A Quantification of VOC Emissions from Carpet in a Residence with a High Level of Formaldehyde

The Indoor Air Quality (IAQ) study at Washington State University strives to better understand the link between indoor air quality, health, and climate change. To combat climate change, building envelopes are tightened to reduce energy losses from heating and cooling. This results in reduced ventilation rates, and consequently, a greater buildup of pollutants from indoor sources. This project seeks to quantify the contribution of VOC emissions from carpet to indoor air pollution in a house (H002) in which high levels of formaldehyde were measured during the IAQ study. This initial analysis shows an average formaldehyde level of 30.1 ppbv. VOC emissions from three carpet samples are measured in an environmental chamber using a PTR-MS and a GC-MS. This experiment is unique because it compares emissions from a 3-year-old carpet (from H002) to emissions from new carpet samples. VOC emissions are also quantified under elevated O₃ concentrations, and under the application of UV light.  Under normal chamber conditions, all three carpet samples meet the Carpet and Rug Institute’s “Green Label Plus” standards. O₃ addition causes concentrations of some primary emissions to decrease and spurs greater emissions of some secondary pollutants. UV light causes emissions of most VOCs to rise considerably, though temperature increase with the activation of the UV light likely influences this result. A simulation of the indoor concentration of formaldehyde in H002 reveals that carpet emissions alone cause a concentration of 10.3 μg/m³ of formaldehyde in H002, which is an unhealthy level for long-term exposure according to standards cited by California’s OEHHA and the U.S. EPA. However, the expected concentration of formaldehyde due to carpet emissions alone accounts for only 32% of the average measured formaldehyde concentration in H002.