Some information based on research by Liz Batten of Clean Air Southampton

There have been loads of small studies done about pollution for inside car vs. outside car, with varying results. But in general, provided you take certain precautions, you are much better off cycling and walking, rather than being in a car. This BBC summary is pretty good and includes a case study of what to expect alongside busy roads vs quiet roads. So the moral of this tale is – when cycling and walking – always take routes that avoid busy roads, especially idling traffic, whenever possible.

Bear in mind that newer diesel cars have filters fitted to remove particulates, but the computer won’t switch it on until the engine has reached a certain temperature. So, on a cold day, by the time you’ve got to the school gate and returned home it might just have switched on. So short journeys are absolutely the worst thing about diesel engines, even Euro 6 standard, because of this. The school run in a car is probably the most polluting thing you can do to yourself, the occupants of your car and those on the pavement.