Air pollution linked to childhood asthma in nearly 50 per cent of cases

Worsening air pollution could be contributing to childhood asthma cases in, a study carried out in Barcelona has found. The Barcelona Institute for Global Health (ISGlobal) collated asthma incidence rates in the city for children between 1 and 18 years of age and concluded that 48 per cent could be attributed to air pollution every year.

Asthma is a chronic disease of the respiratory system, caused by inflammation of the airways and is associated with increased morbidity and mortality. It is the most common chronic childhood disease and there is currently no cure, although symptoms can be managed with treatment.

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The study took data from the Global Burden of Disease database, which describes mortality and morbidity from major diseases and calculated exposure levels for particles and gases associated with air pollution.

Two scenarios were considered. The first, based on the World Health Organisation (WHO) guidelines for maximum air pollution exposure levels, found that if guidelines on annual exposure levels were met, up to 19 per cent of childhood asthma cases attributable to the fine particulate matter (PM_2.5), and 18 per cent attributable to nitrogen dioxide (NO₂), could be prevented each year.

The second scenario reflected the minimum levels of air pollution. By reducing air pollution to the minimum reported levels, up to 48 per cent of cases attributable to NO₂ inhalation, 39 per cent attributable to PM_2.5 and 31 per cent of cases attributable to black carbon (BC), could be prevented each year.

“Road transport is one of the major air pollution sources. Barcelona urgently needs interventions to reduce the amount of motor-vehicle traffic, which has a negative impact on the health of the city's children,” said Mark Nieuwenhuijsen, director of the Urban Planning, Environment and Health Initiative at ISGlobal. "Reducing traffic does not only reduce air pollution, but also reduce noise and heat island effects and increases physical activity which are all beneficial to health.”