北京臭氧污染特征及污染气象条件分析

Characteristics and Meteorological Conditions of Ozone Pollution in Beijing

根据2013—2017年北京市地面常规气象观测资料、太阳辐射资料以及北京市环保局22个监测站点的臭氧(O3)数据,分析北京市近5年的O3污染特征,并探讨北京发生O3污染时的气象条件。研究表明:2013—2017年北京市O3质量浓度呈逐年增加趋势,郊区浓度整体高于城区,存在远距离输送,污染过程变多,持续时间变长,光化学污染加强;O3质量浓度夏季最高,春季次之,冬季最低,在5—8月13:00—18:00 O3污染最严重;O3日变化和月变化都呈单峰型,NO2日变化呈双峰型,周末效应显著,O3与NO2质量浓度呈明显负相关;O3质量浓度与太阳辐射、温度和日照时间呈正相关,春季最有利于O3质量浓度增加的相对湿度区间在45%~50%,夏季和秋季最有利于O3生成的相对湿度区间在60%~65%,冬季相对湿度与O3质量浓度呈明显负相关;高湿度、高风速不利于O3质量浓度增加,平均风速在2.0~2.5 m/s最有利于O3质量浓度增加。

Based on the meteorological data from the conventional ground observations and ozone(O3)data from 22 monitoring stations of the Beijing Municipal Environmental Protection Bureau,as well as solar radiation data during 2013—2017 in Beijing,the characteristics of ozone pollution were analyzed,and the meteorological condi?tions in the events of ozone pollution were discussed.The results show that during 2013—2017 the concentra?tion of O3 in Beijing was increasing year by year;the concentration of O3 in suburbs was higher than that in ur?ban areas;the pollution experienced a long-distance transportation with more and more processes and longer du?ration;and the photochemical pollution was strengthened.The O3 concentration was the highest in summer,the second in spring,and the lowest in winter,with the most heavy ozone pollution occurred at local times of 13:00—18:00 from May to August.The daily and monthly change of O3 concentration exhibited a pattern of unimodal,but the daily change of NO2 concentration exhibited a pattern of bimodal as well as significant weekend effect.The concentration of O3 was obviously negatively correlated with that of NO2;the ozone concentration was positively correlated with solar radiation,temperature and sunshine time.The most favorable relative humidity for the increase of ozone concentration was at 45%~50%in spring,and 60%~65%in summer and autumn.Relative humidity was significantly and negatively correlated with ozone concentration in winter;high humidity and high wind speed were not conducive to the increase of ozone concentration,average wind speed of 2.0~2.5 m/s was most beneficial to the increase of ozone concentration.