Most CPAP machines today have 2 filter options: Pollen and Ultrafine. Pollen filters can be reused and therefore more cost effective. The pollen filter will filter out larger particles like pollen, dust and pet dander.
Pollen filters will not filter out microbial particles (i.e. viral and bacterial particles).
Ultra-fine Filters will filter out smaller particles but are not reusable.
Pollen filters are the reusable counterpart to Ultra-fine Filters which are disposable.
Pollen filters can be washed and reused up to 5 times or until they become deteriorated.