太原大气中NO_x、O_3和OX的污染特征及相关性研究

Pollution Characteristics of NO_x, O_3 and OX in the Ambient Airof Taiyuan City and Relativity Study

臭氧(O3)是城市大气光化学污染的首要污染物,其变化规律与氮氧化物(NO,NO2)关系密切。2013年5月采用美国热电环境设备公司生产的臭氧分析仪和氮氧化物分析仪对太原市某工业区点位A和清洁对照点B进行了连续同步观测。结果表明,A和B点环境空气中O3均呈单峰型日变化,午后16:00左右出现最大值;但2个点位NOx的日变化不同,其中A点NOx的日变化为低谷型,B点的则呈单峰型;A和B环境空气中的NO2和O3均存在NOx浓度分界点,分界点以下O3占多数,分界点以上NO2占大部分;A和B环境空气中的OX均以O3为主,且与温度成显著正相关。但A点的OX、O3与NO2成负相关,O3控制属于VOCs敏感区,且区域贡献较大;B点的OX、O3则与NO2成显著正相关,以本地生成为主。值得注意的是,A点OX与NOx成负相关,与已有报道不同,需进一步研究。

Ozone（O 3） is a primary gaseous pollutant and its variation is correlated with nitrogen oxides（NO and NO 2）. In May 2013, 49 i ozone analyzer and 42 i NO-NO 2- NOx gas analyzer were used for continuous monitoring of point A at one industrial area of Taiyuan City and point B as clean control. The results showed that O3 concentration in the ambient air of both point A and B presented a single-peak diurnal variation with the maximal peak at about 16：00 in the afternoon. However, the diurnal variation of NOx at the two points was different. That was, the diurnal variation of NOx at A was trough type, while that at B was single-peak type. With regard to the NOx concentration demarcation point, O3 accounted for the majority below the point and NO2 occupied the majority above the point. OX（defined as O 3 ＋NO 2） in the ambient air of both A and B was mainly composed by O 3, with significant positive correlation with temperature. Nevertheless, OX and O3 at A were negatively correlated with NO 2. O3 was more sensitive to VOCs and greatly contributed by regional pollution. OX and O3 at B were positively correlated with NO2 and mainly contributed by local pollution. It should be noted that OX at A presented negative correlation with NOx, which was different from the previous reported studies. Therefore, further research was needed.