Particulate air pollution in transport micro-environments

To understand the dynamics of particulate matter inside train coaches and public cars, an investigation was carried out during 2004-2006. For air-conditioned rail coaches, during peak journey times, the mean concentrations of PM<inf>10</inf>, PM<inf>2.5</inf> and PM<inf>1</inf> were 44 g m ^-3, 14 g m^-3 and 12 g m^-3, respectively. The levels fell by more than half (21 g m^-3, 6 g m^-3, and 4 g m^-3) for the same size fractions, on the same route, during the off-peak journeys. On the other hand, in non-air-conditioned coaches, the PM<inf>10</inf> concentrations of up to 95 g m^-3 were observed during both peak and off-peak journeys. However the concentrations of PM<inf>2.5</inf> and PM<inf>1</inf> were 30 g m^-3 and 12 g m^-3 in peak journeys in comparison to 14 g m^-3 and 6 g m^-3 during off-peak journeys. Over a period of four months the concentrations of PM <inf>10</inf>, PM<inf>2.5</inf> and PM<inf>1</inf> in car journeys were generally similar during both morning and evening journeys with average values of 21 g m^-3 for PM<inf>10</inf>, 9 g m^-3 for PM <inf>2.5</inf> and 6 g m^-3 for PM<inf>1</inf>. However during October the average concentration of PM<inf>10</inf> was 31 g m^-3. An analysis of nearby fixed monitoring sites for both PM<inf>10</inf> and PM <inf>2.5</inf> revealed an episode of high particulate pollution over southern England during one week of October. There was no statistically significant difference between particulate matter levels for morning and evening car journeys. A statistically significant correlation was found between morning and evening PM<inf>10</inf> (0.45), PM<inf>2.5</inf> (0.39) and PM<inf>1</inf> (0.46). In train journeys, a statistically significant difference was observed for peak and off-peak levels of PM<inf>10</inf>, PM<inf>2.5</inf> and PM <inf>1</inf> in air-conditioned coaches. On the other hand, in non air-conditioned coaches a significant difference was documented only for PM <inf>2.5</inf> and PM<inf>1</inf>. © 2009 The Royal Society of Chemistry.