Ultraviolet irradiation could reduce office sickness

Sickness among millions of office workers in industrialised countries could be reduced by the use of ultraviolet radiation to kill bacteria and moulds in ventilation systems, conclude the Canadian authors of a study published in The Lancet journal.

Around 70% of employed people in industrialised countries work in air conditioned offices. These workers frequently have unexplained work-related symptoms such as irritation of the mucous membranes of the eyes, throat, and nose, as well as respiratory symptoms. Dick Menzies from the Montreal Chest Institute, McGill University, Canada, and colleagues assessed whether ultraviolet germicidal irradiation (UVGI) of drip pans and cooling coils within office ventilation systems would reduce microbial contamination, and thus occupants' work-related illnesses.

Employees from three offices in Montreal participated in the study. UVGI was off for 12 weeks, then on for four weeks for three cycles totalling 48 weeks. UVGI had a substantial effect in reducing reported work-related illnesses. In workers with symptoms in some, but not all weeks, UVGI resulted in a 20% overall reduction in all symptoms; a 40% reduction in respiratory symptoms; and a 30% reduction in mucosal symptoms. These benefits were greatest for workers with known allergies and for people who had never smoked. Muscular complaints were halved among non-smokers when UVGI was in use.