安阳市近地面臭氧污染特征及气象影响因素分析

Characteristic of Surface Ozone and Meteorological Parameters Analysis in Anyang City

基于国控环境空气质量监测站数据分析了安阳市2014~2017年不同功能分区(城市、郊区和工业)点位的臭氧(O3)污染特征和变化规律,并研究了O3污染的气象影响因素和潜在源分布.结果表明,2014~2017年安阳市各站点O3年均浓度上升明显,O3超标日的出现从2015年开始不断提前,最早在2017年4月出现;工业区点位O3第90百分位数和平均值增长最快,年均分别增长16. 0μg·m-3和13. 0μg·m-3,郊区点位O3第5百分位数增长最快,年均增长13. 2μg·m-3;安阳市O3月变化呈"M"型,且具有明显的空间差异;温度对O3浓度起主导作用;气温大于23℃、相对湿度小于58%和西南偏南方向5m·s-1风速与高浓度O3污染密切相关;不同季节O3潜在来源差异明显,夏季主要分布在河北南部、湖北北部和沈阳北部.2017年5月首次出现O3重污染日,工业点位O3小时平均浓度高达405μg·m-3,重污染事件与西部干热气团转移导致持续高温有关.

This study uses the national ambient air quality station data of Anyang City from 2014 to 2017 to analyze the characteristics and variation rules of ozone( O3) in different functional zones( urban,suburban,and industrial),and also studies meteorological influencing factors and potential source distributions of O3 pollution. The results showed that the O3 concentration in Anyang increased significantly between 2014 and 2017,whereby pollution started to advance from 2015 and the earliest occurrence of an O3 pollution episode was in April 2017. The 90 thpercentile and average concentrations of O3 in the industrial zone increased at faster rates( average annual growth of 16. 0 μg·m-3 and 13. 0 μg·m-3,respectively) than of those in the urban and suburban zones. The O3 concentrations at the suburban site showed the fastest increase of all zones at the 5 thpercentile( average annual growth of 13. 2 μg·m-3). The monthly variation in O3 concentrations in Anyang showed an "M"pattern that varied spatially depending on the zone. Temperature played a leading role in O3 concentrations;air temperatures > 23℃,relative humidity < 58%,and a wind speed of 5 m·s-1 in a south-southwesterly direction were closely related to the occurrence of high O3 concentrations. Potential sources of O3 in different seasons were significantly different,and mainly distributed in southern Hebei,northern Hubei,and northern Shenyang in summer. The first heavy O3 pollution day in the studied period was in May 2017,at which time the highest O3 concentration was found in the industrial zone( up to 405 μg·m-3). This heavy O3 pollution episode was related to the continuous high temperature that was caused by the transfer of a dry,hot air mass in western China.