Commuter exposure concentrations and inhalation doses in traffic and residential routes of Vellore city, India

Abstract

Commuting adds a significant proportion to the total PM2.5 and PM1 exposure concentration, especially in urban areas. However, spatial and inter-day variations of commuter exposure concentrations are rarely assessed in India. This study investigates the personal exposure concentration of PM2.5 and PM1 in Vellore city, India while commuting in active (pedestrian and bicycle) and motorized (motorbike, car, auto-rickshaw, and bus) transport modes. A total of 312 one-way trips were completed in urban traffic route and residential route during morning and afternoon periods to assess spatial and inter-day variations. The inhaled dose per trip and inhaled dose per kilometre travelled were also estimated using exposure concentrations, minute ventilation rates, travel time, and distance travelled. Irrespective of travel mode, PM2.5 and PM1 exposure concentrations in traffic route was consistently higher than the residential route. Morning trips were highly polluted than afternoon trips in traffic route, whereas afternoon trips registered marginally higher concentration than morning trips in the residential route. Motorized transport modes were observed with the highest exposure concentration compared to active commuters in both traffic and residential routes. Median PM2.5 and PM1 exposure concentration of motorized commuters across all routes and trips ranged from 54 to 202 and 21–153 μg m−3. Car commuters experienced the highest PM2.5 and PM1 exposure concentration. Pedestrian and bicycle commuters registered maximum inhaled doses per trip in traffic and residential routes, respectively. Also, inhaled doses per kilometre travelled in active commuters were 4–8 times higher than motorized commutes. Motorbike commuters experienced the lowest doses among all six commutes.