三亚市臭氧污染特征、输送路径及潜在源区分析

Characteristics,Transport Routes and Potential Sources of Ozone Pollution in Sanya

基于2015—2019年三亚市空气质量自动监测数据和气象观测资料,结合后向轨迹聚类与潜在源区分析等方法,分析了三亚市O_(3)污染特征。结果表明:2015—2019年三亚市O_(3)浓度总体优良,优良天数比例为97.9%(标准状态),超标天均为轻度污染,多发生在秋冬季。O_(3)浓度与平均相对湿度、气温和降水量呈负相关关系,与平均风速呈正相关关系,同时与风向密切相关。6—8月气温较高,主导风向为偏南风,O_(3)及其前体物以本地排放为主,O_(3)浓度较低;秋冬季盛行东北风,易受到来自内陆的污染传输影响,O_(3)浓度相对较高。当日最高气温为20~30℃、日均相对湿度为65%~85%、日均风速为3~8 m/s、主导风向为东北风时,三亚市发生O_(3)超标的概率较高。台风外围和冷高压南下是导致三亚市O_(3)超标的2种典型天气形势。经聚类分析得到,2019年2个污染过程气团输送路径均来自东北方向,潜在源区分析WPSCF与WCWT的高值区一致性较好,均表明珠三角地区是三亚市重要的O_(3)污染潜在源区,需要加强与珠三角地区O_(3)污染的联防联控。

Based on the automatic monitoring data of air quality and meteorological observation data in Sanya from 2015 to 2019,combined with the backward trajectories clustering analysis and potential pollution sources analysis,the characteristics of ozone pollution in Sanya were analyzed.The results showed that the overall air quality of ozone was good in Sanya from 2015 to 2019,with 97.9% of good and moderate days(standard state).The pollution days were all lightly polluted and mostly occurred in autumn and winter.The O_(3) concentration was negatively correlated with average relative humidity,temperature and precipitation,positively related to average wind speed and closely related to the wind direction.The temperature was high from June to August,meanwhile,the dominant wind direction was southerly,and ozone and its precursors were from local emission sources,therefore,the ozone concentration was relatively low.On the contrary,ozone concentration was relatively high in autumn and winter due to the external pollution transport when the dominant wind direction was northeast.When the daily maximum temperature was 20-30 ℃,the 24-hour average relative humidity was 65%-85%,the 24-hour average wind speed was 3-8 m/s,and the dominant wind direction was northeast,the probability of O_(3) concentration exceeding the standard was high in Sanya.Typhoon periphery and the cold high pressure southward type were two typical weather situations that led to ozone pollution in Sanya.The backward trajectories clustering analysis indicated that the air mass transporting pathways of two pollution processes in 2019 were both from the northeast.As for the potential sources analysis,the areas with high WCWT value distribution matched the WPSCF results,indicating that the Pearl River Delta was a significant potential source of ozone pollution,and ozone pollution control of Sanya required joint prevention and control strategies with the Pearl River Delta.