PURPOSE: The main aim of the study was to provide evidence whether professional cleaning was associated with biomarkers of lung damage in non-invasively collected biological fluids (exhaled air and exhaled breath condensate--EBC). MATERIALS AND METHODS: This cross-sectional study involved 40 cleaners regularly exposed to cleaning detergents and 40 controls. The subjects completed a standard questionnaire from European Community Respiratory Health Survey (ECRHS II) and underwent a spirometry. Fractional exhaled nitric oxide (F(E)NO) was measured online, and pH, ammonium (NH(4) (+)), H(2)O(2) and 4-hydroxynonenal (4-HNE) were assayed in EBC. RESULTS: Among the cleaners, the frequency of asthma and rhinitis was, respectively, 2.5 and 20%. The most frequently reported symptoms were sneezing (27.5%), nasal and/or pharyngeal pruritus (25%), ocular pruritus (22.5%) and cough (22.5%). There were no significant differences in comparison with the control group. Median F(E)NO levels were higher in African than in Caucasian cleaners (21.5 [16.5-30.0] ppb and 18.0 [13.5-20.5] ppb; p