(CNN) As fears grow about the spread of novel coronavirus, there's increasing demand for facial masks. But there's something that can interfere with how effective those are -- and that's facial hair.

Side whiskers, soul patches, lampshades and handlebar moustaches are good to go, according to a 2017 Centers for Disease Control and Prevention infographic on filtering facepiece respirators. But styles like long stubble, a beard, the Dali and mutton chops are not recommended because they are likely to interfere with a facepiece respirator's sealing surface.

Masks and respirators are being utilized around the world to prevent the spread of the novel coronavirus , which has reached more than 80,000 cases globally.

A respirator covers at least the nose and mouth and protects against particles including infectious agents, the CDC said. However, the CDC does not recommend routine use outside of workplaces.

Facial hair poses a risk to the effectiveness of respirators because it may keep the exhalation valve from working properly if the two come into contact, the infographic said.

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