Reducing air pollution levels by 20 per cent could put children a month ahead in their learning

Cutting air pollution outside schools could boost children’s memories, putting them the equivalent of a month ahead in school, experts suggest.

A reduction of a fifth in nitrogen dioxide pollution, produced by traffic fumes and industry among other sources, could improve schoolchildren’s memory by 6.1 per cent, according to researchers at the University of Manchester.

Experts suspect that inhaling microscopic particles of pollution may affect the development of children’s brains.

Researchers did not actually test British schoolchildren’s memories or achievement in school.

But previous Spanish research has shown children at schools in highly polluted areas, similar to those in the UK, see slower than normal memory improvements over time.

A 20 per cent reduction in pollution could help children’s memories improve up to four weeks faster in a year, based on the Spanish evidence.

The findings will raise concerns about further risks to children from dirty air beyond asthma and respiratory problems.

However some doubt remains on whether pollution really can affect memory, as previous studies have not always found a link.

But Professor Martie van Tongeren, an environmental health expert at the University of Manchester, who led the research, said: ‘Pollution of indoor and outdoor air affects the health of our children.

‘In addition, the available evidence indicates that it affects their cognitive development, which may affect educational attainment.

‘Policies should be set out by ministers to tackle this urgent challenge, immediately.’

Last month new analysis, commissioned by Asthma UK and the British Lung Foundation, found more than a quarter of British schools, nurseries and colleges are in areas with ‘dangerously high’ levels of pollution particles called PM2.5, which can trigger asthma attacks in children.

To see how pollution might affect children’s thinking skills, researchers referred to two recent Spanish studies.

These looked at nitrogen dioxide levels in school grounds, and PM2.5 levels inside school, as well as pupils’ memory tests.

Children were shown a series of images, such as numbers, colours or words, and asked to remember one they had seen previously – up to three images ago.

In polluted areas, children were slower and less accurate on average, and this allowed researchers to work out how pollution in British schools could affect pupils.

They could also see the rate at which children’s memories improved over a year, and calculate how many weeks of additional improvement a cut in pollution might provide.

Halving nitrogen dioxide levels in schools could give children the equivalent of up to seven weeks of extra learning in a year, the scientists suggest.

An air purifier in a classroom was found to reduce pollution by 30 per cent in a Manchester primary school.

The research was carried out to mark Clean Air Day, and commissioned by its coordinators, the charity Global Action Plan and the Philips Foundation.

Global Action Plan is calling for Government action to reduce pollution at schools and provides advice through its Clean Air for Schools Framework on measures such as improved ventilation and traffic-free streets (SUBS – pls keep).

Responding to the findings, Jonathan Grigg, professor of paediatric respiratory and environmental medicine at Queen Mary University of London, said: ‘There is emerging evidence that air pollution has effects on the developing brain and this type of modelling, based on a peer-reviewed study, helps to showing the benefits of reducing air pollution.

‘Reducing children’s exposure will have many other positive outcomes, including less cases of asthma and better lung growth.’