Inhaled ozone as a mutagen: I. Chromosome aberrations induced in Chinese hamster lymphocytes

Ozone levels in airplane cabins, and factors that influence them, were studied on northern hemisphere commercial passenger flights on domestic U.S., transatlantic, and transpacific routes. Real-time data from 76 flights were collected in 2006–2007 with a battery-powered UV photometric monitor. Sample mean ozone level, peak-hour ozone level, and flight-integrated ozone exposures were highly variable across domestic segments (N = 68), with ranges of <1.5 to 146 parts per billion by volume (ppbv), 3−275 ppbv, and <1.5 to 488 ppbv-hour, respectively. On planes equipped with ozone catalysts, the mean peak-hour ozone level (4.7 ppbv, N = 22) was substantially lower than on planes not equipped with catalysts (47 ppbv, N = 46). Peak-hour ozone levels on eight transoceanic flight segments, all on planes equipped with ozone catalysts, were in the range <1.5 to 58 ppbv. Seasonal variation on domestic routes without converters is reasonably modeled by a sinusoidal curve that predicts peak-hour levels to be approximat...

Ozone Levels in Passenger Cabins of Commercial Aircraft on North American and Transoceanic Routes

UNLABELLED: Ozone concentrations were passively monitored in passenger cabins of commercial airliners flying domestic, Pacific, and south-east Asian routes. One-hundred and six flight segments were monitored for either the full duration and/or approximately 3 h during the middle portion of the flight for a total of 145 time-integrated measurements. Over all samples the mean (+/-SD) concentration was 80 p.p.b. (30.1). Twenty percent of the measurements exceeded 100 p.p.b., the FAA-recommended level. Eleven percent of the measurements exceeded 120 p.p.b., the US EPA's short-term National Ambient Air Quality Standard for ozone. Ozone concentrations measured on Pacific flights were substantially higher during mid-flight than over the full flight (95 p.p.b. vs. 56 p.p.b). Ozone concentrations on the northern Pacific routes were higher than concentrations for other Pacific flights. Season comparison showed that ozone levels were higher during the winter and spring than for the summer and fall. Our study shows that even in aircraft with catalytic ozone converters, passengers and flight crew may be exposed to elevated ozone levels on domestic and international flights. Given the frequency of ozone excess, it is recommended that (1) ozone converters should be required equipment on all commercial passenger aircraft for mid and high latitude routes (2) improved maintenance procedures should be required for catalytic converters (e.g., more frequent servicing/replacement), and (3) ozone should be routinely monitored on all mid and high latitude flights. PRACTICAL IMPLICATIONS: The authors have demonstrated elevated ozone concentrations in passenger cabins. They give several practical recommendations to help solve the problem.

Ozone exposures during trans-continental and trans-pacific flights

Inhaled ozone as a mutagen. II. Effect on the frequency of chromosome aberrations observed in irradiated Chinese hamsters.

The smaller size and lighter weight of the Boeing 747SP aircraft, introduced into passenger service in 1976, permitted higher-altitude flight than older commercial aircraft and thus potentially greater ozone exposure, for those on board. Concerned flight attendants distributed questionnaires relating to symptoms experienced on the Boeing 747SP and/or conventional 747 aircraft to Los Angeles- and New York-based flight attendants. Respondents reported symptoms by frequency and severity and by in-flight and after-flight occurrence. Based on the assessment of three health scientists as to ozone-relatedness, the frequency of “definite” and “probable” ozone-related symptoms of any severity reported by both groups of attendants was significantly associated with 747SP flights (chi-squares: P<0.05). After-flight symptoms significantly associated with 747SP experience, although fewer in number than in-flight symptoms, were all in the scientists' “definite” category. In 21 flight attendants who complained of moderate to severe symptoms during 747SP flights, a battery of pulmonary function tests performed approximately two weeks after their last 747SP flight failed to reveal abnormalities. The symptom questionnaire results are consistent with possible exposure of cabin attendants to toxic levels of ozone during the higher-altitude flights of the Boeing 747SP compared to conventional 747 aircraft.

Respiratory symptoms of flight attendants during high-altitude flight: possible relation to cabin ozone exposure.

: A survey was made to (1) measure ozone concentrations in CAR 4b jet aircraft cabins and cockpits on flights above 25,000 ft to obtain a 12-month evaluation with emphasis on seasonal and meteorological correlation and (2) locate and chart ozone-enriched air masses to obtain further correlations and to find any abnormal conditions that result in high ozone concentration. The data obtained by monitoring jets showed: (1) External ozone enters via the pressurization system. (2) Ozone concentration varies with altitude, latitude, and season. (3) Pressurization systems of various aircraft do not differ in ozone-decomposing efficiency. (4) Internal ozone concentration is negligible on flights made below the tropopause.

Robert I. Brabets

Papers

Ozone measurement survey in commercial jet aircraft.