Project at a Glance
Title: Common indoor sources of volatile organic compounds: emission rates and techniques for reducing consumer exposures.
Principal Investigator / Author(s): Hodgson, Alfred T
Contractor: Lawrence Berkeley National Laboratory
Contract Number: 95-302
Topic Areas: Indoor Air Quality, Stationary Sources, Toxic Air Contaminants
This investigation characterized the emissions of volatile organic compounds (VOCs) from interior latex paints and newly manufactured carpet and vinyl flooring materials that are representative of materials widely used in Califomia. Specimens of three or more materials in each major source category were obtained and screened for their emissions of VOCs over 48 or 96 hours using small-scale chambers. Forty-five experiments were conducted with 24 primary materials. Seventeen of the VOCs measured have been identified as toxic air contaminants by the Califomia Air Resourses Board. Based on small-chamber results, a paint combination, a carpet assembly, and a vinyl flooring assembly were selected for investigation in large-scale chamber experiments designed to simulate conditions in a small residential room environment. Thirteen large-scale experiments were conducted to provide real-world emissions data and evaluate the effectiveness of several techniques that consumers might use to reduce concentrations of VOCs and their cumulative exposures to these compounds. The exposure reduction techniques included additional ventilation for three days following installation (all source assemblies), additional air mixing (paint combination), airing out of materials prior to installation (carpet and vinyl flooring assemblies), and room heating at 330 C subsequent to installation (all sources present together). The assemblies were installed following typical construction industry practice and concentrations of selected VOCs in chamber air were measured over the following two weeks. For each assembly, one or two experiments were performed using a base-case low ventilation rate scenario and two experiments were performed to evaluate the treatments. Two of the 13 experiments employed a combination of all three assemblies. One of these was extended for a period of three months to obtain information on the longer-term emission characteristics of the sources. There were clear differences in VOC emissions among materials in each class. Therefore, the results demonstrated that there are opportunities to reduce exposures by selecting materials that emit lower amounts of toxic or odorous VOCs. A short period of additional ventilation following material installation generally increased the mass emissions of the compounds and also reduced the cumulative exposures for many compounds during the period of additional ventilation. After the period of additional ventilation, room concentrations were similar to concentrations in experiments without additional ventilation. This suggests that additional ventilation is likely to be a more effective treatment if it can be maintained for longer periods. Airing out carpet material for several days prior to installation effectively reduced the emissions of VOCs. After installing materials, applying heat to the chamber, in conjunction with additional ventilation, increased the emissions of VOCs during the heating period, but was relatively ineffective for reducing the subsequent concentrations and exposures for most compounds.
For questions regarding this research project, including available data and progress status, contact: Heather Choi at (916) 322-3893
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