Here's how to stay safe from wildfire smoke amid reduced air quality

Smoke from wildfires in Canada has spread across the Midwest and northeastern U.S., triggering air quality alerts in 20 states. The poor air quality extends from Minnesota down to Georgia and as far north as western New York.

Wildfire smoke and ash can irritate eyes, nose, throat and lungs, making you cough or wheeze and can make it hard to breathe, according to the Centers for Disease Control and Prevention.

The most effective way to protect yourself during wildfire emergencies is to stay indoors or limit time outdoors when there is smoke in the air, according to the CDC. This is especially important for those with heart or lung conditions who are at higher risk for adverse health effects.

"People who are most at risk are [the] elderly, immunocompromised, young children and people who already have respiratory problems, people with asthma and things like that," said Dr. Stephanie Widmer, a member of ABC News' Medical Unit.

Kids with asthma should avoid playing outside and going to playgrounds until the air quality improves, Widmer said. It is best to stay inside and wear masks in the meantime.

If you can, try to avoid exercising outdoors until the air quality improves, especially those with underlying lung disease.

"People with asthma and people who already have lung disease or underlying lung problems, it can exacerbate that, it can irritate that. And if the air quality is bad enough, it can even cause some symptoms of feeling unwell and respiratory symptoms in people who are healthy," Widmer said.

"Some people are more vulnerable than others, some people can be outside for longer than others. Try to limit your time outside as best as you can and if you can't and if you're not sure how long you'd be outside, throw on a mask," Widmer said.

Pregnant people should also try to avoid spending time outdoors, especially those who are further along, Widmer said.

"A lot of times, very pregnant people are carrying almost a large weight that sometimes can compromise their respiratory ability. And sometimes they feel short of breath at baseline. So very poor air quality could worsen that," Widmer said.

You should wear a mask that covers your nose and mouth, fits tightly to your face and can filter out smoke or ash particles before you breathe them in, according to the CDC. N95 or P100 masks can help protect your lungs from smoke or ash.

Those spending extensive time outdoors in smoky air or an ash-covered area should use a tight-fitting N95 or P100 mask to reduce exposure. Make sure the mask fits over your nose, under your chin and seals tightly to your face. Any leakage around your face will cause unfiltered air to enter and be inhaled, according to the CDC.

Because the particles are so small, Widmer said P100 masks may be more effective in filtering out the smoke particles. But an N95 mask is also a good option.

Wearing a mask while it is hot outside or you are physically active can increase the risk of heat-related illness. Make sure to take breaks often and drink water, according to the CDC.

When inside your house, choose a room closed off from outside air. You could set up a portable air cleaner or a filter to keep the air in this room clean even when it's smoky in the rest of the building and outdoors, according to the CDC.

Keep an eye out for any signs of illness in pets too, including trouble breathing, fatigue, coughing or gagging, red or watery eyes, nasal discharge, inflammation of throat or mouth or reluctance to eat hard foods. Call your veterinarian if you notice any of these symptoms develop.

The CDC advises people avoid using candles, gas, propane, wood-burning stoves, fireplaces or aerosol sprays and don't fry or broil meat, smoke tobacco products or vacuum.

Be on the lookout for coughing, wheezing, general shortness of breath and a general sense of not feeling well, Widmer said.

"If you don't feel right, call your doctor," Widmer said.