Aviation Safety:

More Research Needed on the Effects of Air Quality on Airliner Cabin Occupants

GAO-04-54: Published: Jan 16, 2004. Publicly Released: Feb 10, 2004.

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Over the years, the traveling public, flight attendants, and the medical community have raised questions about how airliner cabin air quality contributes to health effects, such as upper respiratory infections. Interest in cabin air quality grew in 2003 when a small number of severe acute respiratory syndrome (SARS) infections may have occurred on board aircraft serving areas that were experiencing outbreaks of the disease. In 2001, a National Research Council report on airliner cabin air quality and associated health effects recommended that additional research be done on the potential health effects of cabin air. GAO reviewed what is known about the health effects of cabin air, the status of actions recommended in the 2001 National Research Council report, and whether available technologies should be required to improve cabin air quality.

Despite a number of studies of the air contaminants that airline passengers and flight attendants are potentially exposed to, little is known about their associated health effects. Reports on airliner cabin air quality published by the National Research Council in 1986 and 2001 concluded that more research was needed to determine the nature and extent of health effects on passengers and cabin crew. Although significant improvements have been made to aircraft ventilation systems, cabin occupants are still exposed to allergens and infectious agents, airflow rates that are lower than those in buildings, and air pressures and humidity levels that are lower than those normally present at or near sea level. The 2001 National Research Council report on airliner cabin air quality made 10 recommendations, 9 of which directed the Federal Aviation Administration (FAA) to collect more data on the potential health effects of cabin air and to review the adequacy of its standards for cabin air quality. FAA has addressed these 9 recommendations to varying degrees as it attempts to balance the need for more research on cabin air with other research priorities (e.g., passenger safety). However, some in the aviation community, including some of the committee members who produced the report on cabin air, do not feel that FAA's planned actions will address these recommendations adequately. For example, most members were concerned that FAA's plan for implementing the report's key recommendations on the need for more comprehensive research on the health effects of cabin air was too limited. FAA plans to address these recommendations in two parts--the first, which started in December 2003, and the second, which will start in December 2004 and end in late 2006 or early 2007. However, FAA lacks a comprehensive plan, including key milestones and funding needs. In addition, most committee members thought that FAA's response to a recommendation for it to improve public access to information on the health risks of flying was inadequate. We also had difficulty accessing this information on FAA's Web site. Several technologies are available today that could improve cabin air quality, (e.g., increasing cabin humidity and pressure or absorbing more cabin odors and gasses); however, opinions vary on whether FAA should require aircraft manufacturers and airlines to use these technologies. GAO found that one available technology, high-efficiency particulate air (HEPA) filtering, was strongly endorsed by cabin air quality and health experts as the best way to protect cabin occupants' health from viruses and bacteria in recirculated cabin air. While FAA does not require the use of these filters, GAO's survey of major U.S. air carriers found that 85 percent of large commercial airliners in their fleets that recirculate cabin air and carry more than 100 passengers already use these filters. However, the use of HEPA filters in smaller commercial aircraft that carry fewer than 100 passengers is much lower. The cost to retrofit the smaller aircraft to accept the HEPA filter, if it were made mandatory, could be expensive.

Recommendations for Executive Action

  1. Status: Closed - Implemented

    Comments: An FAA economist completed the report on the cost and benefits of requiring the use of HEPA filters on commercial aircraft with ventilation systems that recirculate cabin air. The report was published in June 2006. According to FAA, the report does not support retro-fitting HEPA filters onto older aircraft that currently do not have them. The estimated cost would be $21.3 million with an annual recurring cost of $1.5 million. An FAA official also stated that FAA has also initiated a HEPA filter analysis research project with Kansas State University through the Airliner Cabin Environment Research Program, but this study is delayed due to a lack of congressional funding.

    Recommendation: In order to help improve the healthfulness of cabin air for commercial aircraft passengers and cabin crews, the FAA Administrator should assess the costs and benefits of requiring the use of HEPA filters on commercial aircraft with ventilation systems that recirculate cabin air. If FAA chooses to require the use of HEPA filters, it should also ensure that the regulation covers the maintenance requirements for these filters.

