The advanced medical technology has extended the lives of people, yet some medical issues need to be discussed. The hospital-acquired infection is one of the most concerned issues, as it increases hospitalization days, medical costs, and mortality. According to the World Health Organization, the occurrence of hospital-acquired infection among inpatients with acute illnesses is approximately 5%~10% in developing countries. Moreover, the infection occurs 14.0/1000 patient-days in adult intensive care unit (ICU) in Taiwan. The ICU patients have lower immunity due to prolonged hospitalization, and stay in the risk of upper airway infection due to prolonged intubation. Hence, the air quality of hospital should be concerned. According to recent research, patients with open suction system had been found higher concentration of bacterial contamination in their sputum and had higher incidence of ventilator-associated pneumonia than the ones with closed suction system. The concentration of airborne PM_(2.5), PM_1, and bacteria was clearly higher when open suctioning was used in mechanically ventilated patients. This phenomenon demonstrated that open suctioning may increase the risk of bacterial exposure for health care providers. When patients with mechanical ventilation receive aerosol therapy, aerosolized drugs tend to stick to a bacterial filter. Therefore, there is a need to examine the filtration efficiency of bacterial filters after repeated autoclaves. However, due to the cost of the catheter, the use of open suction system is still favored in Taiwan. Suggestions are made for health care providers to implement self-protection strategies while open suctioning is used. Meanwhile, increasing air circulation and periodically inspecting the ventilation system are recommended to improve hospital air quality. To minimize environmental pollution in hospitals and decrease the risk of bioaerosol exposure, continuing education may focus on proper precautions, hand hygiene, and wearing suitable personal protective equipment.