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Roads’ impact on asthma underestimated

Air pollution from roads can be a major contributor to asthma

Louise Prime

Tuesday, 25 September 2012

Air pollution from living close to main roads is a major contributor to asthma, US research has shown. Authors of the study, published online in Environmental Health Perspectives, call for policies to reduce children’s exposure to traffic-related pollution.

They say that previous estimates of the impact of air pollution on asthma exacerbations in children have underestimated its true burden – and they have calculated that at least 8% of the more than 300,000 cases of childhood asthma in Los Angeles County are attributable to traffic-related pollution at homes within 75m of a busy road.

The researchers used data from the long-term, ongoing Children’s Health Study to estimate the effects of air pollution on children suffering from asthma in the LA Basin. They used government regional air pollution measurements and area maps to estimate exposure to near-roadway pollution in the Los Angeles area, then linked this information to population data.

Asthma exacerbation was associated with regional pollutants including nitrogen dioxide and ozone that cover large parts of the air basin, and to near-roadway pollutants that are responsible for the development of asthma. Living near busy roads contributed disproportionately to the more serious exacerbations of asthma in children, including visits to A&E and hospital admissions.

The study authors calculated that cutting children’s near-roadway pollution exposure by 20% would result in about 5900 fewer cases of childhood asthma in LA County; and that a 20% rise in exposure would lead to 5900 more cases of asthma.

They wrote: “Our findings suggest that there are large and previously unappreciated public health consequences of air pollution in Los Angeles County and probably other metropolitan areas with large numbers of children living near major traffic corridors.”

The called for strategies to reduce urban sprawl, and encourage walking and use of fuel-efficient public transport, as well as to reduce children’s exposure to traffic pollution from nearby major roads.

They concluded: “There is also emerging evidence that other diseases may be caused or exacerbated by urban air pollution, including atherosclerosis, lung cancer, chronic obstructive pulmonary disease (COPD) and neurological disorders.

“Thus, policies to combat climate change may have near-term health benefits beyond reducing the burden of disease due to asthma.”

Study: Perez, L., Lurmann, F., Wilson, J., Pastor, M., Brandt, S.J., Künzli, N., McConnell, R. (2012). Near-roadway pollution and childhood asthma: Implications for developing "win-win" compact urban development and clean vehicle strategies, Environmental Health Perspectives, Published online Sept. 24, 2012; http://dx.doi.org/10.1289/ehp.1104785

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