Diel variation of formaldehyde levels and other VOCs in homes driven by temperature dependent infiltration and emission rates

• Published in: Building and environment Vol. 159; p. 106153
• Main Authors: Huangfu, Yibo, Lima, Nathan M., O'Keeffe, Patrick T., Kirk, William M., Lamb, Brian K., Pressley, Shelley N., Lin, Beiyu, Cook, Diane J., Walden, Von P., Jobson, Bertram T.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 15.07.2019; Elsevier BV
• Subjects: Abundance; Air pollution; Air quality; Climate change; Diel variation; Drywall; Emission; Formaldehyde; Gypsum; Heat waves; Impact prediction; Indoor air; Indoor air pollution; Indoor air quality; Indoor environments; Infiltration; Infiltration rate; Mercury; Mercury (metal); Organic compounds; Pollutants; PTR-MS; Radiant heating; Summer; Temperature dependence; Temperature effects; Variation; VOCs; Volatile organic compounds; Winter; Volatile organic compounds; Infiltration; Diel variation; PTR-MS; Formaldehyde; Indoor air
• ISSN: 0360-1323; 1873-684X
• DOI: 10.1016/j.buildenv.2019.05.031

High time resolution monitoring of formaldehyde and other volatile organic compounds in the air of four homes in winter and summer revealed diel variation of VOC levels driven by infiltration and temperature dependent whole house emission rates. In unoccupied homes, these pollutants displayed a large diel concentration variation, with an afternoon maxima and early morning minima. VOC abundance lagged about 2 h behind changes in infiltration rates measured by a tracer release method, resulting in poor correlations between VOC concentration and air change rate. The data demonstrate that VOC abundance was not in steady state with respect to whole house emission rates. Formaldehyde and other VOCs displayed a positive correlation with indoor temperature in both winter and summer. Formaldehyde sensitivity to temperature ranged from 3.0 to 4.5 ppbv per °C, a useful metric for predicting the impact of heat waves and changing regional climate on indoor air quality. Gypsum wallboard used as radiant ceiling heating product in one home was identified as source of formaldehyde and potentially mercury. •Diel variation of indoor formaldehyde and other VOCs were found.•VOC levels are in dynamic state due to the time of day variation of infiltration rate.•VOC levels lag behind the air change rate.•Formaldehyde levels have temperature dependence of 3.0–4.5 ppbv per °C.•Gypsum wallboard is a formaldehyde source when heated.