Spatio-temporal exposure assessment of particulate matter pollution in auto-rickshaw drivers in Chennai, India

Abstract

Rapid urbanization and population growth have put a lot of stress on the urban infrastructure. The number of vehicles, particularly the three wheeled auto-rickshaws, have increased drastically in the past decade in developing countries like India, Pakistan, Bangladesh, etc. The distinct design of these vehicles make the drivers and the passengers vulnerable to the traffic emissions and resuspended dust. With the objective of assessing the exposure of auto-rickshaw drivers to particulate matter in Chennai, this study used an auto-rickshaw to monitor the particulate matter (PM10, PM2.5 and PM1) concentrations during weekday peak and non-peak hours, across 15 administrative zones of Chennai, India. The particle size distribution profile for each zone was identified to understand the source contribution. Low PM2.5/PM10 ratio (<0.15) was observed in the western parts of Chennai consisting residential and commercial zones (zone 10 and 11), and high PM1/PM2.5 ratio (>0.8) in the highly industrialized northern parts of Chennai (zone 4 and 5). The coarse particles of size 31 μm and 34 μm were predominant in most of the zones. Northern and central Chennai had 100 % exceedances in PM10 and PM2.5 during both peak and non-peak hour. Auto-rickshaw drivers were exposed to a maximum of 4.26 μg/km and 0.12 μg/km of PM2.5 and PM1, respectively. Based on these results, we suggest the auto-rickshaw drivers and passengers to follow necessary precautions like wearing masks, and the policymakers to develop control measures based on such spatial studies of air pollution across the entire city.