Public transportation remains an integral part of urban transportation
systems, but occupational and non-occupational exposures
to pollutants in public transportation have received little
research. Most previous research has focused on the concentration
and distribution of indoor and outdoor environmental pollutants.
However, no study has been conducted on the health effects of
exposure to pollutants inside public transportation systems.
Considering the relatively little time spent by urban populations in
outdoor environments, the dilution effects of natural wind, and the
shorter cleaning cycle of indoor environments than of buses,
studying the microenvironment of the urban transport system is
essential for understanding how non-dietary exposure to PAHs
affects urban populations. Elucidating the concentrations of PAHs is
thus essential for estimating their inputs into the bus microenvironment
and the commuter respiratory system, tracing their origins,
and understanding their transformation and transportation.
As both a source and sink of suspended particulate matter in the
microenvironment of a bus, settled dust may play an important role
in the exposure to PAHs in urban public transport systems. In this
study, we undertook a preliminary study to measure PAH concentrations
in the resuspendable fraction of settled dust on major bus
lines in Harbin, China and estimated the subsequent human
exposure.