There are 4 main types of masks or respirators that are being discussed in relation to coronavirus. Masks (and respirators) are often rated by their filtration efficiency. Generally, filtration efficiency refers to the ability of a mask or material to filter out or block particles from passing through the mask. Filtration efficiency is typically presented as a percentage with higher numbers representing better performance. Filtration efficiency may vary by particle size and masks or respirators may be tested against a range of sizes to assess their ability to filter both small and large particles. Filtration efficiency is typically not based on a mask or respirator’s ability to filter out a particular pathogen but rather is based on filtration of generic, machine generated particles (typically made of salt solution). A summary of masks and respirators, with links to further information, is available below.
Summary of types of masks and respirators
The CDC highlights the differences and similarities of N95 respirators and surgical masks in the graphic below:
Want to learn more about mask use for interrupting the spread of COVID-19?
- How could wearing a mask reduce COVID-19 transmission?
- What is a N95 respirator and who should use one?
- What is a surgical mask and who should use one?
- What is a fabric mask, who should use one, and how should they be made?
- What should be considered when making fabric masks?
- Hygienic use of fabric face masks
- What is an occupational mask and who should wear one?
- Why doesn’t the WHO recommend that everyone wears face masks in all settings?
- What do we know about the effectiveness of masks to prevent and COVID-19 transmission in community settings?
- What can modelling studies tell us about the effectiveness of wearing masks?
- How well do masks work under laboratory (experimental) conditions?
- Do homemade masks increase the risk of respiratory disease?
- How might an evolving understanding of virus transmission affect mask recommendations?
- Should hygiene promotion staff wear masks to protect themselves and others?