ywp wrote:The filter is to protect the machine not to provide you filtered air. You breath unfiltered air all day and all your life.Your body comes with it own filtering equipment. The machine has high speed moving parts close together. A hair or particle can drag on fan shrouds, shafts, bearings and wear seals. You car engine, dryer, etc. need filters. They are a "coarse" filter Sunlight will pass thu.
Fair point that the main reason for filtering is to protect the machine - the manual for my Respironics cautions that dirty filters will lead to excessively high operating temperatures for the device.
However, if you filter crud out for the machine's sake, it is also crud that you are not breathing, crud that is not being delivered directly to your nose, sinuses, and lungs at pressures above normal atmospheric pressure. For those of us with allergies or other breathing issues, it matters.
I look forward to masking up at night because I know that within a few minutes, my daily congestion will clear and I'll breathe freely as long as I have the mask on. I keep my filters scrupulously clean for this reason - I really like breathing freely, and clean filters are a cheap way to accomplish that.