Many Northern California counties and cities now require people to wear face coverings or masks in public to prevent the spread of COVID-19. And the Centers for Disease Control and Prevention recommends everyone wear a face covering in public.

Cristine Lacerna, Kaiser Permanente Northern California regional director of infection prevention and control, answers some basic questions on masking.

What is the proper way to wear a mask?

The most important thing is that it needs to cover your nose and mouth. The virus comes out of your mouth and nose, and the mask prevents virus droplets from landing on someone else.

What is the proper way to put it on and take it off?

Wash your hands before either instance. Take it off and put it on from the back, so you are not touching the front. Avoid touching the front of your facial covering or mask, and if you do, wash your hands.

What is the wrong way to wear a mask?

Don’t tug it down to your chin and put it back up, which people do. If you tug it down, your nose and mouth may come in contact with the dirty side, and you are at risk of contaminating yourself. And don’t turn it inside out. You’re catching germs on the front of the mask, so if you turn it inside out, you are possibly exposing yourself to contaminants. 

Who does a mask protect — me, other people, or both?

Both. You are protecting yourself from others who may not be wearing a mask, where you can’t maintain social distance of 6 feet. And you are protecting others around you.

A mask also protects the environment around you, such as surfaces where the virus can live if you cough or sneeze.

When I wear a face mask, do I still have to wash my hands and stay away from other people?

Yes. Wearing a face covering is one way to reduce the spread of the virus but doing so is not a substitute for sheltering in place, physical distancing of at least 6 feet, and frequent hand washing.

If I use a dust mask or an N95 mask, how long can I use it, and should I clean it? What about homemade masks or scarves?

For any of those manufactured masks, you can keep wearing them as long as they are not visibly soiled, damaged, or wet. Once they get wet, they are no good. You don’t clean or wipe them with anything; that will ruin the mask, too.

For all masks, whether they are manufactured or homemade, you can do natural decontamination. If you let it sit for up to 3 days, that should do the trick. While it’s sitting, you can alternate among other masks. Wash a cloth mask.

Do I need to wear a mask outdoors, such as in parks or open spaces?

That depends on your county. Some counties have different requirements. For the most part, if you stay 6 feet away from people, you don’t need to wear a mask.

Do I need to wear a mask while driving?

Don’t use it in your car. If you are in your car, it’s a self-contained environment, and you don’t need to wear it.

Learn more about what makes COVID-19 different from other global outbreaks, how to cope with a bad news cycle, and tips for social distancing.