• 关键词：重庆  PM_2.5  NO_x  SO₂  O₃

• 基金项目：国家自然科学基金重点项目(No.41230642);中国科学院战略性先导科技专项(No.XDA05100100);国家自然科学基金项目(No.41275160,41005069)及中央高校基本科研业务费专项(No.XDJK2013A009,XDJK2015A013)

• 徐鹏
• 西南大学三峡库区生态环境教育部重点实验室, 西南大学资源环境学院, 重庆 400715

• 郝庆菊
• 西南大学三峡库区生态环境教育部重点实验室, 西南大学资源环境学院, 重庆 400715

• 吉东生
• 中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室, 北京 100029

• 张军科
• 中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室, 北京 100029

• 刘子锐
• 中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室, 北京 100029

• 胡波
• 中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室, 北京 100029

• 王跃思
• 中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室, 北京 100029

• 江长胜
• 西南大学三峡库区生态环境教育部重点实验室, 西南大学资源环境学院, 重庆 400715

• 摘要：重庆是我国西南工业重镇,但长期受大气污染困扰.利用全自动在线环境监测仪器,于2012年1月-2014年2月,对重庆市北碚区大气中的典型污染物PM_2.5、NO_x、SO₂和O₃进行了观测研究.结果表明:重庆北碚大气首要污染物为PM_2.5,2012和2013年平均浓度分别为(67.5±31.9)和(66.6±37.5) μg·m^-3,是国家环境空气质量一级标准35μg·m^-3的1.9倍,两年超过国家二级标准的天数分别为119和126 d,年超标率均大于1/3;两年NO_x, SO₂及O₃的年平均浓度分别为(57.1±24.6)和(55.1±36.6), (43.1±24.0)和(35.0±21.9)及(31.1±24.9)和(48.5±37.4) μg·m^-3.大气污染物浓度具有明显的季节变化特征,PM_2.5和NO_x冬季污染最为严重,两年冬季平均值分别比两年年平均值高33.6%、59.6%和43.2%、8.5%;O₃表现为夏高冬低;SO₂春季最高且污染最轻.大气污染物日变化显示PM_2.5和NO_x浓度呈双峰日变化形式,有早晚两个峰值,与城市交通高峰相对应.SO₂和O₃浓度呈单峰日变化,前者峰值出现在午前10:00-12:00大气对流层被打破之后,而后者峰值出现在午后16:00局地光化学最强之时.消减各种污染源的颗粒物直接排放,消减气态污染物SO₂和NO_x的工业排放,消减机动车NO_x和VOCs等的排放,才有可能使重庆北碚的大气污染状况得到改善.

• Abstract：Chongqing is an industrial powerhouse in Southwestern China with significant air pollution. In this paper, automatic on-line continuous monitoring equipments are used to acquire the ambient concentrations of PM_2.5, NO_x, SO₂ and O₃ from Jan. 2012 to Feb. 2014 in Beibei district of Chongqing. The results indicated that PM_2.5 was the most serious pollutant, with the annual mean values of (67.5±31.9) and (66.6±37.5) μg·m^-3 in 2012 and 2013, respectively, 1.9 times the National Ambient Air Quality standard (35 μg·m^-3). In 2012 and 2013, there were 119 and 126 days with PM_2.5 concentrations exceeding the corresponding values of the new National Ambient Air Quality Standards, respectively. Annual mean value of NO_x, SO₂, O₃ was (57.1±24.6) and (55.1±36.6), (43.1±24.0) and (35.0±21.9), (31.1±24.9) and (48.5±37.4) μg·m^-3 in 2012 and 2013, respectively. The atmospheric pollutants concentration has obvious seasonal variation characteristics. PM_2.5 and NO_x pollution was the most severe in winter, with winter averages value 33.6% and 59.6% higher than annual average in 2012 and 43.2% and 8.5% higher than 2013. The concentration of O₃ was the highest in summer and lowest in winter, while SO₂ was the highest in spring. NO_x and PM_2.5 showed bimodal distribution in the morning and evening in their diurnal variation, corresponding to urban traffic peak hour emissions. In comparison, daily variation of SO₂ and O₃ concentration show unimodal type distribution. SO₂ peak appeared at 10:00-12:00 when the boundary layer expanded, while O₃ peak appeared at 16:00 when local photochemical reaction is the most significant. Simultaneous reduction on direct emission of particulate matter, industrial emissions of NO_x and SO₂, and vehicle emissions of NO_x and VOCs may gradually reduce the serious air pollution of Chongqing district.

• Key words：Chongqing  PM_2.5  NO_x  SO₂  O₃

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