pollutant accounted for 72%of the total.There were significant negative correlations between surface ozone mass concentrations and NO 2 and CO.There were significant positive correlations between maximum hourly-averaged surface ozone mass concentrations in a day and daily UV radiation and daily highest temperature,while there were significant negative correlations between maximum hourly-averaged surface ozone mass concentrations in a day and daily average pressure,daily maximum pressure and daily minmum pressure,and there was no significant correlation between maximum hourly-averaged surface ozone mass concentrations in a day and daily average relative humidity.Different wind speeds and wind direction frequencies had different effects on surface ozone mass concentrations in different seasons.The prevailing wind direction at 500 hPa was WNW mainly,which was conducive to diffusion.The monthly average mass concentrations of ozone in most parts of Qinghai Province increased first and then decreased in 2017.The lower latitude,the higher altitude,the earlier surface ozone mass concentrations rose.And the difference in precipitation had little effect on surface ozone mass concentrations.