Our objective was to study the perception of cabin air quality (CAQ) and cabin environment (CE) among commercial cabin crew, and to measure different aspects of CAQ on intercontinental flights. A standardized questionnaire was mailed in February-March 1997 to all Stockholm-based aircrew on duty in a Scandinavian flight company (n = 1,857), and office workers from the same company (n = 218). The answers were compared with an external reference group for the questionnaire (MM 040 NA). During this time, smoking was allowed on intercontinental flights, but not on other shorter flights. Smoking was prohibited on all flights after 1 September 1997. The participation rate was 81% (n = 1,513) in the aircrew, and 77% (n = 168) in the office group. Air humidity, temperature, carbon dioxide (CO2) and respirable dust were measured during intercontinental flights, during both smoking and nonsmoking conditions. Statistical analysis was performed by multiple logistic regression analysis, keeping age, gender, smoking, current smoking, occupation, and perceived psychosocial work environment simultanously in the model. Air humidity was very low (mean 5%) during intercontinental flights. In most cases (97%) the CO2 concentration was below 1,000 ppm. The average concentration of respirable particles was 67 microg x m during smoking conditions, and 4 microg x m(-3) during non-smoking conditions. Complaints of draftiness, too high temperature, varying temperature, stuffy air, dry air, static electricity, noise, inadequate illumination, and dust were more common among aircrew as compared with office workers from the same company. Female crew had more complaints on too low temperature, dry air, and dust. Current smokers had less complaints on stuffy air and environmental tobacco smoke (ETS). Younger subjects and those with atopy (childhood eczema, allergy to tree or grass pollen, or furry animals) reported more complaints. Reports on work stress and lack of influence on working conditions were strongly related to perception of a poor cabin environment. Flight deck crew had more complaints about inadequate illumination and dust, but less complaints about other aspects of the cabin environment, as compared with flight attendants. Aircrew who had been on a flight the previous week, where smoking was allowed, had more complaints on dry air and ETS. Complaints about work environment seems to be more common among aircrew than office workers, particularly draft, stuffy air, dry air, static electricity, noise, inadequate illumination and dust. We could identify personal factors of importance, and certain conditions that could be improved, to achieve a better perception of the cabin environment. Important factors were work stress, lack of influence on the working conditions, and environmental tobacco smoke on some longer flights. The hygienic measurements in the cabin, performed only on intercontinental smoking flights, showed that air humidity is very low onboard, and tobacco-smoking onboard leads to significant pollution from respirable dust.