Abstract: ［Abstract］Objective〖HTSS〗〓To learn the hygiene status of central air conditioning ventilation system in Hebei province and find the existing problems in hygiene detection in public places.
〖HTH〗〖WTHZ〗Methods〖HTSS〗〓A total of 90 central air conditioning ventilation systems in public places were sampled. Legionella pneumophila in cooling water, hemolytic streptococcus in the supply air, accumulated dust, total bacteria, and total fungi on the internal surface of ventilation ducts were detected.
〖HTH〗〖WTHZ〗Results〖HTSS〗〓Legionella pneumophila was not detected in cooling water  but the detection rate of hemolytic streptococcus in the supply air was 13.3%. The qualified rates of accumulated dust, total bacteria, and total fungi on the internal surface of ventilation ducts were 96.4%, 95.5% and 99.2%, respectively.
〖HTH〗〖WTHZ〗Conclusion〖HTSS〗〓There are some problems in the health status of centralized air conditioning ventilation system in public places in Hebei province, wherein hemolytic streptococcus contamination severe.

Key words: public facilities, ventilation, pathogen contamination