Characteristics of particulate matter pollution in the Pearl River Delta region, China: an observational-based analysis of two monitoring sites

Abstract

Two-year monitoring data (2006 and 2009), collected at the sub-urban site (WQS) and the background site (TH), were used to study the characteristics of Particulate Matter (PM) pollution in the Pearl River Delta region, China. Similar levels of PM_2.5 concentration measured at both sites seem to confirm that the fine particles have emerged as a major regional pollution issue. The seasonal variation of PM_2.5 concentration is associated with the regional monsoon circulations while the diurnal variation is related to land-sea breeze, traffic emissions and boundary layer development. Negative correlation was found in PM_2.5–wind speed and PM_2.5–humidity. Analysis of radiation, temperature and ozone suggests the existence of secondary aerosol formation. Transport effect may be another contributing factor to high PM pollution in the region, such as occasional long-distance dust intrusion and trans-boundary effects from upwind areas.