郑州市西郊臭氧浓度变化特征分析

Feature Analysis of the Variation of Ozone Concentration Over the Western Suburb of Zhengzhou

臭氧(O_3)是大气中的微量组分,对流层中大部分臭氧是NO_x(氮氧化物)和HC(碳氢化合物)经光化学反应生成的二次污染物,是城市光化学烟雾的主要成分。近年来郑州市区域性的O_3污染越来越严重。利用2014年6月—2015年5月郑州市西郊环境监测站点大气污染物的小时浓度资料,结合相应气象要素资料分析郑州市西郊O_3污染变化特征及其影响因素,为郑州市空气污染治理提供基础资料。郑州市2014、2015年首要大气污染物以大气颗粒物(特别是细颗粒物)为主,约占80%~90%左右,2015年颗粒物污染有一定程度的下降,但臭氧污染和NO_2污染被凸显出来,臭氧污染天数急剧增加。郑州环境监测站O_3日逐时变化为典型的单峰型,O_3在8:00出现最小值33.08μg?m^(-3),在15:00出现最大值84.02μg?m^(-3)。不同季节对O_3逐时浓度的变化影响很大,春夏两季,O_3在15:00左右出现较大的最高值;而在秋冬两季,O_3虽然也会在15:00—16:00达到较高值,但其数值较小。按季节统计,郑州市环境监测站O_3浓度的季节平均值排序为:夏(72.60μg?m^(-3))>春(63.12μg?m^(-3))>冬(41.06μg?m^(-3))>秋(38.99μg?m^(-3))。臭氧污染主要发生在光化学反应强烈的条件下,天气条件对臭氧浓度的影响较大,紫外线较强的晴天、温度较高时臭氧浓度较高,容易发生臭氧污染,而在出现雨雪天气、阴天和灰霾天气时臭氧浓度较低。

Ozone (O3) is a trace component in the atmosphere. As the principal constituent of urban photochemical smog, most of the tropospheric ozone is the secondary pollutants generated from the photochemical reaction of NOx (nitrogen oxides) and HC(Hydrocarbon). In recent years, the city of Zhengzhou, located in the transition zone of south and north of China, has represented agrowing regional O3 pollution. In this study, the hourly concentration data of the pollutants combined with the meteorological datawere collected from June 2014 to May 2015 at the environmental monitoring site in the western urban area of Zhengzhou and thenanalyzed the variation characteristics and impact factors of O3 pollution. The purpose is to provide fundamental data for the controlof air pollution in Zhengzhou. The atmospheric particulates (especially fine particles) were the main air pollutants, around80%~90%, in Zhengzhou during 2014 and 2015. Although the particulate pollution showed decline in some extent during 2015, theozone and NO2 pollution was prominently presented. The days of ozone pollution were sharply increased. At Zhengzhouenvironmental monitoring site, the hourly variation of O3 concentration appeared as a typical single peak. The minimum value of O3concentration was 33.08 μg?m-3 at 8:00 and the maximum value was 84.02 μg?m-3 at 15:00. The difference of season showed a greatinfluence on the hourly concentration of O3. In spring and summer, the maximum values of O3 concentration appeared around 15:00.Although O3 concentration also reached the highest value between 15:00 and 16:00 in autumn and winter, this highest value was smaller than that of spring and summer. According to the seasonal statistics, the average values of O3 concentration in Zhengzhou environmental monitoring station were as follows: summer (72.60 g?m-3)>spring (63.12 μg?m-3)>winter (41.06 μg?m-3)>autumn(38.99 μg?m-3). O3 pollution mainly occurs in the weather conditions with strong photochemical reaction. The weather conditions showed great influence on O3 concentration. In sunny day with strong ultraviolet and high temperature, the higher O3 concentrations were reached and O3 pollution was most likely to transpire. However, the lower O3 concentrations were appeared when the weather was rainy, snowy, cloudy, or hazy.