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Formaldehyde emissions from ventilation filters under different relative humidity conditions.

Authors
Sidheswaran-M; Chen-W; Chang-A; Miller-R; Cohn-S; Sullivan-D; Fisk-WJ; Kumagai-K; Destaillats-H
Source
Environ Sci Technol 2013 May; 47(10):5336-5343
NIOSHTIC No.
20044013
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 cm(2) 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-m(2) 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 g/m(3) to 12-20 g/m(3), 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.
Keywords
Ventilation; Ventilation-equipment; Ventilation-systems; Formaldehydes; Emission-sources; Filter-materials; Filters; Humidity; Relative-humidity; Filtration; Air-flow; Air-filters; Air-contamination; Fibrous-glass
Contact
Hugo Destaillats, Lawrence Berkeley National Laboratory, Indoor Environment Group, Berkeley, CA
CODEN
ESTHAG
CAS No.
50-00-0
Publication Date
20130521
Document Type
Journal Article
Email Address
HDestaillats@lbl.gov
Funding Type
Grant
Fiscal Year
2013
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R21-OH-008891
Issue of Publication
10
ISSN
0013-936X
Source Name
Environmental Science and Technology
State
CA
Performing Organization
University of California-Lawrence Berkeley Laboratory
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