青海门源地区O_3浓度水平及影响因子分析

O_3 Concentration in Menyuan Area,Qinghai Province,China and Its Affect Factor

为研究高原背景地区O_3的浓度水平,于2013年9月13日至2013年10月14日期间,在国家大气背景站青海门源站开展了为期32天的观测。观测结果显示,门源地区O_3小时浓度均值为115.0±22.6μg/m3,低于《环境空气质量标准》(GB3095-2012)中O_3小时平均浓度限值的一级标准(160μg/m3)。通过分析O_3和NOx实时浓度在一天24小时内随时间变化的特征序列,发现在多数观测天内O_3和NOx呈现此消彼长的变化规律,表明O_3主要来自有NOx参与的光化学反应;另有几天NOx和O_3的浓度出现同峰同谷的现象,推测这种变化主要是大气运动传输造成的。相关性分析表明,臭氧浓度与温度、湿度、风速、SO2、NOx以及CO的浓度都显著相关(P<0.01);多元线性回归分析表明O_3与温度、湿度、气压、风速的关系近似符合Y=0.630T-0.192H-0.004P-0.091W+196.039,拟合结果与真值误差2.88%。综上分析,门源地区O_3浓度水平较低,但在高温低湿、风速较高、NOx浓度较低的情况下,O_3容易积累,O_3浓度主要受光化学反应和大气运动传输过程两个因素影响。

Concentrations of O3 had been monitored by O3 analyzer M400EU,at national background station in Menyuan area,Qinghai Province,China,during the period from Sep.13th2013 to Oct. 14th2013. Observation results show that the hourly average concentration of O3 is 115. 0±22. 6 μg / m3,lower than the limiting value（ 160 μg/m3） and 1-hour average O3 concentration is taken as grade 1,based on Ambient Air Quality Standards（ GB3095-2012）.The synchronism of NOxand O3 concentration was checked detailedly. Most of the time,analysis result showed negative synchronism,which means decreasing NOxwith increasing O3 concentrations,revealing that concentration of O3 is controlled by photochemical reaction with NOxas gas precursor. While during the rest of the sampling period,positive synchronism of NOxand O3 were found,waving with ups and downs together,indicating that the atmospheric transmission process is responsible for accumulation of O3.Meanwhile,multiple linear regression analysis of O3 and environmental parameters show that the equation of linear regression is Y = 0. 630T- 0. 192H- 0. 004P- 0. 091 W ＋ 196. 039. Based on analysis above,concentration of O3 is controlled by both photochemical reaction and atmospheric transmission process,while low NOxconcentration combined with high temperature,low humidity and high wind speed,might promote the accumulation of O3.