Trends in Cabin Air Quality of Commercial Aircraft: Industry and Passenger Perspectives

Abstract

The small air space available per person in a fully occupied aircraft passenger cabin accentuates the human bioeffluent factor in the maintenance of air quality. The accumulation of carbon dioxide and other contributions to poor air quality that can occur with inadequate ventilation, even under normal circumstances, is related to the volume of available air space per person and various ventilation rates. This information is compared with established air quality guidelines to make specific recommendations with reference to aircraft passenger cabins under both normal and abnormal operating conditions. The effects of respiration on the air quality of any enclosed space from the respiration of a resting adult are estimated using standard equations. Results are given for different volumes of space per person, for zero air exchange, and for various air change rates. The required ventilation rates estimated in this way compared closely with results calculated using a standard empirical formula. The results confirm that the outside air ventilation required to achieve a target carbon dioxide concentration in the air of an occupied enclosed space remains the same regardless of the volume of that space. The outside air ventilation capability of older and more recent aircraft is then reviewed and compared with the actual measurements of cabin air quality for these periods. The correlation between calculated and measured aircraft cabin carbon dioxide concentrations from other studies was very good. Respiratory benefits and costs of returning to the 30% higher outside air ventilation rates and 8% higher cabin pressures of the 1960s and 1970s are outlined. Consideration is given to the occasional occurrence of certain types of aircraft malfunction that can introduce more serious contaminants to the aircraft cabin. Recommendations and suggestions for aircraft builders and operators are made that will help improve aircraft cabin air quality and the partial pressure of oxygen that is available to passengers at minimal cost. Also suggested are some measures that passengers can take to help improve their comfort and decrease their risk of illness, particularly on long-haul flights.

Modeling Flight Attendants’ Exposure to Secondhand Smoke in Commercial Aircraft: Historical Trends from 1955 to 1989

“…Since manufacturers recommend air exchange rates of airline cabins be greater than 10 exchanges/ hour, (20) the passenger cabin was assumed to be well mixed during flights. Smoking was generally unrestricted in passenger cabins before 1973, thus a one-compartment model was used to estimate in-cabin SHS concentrations (Figure 1).…”

“…(35,36) Emission factors (μg/cigarette) of RSP and airborne nicotine from cigarette smoking were based on emission factors of these two markers by type of cigarettes (full flavor, with mainstream tar ≥15 mg/cigarette; full flavor, low tar, with mainstream tar 6-15 mg/cigarette; and ultra-low tar, with mainstream tar ≤6 mg/cigarette) (37) from the 1960s to 1991 as reported in the literature, (38)(39)(40) and the market shares of those types of cigarettes from 1967 to 1989 reported by the Federal Trade Commission (FTC) for the years from 1967 to 1989. (41) Cabin volumes and number of passenger seats of the major models of aircraft from 1964 to 1995 were estimated from a review by Hocking, (20) and were integrated into one parameter, volumn/N seat to represent volume per passenger seat. The effective removal rates by ventilation were estimated for RSP and nicotine separately basing on whether recirculation systems were used or not.…”

“…The air exchange rate of total air or fresh air by different aircraft models in different time periods were obtained from the reports by Hocking and by the National Research Council (NRC). (1,20) Removal rate of RSP by deposition was ignored because it was much smaller than the removal rate by ventilation, and removal rate of nicotine by deposition and absorption was estimated according to the paper by Van Loy et al (42) Details on how all these parameters were obtained or estimated are presented in the supplemental.…”

“…Monte Carlo simulations were used to estimate the annual SHS concentrations to which flight attendants were exposed in cabins for select years from 1955 to 1989 when the The CV and the range were based on the report by the 1989 DOT Survey, (29) ; the average was adjusted with the number of cigarettes consumed among (42) and an assumption of a (1,20) Notes: CV, coefficient of variation; ND: normal distribution; DTND: double truncated normal distribution. Results for the two B727 flights and for the two B767 flights were combined, respectively, since the smoking rates and the operational status were quite similar.…”

A correlation linking the predicted mean vote and the mean thermal vote based on an investigation on the human thermal comfort in short-haul domestic flights

“…The small air volume available per person in a fully occupied aircraft cabin accentuates the human bioeffluent factor in the maintenance of air quality (Hocking, 2002). The poor level of air quality may also cause intolerance to contact lenses and may be a health hazard to both passengers and crew members (Backman and Haghighat, 2000).…”