Cabin Air Quality

Friday, December 18, 2020

The FAA is committed to protecting the safety and health of passengers and cabin crews on our nation's airlines. The FAA has strict cabin air standards, and studies have shown cabin air is as good as or better than the air found in offices and homes. In rare instances, certain mechanical issues can cause fumes to enter the cabin. Airlines are required to report to these incidents to the FAA. The FAA thoroughly investigates the causes of these events and makes sure the cause is fixed before the aircraft is returned to service.


  • The FAA requires manufacturers to show that the airplane crew and passenger compartment air is free from harmful or hazardous concentrations of gases and vapors.
  • FAA regulations require airliners' ventilation systems to supply clean air to both passengers and crew members. Airplanes must be designed to provide the equivalent of at least 0.55 pounds of fresh air per minute per occupant, a ventilation rate that is consistent with other public environments.
  • Most of today's large transport category airplane ventilation systems provide a mix of fresh air/engine bleed and recirculated airflow. The mix is approximately 50 percent, but can vary depending upon the flight altitude and power settings.
  • Most U.S. commercial airplanes use High Efficiency Particulate (HEPA) filters, which remove 99.97 percent of particulate material.
  • While the FAA does not have a definition for a "fume event," airlines are required to file Service Difficulty Reports (SDRs) when smoke, vapor or noxious odors enter the cockpit or passenger cabin. In 2018, US airlines conducted more than 12 million flights. The FAA's SDR database shows 232 submissions from air carriers that referenced a fume event that year.
  • The FAA, manufacturers, and air carriers currently maintain cabin air quality by defining appropriate design standards, designing the environmental control systems to meet those standards, and conducting proper maintenance, respectively.

Research Initiatives and Actions

  • In January 2018, the FAA participated in meetings with the Cabin Air Quality Task Group (CAQTG), which consists of Airlines for America, aircraft manufacturers, labor unions, research groups and other airline interests. The CAQTG identified a number of goals, including developing procedures for effectively following up on reported events, creating common terminology for reports and data collection, working with training providers to better identify certain odors/fumes, and working with other stakeholders for further research. In support of this effort, the FAA published a Safety Alert for Operators, Procedures for Addressing Odors, Smoke and/or Fumes in Flight.
  • The FAA created and sponsored the Research in the Intermodal Transport Environment /Airliner Cabin Environment Research (ACER) Center of Excellence from 2004 through 2015. Research conducted is available for public review on the FAA website. The research shows:
    - FAA air quality regulatory requirements reflect a general consensus of aircraft manufacturers that the minimum levels of CO (carbon monoxide) and CO2 (carbon dioxide) are good indicators of overall air quality.
    - The existing design standards have assured airplane passengers and crewmembers an acceptable cabin environment during normal operations.
    - The environmental control systems on board commercial transport category airplanes provide an environment that is equivalent to or better than that of other forms of commercial transport when they are properly operated and maintained.
  • In response to provisions of the 2012 FAA Modernization and Reform Act, the FAA assessed cabin air quality. In December 2015, the FAA published a report called "Aircraft Cabin Bleed Air Contaminants: A Review," which described the potential health-related risks of human exposure to bleed-air contaminants generated during fume events. The report found that the rate of actual cabin air quality events is less than 33 events per million aircraft departures.
  • The FAA has worked closely with airplane manufacturers, air carriers, and research institutes to study the cabin air quality of in-service aircraft in order to ensure a safe cabin environment. The FAA, European Aviation Safety Agency (EASA), and industry experts have conducted several studies that indicate the air quality of transport airplane cabins is on par with other forms of public transportation and with public buildings and homes.

Ongoing Research and Initiatives

  • The FAA is working to address air-quality provisions of the FAA Reauthorization Act of 2018.
    - The FAA in December 2018 commissioned a study by the RITE/ACER Center of Excellence to develop techniques to monitor cabin bleed-air quality. The FAA formed a team of subject matter experts to review previous research and published reports on cabin air quality, including assessments by the National Academy of Sciences and work by the NASA Vehicle Integrated Propulsion Research (VIPR) project. The team will provide direction to the RITE-ACER Center of Excellence. The study will take approximately 54 months to complete.
    - The FAA is working with the CAQTG to help airlines better report cabin air-quality issues, conduct safety assessments and identify the cause following cabin air events.
    - The FAA is conducting a literature review and consulting with relevant stakeholders through the CAQTG to develop educational materials on how to best respond to smoke or fume incidents on board aircraft.