Stephen Holgate (Medical Research Council Clinical Professor of Immunopharmacology at Southampton University) says polluted air contributes to lung, heart, and many other diseases, especially in young people. It is a factor in 40,000 deaths in the UK every year. As I’ve said many times, letting traffic filter at low revs would cut fuel use and emissions in half, overnight. Yet government remains oblivious, and traffic authorities persist in regulation that blocks flow and maximises emissions. In addition, vexatious regulation produces the stress hormone cortisol which shortens life.