Potential Health Impact of Switching From Car to Public Transportation When Commuting to Work

We assessed humidity corrected particulate matter (PM(2 5)) exposure and physical activity (using global positioning system monitors and diaries) among 18 people who corn muted by car to Queens College New York New York for 5 days and then switched to commuting for the next 5 days via public transportation The PM(2 5) differed little between car and public transportation commutes (1 41 mu g/M(3) min P = 226) Commuting by public transportation rather than by car increased energy expenditure (+124 kcal/day P < 001) equivalent to the loss of 1 pound of body fat per 6 weeks (Am J Public Health 2010 100 2388-2391 doi 10 2105/AJPH 2009 190132)