Evaluation of In-Vehicle Pollutants Exposure and Respiratory Symptoms among Bus Drivers in Kota Bahru, Malaysia

Abstract

Exposure to in-vehicle air pollutants has been recognized as a risk factor for respiratory diseases. The present study, therefore, investigates the factors, including duration of employment and in-vehicle concentrations of fine particulate matter (PM2.5), carbon dioxide (CO2) and nitrogen dioxide (NO2) that can influence the prevalence of respiratory symptoms in commercial bus drivers. A total of 34 bus drivers and 51 administrative staff (comparative group) from the bus operator in Kota Bahru, Malaysia were randomly enrolled in this cross-sectional study. The personal characteristics and respiratory symptoms were reported using a validated questionnaire from the American Thoracic Society (ATS-DLD-78-A). In-vehicle concentrations of PM2.5, CO2 and NO2 were continuously measured over eight hours on each bus driver. The prevalence of self-reported cough, phlegm and chronic phlegm among bus drivers were 55.9%, 73.5% and 35.3%, respectively, significantly higher compared to the comparative group (p < 0.001). Moreover, the duration of employment with bus operators for more than four years was significantly related to the manifestation of phlegm (OR = 8.27, 95% CI = 3.12-21.89) and cough (OR = 4.57, 95% CI = 1.66-12.59). Among the pollutants measured, concentrations of PM2.5 (92.1 µg/m3) and CO2 (286.9 ppm) inside the buses were significantly higher in the morning compared to afternoon hours (p < 0.001). These findings provide important evidence for further surveillance programs that could reduce occupational exposure for bus drivers.

Effects of Residential Proximity to Industrial Zone on Respiratory Symptoms among Residents in Parit Raja, Batu Pahat

“…Also, information on respiratory symptoms was gathered by using a questionnaire, which was adapted from American Thoracic Society "ATS-DLD-78". The standardized questionnaire has been translated and proved to be valid in previous studies (22,23). In this study, we focused on four distinct respiratory symptoms that were treated as outcome variables: cough, phlegm, and wheeze for the last 3 months as well as chest tightness for the last 3 years.…”