Hygienic Status of Central Air-conditioning Ventilation System in Public Places of Sichuan

Objectives To investigate the hygienic status and the trend of variation in central air-conditioning ventilation system in public places of Sichuan province in 2011-2014.

Methods Central air-conditioning ventilation system in 65 public places were randomly selected in Sichuan province to detect the accumulated dust, total bacteria, and total fungi on the inner surface of ventilation duct and the pollution of Legionella pneumophila in cooling water.

Results The qualified rates of samples collected in 2011, 2012, 2013 and 2014 were 73.75%, 83.33%, 93.33% and 78.33% respectively, and the qualified rate in 2014 was significantly lower than that in 2013 (P<0.05). The qualified rates of accumulated dust, total bacteria counts, and total fungi on the inner surface of ventilation duct were 90.77%, 67.69% and 78.46% respectively; and the qualified rate of total bacteria counts was lower than that of accumulated dust. There was a positive correlation between each of two indicators in these three indicators. The detection rate of Legionella pneumophila in water in the cooling tower of markets (21.87%) was higher than that of hotels 0% (P<0.05).

Conclusions More attention should be paid to the hygienic status of central air-conditioning ventilation system in public places to prevent the trend of deterioration; and more work should be done to adjust detection indeces and optimize evaluation system.