Road traffic pollution gives children asthma

April 13, 2013 - 06:38

But children in rural areas face other allergens that can trigger the disease.

Secondary smoke or heavy traffic – both are bad. (Photo: Istockphoto)

A newly published comparative study of asthma and road traffic using data from ten European cities presents estimates of the percentage of children whose asthma is due to traffic pollution.

“We know that air pollution can trigger asthma symptoms. But this is the first time we have gotten an estimate of the percentage of asthmatic children who would not have been afflicted at all if they hadn’t been exposed to pollution from road traffic,” says Laura Perez in a press release.

Perez works at the Swiss Tropical and Public Health Institute, and is the first author of the new study.

The researchers conclude that 14 percent of children with chronic asthma got it because of traffic pollution. Stockholm was the only Nordic city represented in the survey.  However, for an overall comparison, more than 20 percent of Norwegian children have, or have had, asthma by the age of ten, according to the Norwegian Asthma and Allergy Association.

Uncertainties

The researchers calculated their figures by collating asthma studies that had already been conducted in the ten cities with statistics of asthma prevalence and residence related to traffic pollution exposure.

They then calculated how much of the blame can be pinned on roads as compared to other factors, such as household smoking or socio-economic background.

They used this data to determine how many cases of asthma they think could have been averted if the children did not live close to a road with heavy traffic.

However, because the researchers had to calculate with some variables that couldn’t be fully verified, their model cannot give definite results.

Bergen points at smoking

The World Health Organization (WHO) has estimated that between 4 and 18 percent of all cases of child asthma can be attributed to secondary smoke.

Perez and her research colleagues, however, think smoking and traffic pollution are equally bad.

Last year the Norwegian Broadcasting Corporation (NRK) reported that children who lived close to busy roads in Bergen had less asthma than those who were subject to secondary smoke.

“In homes with a lot of cigarette smoke the particles are closer and thus worse than in areas with high levels of air pollution,” said Per Schwarze, a director at the Norwegian Institute of Public Health, to NRK.

Chief Physician Zuzana Magnussen suggested at the same time that many families who have children with respiratory problems are likely to move to more rural areas with fresher air, which statistically lowers the number of asthmatic children who live close to roads with heavy traffic.

Scandinavian responses

Swedish researchers have already found that a key factor is where the child lives in its first year.

Children who lived close to busy roads in their first 12 months were more at risk of poor lung function later. But kids who moved to areas with heavy traffic later in their childhood did not appear to be affected by road dust pollution.

A Danish study looked at children who grew up on farms and concluded that they have half the risk as their urban peers of developing asthma and allergies.

This may make you think you should move out of town right away. But even if you have allergy problems you needn’t start packing yet. 

Common sense

The grass is not always greener in the suburbs - partly because of the grass itself. There's lots of pollen out there in rural areas or the suburbs. Too much of it during the last trimester of a pregnancy can increase the risk of a child developing asthma early in life.

Young parents are constantly being bombarded with conflicting research conclusions, whether about coffee, kindergartens, asthma prevention or some other concern.

One thing to consider – neither the automotive industry nor the tobacco giants are claiming that traffic pollution and smoking are particularly beneficial to small or fully developed lungs.

So even though scientists don’t concur as to exactly how pernicious these factors are, it’s a good idea to quit smoking and try to keep infant lungs pure.

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Read the Norwegian version of this article at forskning.no

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Translated by
Glenn Ostling

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