Exposure to various air pollutants depends largely on their concentrations and amount of time spent by the people in a specific micro-environment. Among a wide range of micro-environments, the transport micro-environment is of great importance due to repeated exposure. To understand the dynamics of particulate pollution in transport micro-environments in developed and developing countries, an investigation was carried out in Pakistan and the United Kingdom. In the UK concentrations of PM10, PM2.5 and PM1 in a car were generally similar during both morning and evening journeys with average values of 21 µg/m3 for PM10, 8 µg/m3 for PM2.5 and 6 µg/m3 for PM1. In Pakistan overall journey-time levels of PM10, PM2.5, PM1 and PM10-2.5 were 103 mg/m3 , 50 mg/m3, 38 mg/m3 and 53 mg/m3 as compared to 489 mg/m3, 91 mg/m3, 52 mg/m3 and 397 mg/m3 at fixed sites.
