Air quality in aircraft

Until the end of 2001, commercial air travel had experienced a substantial growth, increasing fourfold in three decades. However, concerns for the health and safety of air quality in the aircraft cabin environment raised by flight crews and passengers also increased greatly. Consequently, the US Congress twice directed the Federal Aviation Administration to commission the National Research Council to study this problem. The concerns included low ventilation rate (less than 5 1/s per person); reduced partial pressure of oxygen and its effect on susceptible people; very low relative humidities (10-20 per cent); ozone (sometimes over 100 ppb); cosmic radiation, which increases with altitude and latitude; fumes from breakdown products of leaks of lubricants and hydraulic fluids; and the airborne spread of infectious diseases. The outbreak of severe acute respiratory syndrome (SARS) and its apparent transmission by and within aircraft in 2003 highlighted the importance of ventilation, filtration and disinfection systems on aircraft, which are reviewed in this paper. This paper is based, in part, upon the NRC 1986 and NRC 2002 reports, in which coauthor John Spengler participated as cochair (1986) and member (2002).