Dirty air blamed for rise in road accidents

Watery eyes and toxic fumes from pollution might make drivers more likely to crash, study warns

AIR pollution could be responsible for hundreds of car accidents a year, scientists have warned.

A study by the London School of Economics, published today, looked at five years of data and showed that when levels of nitrogen dioxide (NO2) rise by just one microgramme per cubic me- tre, the number of collisions rises by 2 per cent.

Although it could be assumed that more road traffic would lead to more pollution and therefore more accidents, the researchers found that the increase remained even when adjusting for extra traffic.

They believe that the toxic air impairs driver fitness, while watery eyes and an itchy nose could also be distracting for motorists.

Another study has found that air pollution inside a car can be more than double that on the outside because the NO2 builds up in a small space.

Lead researcher Lutz Sager, of the Grantham Research Institute on Cli- mate Change and the Environment, said: “Although it has already been shown that air pollution adversely affects human health and the ability to carry out mental tasks, this is the first published study that assesses the impact on road safety.

“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.”

Air pollution can result from many toxins, including carbon monoxide, ni- trogen dioxide, sulphur dioxide, small particulate matter and ozone. But NO2 was found to have the biggest impact.

Mr Sager, a postdoctoral candidate, divided the UK into a grid of 32 areas each covering about 4,784 square miles (7,700 sq km) and mapped accidents to the level of air pollution between 2009 and 2014 provided by the Department for the Environment.

He found that a rise in the concentration of nitrogen dioxide of just one microgramme per cubic metre above the daily average could increase the average number of accidents each day by 2 per cent.

He calculated that in west London, which has some of the highest pollution levels, cutting NO2 by 30 per cent could reduce the number of road accidents every day by almost 5 per cent.

Levels of NO2 in polluted areas of London can reach beyond 97 microgrammes per cubic metre on average.

There are about 150,000 collisions in which someone is injured in Britain every year so preventing just 2 per cent could avert thousands of accidents. Mr Sager added: “Whatever the exact mechanisms responsible, the robust finding of a significant effect of air quality on road safety is important given the high cost of road traffic accidents through damage to vehicles and deaths and injuries to people.”

However, Edmund King, the president of the AA, said: “If you think about areas which are high in air pollution they are a lot busier, with taxis and buses and lorries, and where you have a greater mix of traffic, you tend to have more accidents.

“It would be hard to tease apart whether a crash is caused by a driver wiping his eyes because of pollution or whether the type of traffic is to blame.”