7This toolkit was developed to assist hospitals in developing and implementing effective respiratory protection programs, with an emphasis on preventing the transmission of aerosol transmissible diseases (ATDs) to healthcare personnel. Healthcare personnel are paid and unpaid persons who provide patient care in a healthcare setting or support the delivery of healthcare by providing clerical, dietary, housekeeping, engineering, security, or maintenance services. Healthcare personnel may potentially be exposed to ATD pathogens. Aerosols are particles or droplets suspended in air. ATDs are diseases transmitted when infectious agents, which are suspended or present in particles or droplets, contact the mucous membranes or are inhaled. This toolkit is written as a practical manual that can be used by anyone charged with setting up and maintaining a hospital respiratory protection program. This toolkit identifies existing public health guidance where available on the use of respiratory protection. Scientific evidence is continuously evolving, particularly with regard to disease transmission. Precautionary use of respiratory protection may be prudent where scientific uncertainty exists.