Respiratory suspended particulate (RSP) concentration and its implications to roadside workers: a case study of Hong Kong.

Respiratory Suspended Particulates (RSPs) have attracted increasing interest in recent years because of the potential risk of RSPs to human health. In Hong Kong, a large population of roadside workers is believed to be continuously exposed to high levels of RSPs. In this study, the roadside RSP concentrations at 72 locations in 6 urban districts of different land use types in Hong Kong are examined. Results show that the RSP pollution in Hong Kong's roadside environment is quite serious. The average RSP concentration at 61.11% of sampling sites is over 180 microg m(-3), the highest 24 h RSP mean concentration recommended by the Environmental Protection Department of Hong Kong. Analyses of RSP concentration data with reference to the local environmental conditions indicate that, among various environmental factors, land use, population density and traffic flow are important determinants of the RSP level. Because many roadside workers are exposed to high levels of RSP for prolonged periods, it is necessary to increase the public awareness of the health hazard of roadside workers.