BBC Radio's Costing the Earth series profiles work by King's College London on measuring air pollution in Britain, including new links between diesel exhaust and heart attacks, how regulation on CO₂ may have led to more diesel vehicles on the road, major discrepancies between advertised emissions in tests and actual emissions on the road, and how tree leaves help to remove PM from the air. Check out the 30 minute programme and the entire Costing the Earth series from the BBC Radio website.