The goals of HVAC design in pharmaceutical companies are to keep the occupants of the room comfortable, to preserve the quality of medicines, and to protect the environment. The comfort of personnel can reduce the amount of dust released by personnel activities and thus reduce the impact of dust and microorganisms on medicines. For some allergenic or harmful medicines, appropriate filtration treatment can also reduce the harm to the environment outside the room. With this goal in mind, air temperature, humidity, and particulates are the primary considerations for air conditioning systems. And some other secondary and indirect factors also need to be considered according to the actual situation, such as room pressure, ventilation rate, air volume, airflow direction, exhaust location and exhaust speed, filtration efficiency, etc.