Car exhaust In the 1920s, pregnant women were encouraged to drink Guinness to increase their iron intake. For decades we were all told to avoid fatty butter and eat synthetic margarine. Both pieces of so-called health advice have since been totally debunked. We are now learning that millions of motorists who’ve bought diesel cars believing they were less harmful to the environment have been equally misguided. Diesel cars emit less carbon dioxide (CO2) than their petrol equivalent, we were told. In fact, not only are CO2 emissions almost indentical on average, but they also produce large quantities of other pollutants linked with thousands of premature deaths . Carmakers say they have already taken action to reduce emissions greatly in the past decade and regulators are beginning to acknowledge the problem, but the challenge remains enormous. The reason is simple: about half of all cars currently sold in Europe are […]