Assessment of Cleaning Effect of Central Air Conditioning Ventilation Systems in Public Places / 环境与健康杂志

ABSTRACT

Objective To assess the cleaning effect of central air conditioning ventilation systems. Methods During 2006—2007, the quality of 15 central air conditioning ventilation systems from 5 hotels in Tianjin were assessed before and after cleaning and disinfection. Results Before the central air conditioning ventilation systems being cleaned and disinfected, the medians of the dust in central air conditioning ventilation system, the aerobic bacterial counts in dust, the fungus counts in dust, the aerobic bacterial count in ventilation system, and the PM10 were 60.67 g/m2, 40 cfu/m2, 14 cfu/m2, 1 074 cfu/m3, 304 cfu/m3 and 0.09 mg/m3 respectively. After that, the medians were 0.26 g/m2, 0 cfu/m2, 0.2 cfu/m2, 219 cfu/m3, 121 cfu/m3 and 0.07 mg/m3 respectively. The eligible rates were 20%(3/15), 87.8%(36/41), 82.9%(34/41), 18.3%(11/60), 66.7%(40/60) and 65.7%(23/35) before the systems being cleaned and disinfected, by comparison, they were 100%(15/15), 100%(41/41), 100%(41/41), 91.7%(55/60), 96.7%(58/60) and 100%(35/35) after being cleaned and disinfected. Before the systems being cleaned and disinfected, the eligible rates of hemolytic streptococcus in ventilation systems, Legionella pneumophila in cooling water and condensed water were 100%(39/39), 80%(4/5) and 100%(5/5), after that, they were all 100%. Conclusion Cleaning and disinfecting is an effective way to improve the hygiene quality of central air conditioning ventilation systems. For protecting the people health, central air conditioning ventilation systems should be cleaned and disinfected regularly.