Indoor air in four First Nations communities in remote northwestern Ontario contains high concentrations of biocontaminants, mold, fine particles, and other substances that increase the risk of respiratory infections, new research reveals.
In a study of the housing conditions and indoor environmental quality (IEQ) in these communities, about 27% of the homes had sustained CO2 concentrations above 1500 ppm. Although 44% of houses had a heat recovery ventilator (HRV), only 8% were in good working condition. Other issues included biocontaminants such as dust mites and fungal glucan, tobacco smoking, and high concentrations of mold.
Dr J. David Miller
“One exposure that led up to the children going to hospital was the chemical called endotoxin,” study author J. David Miller, PhD, distinguished research professor at Carleton University in Ottawa, Ontario, told Medscape Medical News. “When concentrations are too high, it affects lung function and causes a greater response to allergens. The values in the Sioux Lookout Zone were around 1000 times higher than I’d ever seen in any study in the United States or Canada. That was a big surprise.”
The study was published online November 22 in PLOS ONE.
Children’s Health Endangered
In their study of four First Nations communities in a remote region of northwestern Ontario, the investigators used statistical methods such as linear regression, mixed models, and logistic regression to assess correlations between housing conditions and biocontaminants and indoor concentrations of fine inhalable particles (PM2.5), CO2, benzene, and formaldehyde.
They investigated 101 homes (40%) in these small communities; each had approximately 1200 residents. Samples were taken, and the homes were inspected by an indoor air quality specialist.
To identify factors affecting IEQ, the investigators considered various issues. For example, the houses were crowded, averaging approximately seven people in each. The most common type of fuel for heating was wood (48%), but only 10% of the wood stoves were certified by the US Environmental Protection Agency (EPA) for lower emissions.
In 94% of the houses, people smoked commercial tobacco. The mean number of smokers per house was 2.6, and the number of smokers per house was as high as seven.
Most HRVs were improperly installed and maintained. Nonworking HRVs were associated with increased fine particle concentrations and higher CO2 concentrations.
Almost half of the homes (46%) had visible mold, and 23% had mold odor. Of the latter homes, 12 had more than 1% visible mold and moisture damage per unit floor area, which is sufficient to increase the relative risk of respiratory disease. Some had much greater areas of damage. Mold-specific cleaning was done often in 41% of homes, rarely in 29%, and never in 31%.
More than half (61%) of the homes had sustained water damage in the past 12 months, and approximately 13% of homes with crawl spaces had serious moisture damage or were improperly constructed.
Fungal glucan was positively associated with the presence of carpets, firewood storage, and a dirt floor crawl space. It was negatively associated with central forced air heating and continuous heating. Higher levels of endotoxin were associated with carpets and pets in the home and tended to be associated with more firewood stored in the living space.
“In summary, houses in these communities were crowded with very high concentrations of endotoxin and exposure to environmental tobacco smoke. Most of the HRVs were not functioning or used,” the authors wrote. “Approximately 12% of the homes had serious mold damage resulting from both design and maintenance issues.
“Five decades after discussion on the quality of housing in Indigenous Communities became a public issue, there have been improvements, but many outstanding issues remain identified,” they continued. “A focus on the health of Indigenous children could be used to incent efforts to fund repairs and maintenance in houses.”
Among the strategies that can help ameliorate the housing and respiratory health situation is education for physicians who work in these areas, said Miller. “Historically, a patient comes in with wheezing, and you’ll most likely give them medicine. What we encourage is that you ask at least a few questions about that patient’s housing conditions. The hope is that physicians will be a bit more sensitive to what the possible housing conditions are. If there seems to be a problem, at least they can counsel the patient, if possible, to have their house looked at by an expert.”
Miller is the senior author of several American Academy of Allergy, Asthma, and Immunology papers on assisting healthcare providers to determine when home assessments for potential mold exposure are warranted and on home assessment and remediation.
Educating the public is also important, he noted. “While organizations like Health Canada and the EPA and Centers for Disease Control and Prevention in the US have good knowledge-translation materials…they’re not in the right context for a community like the Sioux Lookouts zone,” he said. Therefore, Miller and his team worked with three indigenous women to create educational materials that are appropriate for these communities.
Dr Deborah Bennett
Commenting on the study for Medscape, Deborah Bennett, PhD, a professor of environmental and occupational health at the University of California, Davis, said, “Sadly, it is common for underserved populations to have poor-quality housing stock with the type of problems seen in this study. Maintaining plumbing and ventilation is expensive, and it is clear systems have not been well maintained for this population. Also, older homes often don’t have systems such as ventilation fans in the bathroom, which results in moisture and mold.” Bennett did not participate in the study.
“Underserved communities in the United States also disproportionately face poor housing conditions,” she noted. In these situations, “clinicians should encourage family members not to smoke indoors. If residents have a range hood, it should be used when the family cooks.
“Beyond that,” she said, “many of the changes that need to be made are costly and might not be realistic, such as changing the heating system to be something other than wood burning, repairing plumbing, and fixing ventilation systems.”
The study was funded by Health Canada. Miller and Bennett have no competing interests.
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