Updated September 16, 2021. 


Masks work. COVID-19 transmission rates are high.  Masks are strongly recommended in all City buildings. Help protect our kids and community. Thank you for your assistance.

While Portsmouth repealed its Mask Ordinance on June 7, 2021 and Governor Sununu repealed the statewide Mask Mandate on April 30, 2021. Businesses and organizations can still require patrons to wear masks on their private property. 

On June 17, 2021, NH DHHS issued new guidance on masks, saying masks and other non-pharmaceutical interventions still offer maximal protection from COVID-19 urging mask protection especially in the following situations:

  • If someone is at high risk for severe consequences from COVID-19 (i.e. is unvaccinated and in a crowded, indoors setting)
  • If someone is immunocompromised or otherwise unable to be vaccinated
  • If a business or organization requires masks, including such Federally-mandated circumstances as in health care facilities and on public transportation and transportation hubs such as airports, train stations, ferry terminals, etc.

While community transmission remains "substantial" (as measured by NH DHHS evaluation of both county positivity and the rate of new infection per 100,000 residents, wearing masks indoors is strongly recommended. For current NH DHHS conditions, click here. Until vaccines receive FDA authorization for use in children under 12, and during phases of high infection rates from COVID-19 variants, masking is especially important in protecting them.


Viruses cannot replicate outside of a host cell. The virus that causes COVID-19 can live on common surfaces such as paper, fabric or metal for varying periods of time, measured in hours to about a week. Importantly, however, the virus cannot replicate or reproduce on these surfaces. A face mask does not serve as an “incubator” for the virus.

People can become infected by the transmission of coronavirus via the eyes, nose and mouth. Reducing the tendency to touch one’s face and eyes is a possible benefit of face coverings.

The CDC updated its guidance on July 27, 2021 that residents in area with “High” or “Severe” Community Transmission rates should consider wearing masks indoors, whether they are vaccinated or not due to the higher rate of contagion with the Delta variant.  


Mask wearing on interstate transportation: through Jan 18, 2022. The U.S. Transportation Security Administration (TSA), which is enforcing the order along with federal, state, and local authorities, is now extending the requirement for a second time through January 18, 2022. It was initially set to expire on May 11 and had been extended through September 13, 2021. The CDC order states passengers on airplanes, trains, buses, subways, ships, ferries, taxis and ride-shares must wear a mask that covers their nose and mouth while getting on such vehicles, during the ride and while getting off.

Centers for Disease Control and Prevention (CDC) has concluded that community masking along with other measures can help to control the spread of COVID-19.  However, getting vaccinated will support increased safe, maskless activities and socialization.

  • Fully vaccinated people (meaning two weeks after last dose of a two-dose vaccine series such as Moderna or Pfizer vaccine or two weeks after the one-dose Johnson and Johnson vaccine) can resume activities without wearing a mask or physically distancing, except where required by federal, state, local, tribal, or territorial laws, rules, and regulations, including local business and workplace guidance.
  • Masking continues to be recommended for unvaccinated individuals in many indoor and some outdoor settings. Details here.
  • Masks are not recommended for children under the age of two years or anyone who has trouble breathing.

What is a mask?

For the purposes of this document, a “mask” is a product, either commercially manufactured or individually constructed, that covers a person’s nose and mouth, and is intended to provide a barrier to the transmission of the virus that causes COVID-19. Masks are sometimes referred to as “face masks” or “face coverings.”

Why are masks important during the COVID-19 pandemic?

The widespread and appropriate use of masks is one strategy to reduce the risk of viral spread. Expert medical and scientific opinion, backed by a wealth of research, strongly supports the use of masks to improve public health and safety.  Early in the pandemic, it was thought that wearing a mask would protect others, but protection of the wearer was uncertain. However, recent demonstrates that masks do protect and reduce risk for the person wearing a mask as well as others.

What should I look for in a mask?

According to the CDC and expert opinion, an effective mask:

  • Has 2-3 layers of tightly woven, washable, breathable fabric
  • Completely covers the nose and mouth
  • Fits snugly with minimal gaps (“face-hugging” fitted shapes have less gapping). A new technique called "knot and tuck" makes adjusts the fit of disposable masks to offer a better fit. 


