2013—2016年珠三角地区PM_(2.5)分布时空演变

Spatial-temporal Evolution of PM_(2.5) Distribution in Pearl River Delta Region in 2013—2016

基于2013—2016年珠三角55个空气质量监测站PM_(2.5)实时浓度监测数据,采用六级分级统计、空间插值方法对珠三角地区PM_(2.5)分布时空演变进行研究,为区域大气联动治理、污染产业的空间布局、城市空间优化、产业结构与能源结构调整提供参考依据。分级统计结果表明,2013—2016年珠三角PM_(2.5)年均质量浓度值减少15.39μg?m^(-3),降幅达32.8%,2015年、2016年均质量浓度低于《环境空气质量标准》(GB3095—2012)二级标准限值(35μg?m^(-3))。研究期间,出现中度污染、轻度污染的天数逐年减少,自2015年开始未出现中度污染,表明研究区内近4年PM_(2.5)污染较轻,且呈现逐渐改善特点。易发生PM_(2.5)污染的时间为1月、10月、11月和12月,尤以1月、12月为多,其次依次是10月和11月,呈现污染发生持续时间短、回落迅速的特点,需要加强即时性监测与质量浓度信息发布,避免高质量浓度PM_(2.5)影响大气能见度,威胁健康。PM_(2.5)月均质量浓度季节差异明显,全年峰值出现在1月或12月,最小值出现在6月或7月,6—8月为全年波谷期。空间插值结果表明,珠三角PM_(2.5)浓度空间分布模式呈现"西北—东南"三级递减分异。珠三角PM_(2.5)浓度值空间分布情况与区域城市化进程、人类活动有较密切的联系;同时海陆分布也会影响PM_(2.5)的监测浓度,下垫面性质不均匀,靠海区形成小尺度区域性环流,海陆风的强度在海岸最大,随着离岸距离的增加而减弱,故深圳、中山、珠海PM_(2.5)监测浓度值较低。

The research of spatio-temporal evolution of PM2.5 concentration and rules can provide a scientific basis for the regional atmosphere joint governance,the spatial layout of polluting industries,urban space optimization,industrial structure and energy structure adjustment.Based on PM2.5 monitoring data from 55 air quality monitoring stations in Pearl River Delta from 2013 to 2016,adopt 6-level hierarchical statistics and spatial interpolation methods to conduct research on the spatial-temporal evolution of PM2.5 distribution in Pearl River Delta(PRD)Region within four years.The annual average concentration of PM2.5 decreased by 15.58μg·m-3 from 2013 to 2016,about 32.8%.The PM2.5 average concentration in 2015 and 2016 was lower than the secondary limit of air quality standard(GB3095-2012,35μg·m-3),and the days with moderate pollution and mild pollution decreased year by year,and no moderate pollution occurred since 2015,indicating that the PM2.5 concentration in PRD had been optimized year by year.The monthly average concentration of PM2.5 in PRD showed significant seasonal variations.The annual peak appeared in January or December,then in October and November;the minimum was in June or July,and June to August was the trough of the whole year.Spatial interpolation results showed a 3-level decline in northwest-southeast.The spatial distribution of PM2.5 concentration in PRD was closely related to the regional urbanization and human activities.At the same time,the sea-land distribution would also affect the monitoring concentration of PM2.5.The nature of the underlying surface was not uniform,and small-scale regional circulation would form in the sea area.The intensity of land and sea breeze was greatest at the coast and weakens with the distance from the shore,affecting the distance about 20~50 km,so that Shenzhen,Zhongshan,Zhuhai PM2.5 monitoring concentration values were lower.