With all the hubbub concerning whether to use N95 respirators or surgical/procedure masks for H1N1 protection, NIOSH posted a nice piece on the history, development, and effectiveness of these medical devices on its science blog .
If you are still confused over the N95 vs. mask debate—one of the problems is that they look similar but are designed for very different purposes— I encourage you to read the complete NIOSH blog post for a thorough and non-geeky explanation.
Here are some tidbits, according to NIOSH:
- Surgical masks were first worn by surgery staff in the early 1900s to prevent contamination of open surgical wounds. Today they are worn in a wide range of healthcare settings protecting patients from the wearers’ respiratory emissions.
- The personal protective aspect of masks started when OSHA issued the Bloodborne Pathogens Standard in 1991, where surgical masks were part of universal precautions to protect workers from splashes and sprays of blood and body fluids.
- Respirators were developed to protect miners from hazardous dusts and gases, soldiers from chemical warfare agents, and firefighters from smoke and carbon monoxide.
- Respirator use in healthcare dates to the 1990s in response to concerns about employee exposures to drug-resistant tuberculosis.
- Respirators and masks capture particles by four methods: inertial impaction, interception, diffusion, and electrostatic attraction. In all cases, once a particle comes in contact with a filter fiber, it is removed from the airstream and strongly held by molecular attractive forces.
The blog post also allows for comments and the authors, Lisa Brosseau, Sc.D., and Roland Berry Ann, are responsive to questions.
For example, they gave a nice explanation of how H1N1 can be both droplet and airborne transmitted, something that many healthcare workers find difficult to comprehend.