A study attempting to find a link between air pollution and car accidents only went and found one, suggesting that even when allowing for the increased levels of traffic that accompanies lower quality air there are more accidents when the air's all stinky.
According to the data collected up and run through the computers of the London School of Economics, a nitrogen dioxide increase of just one microgramme per cubic metre leads to a two per cent increase in collisions out on the road. The reasons why aren't entirely clear. It might be the fumes breaking our brains or something more random like an increased amount of sneezing, nose rubbing, window closing and opening, fan fiddling or the pulling up of jumpers over mouths.
Lead researcher Lutz Sager said of the findings: "The analysis identifies a causal effect of air pollution on road accidents, but I can only speculate about the cause of the link. My main theory is that air pollution impairs drivers' fitness. However, other explanations are possible such as air pollution causing physical distractions, perhaps an itching nose, or limiting visibility." [Telegraph]