The options of respirators available to healthcare workers treating COVID-19 patients are either a non-powered air-purifying respirator (APR) or a powered air-purifying respirator (PAPR).
An example of a disposable APR is the N95 mask which you can read more about here.
A reusable APR is an elastomeric device which elevates protection when used with filters that remove specific contaminants. It is available as a half-mask, which has an assigned protection factor (APF) of 10. The full-mask equivalent scores an APF of 50. When wearing the full mask, no alternative PPE is required to protect the eye area. However, there is a risk that contaminated air can leak into the face piece and communication can be challenging.
By contrast, a PAPR uses a blower to force air through filter cartridges or canisters and into the breathing zone of the wearer. This process creates an airflow inside either a tight-fitting face piece or loose-fitting hood. Both types of PAPR provides an APF of 25 and, despite their bulkiness, they are more comfortable to wear than APRs. Chemical cartridges and canisters are available to eliminate organic vapors from permeating. A PAPR can be used for protection during procedures which expose practitioners to higher risks of aerosolised pathogens that cause acute respiratory infections.