    Agency Affected: Department of Transportation: Federal Aviation Administration

  2. Status: Closed - Implemented

    Comments: The appropriation legislation sets forth an initial reporting requirement for initial research and surveillance efforts. FAA submitted the initial report to Congress on July 25, 2006. In June 2005 FAA told us that subsequent annual reporting will begin to ensure Congress is fully and effectively informed of research and surveillance results. However, FAA now states that it does not plan on doing annual updates since this is not required by legislation. FAA also noted that continued research is dependent on continued annual funding from Congress

    Recommendation: To help ensure that FAA's research and surveillance efforts on airliner cabin air quality answer critical outstanding questions about the nature and extent of potential health effects of cabin air quality on passengers and flight attendants, the Secretary of Transportation should direct the FAA Administrator to report to Congress annually on the progress and findings of the research and surveillance efforts and funding needs.

    Agency Affected: Department of Transportation

  3. Status: Closed - Implemented

    Comments: FAA's Cabin Environmental Quality Technical Group has been established. This technical group is subordinate to the FAA/EU Joint Aviation Authority/Transport Canada Civil Aviation Research and Development Joint Coordinating Committee. The FAA is participating in forums such as the International Aero Industry Conference on Contaminated Air Protection, Air Safety and Cabin Air Quality at the Imperial College of London held in April 2005. Close liaison with the British Building Research Establishment continues.

    Recommendation: To help ensure that FAA's research and surveillance efforts on airliner cabin air quality answer critical outstanding questions about the nature and extent of potential health effects of cabin air quality on passengers and flight attendants, the Secretary of Transportation should direct the FAA Administrator to leverage the findings of international research on airliner cabin air quality to inform FAA's surveillance and research efforts.

    Agency Affected: Department of Transportation

  4. Status: Closed - Implemented

    Comments: Invitations have been extended to subject matter experts to participate on an Advisory Board for the Airliner Cabin Environment Research program. EPA, NIOSH, and CDC have been invited to participate. The first meeting of the ACER is planned for August 2005.

    Recommendation: To help ensure that FAA's research and surveillance efforts on airliner cabin air quality answer critical outstanding questions about the nature and extent of potential health effects of cabin air quality on passengers and flight attendants, the Secretary of Transportation should direct the FAA Administrator to appoint a committee of acknowledged experts in the fields of aircraft ventilation and public health, including representatives of the Environmental Protection Agency and the National Institute for Occupational Safety and Health, to assist in planning and overseeing the research and surveillance efforts recommended by the National Research Council in 2001.

    Agency Affected: Department of Transportation

  5. Status: Closed - Implemented

    Comments: FAA's Center for Excellence for Airliner Cabin Environment Research was established in August 2004 in response to the GAO recommendation. A fully integrated research plan was developed to study issues concerning cabin air quality. Research proposals have been submitted against that plan to address all of the congressionally mandated concerns. Of the $15M appropriated in FY 04 and 05, $13M has been committed to carry out the approved research proposals.

    Recommendation: To help ensure that FAA's research and surveillance efforts on airliner cabin air quality answer critical outstanding questions about the nature and extent of potential health effects of cabin air quality on passengers and flight attendants, the Secretary of Transportation should direct the FAA Administrator to develop a detailed plan for the research and surveillance efforts,including key milestones and funding estimates, in accordance with generally accepted practices for oversight and independence.

    Agency Affected: Department of Transportation

  6. Status: Closed - Implemented

    Comments: FAA improved its web site access of health and safety information to the traveling public, which is readily available on FAA's main page under the heading "Passengers." The current Passenger Health and Safety Section contains numerous downloadable documents, reports, and links to other Web sites that provide comprehensive information on health and safety issues in aviation.

    Recommendation: In addition, to increase access to information on the health risks related to air travel, the FAA Administrator should direct the staff responsible for the FAA Web site to improve the links to other Web sites containing this information. The Administrator should also consult with medical associations and health organizations, such as the Centers for Disease Control and Prevention, on other ways to increase the dissemination of this information.

    Agency Affected: Department of Transportation: Federal Aviation Administration

 

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