Formaldehyde and Other Pollutants from Ozone Reactions in Ventilation Systems

Details

• Personal Author:
  Apte MG ; Destaillats H ; Fisk WJ ; Gundel LA ; Sidheswaran MA
• Description:
  Formaldehyde is a harmful pollutant emitted by several sources in the indoor work environment. In office buildings provided with heating, ventilation and air conditioning (HVAC) systems, chemical reactions of atmospheric ozone or water vapor with filtration media may contribute to the formation of formaldehyde and other pollutants of concern. Understanding these reaction mechanisms and assessing their overall contributions to indoor pollutant levels will allow for an efficient control of those sources. We investigated chemical reactions on the surface of filters used in HVAC systems that lead to the formation of indoor pollutants. Specific Aims of the study were 1) to identify key constituents of particle-loaded HVAC filters that may react with ozone to generate indoor pollutants, 2) to establish the reaction rates and mechanisms that lead to the formation of pollutants, assessing the effect of filter moisture content on pollutant yield, and 3) to evaluate the overall impact on the indoor work environment. This project involved the experimental study of reactions of ozone and water vapor with used and unused filtration media under controlled conditions in a laboratory setting. Different types of filters were used to compare across a wide range of materials. Tested filters were installed and retrieved from two buildings in the Berkeley/Oakland area under different types of environments with prevalence of vegetation and urban pollution, respectively. Chemical analysis revealed the presence of mineral dust, black carbon, polymeric species and semivolatile organic compounds (SVOCs) on the surface of used filters, with variations associated to the different local environments at each site. We identified precursors and byproducts of ozone chemistry on filter surfaces. Our results confirmed that reaction with ozone and with water vapor (hydrolysis) as air flows through particle filters can constitute a small, albeit measurable, source of formaldehyde and other indoor pollutants. The effect of moisture was observed at 50% relative humidity (RH) and increased significantly at 80% RH. High formaldehyde levels were observed when humidified air passed through fiberglass filters, yielding estimated indoor concentration increases of up to 4 - 6 ug/m3. These values are comparable with typical formaldehyde levels in office buildings, suggesting that hydrolysis of filter constituents in some cases may become a significant source under high relative humidity conditions. [Description provided by NIOSH]
• Subjects:
  Air Pollution, Indoor Formaldehyde Humidity Occupational Health Safety Ventilation
• Keywords:
  Air Conditioning Equipment Air Filters Indoor Air Pollution Office Environments Ventilation Systems
• Series:
  Grant Final Reports
• Publisher:
  National Institute for Occupational Safety and Health
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Final Grant Report
• Place as Subject:
  California ; OSHA Region 9
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  OEP - Office of Extramural Programs
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-110
• NIOSHTIC Number:
  nn:20057271
• Citation:
  Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, R21-OH-008891, 2012 Nov; :1-110
• Contact Point Address:
  Hugo Destaillats, Lawrence Berkeley National Laboratory, Indoor Environment Group, 1 Cyclotron Road, MS 70-108B, Berkeley CA 94720
• Email:
  HDestaillats@lbl.gov
• CAS Registry Number:
  Formaldehyde (CAS RN 50-00-0)
• Federal Fiscal Year:
  2013
• NORA Priority Area:
  Healthcare and Social Assistance ; Manufacturing
• Performing Organization:
  University of California-Lawrence Berkeley Laboratory
• Peer Reviewed:
  False
• Start Date:
  20090915
• Source Full Name:
  National Institute for Occupational Safety and Health
• End Date:
  20120914
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:647a5fb57d52ba495109e72f1b595281ac3db9fbad1eee5aaba41e01de3d3a523deae8e1f3b17a7471de668d828df5f143cc21aa22779f9da4cbee35d202d279
• Download URL:
  https://stacks.cdc.gov/view/cdc/218928/cdc_218928_DS1.pdf
• File Type:
  [PDF - 2.46 MB ]