Increase in pollution causes dangerous driving, study claims

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A high level of pollution in the air increases dangerous driving, claims a new study by a London School of Economics PhD student.

Lutz Sager has released his paper into the effect of air pollution on drivers, in which he found it to have a judgment-impairing effect.

By dividing a map of the UK into 32 squares and comparing the areas' average daily nitrogen dioxide (NO2) readings from 2009 to 2014 with the government's statistics on road accidents, he ascertained that the number of accidents on British roads fluctuated in line with the NO2 levels.

He also utilised weather data from Nasa's Aqua satellite to factor in temperature inversion. In this phenomenon, pollutants are prevented from rising up through the atmosphere by a blanket of warm air, which leaves the smog trapped around ground level.

Sager found that on average every additional microgram per cubic metre of nitrogen dioxide resulted in 0.3 more accidents a day – a two per cent rise.

In the working paper, which is expected to be published in a scientific journal over the upcoming months, Sager wrote: "We believe that our analysis identifies a causal effect of pollution on road safety, but can only speculate regarding the exact mechanisms involved.

"Our initial hypothesis has been that pollution impairs drivers' fitness, just as it has previously been shown to affect cognitive performance in other areas.

"However, we cannot exclude other possible explanations, such as pollution causing physical distractions — eg itching nose — or impaired visibility."

A number of flaws in the study have already been pointed out, with the link between short-term exposure to air pollution and poor driving questioned.

Traffic statistics were not included in the study, and could be responsible for some of the accident statistics.