Children may develop asthma from breathing traffic-related air pollution.

Gehring U, AH Wijga, M Brauer, P Fischer, JC de Jongste, M Kerkhof, M Oldenwening, HA Smit and B Brunekreef. Traffic-related air pollution and the development of asthma and allergies during the first 8 years of life. American Journal of Respiratory and Critical Care Medicine http://dx.doi.org/10.1164/rccm.200906-0858OC.

Some children who breathe air pollution from cars and trucks may develop asthma and its related symptoms, finds a unique long-term study that followed the children for eight years. 

Prior studies have shown that children who have asthma and are exposed to air pollution are at increased risk for asthma symptoms and attacks.

But, this is one of the first studies to assess both the children and the air pollution exposure annually starting at age 1. From this, the researchers determined that exposure to traffic-related pollutants during childhood may also cause the asthma to initially develop.

Asthma can be debilitating. The hallmark symptoms – wheezing, shortness of breath and coughing – limit physical activity and can be fatal. According to the Centers for Disease Control about 7 million U.S. children – roughly 9 percent – have asthma.

Researchers at Utrecht University in the Netherlands followed 3,863 children from birth to age 8. They estimated the levels of traffic-related air pollutants – including particulate matter, nitrogen dioxide and ‘soot’ – at the children's homes. Parents were asked to report asthma and allergy symptoms yearly starting at age 1.

They found that higher levels of the three components of air pollution they studied were related to increased risk for new asthma cases. These air pollutants remained risk factors even after social and economic characteristis were accounted for. The research also showed that children exposed to higher levels of traffic-related pollution were about 25 percent more likely to have asthma prior to age 8. 

The study was not able to determine which air pollutant was responsible for the observed effects or the age at which children are most vulnerable to the pollution. However, the study's design allowed researchers to show that symptoms present at ages 2 and 4 persisted through age 8.