Spatial variation of mass concentration of roadside suspended particulate matter in metropolitan Hong Kong

This study conducted roadside particulate sampling to measure the total sus pended particulate (TSP), PM10 (particles < 10 mum in aerodynamic diameter) and PM2.5 (particles <2.5 mum in aerodynamic diameter) mass concentration in 11 urbanized and densely populated districts in Wong Kong. One hundred a nd thirty-three samples were obtained to measure the mass concentrations of TSP, PM10 and PM2.5. According to these results, the TSP, PM10 and PM2.5 m ass concentrations varied from 94.85 to 301.63 mug m(-3), 67.67 to 142.68 m ug m(-3) and 50.01 to 125.12 mug m(-3), respectively. The PM2.5/PM10 ratio of all samples was 0.82 which ranged from 0.62 to 0.95. The PM levels and P M ratios in metropolitan Hong Kong significantly fluctuated from site-to-si te and over time. The PM2.5 mass concentration in different districts corre sponding to urban industrial, new town, urban residential and urban commerc ial were 77.64, 87.50, 106.96 and 88.54 mug m(-3), respectively. The PM2.5 level is high in Hong Kong, and for individual sampling, more than 60% dail y measurements exceeded the NAAQS. The mass fraction of PM2.5 in PM10 and T SP is relatively high when compared with overseas studies. (C) 2001 Elsevie r Science Ltd. All rights reserved.