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Member Research & Reports

Member Research & Reports

Iowa: Research Highlights Synergies Between Indoor, Outdoor Air Pollution and Increased Asthma

New University of Iowa research demonstrates that interactions between indoor and outdoor air pollution contribute to increased emergency room visits for asthma in both children and adults.

The research by investigators in the University of Iowa College of Public Health is the first nationwide study to examine children and adults co-exposed to house dust endotoxin and outdoor air pollutants such as ozone, nitrogen dioxide, and particulate matter. Endotoxins are molecules found in the outer membrane of common bacteria that cause inflammation in the airways of animals and humans.

Investigators studied 6,488 participants in the 2005-2006 National Health and Nutrition Examination Survey (NHANES). Dust collected from bedding and bedroom floors was analyzed for endotoxin, while modeled and monitored air pollution data were used to estimate annual average ambient pollution exposure levels at participants’ homes.

The analysis found that among all study participants, co-exposure to elevated levels of house dust endotoxin and particulate matter was associated with a five-fold increase in emergency room visits for asthma in the preceding 12 months. Meanwhile, exposure to higher endotoxin and nitrogen dioxide concentrations was associated with increased emergency room (ER) visits in children.

“This new research demonstrates that the combined exposures of endotoxin and ambient air pollution send people to the emergency room even at exposure levels that are considered safe,” says Dr. Peter Thorne, UI professor and head of occupational and environmental health and senior author on the paper, recently published in the American Journal of Respiratory and Critical Care Medicine. Dr. Thorne also directs the UI Environmental Health Sciences Research Center.

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