Bad breath is a part of everyone’s life from time to time. There are many reasons you might experience temporary bad breath, such as eating strong-smelling food or drinking coffee or alcohol. Or, simply because you’ve just woken up and haven’t brushed your teeth yet.

A more serious and longer lasting cause of bad breath (also called halitosis) is often poor oral hygiene habits, such as not regularly brushing your teeth.

Another long-term cause of bad breath is smoking tobacco. Tobacco coats the teeth and mouth in foul-smelling chemicals.

Some people have noticed they’ve experienced temporary or chronic bad breath during the COVID-19 pandemic, when they’ve been wearing facial coverings frequently.

Many facial coverings can prevent bad breath from escaping and stop others from smelling your breath when you’re wearing one.

But facial coverings also trap your breath inside and can make you more aware of any bad breath. In some cases, wearing masks can cause or worsen bad breath.

Read on to learn more about the relationship between bad breath and facial coverings.

Whether other people can smell your breath through your mask depends on several factors. First, consider what type of mask you’re wearing. Some prevent more airflow than others and restrict the amount of breath that escapes.

Generally, there are three kinds of facial coverings people wear to protect themselves and others from COVID-19 and other respiratory illnesses. These include:

  • cloth face masks
  • surgical masks
  • KN95 and N95 respirators

Surgical masks and cloth masks (including neck gaiters) tend to allow the most amount of breath to escape. Often, it’s through the sides or tops of these facial coverings. Thin fabrics like polyester can also allow your breath to escape.

Some facial coverings cling more tightly to the face and are made of less breathable materials, like N95s and KN95s. These masks are the most effective at filtering germs. But they also prevent any bad breath from escaping. That’s because these masks have low levels of air exchange, meaning less air is brought in and out, than more-breathable types of masks.

Facial coverings, especially less-breathable options like N95s and KN95s, seem to trap your breath inside for prolonged periods. When you’re wearing a facial covering, especially for hours at a time like at school or the workplace, you’re unlikely to remove your mask.

Dry mouth is a common issue among people who wear facial coverings often. A major cause is dehydration. When you’re wearing a mask, you may be less likely to drink regularly — which requires frequent mask removal and replacement.

When you have less saliva in your mouth — often from a lack of hydration — your mouth cannot clean itself.

Saliva helps keep your mouth clean by rinsing away food particles and debris. Certain medications and salivary disorders often cause dry mouth, but breathing through your mouth instead of your nose can cause it too.

Mouth breathing is common while wearing a facial covering. It can also lead to a buildup of bacteria in your mouth that can contribute to bad breath.

According to a 2021 study about breath odor and COVID-19 face masks, many study participants began noticing or experiencing bad breath during the pandemic when they started regularly wearing facial coverings.

While facial coverings play an important role in helping stop the spread of disease, bad breath is less desirable.

You can prevent bad breath while wearing a mask by doing the following:

  • Maintain good oral hygiene. Brush your teeth twice a day and floss at least once a day.
  • Avoid smoking cigarettes.
  • Choose a more-breathable facial covering, like a surgical mask, when appropriate.
  • Stay hydrated to prevent dry mouth, a major contributor to bad breath.
  • Visit a dentist at least once per year to stay on top of your dental health.

Many masks may worsen or cause bad breath, but you can take steps to manage it. Take good care of your dental health, stay hydrated, and visit your dentist regularly.