Properties Of Individual Airborne Particles In Typical Cities Of Pearl River Delta Region In Winter Of 2004

PM10 samples were collected in Dongguan and Guangzhou in winter of 2004 to study the properties of individual airborne particles in typical cities of Pearl River Delta Region. Morphology and chemical compositions of individual particles were analyzed with high resolution Scanning Electron Microscopy, images analysis and Energy Dispersive X-ray Spectrometry. Soot aggregates, subrounded particles, mineral particles, biologic particles and coal fly ash were found in the PM10 samples of Dongguan and Panyu. Soot aggregates, subrounded particles and mineral particles were the main component of PM10 samples collected in Dongguan and Panyu district of Guangzhou. This indicated that the resources of PM10 were secondary pollution, vehicle and dust. The subrounded particles were ubiquitous in PM10 of Dongguan and Panyu, and they could be divided into several species by cluster analysis. The subrounded particles of Dongguan were classified into five groups: S-N , S-K-Ca-Na, S-K, Si-S and carbonaceous particles. While in Panyu they could be divided into seven groups: S-N, S-K, S-Na, Na, Si-S and carbonaceous particles. The mineral particles that mainly contain Si,Al,Ca and Fe and other crustal elements. Many of them are coated with other species such as salt. Clay minerals are the most abundant species in mineral particles. Cluster and triangle plot analysis showed that many mineral particles were internally mixtures of clay and other mineral such as CaCO3. The number-size distributions of soot aggregates, subrounded particles and mineral particles revealed by the image analysis peak at 200~300nm, 100~200nm and 1000nm, respectively. This study shows that the most abundant species of PM10 in Dongguan and Humen are soot aggregates, while that in Panyu are subrounded particles.