Liu Jian, Wu Dui, Fan Shao-jia
Huan Jing Ke Xue. 2015 Nov;36(11):3989-98.
Based on the data of hourly PM2.5 concentration of 56 environmental monitoring stations and 9 cities over the Pearl River Delta (PRD) region, the distributions of PM2.5 pollution in PRD region were analyzed by systematic cluster analysis and correlational analysis. It was found that the regional pollution could be divided into 3 types. The first type was the pollution occurred in Dongguan, Guangzhou, Foshan and Jiangmen (I type), and the second type was the pollution occurred in Zhongshan, Zhuhai, Shenzhen and Huizhou (II type), while the last type was the pollution only occurred in Zhaoqing (III type). During the study period, they occurred 47, 7 and 128 days, respectively. During events of pollution type I, except Zhuhai, Shenzhen and Huizhou, the PM2.5 concentrations of other cities were generally high, while the PM2.5 concentration in whole PRD region was over 50.0 μg x m(-3) during events of pollution type II. The regions with higher PM2.5 concentration was mainly concentrated in Zhaoqing, Guangzhou and Foshan during events of pollution type III. The wind data from 4 wind profile radars located in PRD region was used to study the characteristics of vertical wind field of these 3 pollution types. It was found that the wind profiles of type I and III were similar that low layer and high layer were controlled by the southeast wind and the southwest wind, respectively. For type II, the low layer and high layer were influenced by northerly wind and westerly wind, respectively. Compared with other types, the wind speed and ventilation index of type II. were much higher, and the variation of wind direction at lower-middle-layer was much smaller. When PRD region was influenced by northerly winds, the PM2.5 concentration in the entire PRD region was higher. When PRD region was controlled by southeast wind, the PM2.5 concentrations of I and II areas were relatively lower, while the pollution in III area was relatively heavier.
基于珠江三角洲（PRD）地区9个城市56个环境监测站的每小时PM2.5浓度数据，通过系统聚类分析和相关性分析对珠三角地区PM2.5污染分布进行了分析。结果发现，区域污染可分为3种类型。第一种类型是在东莞、广州、佛山和江门出现的污染（I型），第二种类型是在中山、珠海、深圳和惠州出现的污染（II型），而最后一种类型是仅在肇庆出现的污染（III型）。在研究期间，它们分别出现了47天、7天和128天。在I型污染事件期间，除珠海、深圳和惠州外，其他城市的PM2.5浓度普遍较高，而在II型污染事件期间，整个珠三角地区的PM2.5浓度超过50.0μg x m(-3)。在III型污染事件期间，PM2.5浓度较高的区域主要集中在肇庆、广州和佛山。利用位于珠三角地区的4部风廓线雷达的风数据研究了这3种污染类型的垂直风场特征。结果发现，I型和III型的风廓线相似，低层和高层分别受东南风和西南风控制。对于II型，低层和高层分别受北风和西风影响。与其他类型相比，II型的风速和通风指数要高得多，且中低层风向变化要小得多。当珠三角地区受北风影响时，整个珠三角地区的PM2.5浓度较高。当珠三角地区受东南风控制时，I区和II区的PM2.5浓度相对较低，而III区的污染相对较重。
