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

Abstract

Flight attendants were exposed to elevated levels of secondhand smoke (SHS) in commercial aircraft when smoking was allowed on planes. During flight attendants' working years, their occupational SHS exposure was influenced by various factors, including the prevalence of active smokers on planes, fliers' smoking behaviors, airplane flight load factors, and ventilation systems. These factors have likely changed over the past six decades and would affect SHS concentrations in commercial aircraft. However, changes in flight attendants' exposure to SHS have not been examined in the literature. This study estimates the magnitude of the changes and the historic trends of flight attendants' SHS exposure in U.S. domestic commercial aircraft by integrating historical changes of contributing factors. Mass balance models were developed and evaluated to estimate flight attendants' exposure to SHS in passenger cabins, as indicated by two commonly used tracers (airborne nicotine and particulate matter (PM)). Monte Carlo simulations integrating historical trends and distributions of influence factors were used to simulate 10,000 flight attendants' exposure to SHS on commercial flights from 1955 to 1989. These models indicate that annual mean SHS PM concentrations to which flight attendants were exposed in passenger cabins steadily decreased from approximately 265 μg/m(3) in 1955 and 1960 to 93 μg/m(3) by 1989, and airborne nicotine exposure among flight attendants also decreased from 11.1 μg/m(3) in 1955 to 6.5 μg/m(3) in 1989. Using duration of employment as an indicator of flight attendants' cumulative occupational exposure to SHS in epidemiological studies would inaccurately assess their lifetime exposures and thus bias the relationship between the exposure and health effects. This historical trend should be considered in future epidemiological studies.

Quantifying Risk to Flight Attendants from Secondhand Smoke Exposure in Airline Cabins Using Pharmacokinetic Modeling: A Case Report

“…Figure 6 shows that the area-monitored peak levels of SHS measured in the aircraft cabin in Figure 7 were comparable to area-monitored levels in a smoky bingo hall (T), and much higher than smoky bars. Liu et al 27 noted that both the concentrations measured in the literature and those simulated in their study confirm that flight attendants were exposed to very high concentrations of SHS in commercial aircraft when smoking was allowed. A flight attendant could be exposed to SHS concentrations greater than 800 μg/m 3 of RSP and 29 μg/m 3 of nicotine in passenger cabins in 1955, and to greater than 250 μg/m 3 of RSP and 17 μg/m 3 of nicotine in passenger cabins in 1989.…”

“…[28][29][30][31] Exposure: Ms. Cheney was exposed to secondhand smoke for 20 years as a flight attendant, 18 of which were spent in the aircraft cabin and 2 years in Eastern Airline's smoky offices. Assuming she experienced 900 flight-hours per year, 27 6). Using these equations, the Mattson study 18 of urine cotinine, when converted to its serum cotinine equivalent, shows that a flight attendant on the transcontinental 727 narrow body and 767 widebody flights studied absorbed doses that were six times the average worker and 14 times the average U.S. adult, indicating very heavy secondhand smoke exposure, consistent with the highest atmospheric measurements in the DOT study 24 that measured Very Unhealthy exposures to secondhand smoke.…”

“…Liu et al, 27 taking an estimated average (occupancy) load factor of 0.5, the average number of passengers per 727 and L10ll as 150 to 288, for an average of 200, and a smoking prevalence of 33%, the average number of smokers per flight would be 33, assuming the average number of flights per day to be 3 for 200 days per year, or 600 flights per year, with 33 smokers per flight, then 600 flights x 33 smokers per flight = 19 800 smokers x 18 years of flying = 356 400 smoker-years, placing Ms. Cheney into the highest category of exposure for chronic lymphocytic leukemia.…”

“…A flight attendant could be exposed to SHS concentrations greater than 800 μg/m 3 of RSP and 29 μg/m 3 of nicotine in passenger cabins in 1955, and to greater than 250 μg/m 3 of RSP and 17 μg/m 3 of nicotine in passenger cabins in 1989. 27 As Table 3, shows, these exposure concentrations range from Hazardous to Significant Harm as judged by the EPA Air Quality Index. By 1985 more than 40 000 flight attendants in the United States worked an average of 900 hours each year.…”

“…By 1985 more than 40 000 flight attendants in the United States worked an average of 900 hours each year. 27 Note that these modeled exposure estimates are conservative, in that they do not incorporate proximity of the flight attendants to the smokers, respiration rates during exposure, or work activity patterns during the flight. This is why dosimetry studies are vital in estimating true risk.…”