青藏高原典型城市拉萨市近地面臭氧污染特征

摘要

As a typical city of the Tibetan plateau, the ambient air quality of Lhasa is better than inland cities, but the pollution of ozone has become more and more serious in recent years. The contributory factors of local ozone pollution were discussed based on its current situation and the characteristics. Results showed that:Compared with inland cities, the ozone concentration reached the annual average(105 μg/m3 in 2015) in March and below the annual average valueafter Septemberwith the characteristic of coming early and disappearing quickly, and the peak values of ozone concentration appeared likely in the ending of spring and the beginning of summer in Lhasa. The hourly concentration of ozone at noon was higher than it in the morning and night. Because of the high altitude and strong UV in the Tibetan plateau, the mean values of ozone in Lhasa was higher comparing to that in inland areas. The mean value of ozone in Lhasa is higher than Beijing and Chengdu at 7. 7％ and 29. 0％. The change of ozone concentration was influenced by air humidity, sunshine time and temperature in Lhasa. The cross-boundary transmission of biomass flue may also contribute as one of the sources of ozone in Tibetan plateau.%拉萨市作为青藏高原典型城市,环境空气质量相对较好,但臭氧污染近年来有所凸显.对拉萨市臭氧的现状与污染特征进行分析基础上,探讨臭氧污染的影响因素.结果表明:拉萨市臭氧污染表现出"来得早,去得快"的特征,与内地城市相比,拉萨市臭氧质量浓度在3月即可达到全年平均值(2015年为105μg/m3),而9月以后将低于全年平均值,并在春末夏初达到峰值;由于青藏高原海拔高,紫外线强,相对内陆地区臭氧均值偏高,2015年拉萨市臭氧年均值比北京市和成都市分别高出7.7％、29.0％,其小时浓度变化呈中午高、早晚低的特征;拉萨市臭氧的浓度变化受空气湿度、日照时间和日均气温的影响;生物质燃料的跨界传输可能也对青藏高原地区臭氧的来源产生一定影响.