Variation of PM2.5 and inhalation dose across transport microenvironments in Delhi

Travelers are exposed to higher levels of Particulate Matter (PM). The present study investigates variability in exposure to PM2.5 for eight transport microenvironments. Data was collected during three time periods for seven days in Delhi, India. The mean PM2.5 concentrations are the highest for bicycle (59.80 mu g/m3), metro (55.75 mu g/m3), and lowest for AC -bus (40.82 mu g/m3) and AC -car (40.17 mu g/m3). Concentrations for all modes gradually increase from Thursday to Saturday. Most of the modes attain the highest values on a weekend day and the lowest value on Sunday due to higher wind speeds. Interestingly, the morning peak has the highest exposure and inhalation dose intake. The inhaled dose is highest for bicycle mode and lowest for AC -bus and AC -car. Higher inhalation doses may pose serious health issues to active -mode travelers. These findings can serve as practical guidelines for travelers and policymakers seeking to decrease exposure and reduce health burdens.