Elevated levels of air pollution cause more children to be admitted to hospital with respiratory problems, a new study has found.

Professor Jill Belch, from the University of Dundee’s School of Medicine, says that youngsters are sustaining irreparable damage to their lungs due to the inhalation of harmful particulates emitted by vehicles.

She has advocated the expansion of Low Emission Zones (LEZs) throughout the UK as a means of reducing the levels of nitrogen oxides in urban areas following the findings, which showed spikes in hospital admissions in under-16s for respiratory problems following periods of high air pollution. These admissions occurred at levels which did not affect adult admissions, providing crucial evidence of how sensitive children are to pollution.

“Children are so much more susceptible to air pollution as their cells are dividing as they grow, and thus are more easily damaged by the toxins, never to recover,” said Professor Belch.

“NO2 is a chemical that inflames the lungs and produces sticky mucus, which congest the lungs causing infections a few days later – around six or seven days - which means that parents may not often associate a respiratory problem with air pollution."

“What is especially worrying is that these admissions occur at pollution levels which leave adults unaffected, thus stressing the vulnerability of this group.”

The World Health Organisation (WHO) estimates that air pollution contributes to 6.7 million premature deaths a year, with Nitrogen oxides (NOx), made up of nitrogen dioxide (NO2), nitrogen oxide (NO) and other smaller fractions of pollutants having been linked to health conditions such as asthma and chronic lung disease.

Using publicly available records from between 2004 and 2017, Professor Belch and colleagues from the Tayside Pollution Research Programme (TPRP) cross-referenced data on almost 35,000 admissions into Dundee’s Ninewells Hospital with the average daily nitric oxide level recorded from local air monitoring sites.

The results showed that respiratory admissions in children were associated with cumulative 14-day exposure to NOx, NO2 and NO, particularly for acute respiratory infections. The team concluded that children may be at a higher risk of hospitalisation at lower levels of NOx pollution exposure than adults due to the increased susceptibility of immature lungs to toxins, and children’s tendency to be outside more frequently than adults, increasing their exposure to polluted air.

The findings come amid the continued rollout and expansion of LEZs throughout the UK. This includes what is already the world’s largest LEZ in London in an effort to encourage drivers to own less-polluting vehicles and improve public health in inner city areas.

“LEZs are undoubtedly the best way to get rid of air pollution, but it does come at a price to local authorities in terms of installation, monitoring and enforcement. That is why community pressure is so important for having these zones adopted. But the benefits to a child’s health, from the evidence we have gathered, is clear."

“The health effects can take two or three years to emerge but if you look at Germany and France then they are already showing benefits, and the same will apply in cities like London and Dundee in years to come."

“We already have some data from London which is showing an increase in walking and cycling to school because it is safer, so there are additional health benefits to LEZs.”

Dr Munro Stewart, a GP at Dundee’s Nethergate Medical Centre and co-author of the study, added, "Our study shows that keeping pollution within safe limits could reduce paediatric respiratory admissions by 40%."

“While Scotland has the tightest air pollution regulations in Europe, we must ensure that they are actually enforced with measures such as LEZs to protect the wellbeing of our children, because we know that the air they breathe now will also affect them for the rest of their lives.”