New UK research has found that babies in strollers could be exposed to up to 60 per cent more pollution than their caregivers, which could negatively affect their cognitive abilities and brain development.

Carried out by researchers at the Global Centre for Clean Air Research (GCARE) at the University of Surrey, the new study reviewed more than 160 references in literature to assess whether babies in strollers have a higher exposure to traffic-generated air pollutants such as particulate matter, including PM10 and the smaller, fine particular matter PM2.5, black carbon, and nitrogen oxides.

The researchers also investigated different types of strollers based on their height, width, and whether they seated one child or two, to see if this affected pollution exposure levels.

They found that infants in strollers breathe in more polluted air since they are usually positioned between 0.55 metres and 0.85 metres above ground level. Vehicle exhaust pipes generally sit within 1m above road level, making the air within the first few meters above road level usually the most polluted.

This increases babies' potential exposure to pollution, which can be up to 60 per cent more than that of adults, depending on pollutant types.

The researchers suggest that a range of actions are needed to protect vulnerable infants, including 'active' solutions such as controlling emissions of road vehicles, and 'passive' actions such as placing roadside hedges between vehicles and pedestrians.

Technological solutions, such as those which help to create a clean air zone around the child's breathing area, could also be an effective solution, while carpooling and using public transportation to reduce traffic levels could significantly improve air quality.

"We know that infants breathe in higher amounts of airborne particles relative to their lung size and body weight compared to adults. What we have proven here is that the height most children travel at while in a stroller doubles the likelihood of negative impacts from air pollution when compared to an adult," said study co-author Professor Prashant Kumar.

"When you also consider how vulnerable they are because of their tissues, immune systems, and brain development at this early stage of their life, it is extremely worrying that they are being exposed to these dangerous levels of pollution."

"With the multitude of evidence we set out in this review, it is important that everyone across the country begin a full and frank conversation about pollution and the impact it has on our most vulnerable -- from parents and community leaders, to government officials and industry."

According to UNICEF, across the world, 17 million children who are less than a year old live in regions where air pollution levels exceed World Health Organization-recommended guidelines.

The results were published in Environment International.