Skip Navigation LinksWhen-and-Why-to-Wear-a-Mask

WHEN AND WHY TO WEAR A MASK

Woman wearing backpack with mask on in airport.

The Benefits of Masking and Tips for Choosing the Right Mask

Wearing a high-quality and well-fitting mask can help protect you from breathing in viruses, wildfire smoke, and other particles or germs in the air.
Respirators, such as N95s, KN95s, or KF94s, are the best type of masks. They offer more protection than surgical or cloth masks, as they generally have better fit and filtration. Examples of other masks​ include surgical masks and cloth face coverings, which tend to be looser and not as protective as respirator masks.
Mask wearing may be an especially good precaution for anyone who has a weakened immune system, is at higher risk for getting very sick from respiratory illnesses, has a history of breathing/lung issues, or has environmental exposures. N95, KF94 and KN95 respirators can be purchased at drugstores, ​hardware supply stores and online.

​When to Consider Wearing a Mask

Protection Against Respiratory Viruses​

Masks are an important way for people – especially higher-risk individuals – to lower their exposure (contact) to respiratory viruses such as COVID-19, flu, respiratory syncytial virus​ (RSV) and many other respiratory infections.
Consider wearing a mask especially if you’re at higher risk for severe disease from respiratory viruses, you are in close contact with someone with a respiratory virus, are in an indoor public setting with poor ventilation, or are traveling. If you have questions about whether you or people you live with or visit are at higher risk, you should talk to your health care provider.
People with higher risk for severe respiratory infection include:
Masking is recommended if you or a close contact have COVID-19 symptoms or test positive. See COVID-19 isolation guida​nce for more details.

Protection Against Harmful Environmental Exposures

Below are a few examples of when masks are highly recommended during an environmental exposure.

Wildfire Smoke

When a wildfire, wildfire smoke, or poor air quality​ is in your area, wearing an N95 mask can help filter out harmful smoke particles, if you must go outside. When fitted correctly, N95 masks that fit over the nose and mouth can significantly reduce breathing in harmful particles.

Valley Fever

 In certain areas of California, the fungus that causes Valley fever grows in the soil and may be in outdoor dust. While working or spending time outdoors in dusty areas where Valley fever is common, wearing a properly fitted, National Institute for Occupational Safety and Health (NIOSH)-approved respirator (mask) such as an N95 or higher level mask, may help protect you from breathing in dust and fungal spores that can cause Valley fever. Learn more about Valley fever safety in the workplace​ and Va​lley fever prevention.

​Choosing the right mask​

​High Quality​

N95s

N95s offer the best protection. Adults should choose an N95 mask or “respirator” that is approved by the National Institute for Occupational Safety & Health (NIOSH). N95s have two head straps and a tight fit. Authentic NIOSH-approved N95 respirators should have specific markings. Learn more about counterfeit (fake) respirator masks and how to use N95 respirators
N95s mask picture

KN95s and KF94s

KN95s and KF94s are respirators that meet international standards and provide good protection, but less protection than N95s. Most KN95s and KF94s have ear loops, which may provide a less-snug fit than respirators with head straps such as N95s.
If you choose to use a KN95 or KF94, one that has been tested by NIOSH and has a minimum "filtration efficiency" of 95% or higher is recommended. While these respirators have been tested by NIOSH, they are not designed and approved according to NIOSH standards.​​ ​
KN95s and KF94s masks

Surgical Masks

Surgical m​asks include various types of loose-fitting disposable ​masks. These masks can block large droplets but don’t fit close to the face. Even when adjusted to fit tightly against your face, surgical masks provide much less protection than a well-fitting respirator (N95, KN95, or KF94).​

Surgical mask picture​​

Cloth Masks

Cloth masks are less protective than surgical masks or high-quality respirators and do not provide good protection.​

Cloth mask picture

Fit

A​ mask should fit snugly to your face, covering both your nose and mouth, with no gaps between the mask and your skin. If your mask has any gaps, it will allow the flow of unfiltered air into your lungs. Also, any facial hair will prevent the mask from working properly. Maintain a clean shave (PDF), if possible.
Face mask picutre
Check for any gaps by cupping your hands around the outside edges of the mask. Make sure no air is flowing from the area near your eyes or from the sides of the mask. If the mask has a good fit, you will feel warm air come through the front of the mask and may be able to see the mask material move in and out with each breath.​​
Change your mask as needed. Do not wear a dirty mask and throw away disposable masks or re​​spirators that become wet or dirty.

For Children

Masks can be worn safely by children 2 years of age and older with rare exceptions. Children under age 2 should not wear a mask. Choose a mask for your child that has the best protection, best fit, and that your child will wear.
Masks should fit over the nose and under the chin with no gaps around the edges and not prevent your child’s from seeing. KN95s and KF94s are both available in "child" or "extra-small" sizes. N95s in size “small" may fit older children but may not fit younger or smaller children. There are no NIOSH-approved N95 masks for children at this time.

Who Sh​ould NOT Wear a Mask

Wearing a mask may be difficult for people with sensory, cognitive, or behavioral issues. Masks are not recommended for children under 2 or for persons who have trouble breathing or are unconscious, incapacitated or otherwise unable to remove the mask without help. Mask wearing can also be hard for people who are hearing impaired or are communicating with a person who is hearing impaired (when you need to see the mouth to communicate).

Other Considerations

Any person who chooses to wear a mask cannot be excluded from participating in an activity or entering a venue or business (including schools or childcare) unless wearing a mask would pose a safety hazard. This information is intended for a general audience. Some workplaces (PDF), local health departments, and Cal/OSHA ​may have additional recommendations or requirements for wearing a mask.


Page Last Updated :