The groups of people who are most at risk of traffic-related
air pollutants are street vendors. Working
day after day selling their goods on the sidewalks
along the streets, there are approximately more
than 28,000 street vendors in the Bangkok area.
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.