New research from the London School of Economics and Political Science suggests there is a link between air pollution levels and an increase in traffic collisions.
Published on 3 October, the research found that ‘small increases in the level of nitrogen dioxide in the air’ are correlated with ‘a measurable rise’ in the number of traffic accidents in the UK.
The results, based on data for the period between 2009 and 2014, show that a rise in the average concentration of nitrogen dioxide of just one microgramme per cubic metre is sufficient to increase the average number of accidents each day by 2%, with the biggest effect occurring in cities.
Although the research cannot identify the link, the author of the report, Lutz Sager, suggests it could be down to impairing drivers’ fitness.
Sager’s analysis divided the UK into a grid of 32 areas each covering about 7,700 square kilometres. He calculated that in the area containing west London, which suffers from some of the highest levels of air pollution, a cut of about 30% in the concentration of nitrogen dioxide could reduce the number of road accidents by almost 5%.
Lutz Sager, a researcher at the Grantham Research Institute on Climate 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.
“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.
“Although this analysis has used data for the UK, I think my findings are relevant to other parts of the world. These additional costs from traffic accidents strengthen the case for reducing air pollution, particularly in congested cities.”
Photo: the British Lung Foundation.