Research Program Area: Health & Exposure
Topic Areas: Indoor Air Quality
Formaldehyde is a toxic air contaminant that poses a risk of cancer and other adverse health impacts. Studies have shown that some fiberglass filters used in commercial heating, ventilation and air conditioning (HVAC) systems can be sources of formaldehyde. This study assessed formaldehyde emissions from residential fiberglass filters relative to synthetic filters, and estimated their contributions to indoor concentrations in California homes. The results showed that fiberglass filters emitted more formaldehyde than synthetic filters. At high relative humidity (RH), fiberglass filters became strong sources of formaldehyde, with emission rates in the range 500-3500 µg h-1 m-2, but emissions from synthetic filters were only 100-120 µg h-1 m-2. Formaldehyde emissions from fiberglass filters increased significantly with RH and face velocity. The core filtration media and the glued frame each contributed about half of the formaldehyde emissions. Under most conditions, contributions of fiberglass filters to indoor formaldehyde levels were estimated to be small. However, under certain conditions (e.g., a very small apartment with low air exchange), fiberglass filters were estimated to increase indoor formaldehyde by 2.5-9.3 ppb, sometimes exceeding the California 8-hr reference exposure level and Proposition 65 no significant risk levels. This study found that the use of synthetic particle filters instead of fiberglass filters could be a part of the solution to reduce indoor formaldehyde exposures.
For questions regarding this research project, including available data and progress status, contact: Research Division staff at (916) 445-0753
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