【摘要】 为研究北京市夏季臭氧特征及污染成因,于2017年7月15日至2017年8月10日期间,在北京市城区进行气象要素、臭氧（O₃）、氮氧化物（NO_x）和一氧化碳（CO）的连续观测,并选取7 d（2017年7月20日、30日和8月1日、4～7日）密集采集大气样品进行挥发性有机化合物（VOCs）和含氧挥发性有机化合物（OVOCs）的分析。结果表明,观测期间北京市夏季O₃污染严重,臭氧污染日以东南风为主,一般伴随着高温、低湿、低压和高前体物（VOCs、CO和NO_x）浓度,占总观测天数的51.8%。密集采样日中臭氧污染日的成因与副热带高压或均压场下的弱高压系统有关。此外,来自河北、内蒙古中部和蒙古国东部途经保定和张家口等地的气流为北京夏季臭氧污染日的形成提供了部分外源,日平均贡献量为16%～37%,最大贡献量为53%,显示区域传输对臭氧污染日形成有重要影响。敏感性试验发现O₃的生成主要受VOCs控制,特别是人为源VOCs。以上结果表明,控制北京本地VOCs的人为排放和周边空气质量将有助于降低北京城区的O₃浓度。更多还原

【Abstract】 To investigate the characteristics and causes of ozone（O₃）pollution in Beijing,continuous measurements of meteorological parameters,O₃,nitrogen oxide（NO_x）and carbon monoxide（CO）were conducted at an urban site in Beijing from July 15 to August 10,2017.In addition,offline one-hour whole air samples were collected on 7 selected days（i.e.20 and 30 July,and 1 and 4–7 August 2017）to analysis volatile organic compounds（VOCs）and oxygenated VOCs（OVOCs）.The results indicated that Beijing suffered from severe O₃pollution,with the O₃ episodes accounting for 51.8%of the whole sampling period.In general,high O₃ days were associated with high temperature,low relative humidity,low pressure,and high levels of precursors（i.e.VOCs,CO and NO_x）.On the VOCs sampling days,high O₃ episodes were predominantly controlled by the Western Pacific Subtropical High or uniform pressure field（weak high pressure）.Furthermore,air masses from Hebei,middle Inner Mongolia and eastern Mongolia,passing by Baoding and Zhangjiakou,partially contributed to the observed O₃ in Beijing.The average regional contribution to O₃ accounted for 16%–37%,with a maximum of 53%The sensitivity analysis revealed that O₃ formation in Beijing was mainly sensitive to VOCs,especially anthropogenic VOCs（AVOCs）.This study indicated that effective control of AVOCs emissions in Beijing and the surrounding cities may help to reduce O₃ levels in Beijing.更多还原