The Pollution Control Department (PCD), Ministry
of Natural Resources and Environment, Thailand,
consistently reports a high concentration of some
air pollutants on the roadside areas of Bangkok.11-12
So far little research has been conducted to study
the adverse health effects of traffic-related air pollutants
among street vendors. This study intends to
compare the level of traffic-related air pollutants,
i.e. fine particulate (PM2.5), sulfur dioxide (SO2),
nitrogen dioxide (NO2) and carbon monoxide (CO),
and the 61-day daily reported respiratory and other
health symptoms by street vendors in a representative
roadside area and a representative residential
area.