UK study: 40 percent of child asthma cases due to air pollution

A new study from the University of Leeds has revealed that nearly 40 percent of childhood asthma cases in Bradford are caused by air pollution each year. Traffic-related air pollution, in particular, is responsible for at least 12 percent of asthma cases.

The team used a newly-developed model to investigate the impact of the gases that make up air pollution, or nitrogen oxides, on the development of asthma in children.

The model combines data on four distinct scenarios of traffic, emissions, atmospheric dispersion, and health assessments to track the pollution all the way from its source to its impact in children.

While the experts estimated that traffic-related pollution contributed to 12 percent of asthma-related illness in children, this estimate had to be adjusted.

Study co-author Professor Mark Nieuwenhuijsen is the Director of the Urban Planning, Environment and Health Initiative at ISGlobal.

“We knew our model was underestimating the traffic related fraction of air pollution,” said Professor Nieuwenhuijsen. “When we adjusted our results using actual measurements of air pollutants we saw that up to 24% of the annual cases could be attributable to traffic related air pollution.”

Study lead author Dr. Haneen Khreis said that traffic pollution is a major concern to the community of Bradford.  

“Overall rates of childhood asthma cases in Bradford are higher than the national average as were emergency hospital admissions for asthmatic children under 16 years of age,” said Dr. Khreis.

“Our team’s previous research has shown that children exposed to high levels of traffic-related air pollution have a higher risk of developing asthma. Quantifying the number of childhood asthma cases that are directly attributable to traffic-related air pollution has not been done in the past and as we show now, a significant portion of cases is largely preventable.”

Dr. Khreis emphasized that, while proposed initiatives such as providing routes with cleaner air for pedestrians are important, traffic pollution mitigation strategies should not be restricted to localized areas.

“New policies aimed at reducing the effects of traffic-related air pollution need to target each link in the full chain of events – from traffic volume and type, to exhaust and non-exhaust emissions, to dispersion to exposure.”

“There is very little research that explores the impact of different exposure assessments,” said Professor Nieuwenhuijsen.

“Cases of childhood asthma have been steadily increasing since the 1950s. Future progress with childhood asthma requires a focus beyond controlling and treating the disease toward asthma prevention starting with reducing traffic related air pollution.”

The study is published in the journal Environment International.

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By Chrissy Sexton, Earth.com Staff Writer