Reuters: Europeans no longer see the kind of pollution that within living memory killed thousands of Londoners in the Great Smog of 1952, but the air they breathe still bears invisible threats scarcely less deadly, and little more controlled.
While attention is given to curbing the carbon dioxide (CO2) emissions blamed for global warming, substances more directly harmful to human health, notably nitrogen oxides, are pumped out of diesel engines and from European power stations burning coal that is getting...