How often do I need to change the filter? Why do they become dirty?
The filter in the machine and in some masks, needs to be changed when it becomes significantly discolored due to dirt particles in the air. The machine filter needs to be replaced when it becomes significantly discolored or after 1,000 hours of machine running time. It is important not to clean these filters as they will no longer function correctly. When they become discolored replace them; do not attempt to clean and reuse them.