为了研究南京夏季光化学污染特征,于2013-05-18~2015-08-31连续观测了臭氧及其前体物的浓度及气象要素。结果表明:臭氧(O3)、氮氧化物(NOx)和挥发性有机物(VOCs)平均体积分数分别为(32.01±15.20)×10-9、(21.50±14.02)×10-9、(33.16±25.20)×10-9,一氧化碳(CO)为(0.66±0.44)×10-6;O3体积分数小时均值最大值可达146.42×10-9;O3超过国家环境空气质量标准14.1%;有11 d出现霾现象,占整个观测时段的11.1%。观测点受周边源排放影响较大。在风速为2~3 m/s的西南风作用下,VOCs中的活性物种体积分数较高,O3体积分数易累积出现高值;偏东风主导下主要来自周围工业源和交通源排放的NOx、CO和VOCs等体积浓度易出现高值。臭氧产生效率(OPE)值比较低约为2.17±0.12。
Measurement of ozone and its precursors conducted from May 18th to August 31st,2013 with the meteorological data recorded simultaneously,was analyzed to characterize the local photochemical pollution in summertime. Results showed that the average mixing ratios of ozone(O3),nitrogen oxide(NOx)and volatile organic compounds(VOCs)in Nanjing northern suburb were about(32.01±15.20)×10^-9,(21.50±14.02)×10^-9 and(33.16±25.20)×10^-9 respectively,and carbon monoxide(CO)(0.66±0.44)×10^-6. For O3,the maximum value reached 146.42×10^-9,exceeding the national ambient air quality standard by a rate of 14.1%. There were 11 days with occurrence of haze,accounting for the entire observation period by a rate of 11.1%. Pollutants were significantly affected by local emission sources near the site. When affected by the southwest wind with the speed of 2 ~3m/s,active species of VOCs were easy to reach high level,accompanied by an increase concentration of O3. Under the influence of easterly winds,NOx,CO and VOCs,mainly emitted from industrial sources and traffic sources,were prone to reach high level. The observation site was located in the downwind area of the urban district so it was easily affected by the power plant plume and the ozone generation efficiency(OPE)was about 2.17±0.12.