Objectives  To analyze the hygienic issue in the design of fresh air system for central air conditioning system in 32 building projects in Shanghai to provide scientific basis for relevant departments to formulate sanitary management measures.

Methods  The possible existence of health hazards in central air conditioning and ventilating system was analyzed by checklists collected from the feasibility report and design proposal of 32 construction projects.

Results  On the design parameter for fresh air in central air conditioning and ventilating system, only 34% of 32 construction projects met the hygienic standard; 69% of them specified the distribution of fresh air in different areas on design drawings, 50% of them were lack of design for fresh air system, 84% of them got fresh air directly from outdoors, 9% of them set up air filter and insect nets, the air inlet position in 31% of them met the hygienic standard.

Conclusions  The design of central air conditioning system in construction projects in Shanghai did not strictly comply with the hygienic standard for central air conditioning and ventilation systems in public places and relevant health standards.Communication among designers and hygienic evaluators and checking central air conditioning and ventilating system regularly should be strengthened. Hygienic supervision and management should be strengthened by health authorities.