For the latest H1N1 facemask recommendations from the CDC (Centers for Disease Control and Prevention) please read this article (Interim Recommendations for Facemask and Respirator Use to Reduce Novel Influenza A (H1N1) Virus Transmission).

The following guide is a short information source to help you decide which facemask is best for you to use during an influenza pandemic or a seasonal influenza epidemic.

Masks and Respirators
It is important for anyone considering using PPE to reduce the risk of infection to understand the difference between surgical masks and respirators.

Surgical masks
A surgical mask acts as a barrier to catch the wearer’s respiratory secretions and protect the wearer’s mouth and nose from splashes or sprays of infectious material. They are commonly used by health care workers, but may also be used to reduce the spread of droplets by people with symptoms of respiratory illness.
Because surgical masks allow air to flow around the edges of the masks, they do not provide protection against inhalation of very small particles or aerosols.

Disposable facemasks
Facemasks reduce the spread of respiratory viruses, which may have been inhaled or deposited on mucous membranes by touch.

P2 masks (equivalent to N95 masks) block the spread of viruses contained within aerosols, providing a good facial fit is achieved. Bearded staff must consider alternative protection or shaving.

P2 Standards: Australian standard P2 facemasks provide 94% filtration. The US equivalent N95 facemasks provide 95% filtration. While N95 and P2 respirators are defined with slight differences, these differences have virtually no impact on the level of respiratory protection provided by the wearer.

P3 Standards: Australian standard P3 facemasks provide 99.997% filtration. Usually P3 masks are not disposable and are designed to last much longer before filter replacement is required.

Disposable masks should be changed when they become moist. They must be fully removed and discarded correctly, after which hand hygiene should always be performed and then a new mask fitted.

Respirators
A respirator is a device designed to protect the wearer from inhaling harmful gases, vapours or particles. Particle filter respirators work by forcing inhaled air to pass through a filtering medium, which traps very small particles. They are only effective if a proper facial seal is achieved, and should always be used as part of an overall respiratory protection program, which includes fit-testing, fit-checking and training.
Particle filter respirators are rated according the percentage of small, inhalable particles that they remove from filtered air. In Australia, the rating system is defined by AS/NZS 1716.

The US Department of Labor, Occupational Safety & Health Administration recommends the use of N95 (95% filtration) particulate respirators. In Australia the equivalent standard is P2 (94% filtration) particulate respirators. While N95 and P2 respirators are defined with slight differences (the air flow rates and particle sizes filtered) these differences have virtually no impact on the level of respiratory protection provided by the wearer.

P2 respirators provide 94% filtration and are considered to give equivalent respiratory protection to masks classified as N95 under the US standard. These are available as disposable masks covering the mouth and nose and are commonly referred to as P2(N95) masks.
Non-disposable respirators are also available, including half face and full-face respirators, which work with a disposable filter cartridge. These are designed for use over longer periods and may be more economical for frequent use.