2014年北京奥体中心空气质量演变特征

利用中国环境监测总站发布的实时大气环境监测资料,选择北京国家奥林匹克体育中心(下称北京奥体中心)为研究对象,分析了2014年全年北京奥体中心空气质量演变特征. 结果表明:①2014年全年北京奥体中心首要污染污染物为PM_2.5,其次是NO₂,而PM_2.5和PM₁₀出现中度污染以上的污染事件主要集中在冬季和春末秋初；②PM_2.5、PM₁₀、SO₂、NO₂、O₃和CO等主要污染物的年均质量浓度分别为89.75、141.12、21.83、64.26、48.60和1 210 μg/m3. 其中年均ρ(PM_2.5)是GB 3095—2012《环境空气质量标准》二级标准限值(35 μg/m3)的2.6倍,年均ρ(PM₁₀)也是其二级标准限值(70 μg/m3)的2.0倍,年均ρ(SO₂)略高于其一级标准限值(20 μg/m3),而年均ρ(NO₂)则高于其标准限值(40 μg/m3)；③北京奥体中心全年逐月ρ(SO₂)/ρ(NO₂)都小于1.00,年均值为0.37,反映出北京目前硝酸型污染特征越来越明显；④针对不同污染等级下各类污染物质量浓度的分析结果显示,严重污染时ρ(PM_2.5)和ρ(PM₁₀)平均值分别高达324.75和494.98 μg/m3,分别是世界卫生组织(WHO)《空气质量准则》推荐24 h平均浓度准则值的13和10倍,其浓度如此之高会对人体健康造成严重危害；⑤ρ(PM_2.5)年均24 h变化趋势表明,ρ(PM_2.5)具有明显的日变化特征,出现2个峰值,高峰值出现在午夜时分(23:00—翌日01:00),次高峰值出现在上午(09:00—11:00),最低值出现在下午(15:00—17:00),次低谷值则出现在凌晨(05:00—07:00),说明ρ(PM_2.5)除与混合层高度日变化特征密切相关外,还与人们的日常生活有一定联系. 

Analysis of Air Quality at Beijing Olympic Sports Center in 2014

Analysis of air quality at the Beijing Olympic Sports Center by hourly monitored readings released by the Environmental Monitoring Station of China in 2014 indicated that:1) PM_2.5 was the principal air pollutant in 2014, while NO₂ was another important pollutant. Winter, late spring and early autumn were the highest incidence periods for air pollution at a medium or worse level, in which the primary pollutants were PM_2.5 or PM₁₀. 2) The annual concentrations of PM_2.5, PM₁₀, SO₂, NO₂, O₃ and CO were 89.75,1.12,1.83,4.26,8.60 and 1210 μg/m3 respectively. The annual concentrations of PM_2.5 and PM₁₀ were 2.6 times and 2.0 times higher than the national secondary standards, respectively, while the annual concentrations of SO₂ and NO₂ were slightly higher than the national standards. 3) The ratio of the annual mean concentration of SO₂/NO₂ was 0.37, which, being less than 1.00, showed that NO₂ made more contribution to air pollution than SO₂, and nitrate pollution is replacing sulfuric acid pollution to become more and more obvious in Beijing recently. 4) The concentrations of PM_2.5 and PM₁₀ in the severe pollution weather were as high as 324.75 and 494.98 μg/m3, which were 13 and 10 times higher than the 24 h average concentration breakpoint of the WHO Air Quality Standards and can harm to human health. 5) Research on average PM_2.5 trends over 24 hours showed that PM_2.5 had two peaks during the whole day. The highest peak appeared in the middle of the night (23:00-01:00), and the second-highest peak appeared from 09:00 to 11:00, the lowest peak appeared from 15:00 to 17:00, and the second-lowest peak appeared from 05:00-07:00. The results indicated that the concentration of PM_2.5 had a close relationship with daily human life, in addition to a connection with the daily mixing layer changes.