A STUDY OF BUS COMMUTER AND PEDESTRIAN EXPOSURE TO TRAFFIC AIR-POLLUTION IN HONG-KONG

Exposure of bus commuters and pedestrians were measured in Hong Kong, a densely populated Asian city. The study found that bus commuters were exposed to an average NO, NO2, SO2 and CO of 0.490 muL/L, 0.077 muL/L, 0.020 muL/L and 1.6 muL/L respectively, for trips lasting between 20 and 45 min. Exposure levels of pedestrians to hourly average NO, NO2, SO2 and CO were 0. 156 muL/L, 0.051 muL/L. 0.011 muL/L and 0.9 muL/L, respectively. Spatial and temporal variation of exposure levels were detected with ANOVA. In-bus concentrations were higher than out-bus concentrations at roadsides. Linear regression models were used to predict in-bus levels of NO, NO2 and SO2 from out-bus levels which in turn could be estimated from traffic flow. Fixed-station data were found to give an unreliable representation of exposure level.