The effect of duct cleaning on perceived work environment and symptoms of office employees in non-problem buildings

The aim of this paper was to study the effect of duct cleaning on the perceived air quality. Duct cleaning was carried out in 10 non-problem Finnish office buildings between 1997 and 2000. Before and after the cleaning, concentrations of particle mass, viable fungal spores and bacteria, TVOC and CO2 were measured in outdoor, indoor and supply air every 6 months. In parallel, a questionnaire about their feeling, was distributed to employees before and after the cleaning. The results showed that the duct cleaning had a positive impact on perceived work environment and the prevalence of work related symptoms in studied offices. Stuffiness and sensation of dry air decreased along with nasal symptoms and concentration difficulties.