Air pollution and wheezing in children

Small particles present in polluted air may cause wheezing and cough in young children.

High air pollution levels have previously been linked to asthma symptoms in children living in urban areas with heavy traffic.

Researchers followed more than 700 American children living in Manhattan from birth to two years. Every three months, parents filled out a questionnaire about respiratory symptoms, if any, experienced by the infants. The study took into account the effect of other contributory factors such as seasonal allergy trends, ethnic group and exposure to tobacco smoke.

After comparing the results of the questionnaires with weekly pollution data from different sites in the city, it was found that high ambient levels of nickel and vanadium were risk factors for wheezing, while exposure to carbon particles, a byproduct of diesel exhaust, was associated with coughing during the cold and flu season. Total amounts of airborne particles were not associated with wheeze or cough, suggesting that individual ingredients of air pollution may be responsible for asthma symptoms in young children.

The researchers concluded that there are multiple components of air pollution that health care workers should be looking at in terms of health effects. The study raises questions about the best way to regulate air pollution to protect young children from its harmful effects and adds to a growing body of research suggesting that exposure to pollutants early in life has health impacts later on.