Babies who are exposed to ambient air traffic pollution are likely to have poorer lung function up to the age of eight, especially those who are sensitized to common allergens, researchers from the Karolinska Institutet, Stockholm, Sweden, reported in the American Journal of Respiratory and Critical Care Medicine.

Researchers have known for many years that air pollution harms health and kills. In 2006, the World Health Organization estimated that globally, two million people died prematurely every year because of air pollution.

Researcher Göran Pershagen, MD, PhD, professor at the Karolinska Institutet, Institute of Environmental Medicine, said:

“Earlier studies have shown that children are highly susceptible to the adverse effects of air pollution and suggest that exposure early in life may be particularly harmful. In our prospective birth cohort study in a large population of Swedish children, exposure to traffic-related air pollution during infancy was associated with decreases in lung function at age eight, with stronger effects indicated in boys, children with asthma and particularly in children sensitized to allergens.”

Dr. Pershagen and team gathered data on over 1,900 children who were monitored regularly from the day they were born until the age of 8 years. Questionnaires were sent to their parents, and several tests were carried out repeatedly during the period, including spirometry and immunoglobulin E measurements.

They used a mathematical model to estimate the children’s exposure to traffic air pollution – they had data on the kids’ residential, daycare and school addresses.

At the age of eight, the 5th to 95th percentile difference in traffic air pollution was linked to a reduced forced expiratory volume in one second (FEV1) of -59.3 mL (95% confidence interval (CI): -113.0 to -5.6).

This poorer lung function was especially noticeable among kids who were sensitized to food allergens and/or common inhalant allergens; boys appeared to be more affected than girls, as well as those with asthma.

The greatest impact appears to be during the first year of an infant’s life, the researchers added. Exposure to air pollution from traffic seemed to affect children less if it began during their second year.

The authors explained that their study has some limitations. Pollution level data came from archives dated back to 2004 and were extrapolated to the years where the children were at specific addresses.

Dr. Pershagen concluded:

“Our study shows that early exposure to traffic-related air pollution has long-term adverse effects on respiratory health in children, particularly among atopic children. These results add to a large body of evidence demonstrating the detrimental effects of air pollution on human health.”



Traffic pollution is a serious problem in the world’s largest cities