中国自然背景地区臭氧浓度时空变化特征分析

Analysis of Ozone Time Series Variation in Atmospheric Background Area in China

为揭示中国自然背景地区臭氧浓度变化特征,并以其为自然背景值指导人为活动导致的臭氧污染控制工作,该研究通过汇总统计中国15个典型自然背景地区与337个地级及以上城市2016—2020年环境空气臭氧自动监测数据,比较分析中国自然背景地区臭氧浓度的年度、季节、日内变化规律与空间分布规律.结果表明:2016—2020年,中国自然背景地区臭氧年均浓度明显高于城市区域,但臭氧日最大8小时平均浓度的第90百分位数(简称“臭氧年90百分位浓度”)明显低于城市,自然背景地区和城市区域臭氧年均浓度同步快速提升,年均增长分别为1.5和2.0μg/m3.中国自然背景地区臭氧浓度季节性变化规律与城市区域存在较大差异,自然背景地区臭氧平均浓度最高值出现在春季,夏、秋、冬三季臭氧平均浓度差异不明显,与东亚环太平洋背景地区臭氧浓度季节性变化规律(春季最高、夏季最低)存在明显差异.部分自然背景地区受人为活动排放的影响较小,臭氧浓度不存在明显的日内峰谷差,全天臭氧浓度基本保持相同水平;部分自然背景地区可能受邻近城市人为活动排放的臭氧前体物影响,臭氧浓度日内变化规律与邻近城市较为一致,存在明显的日内峰谷差.研究显示,中国自然背景地区臭氧浓度变化规律与城市区域存在显著差异,臭氧浓度年均值升高迅速,部分自然背景地区臭氧浓度变化规律可能受邻近城市人为活动排放的臭氧前体物传输的影响.

In order to reveal the time series characteristics of ozone concentration in atmospheric background area in China,we used the air ozone monitoring data of 15 background air monitoring stations and 337 cities from 2016 to 2020 to compare the annual,seasonal and daily change trends of ozone concentration in the atmospheric background and urban area.The results show that:(1)The annual average ozone concentration in the atmospheric background area is higher than cites,while the annual 90 percentage ozone concentration is lower than cities.The variation of annual average and 90%ozone concentration is similar between atmospheric background area and cities.(2)The ozone concentration in the atmospheric background and urban areas increase by 1.5 and 2.0μg/m3 per year,respectively.(3)The seasonal variation of ozone concentration in the atmospheric background area is different from urban area and the background area in the East Asia Pacific Rim.The highest background ozone concentration(89μg/m3)occurs in spring,and there is no significant variation of the background ozone concentration between summer(74μg/m3),autumn(75μg/m3)and winter(72μg/m3).(4)The daily ozone variation in some atmospheric background areas is different from neighboring city and there is no peak-to-valley distribution.However,under the transport effect of ozone precursors from the neighboring cities,the daily ozone variation in some atmospheric background areas is similar to the neighboring cities and has a significant peak-to-valley distribution.Thus,the time-series variation of ozone concentration in air background area is different from urban area,and the ozone concentration in background and urban areas both increase rapidly.Besides,ozone concentration in some background areas in China is affected by the transport of ozone precursors from neighboring cities.