The Centers for Disease Control and Prevention (CDC) posted on Wednesday two reports from its work related to assessing the levels of formaldehyde in the indoor air of travel trailers used by the Federal Emergency Management Agency (FEMA) for emergency housing of Gulf Coast residents. One report, the results of which have been previously reported, assessed indoor formaldehyde levels. The other looked at emissions from specific travel trailer components and construction materials.
In the aftermath of Hurricane Katrina, FEMA provided travel trailers, park models and mobile homes to Gulf Coast residents who had lost their homes in the hurricane. CDC has been working with FEMA and other agencies to investigate the levels of formaldehyde in the trailers and mobile homes.
“These two studies provide much helpful information,” said Michael McGeehin, director of the Division of Environmental Health Hazards at CDC. “But the findings are only applicable to those trailers distributed by FEMA in the Gulf Coast Region; they do not apply to other trailers in use elsewhere in the country. However, taken together, the two studies indicate that manufacturers of travel trailers and the government agencies that influence their design, should consider using construction materials that emit lower levels of formaldehyde as well as designs that increase outside air ventilation.”
McGeehin noted that, as CDC previously recommended, families that include children, the elderly, and those with chronic diseases such as asthma should make relocating to permanent housing a priority.
Assessment of Unoccupied Travel Trailer Building Materials and Components (newly released study)
In an effort to identify and better understand factors that could foster high levels of formaldehyde and other volatile organic compounds, CDC had the Lawrence Berkeley National Laboratory (LBNL) measure air formaldehyde concentrations in whole trailers and emissions from specific parts of each trailer, such as walls, floors, ceilings, tables and cabinets. Four vacant, never-used trailers were provided by FEMA, including two trailers that were specifically designed to be used as temporary emergency housing and thus not commercially available.
“Even with a limited sample of trailers, this study affirms what would be expected, that construction materials that emit high concentrations of formaldehyde, when part of a relatively small structure that has poor ventilation, have the potential to produce elevated levels of formaldehyde in the indoor air,” McGeehin, said. “This suggests that efforts to design and build emergency housing units may be able to greatly improve indoor air quality by using different construction materials and ensuring that ventilation systems let in fresh air.”
Formaldehyde emissions from the four whole trailers studied ranged from 173 to 266 micrograms per meter per hour in the morning to 257 to 347 micrograms per meter per hour in the afternoon due to increasing temperatures. Median formaldehyde emissions in previously studied, newer (six months or less) site-built and manufactured homes were 31 and 45 micrograms per meter per hour, respectively. Researchers also found phenol, and TMPD-DIB1 (which is used to make plastic) at levels higher in the trailers than commonly found in site-built or manufactured homes. Though elevated, neither phenol nor TMPD-DIB levels were found at high enough levels to pose health hazards.
McGeehin stressed that the CDC study, because it only examined four travel trailers, did not provide results that could be applied to all FEMA-supplied travel trailers or to other types of temporary housing, such as park models or mobile homes. He noted the FEMA-supplied trailers were different from other types of housing because they contain extensive wood surface areas packed into relatively small spaces, and often let in less fresh air than site-built or manufactured houses.
“This detailed analysis does help us identify the sources of formaldehyde and other volatile organic compounds that may make the largest contributions to poor indoor air quality,” McGeehin said. “It also indicates that, even though individual construction materials can meet standards that are generally accepted by the construction industry and others, the amount of space and the amount of ventilation also affect the concentrations found in the air.”
In the aftermath of Hurricane Katrina, FEMA provided travel trailers, park models and mobile homes to Gulf Coast residents who had lost their homes in the hurricane. CDC has been working with FEMA and other agencies to investigate the levels of formaldehyde in the trailers and mobile homes.
“These two studies provide much helpful information,” said Michael McGeehin, director of the Division of Environmental Health Hazards at CDC. “But the findings are only applicable to those trailers distributed by FEMA in the Gulf Coast Region; they do not apply to other trailers in use elsewhere in the country. However, taken together, the two studies indicate that manufacturers of travel trailers and the government agencies that influence their design, should consider using construction materials that emit lower levels of formaldehyde as well as designs that increase outside air ventilation.”
McGeehin noted that, as CDC previously recommended, families that include children, the elderly, and those with chronic diseases such as asthma should make relocating to permanent housing a priority.
Assessment of Unoccupied Travel Trailer Building Materials and Components (newly released study)
In an effort to identify and better understand factors that could foster high levels of formaldehyde and other volatile organic compounds, CDC had the Lawrence Berkeley National Laboratory (LBNL) measure air formaldehyde concentrations in whole trailers and emissions from specific parts of each trailer, such as walls, floors, ceilings, tables and cabinets. Four vacant, never-used trailers were provided by FEMA, including two trailers that were specifically designed to be used as temporary emergency housing and thus not commercially available.
“Even with a limited sample of trailers, this study affirms what would be expected, that construction materials that emit high concentrations of formaldehyde, when part of a relatively small structure that has poor ventilation, have the potential to produce elevated levels of formaldehyde in the indoor air,” McGeehin, said. “This suggests that efforts to design and build emergency housing units may be able to greatly improve indoor air quality by using different construction materials and ensuring that ventilation systems let in fresh air.”
Formaldehyde emissions from the four whole trailers studied ranged from 173 to 266 micrograms per meter per hour in the morning to 257 to 347 micrograms per meter per hour in the afternoon due to increasing temperatures. Median formaldehyde emissions in previously studied, newer (six months or less) site-built and manufactured homes were 31 and 45 micrograms per meter per hour, respectively. Researchers also found phenol, and TMPD-DIB1 (which is used to make plastic) at levels higher in the trailers than commonly found in site-built or manufactured homes. Though elevated, neither phenol nor TMPD-DIB levels were found at high enough levels to pose health hazards.
McGeehin stressed that the CDC study, because it only examined four travel trailers, did not provide results that could be applied to all FEMA-supplied travel trailers or to other types of temporary housing, such as park models or mobile homes. He noted the FEMA-supplied trailers were different from other types of housing because they contain extensive wood surface areas packed into relatively small spaces, and often let in less fresh air than site-built or manufactured houses.
“This detailed analysis does help us identify the sources of formaldehyde and other volatile organic compounds that may make the largest contributions to poor indoor air quality,” McGeehin said. “It also indicates that, even though individual construction materials can meet standards that are generally accepted by the construction industry and others, the amount of space and the amount of ventilation also affect the concentrations found in the air.”
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