Work-related exposure
Lifeguards, swim teachers and physiotherapists have the highest CBPs cumulative exposure when compared to other swimming-pool workers21. In order to protect workers but also swimmers, WHO has imposed a reference value for NCl3 of 0.5 mg/m3. However, airborne NCl3 is not regularly monitored in most European countries.
Dose-response relationships between NCl3 levels and different respiratory (runny nose, blocked nose, voice loss) and ocular (red or itchy eyes) symptoms have been reported from a level of 0.5 mg/m3 onwards35. Interestingly, another study demonstrated increasing risk of respiratory symptoms up to a level of 0.2-0.3 mg/m3 of NCl3, urging to revisit the WHO occupational exposure limit21. This is also in line with other study, where very low levels of NCl3 in indoor swimming-pools (0.017-0.15 mg/m3) were detected with increased risk for sore throat (OR: 11.28; 95% CI: 1.44–88.33) and phlegm (OR: 4.22; 95% CI: 1.16–15.4)36.
Upper and lower respiratory symptoms while on duty were related to duration of lifetime exposure. Lifeguards exposed > 500 hours in the previous 12 months experienced more cough, throat and eye irritation than non- or less-exposed lifeguards, and those with prior asthma had a significantly higher risk of suffering from asthma attack(s) than non-exposed asthmatic subjects37. Physician-diagnosed asthma was high among lifeguards (23%)37.