Formaldehyde Emissions from Ventilation Filters Under Different Relative Humidity Conditions

Title Formaldehyde Emissions from Ventilation Filters Under Different Relative Humidity Conditions
Publication TypeJournal Article
Refereed DesignationRefereed
Year of Publication2013
AuthorsSidheswaran, Meera A., Wenhao Chen, Agatha Chang, Robert Miller, Sebastian Cohn, Douglas P. Sullivan, William J. Fisk, Kazukiyo Kumagai, and Hugo Destaillats
JournalEnvironmental Science and Technology
Volume47
Start Page5336
Issue10
Pagination5336-5343
Date Published04/2013
Abstract

Formaldehyde emissions from fiberglass and polyester filters used in building heating, ventilation, and air conditioning (HVAC) systems were measured in bench-scale tests using 10 and 17 cm2 coupons over 24 to 720 h periods. Experiments were performed at room temperature and four different relative humidity settings (20, 50, 65, and 80% RH). Two different air flow velocities across the filters were explored: 0.013 and 0.5 m/s. Fiberglass filters emitted between 20 and 1000 times more formaldehyde than polyester filters under similar RH and airflow conditions. Emissions increased markedly with increasing humidity, up to 10 mg/h-m2 at 80% RH. Formaldehyde emissions from fiberglass filters coated with tackifiers (impaction oils) were lower than those from uncoated fiberglass media, suggesting that hydrolysis of other polymeric constituents of the filter matrix, such as adhesives or binders was likely the main formaldehyde source. These laboratory results were further validated by performing a small field study in an unoccupied office. At 80% RH, indoor formaldehyde concentrations increased by 48–64%, from 9–12 μg/m3 to 12–20 μg/m3, when synthetic filters were replaced with fiberglass filtration media in the HVAC units. Better understanding of the reaction mechanisms and assessing their overall contributions to indoor formaldehyde levels will allow for efficient control of this pollution source.

DOI10.1021/es400290p
Short TitleEnviron. Sci. Technol.
Refereed DesignationRefereed