Boundary layer characteristics of typical haze process in the Pearl River Delta region

A heavy haze weather occurred in Pearl River Delta (PRD) region during January 2014. Based on urban air quality data of Guangdong Province, hourly data of PM10, PM2.5 and visibility from China Meteorological Agency Panyu atmospheric composition station, wind data of 946 auto stations and Guangzhou station, data from the boundary layer observation experiment in Dongguan and Foshan during the winter of 2013, boundary layer characteristics of a typical haze process in PRD during 1~8 January 2014 had been researched. It was found that, continental cold high was the major weather system at this haze process. It caused stability weather which produced breeze or calm wind condition, lower boundary layer and inversion structure occurred in PRD. Air quality of major cities in PRD had different variations during 6th January, mainly due to the change in wind direction over the Pearl River Delta region. In the morning of 5th January, the Pearl River Delta region was prevailing with weak northerly winds, it caused the entire Pearl River Delta suffer with haze weather. While on the afternoon, the wind direction had been changed that the northerly winds turned to southerly winds, it improved the air quality over the southeastern Pearl River Delta region. However, air quality of the northern (inland) region deteriorated. Backward trajectory analysis found that all airflow with obviously sinking process, and the trajectory clusters that began at 20:00 5th January were come from the land surface, while the trajectory clusters that began at 20:00 6th January were come from the sea. These two kinds of trajectory clusters have different effects on air quality in the Pearl River Delta. ©, 2015, Chinese Society for Environmental Sciences. All right reserved.