Abstract
People working at toll plazas are continuously exposed to high pollutant concentrations due to traffic congestion at toll booths. However, there are fewer studies available which focus on toll workers' exposures. Therefore, a study was conducted at a toll plaza on a busy national highway (NH) in India to assess black carbon (BC), particulate matter with aerodynamic diameter <= 2.5 mu m (PM2.5), and ultrafine particles (UFP) concentrations and their associated health risks on the toll workers inside toll cabin and kerbside. Higher BC (34 mu g m(-3) vs. 18 mu g m(-3)) and PM2.5 (86 mu gm(-3) vs. 79 mu gm(-3)) concentrations were observed inside the cabin than at kerbside. On the contrary, UFP concentrations were higher at the kerbside (22,790 pt cm(-3)) than in-cabin (18525 pt cm(-3)). All pollutant concentrations were higher during evening hours than in the morning hours. BC and PM2.5 con-centrations were found to be higher during the weekdays. Positive correlations were found between traffic volume and all pollutant concentrations. Negative correlations were observed for solar radiation and boundary layer height with pollutant concentrations. Additionally, it was found that the health risk of toll workers was higher (risk quotient, RQ range: similar to 2-5) than the prescribed limit (RQ < 1). The present study demonstrates that there is a need to control personal exposure to pollutants in the workplaces, especially locations with traffic proximity.