The current NIOSH service-time-limit recommendations for non-powered particulate filter respirators are that filter elements should be replaced at the following frequencies:

• The service life of all filters on NIOSH-approved respirators is limited by considerations of hygiene, damage, and breathing resistance.
• All filters should be replaced whenever they are damaged, soiled, or causing noticeably increased breathing resistance.
• N-series filters generally should be used and reused subject only to considerations of hygiene, damage, and increased breathing resistance.
• However, for dirty workplaces that could result in high filter loading (i.e., 200 mg), service time for N-series filters should only be extended beyond eight hours of use (continuous or intermittent) by performing an evaluation in specific workplace settings that demonstrates: (a) that extended use will not degrade the filter efficiency below the efficiency level specified in 42 CFR 84, or (b) that the total mass loading of the filter(s) is less than 200 mg. These determinations would need to be repeated whenever conditions change or modifications are made to processes that could change the type of particulate generated in the user’s facility.
• For healthcare applications where use is for protection against confirmed or suspected 2009 H1N1 influenza, please refer to: Interim Guidance on Infection Control Measures for 2009 H1N1 Influenza in Healthcare Settings, Including Protection of Healthcare Personnel.
• For more information, please see the NIOSH Guidance on Extended use and Reuse of N95 Respirators. (Content source: National Institute for Occupational Safety and Health)

• SURGICAL MASKS ARE NOT RESPIRATORY PROTECTION
• A surgical mask can help block large particle droplets, splashes, sprays or splatter that may contain germs, viruses, and bacteria from reaching the nose and mouth. However, surgical masks are primarily intended to protect the patient from the healthcare worker by reducing exposure of saliva and respiratory secretions to the patient. They do not form a tight seal against the skin or filter very small airborne pathogens, such as those involved in airborne disease transmission. (Source:DHHS (NIOSH) Publication Number 2013-138 \ June 2013)