Surgical Mask:
Historically, this type of mask has been used in the operating room by health care personnel to minimize the chance of a patient’s operative wound becoming infected by health care workers. This type of mask is produced by a variety of manufacturers using different materials, and no standard for minimal filtration efficiency exists. Therefore, it is best to consider the mask as a barrier with marginal filtration and no protection against gas, vapor, or most particulate hazards.

 
N95 Respirator:
The N95 mask is one member of a family of air-purifying masks that use both a letter and number system to describe their properties. The number designation of the mask describes its filtering efficiency. “95” means that the mask is able to remove 95 percent of particles with a median diameter greater than 0.3 mm. The letter “N” designates that the mask is “not oil proof.” Similar to surgical masks, the N95 mask does not offer protection against any type of gas or vapor, which are the likely dissemination methods for most types of chemical weapons.
 

The relative protection afforded by surgical and N-95 masks is an important issue that is prompting much debate in the process of planning for outbreaks of infectious respiratory diseases such as SARS or an influenza pandemic. In an article published recently in the American Journal of Industrial Medicine, Y. Li and colleagues from The Hong Kong Polytechnic University report the results of their study comparing the performance of surgical masks and N95 respirators. The authors found that N95 respirators filtered out 97% of a test aerosol while surgical masks did almost as well, filtering out 95% of the aerosol.

Wear a respirator type mask such as an N95, N99 or N100 rated mask only when close (within 1 meter) to the patient. Do not reuse the mask once it is taken off. At other times a surgical mask should be worn. We can estimate the need of around 90 masks for a six week period per family member in direct contact with patients. Remember that respirator type masks are not made to fit children so children should be kept away from infected individuals and other sources of infection.

• Cup both hands over the front of the mask (to cover the filter media) and inhale. Do not push on the mask.
• Check to see if the mask pulls in toward your face.
• If the mask is drawn in and no air leaks are detected around the mask, you have a proper fit. If you detect any leakage of air, try readjusting the nosepiece and/or the straps until you achieve a good fit.