Hygienic status of central air conditioning ventilation systemsin public places in urban areas of Ma'anshan City / 预防医学

ABSTRACT

Objective@#To investigate the hygienic status of the central air conditioner ventilation system in public places in urban areas of Ma'anshan City, Anhui Province, so as to provide insights into formulation of supervision and management interventions.@*Methods@#A total of 15 public places with the central air conditioner ventilation system were randomly sampled from main urban areas in Ma'anshan City in 2022. Sampling and detection were performed following the standard GB/T 18204.5—2013 Examination methods for public places Part 5: Central air conditioning ventilation system, including total number of bacteria and total number of fungus on the inner surface of wind pipes, total number of bacteria and fungus, particulate matter (PM10) and β-hemolytic streptococci in the air supply system, and Legionella pneumophila in the cooling water, and the detection indicators were assessed following the WS 394—2012 Guideline for hygiene of the central air conditioner ventilation system in public places. The eligible rate of samples, the detection rate of L. pneumophila were analyzed.@*Results@#A total of 368 samples were collected from 15 public places, and the qualified rate was 50.54%, no places had all eligible measurement indicators. The qualified rates of total bacteria and fungus numbers on the inner surface of wind pipes were 52.67% and 59.33%. The qualified rates of total bacterium number, total fungus number, PM10 and β-hemolytic streptococci were 12.00%, 28.00%, 90.00% and 96.00% in the air supply system. The qualified rates of samples in administrative workplaces, hotels, bathing places and malls (supermarkets) were 32.50%, 59.24%, 61.09% and 68.92%, the qualified rates of total bacteria on the inner surface of air ducts were 8.33%, 72.46%, 66.67% and 61.90%, and the qualified rates of total fungus numbers in air supply were 0, 21.70%, 33.30% and 71.40%, respectively, with statistical significance (P<0.05). A total of 18 cooling water samples were collected, and L. pneumophila was detected in three samples (16.67%).@*Conclusions@#Poor hygiene is seen in the central air conditioning ventilation systems in public places in main urban areas of Ma'anshan City. High attention needs to be paid to contamination of bacterium, fungus and L. pneumophila, and expansion of supervision coverage and improved supervision intensity are recommended.