Abstract: A respiratory system includes: a mask body adapted for attachment to a user's face; a gas supplier connected to the mask body to supply a gas to the mask body; a central control unit associated with the gas supplier to control temperature and humidity of the gas supplied from the gas supplier to the mask body; a sensor unit disposed in the mask body to produce sensing signals and to convert the sensing signals into a signal output that is related to at least temperature and humidity of the gas; and a transmitting unit to transmit the signal output to the central control unit. The temperature and humidity of the gas supplied from the gas supplier is controlled based on the signal output.

Abstract: A gas supply apparatus is adapted for supplying gas to a respiratory mask or patient interface, and includes: a housing including a gas inlet, a gas outlet, and a gas flow path; a blower disposed within the gas flow path; a gas filter disposed within the gas flow path; a breath tubing for connecting to the respiratory mask or patient interface; a particle sensor operable to sense a particle concentration and to generate a concentration signal representative of the particle concentration; a signal processor operable to evaluate when the gas filter should be replaced or cleaned according to the concentration signal and to generate an output signal; and an indicator device generating an alarm signal in response to the output signal.