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Sunday, February 21, 2016

Is there Asthma in your House?

Here's an excerpt from a recent study that you should become aware, if you're a home owner or thinking of purchasing a home soon.

Ted Schettler | Science & Environmental Health Network; Ames, IA; USA
Michael Wolfe | WOLFE, San Francisco, CA; USA


The Gulf Coast region understands the relationship between building materials and asthma. After Hurricanes Katrina and Rita struck in 2005, FEMA awarded $2.7 billion in contracts to shelter displaced residents. By August 2006, FEMA purchased 144,000 trailers and mobile homes.[1] A human-made health disaster ensued. Connections between building materials, formaldehyde air emissions, and asthma were well established when FEMA put the Katrina trailers out to bid.[2] Formaldehyde resins bind composite wood casework, flooring, and wall panels. In 1992, the California Air Resources Board identified formaldehyde resins in these products as major sources of formaldehyde in indoor air. But FEMA’s bidding process did not consider the potential health impacts of bringing these materials into a hot and humid climate where formaldehyde is more readily volatilized. A meta-analysis of seven studies in homes and schools from several different countries concluded that asthma risk in children increased 3-17 percent for every 10 µg/m3 [8.1 parts per billion (ppb)] increase in formaldehyde in indoor air. In these studies, formaldehyde levels varied from very low to > 80 µg/m3 (65 ppb). [3] A U.S. Centers for Disease Control (CDC) study of Katrina FEMA trailers found formaldehyde well above these levels. The mean for the 519 tested trailers was 77 ppb.[4] In some, air concentrations exceeded 300 ppb. The most common unit - Gulfstream - had a median concentration of 111 ppb, almost seven times the national median of 17 ppb. Using the meta-analysis’ correlation rate, children living in the Gulfstream FEMA trailers had a 35% to 200% elevated risk of having asthma. In a federal health survey of FEMA trailer residents, 31% of the participating children reported having a diagnosis of asthma, nearly three-fold higher than the prevalence of childhood asthma nationally (11% in 2010).[5, 6] Department of Homeland Security (DHS) Inspector General Richard Skinner reviewed the situation. “All of the units were some form of manufactured housing and therefore tended to have more of the manufactured wood products that can emit formaldehyde gas,” he reported. And the FEMA contracts “did not contain protections against excessive formaldehyde concentrations.”[7]

DHS Inspector General Skinner laid bare this reality: “Although workplace standards and recommendations for allowable exposures to formaldehyde have been implemented to protect workers who are exposed to formaldehyde, there is far less guidance as to what levels should be avoided in residences.” Similarly, authoritative lists of asthmagens are based largely on studies involving worker exposures—hence the commonly used term “occupational asthma.” However, the extent to which chemicals known to cause occupational asthma may have similar effects within the general public, especially children, is often unclear for several reasons: 1. Occupational exposures are often much higher than residential exposures; 2. Dose-response levels are often not well enough established to allow extrapolation to low levels of prolonged exposure; 3. The importance of multiple factors in the origins of asthma, including co-exposure to allergens in residences, may make it more difficult to estimate the contribution of toxic exposures to asthma risk in homes compared to the workplace; and, 4. Occupational asthma generally affects adults whereas most asthma in the general public is among children, who are more vulnerable due to their smaller size and developing immune and respiratory systems.[8] These challenges clearly pertain to chemicals in building products. Workers exposed to occupational asthmagens during product manufacture or building construction will be at increased asthma risk. But, after construction and building occupancy, exposure levels are generally unknown for most asthmagens.

To read more of the study click the link below