Air pollution linked with respiratory symptoms in young inner-city children: Study

Exposure shortly after birth to ambient metals from fuel oil combustion and particles from diesel emissions is associated with respiratory symptoms in young inner-city children, according to a new study by researchers at the Columbia Center for Children's Environmental Health (CCCEH) at Columbia University's Mailman School of Public Health.

The study is published in the December 1, 2009, issue of the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.

"It appears that exposure to ambient metals and diesel-exhaust particles in our air may lead to several respiratory symptoms for young children living in urban areas," said senior investigator Rachel L. Miller, M.D., associate professor of Medicine and Environmental Health Sciences (in Pediatrics) at New York-Presbyterian Hospital/Columbia University Medical Center and co-deputy director of CCCEH at the Mailman School of Public Health. "The effects of exposure to airborne metals had not been studied previously in children so young, and these findings could have important public health implications for members of inner-city communities in New York City and elsewhere."

To determine these effects, the researchers studied pollutant levels and respiratory symptoms in a cohort of more than 600 New York City children from Northern Manhattan and South Bronx between birth and two years of age. They used monitoring data to gauge three-month average ambient air concentrations of nickel, vanadium, elemental carbon and zinc as well as particulate matter. After controlling for exposure to second-hand tobacco smoke, sex, ethnicity and seasonal trends, they found that the airborne metals nickel and vanadium, whose major source in New York City is residual oil combustion for heating, were risk factors for wheezing in young children. Elemental carbon, an indicator of diesel exhaust, was associated with increased frequency of coughing only during cold and flu season months (September through April).

"These findings increase our understanding of the effects of specific pollutants from heating oil combustion and traffic on respiratory health in very young children," said Molini M. Patel, Ph.D., M.P.H., lead author and (previously) a research scientist in the Division of Pulmonary, Allergy, and Critical Care Medicine at Columbia College of Physicians and Surgeons and a CCCEH investigator. "Our results are of concern especially because levels of nickel in our study area, Northern Manhattan and the South Bronx, are among the highest in New York City and in the U.S., as are the rates of pediatric asthma."

These findings contribute to a further understanding of how specific sources of air pollution may impact child health.

Prior research from the Columbia Center for Children's Environmental Health showed that exposure to multiple environmental pollutants may be associated with an increase in risk for asthma symptoms among children. The researchers suggest that improved regulatory action directed at specific pollution sources— such as reducing residential boiler and emissions of airborne pollutants such as nickel or elemental carbon— is needed to help protect young children living in urban areas. A prospective follow-up of this birth cohort and measurement of residential levels of metals and traffic-related particles will help determine whether exposures to these pollutants are associated with increased respiratory morbidity and development of asthma at later ages, according to the researchers.

Source: Columbia Center for Children's Environmental Health