For asthma sufferers, even the slightest change in environment can trigger a respiratory attack.
The role that home stoves and heating systems may play in the onset of asthma and its severity has been much studied and debated. Two researchers from the Yale School of Public Health, Kathleen Belanger, Ph.D., and Elizabeth W. Triche, Ph.D., reviewed dozens of unrelated international studies on the topic and found that most research supports a link between indoor combustion sources—fireplaces, woodstoves, kerosene heaters, gas stoves and flued or nonflued gas heaters—and asthma, particularly in children.
The Yale researchers reviewed published studies done in Asia, Europe, Australia and the United States. And while there were some discrepancies in their conclusions, most of the research found that repeated exposure to an indoor combustion source (or sources) appeared to put both adults and children at greater risk of asthma or exacerbated existing symptoms. Indoor combustion produces a variety of gases and particulate matter in a house that residents end up inhaling.
“Exposure to nitrogen dioxide and fine particles in inner city homes can exceed levels allowable in outdoor air by the U.S. Environmental Protection Agency, and the population exposed is the most vulnerable: asthmatics, infants and the elderly,” Belanger said.
In particular, the Yale researchers drew the following conclusions from the research papers surveyed:
- Indoor combustible heating appears to pose a greater risk for asthmatics than exposure to cooking sources.
- Exposure to coal is particularly risky. The effects of wood burning stoves and fireplaces on asthma were less conclusive.
- Nonflued gas heaters in a home pose a significant risk. Removing this type of heating system appears to reduce asthma symptoms in children.
- Differences in asthma symptoms between boys and girls may be related to differences in exposure, or may be due to gender differences in susceptibility.
A factor that could have contributed to the varied results in the different studies could be the characteristics of the combustible appliance in question (including type, age and the frequency and duration of its use) along with the type of home in which it is installed.
Details of the study will appear in the August issue of the journal Immunology and Allergy Clinics of North America.