Project at a Glance
Project Status: complete
Report Published November 1996:
Title: Determination of formaldehyde and toluene diisocyanate emissions from indoor residential sources.
Principal Investigator / Author(s): Kelly, Thomas J
Contract Number: 93-315
Topic Areas: Indoor Air Quality, Stationary Sources, Toxic Air Contaminants
Building materials and consumer products found in California residences were subjected to chamber testing to determine the emission rates of formaldehyde (HCHO) and of toluene diisocyanates (mI). The emissions of formaldehyde were determined from bare urea- formaldehyde (UP) and phenol-formaldehyde (PF) wood products, UP wood products with vinyl, paper, and other coatings, and from decorative laminates, permanent press fabrics, fiberglass insulation, paper goods, paints, cosmetics, and acid-cured coatings. Other compounds determined along with HCHO included acetaldehyde, propionaldehyde, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK). A separate set of polyurethane (PU) products, including PU foam carpet padding, furniture cushions, sheet foam, PU varnishes, caulks and sealants, and a commercially-applied water stop product for concrete, were tested for emissions of toluene diisocyanate (TDI).
Testing of products for emission of formaldehyde and the other target carbonyl compounds was conducted simultaneously at two sets of test conditions, using twin 1.43 m3 chambers. Both an integrated method and a sensitive real-time continuous method for formaldehyde were used. Quality assurance efforts included duplicate sampling with the integrated method, performance of confirmatory analyses by an outside laboratory, comparison of the real-time and integrated results for formaldehyde, duplicate chamber tests on 10 products, and testing of two products in both large and small chambers to assess comparability. Formaldehyde emission rates ranged from about 1 to over 1,000,000 µg/m2/hr. Among the dry products tested, bare UP wood products showed the highest formaldehyde emissions, followed by new permanent press fabrics, then by coated UF products, bare PF products, insulation, and decorative laminates, with no significant emissions from paper goods. Emissions from permanent press fabrics decreased by 60 percent after a single washing. An acid-cured floor finish and an acid-cured coating on cabinet doors exhibited high formaldehyde emissions. Cosmetics exhibited relatively high initial formaldehyde emissions, but low total amounts of emissions because of the small area of use. HCHO emissions greatly exceeded those of acetaldehyde and propionaldehyde from nearly all products; no emission of MEK or MIBK was observed from any product.
The PU products were screened under elevated temperature and chamber loading conditions, using both an integrated method specific for WI and a continuous but non-specific real-time monitor for isocyanates. The screening procedure was sensitive to TDI emission rates corresponding to indoor lifetime cancer risks from WI of about 1 x 10-6. None of the products normally found in residences showed a positive response in the screening tests. Only the commercially-applied water stop product, containing up to 4 percent WI by weight, gave a positive response in the screening test. Final testing of that product at realistic temperatures showed initial TDI emission rates of about 300,000 µg/m2/hr, with emissions lasting only one hour or less.
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