摘要
近地层臭氧(O3)是由挥发性有机物(VOCs)和氮氧化物(NOx)等物质在光照条件下形成的二次污染物,近年来已成为我国不少地区的首要污染物.本文利用2017年平潭综合实验区4个空气自动监测站监测数据,分析了海峡西岸清洁岛屿平潭O3污染特征及其与气象条件、前体物、区域输送等影响因素之间的关系,以探索清洁岛屿O3污染影响因素.结果表明,2017年平潭4个监测站的O3浓度基本相近,最大监测浓度为241μg·m-3(JS站、JJW站)、247μg·m-3(36JH站)、256μg·m-3(XZF站),全年平均值为89.3μg·m-3(JS站)、82.9μg·m-3(JJW站)、86.4μg·m-3(36JH站)、88.8μg·m-3(XZF站);O3日变化因光化学反应呈现出单峰特征,受季风及气象因素影响,月变化呈现春秋高夏季低的双峰特征;高压、高温、低湿是引起平潭O3污染的主要气象因素;非降雨日的O3浓度要比降雨日高3—5μg·m-3,超标率高5%左右;O3与CO正相关,与NOx负相关,O3浓度高值出现在CO浓度为400—1000μg·m-3、NOx浓度为5—20μg·m-3范围内;区域输送对平潭O3污染存在一定的贡献,2017年9月12日的O3浓度突升是一次典型的污染物外来输送,同时叠加本地生成造成的污染过程.可见,气象条件、前体物、区域输送是清洁岛屿O3污染的重要影响因素.
Ground ozone(O3) is an atmospheric secondary pollutant formed by volatile organic compounds(VOCs) and nitrogen oxides(NOx) under light conditions, which has become the major pollutant in many regions of China in recent years. One year hourly data collected from four air automatic monitoring stations in clean islands were used to explore the impact factors of O3 pollution, such as meteorological conditions, precursors, and regional transport. The results showed that the O3 concentrations of the four monitoring stations in Pingtan in 2017 were similar. The maximum concentrations at each site were 241 μg·m-3(JS, JJW), 247 μg·m-3(36 JH), 256 μg·m-3(XZF), respectively. The annual mean concentrations were 89.3 μg·m-3(JS), 82.9 μg·m-3(JJW), 86.4 μg·m-3(36 JH), 88.8 μg·m-3(XZF), respectively. Diurnal variation of O3 was unimodal due to photochemical reaction. Influenced by monsoon and meteorological factors, the monthly variation presented a bimodal characteristic of high concentration in spring and autumn while low concentration in summer. High pressure, high temperature and low humidity were the main meteorological factors causing O3 pollution in Pingtan. The O3 concentration on non-rainfall days was 3—5 μg·m-3 higher than that on rainfall days, and the excess rate was about 5% higher. O3 was positively correlated with CO while negatively correlated with NOx. The high concentration of O3 occurred in the range of CO concentration of 400—1000 μg·m-3 or NOx concentration of 5—20 μg·m-3. Atmospheric regional transport contributed to O3 pollution in the clean island. The sudden increase of O3 concentration on September 12, 2017 was a typical external transport combined with local photochemical formation. It was concluded that meteorological conditions, precursors and regional transport were key factors causing O3 pollution on clean islands.
作者
杨玉香
陈乃华
胡宝叶
游建勇
林浩然
杨育姗
邓以勤
YANG Yuxiang;CHEN Naihua;HU Baoye;YOU Jianyong;LIN Haoran;YANG Yushan;DENG Yiqin(Pingtan Environmental Monitoring Center of Fujian,Pingtan,350400,China;Center for Excellence in Urban Atmospheric Environment,Institute of Urban Environment,Chinese Academy of Sciences,Xiamen,361021,China;Key Laboratory of Urban Environment and Health,Institute of Urban Environment,Chinese Academy of Sciences,Xiamen,361021,China;University of Chinese Academy of Sciences,Beijing,100049,China;Pingtan Comprehensive Experimental Area Meteorological Bureau,Pingtan,350400,China)
出处
《环境化学》
CAS
CSCD
北大核心
2020年第7期1733-1743,共11页
Environmental Chemistry
关键词
臭氧
污染特征
气象因素
前体物
区域输送
清洁岛屿
ozone
pollution characteristics
meteorological factors
precursors
regional transport
clean island