  • Masks with exhalation valves or vents as these will allow the virus to escape
  • Thin or loosely- woven fabrics (if you can see light through the mask, it is probably inadequate)
  • Scarves, ski masks, and single layer gaiters or balaclavas are not substitutes for masks, but may be worn OVER an adequate face mask for warmth.

How should a mask be worn?

  • With clean hands, put the mask over your nose and mouth and secure it under your chin.
  • Fit the mask snugly against the sides of your face, secure the loops over your ears or tie the strings behind your head, and pinch the nose clip (if the mask has one). The properly fitting mask should fit snugly and not slip down easily.

Further handling of the mask (adjusting, pulling down, etc.) should be minimized and done with clean hands. 

Keep a spare mask on hand. Change your mask if it becomes wet. A wet mask is harder to breathe through, is less efficient at filtering, and vents more around the edges of the mask.

Place any used wet or dirty masks in a plastic bag to avoid contamination of other surfaces with the virus. Wash cloth masks frequently. Throw away disposable masks after using.

Disposable masks: Because disposable surgical masks made from a plastic-derived material called polypropylene have been shown to be more effective at filtering particles than just a cloth mask, the wearing of a disposable mask under a cloth mask is more effective than just two cloth masks, or a double-layer cloth mask. 

The CDC offers recommendations to  "Improve how your mask protects you" including a method for knotting and tying the ear loops of your face mask for a better fit as demonstrated here in a YouTube video from the University of North Carolina.

N95 Masks: N95 respirators are face masks that are designed to fit very close to the face, forming a seal that filters 95% of airborne particles. These masks are not recommended for the general public, because they should be reserved for healthcare workers and medical first responders.

KN95 Masks: Consider a carefully-sourced KN95 mask. According to medical experts as reported by Healthline, a KN95 mask can filter 95 percent of aerosol particles similar to the N95. Both masks are made from several synthetic material layers but only the N95 has been approved by the National Institute for Occupational Safety and Health (NIOSH). However, one review found that nearly 70 percent of the KN95s produced in China did not meet the NIOSH filtering requirements, so buying from a reputable source is critical.

A mask alone does not provide perfect protection. Use masks along with other strategies such as physical distancing, frequent hand-sanitizing and avoiding gathering in poorly-ventilated spaces.

A CDC report (February 10, 2021) added to information about the effectiveness of different mask behaviors.

What is already known about this topic?

Universal masking is recommended to slow the spread of COVID-19. Cloth masks and medical procedure masks substantially reduce exposure from infected wearers (source control) and reduce exposure of uninfected wearers (wearer exposure).

What does the report say?

CDC conducted experiments to assess two ways of improving the fit of medical procedure masks: fitting a cloth mask over a medical procedure mask, and knotting the ear loops of a medical procedure mask and then tucking in and flattening the extra material close to the face. Each modification substantially improved source control and reduced wearer exposure. 

Mask Effectiveness study

What are the implications for public health?

These experiments highlight the importance of good fit to maximize mask performance. There are multiple simple ways to achieve better fit of masks to more effectively slow the spread of COVID-19.

The Centers for Disease Control and Prevention (CDC) suggest that the general public not use products intended for healthcare workers, such as N95 respirators (details below), as this could lead to shortages of equipment where most needed.

Can the coronavirus grow on the mask?

No. Viruses cannot replicate outside of a host cell. The virus that causes COVID-19 can live on common surfaces such as paper, fabric or metal for varying periods of time, measured in hours to about a week. Importantly, however, the virus cannot replicate or reproduce on these surfaces. A face mask cannot and does not serve as an “incubator” for the virus.


What about face shields? How are they different from masks?

There is little to no research as yet on the use of face shields in community settings. Most are open below the chin, which can allow the virus to spread outside of the shield.  If used, wear the face shield over a mask.

  • It is not known if face shields provide any benefit as source control to protect others from the spray of respiratory particles. CDC does not recommend use of face shields for normal everyday activities or as a substitute for cloth face coverings.
  • Some people may choose to use a face shield when sustained close contact with other people is expected. If face shields are used without a mask, they should wrap around the sides of the wearer’s face and extend to below the chin.
  • Disposable face shields should only be worn for a single use. Reusable face shields should be cleaned and disinfected after each use. Plastic face shields for newborns and infants are NOT recommended.


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