Assessment of Health Risk from Exposure to Respirable Particulate Matter (RPM) among Motorcycle Taxi Drivers in Bangkok and Adjacent Provinces, Thailand

Exposure to outdoor air pollutants, particularly respirable particulate matter (RPM), can cause adverse health outcomes. The cross-sectional study aimed to assess motorcycle taxi driver’s health risk from exposure to RPM. A total of 153 motorcycle taxi drivers were recruited in Bangkok and five adjacent provinces during May and June 2022. The standardized questionnaire for data collection contained exposure time (hour/day), frequency of exposure (days/years), duration of exposure (year), body weight (kg), and averaging time (days). The average RPM concentration from six provinces were assessed personal air sampling pumps and ranged from 0.006-0.031 mg/m3. Bangkok showed the highest average RPM concentration (0.031 mg/m3), followed by Pathumthani (0.028 mg/m3), Samut Prakan (0.009 mg/m3), Nakhon Pathom (0.008 mg/m3), Nonthaburi (0.007 mg/m3), and Samut Sakhon (0.006 mg/m3), respectively. The Hazard Quotient (HQ) values for a non-carcinogenic risk to human health caused by RPM exposure in each province indicated a negligible risk (HQ=0.005-0.028). HQ averages (HQ=0.013) from all provinces were also at an acceptable level (≤1). Not all motorcycle taxi drivers are safe from RPM exposure, although their exposure is within acceptable limits depending on their individual susceptibility. Therefore, this is the first report on quantifying exposure to RPM from personal air sampling and health risk assessment among motorcycle taxi drivers. These findings would be useful information for further preventing and controlling ambient air pollution including policies and strategies to mitigate the risks for motorcycle-taxi drivers and the other exposed populations.