A study on the human exposures in diesel and LPG taxis in Hong Kong  

Project Title: A Study on the Human Exposures in Diesel and LPG Taxis in Hong Kong

Applicant: The Hong Kong Polytechnic University

Total Approved Grant: $350,565.70 (jointly funded by ECF and WWGF on an equal share basis)

Duration: June 1999 to January 2001

Project Status/Remarks: Completed

Scope: To explore the human exposure levels of taxi drivers as well as passengers and to compare the indoor and outdoor air quality of taxis running on diesel and LPG.

Summary of the Findings/Outcomes:
The concentrations of some hydrocarbons measured in LPG taxis were higher than those in diesel taxis in the study, except for benzene ( 苯 ) which is the only confirmed human carcinogen measured in the study. The concentration level of benzene, which is a human carcinogen, found in LPG taxis are actually lower than that in diesel taxis. The levels found in both LPG and diesel taxis are in compliance with the relevant occupational health safety standards. Drivers need not worry. The concentrations of hydrocarbon found in both LPG and diesel taxis would not cause a health threat to the general public and are in compliance with the relevant occupational health standards.
The sources of hydrocarbon found in LPG taxis was not covered in the project, so it was not studied.
The Hong Kong Polytechnic University recommends that further studies be conducted to ascertain the sources of the hydrocarbons, whether the concentrations are transient and whether it would pose any health risk to LPG vehicle drivers.