Effect of ventilation on perceived air quality in 18 classrooms

The aim of this paper is to assess whether reducing the minimum ventilation airflow rate (Vmin) has any negative impacts on perceived air quality (PAQ) upon entering an unoccupied room. Seventeen healthy young adults were asked to assess PAQ in 18 unoccupied classrooms upon entry. Extra pollution sources were introduced in two classrooms, while three other classrooms were not cleaned. The ventilation rate in each classroom was set in a random order to off, low (0.9/1.1 l/s per m2), medium (1.3 l/s per m2) and high (2.0 l/s per m2). Increasing the ventilation rate resulted in a significant improvement of the PAQ-score, with highest PAQ-score when Vmin is set to high and lowest when the ventilation is off. However, most of this increase occurred when increasing ventilation to the low rate. Classrooms that were not cleaned for two days of normal use prior to the test only showed a marked reduced PAQ at all ventilation rates.publishedVersio