Objective To investigate the sanitation status of centralized air ventilation system in Putuo District of Shanghai, to analyze correlation between different indexes and to provide basis for improving the health status of public places and strengthening health supervision.

Methods According to the requirements of WS 394-2012 The Sanitation Criterion of the Centralized Air Ventilation System in Public Places, 18 centralized air ventilation systems in public places in Putuo District of Shanghai were randomly selected for sampling, testing and evaluation during 2014-2018, and 9 indexes of air supply, inner surface of air duct and indoor air were analyzed for correlation.

Results The overall qualified rate of centralized air ventilation system in 10 hotels, 4 restaurants and 4 supermarkets was 86.0%.The over standard rate of PM₁₀, bacteria and fungi in air supply was 3.4%, 31.8% and 33.0%, respectively, but β-hemolytic streptococcus was not detected.The dust amount and microbial index on the inner surface of the air duct were up to standard.Another two indexes of fresh air quantity and Legionella pneumophila were tested in the hotel.The qualified rate of fresh air quantity was 25.6%, the positive rate of Legionella pneumophila type 1(LP1) in cooling water was 30.0%, and no Legionella pneumophila was detected in condensate water.The correlation analysis of 9 indexes showed that there was a significant positive correlation between PM₁₀ in air supply and in indoor air; the amount of microbial pollution on the inner surface of air duct and in air supply; and the amount of microbial pollution in air supply and in indoor air.

Conclusions In Putuo District, the general sanitary condition of the centralized air ventilation system in public places is not to be optimistic.The qualified rate of bacteria and fungi in the air supply and fresh air quantity is low, and Legionella pneumophila was detected.The indoor air quality can be improved by installing efficient air purification device and regular cleaning and disinfection.