ALBEMARLE COUNTY, Va. (CBS19 NEWS) -- Smoke from Canadian wildfires has caused hazy skies and poor air quality in recent weeks. Poor air quality can have negative health impacts, even for healthy people.

"I have had several patients who came in with worsening symptoms with the poor air quality," said Dr. John Watson, a pulmonary medicine physician at Sentara Martha Jefferson Hospital.

The air quality index measures air quality in a given area. The higher the AQI, the greater level of air pollution, and the greater the health concern. Poor air quality can have an immediate impact on people with asthma, COPD, and heart disease.

"The pollutants are extremely fine particles, very small particles, that your body basically doesn't have any defenses for, so when you're breathing air, you can filter out some of the bigger pollen, sometimes, through your nasal passages, and airway, but the really fine particles are particularly irritating to airways, and especially in the long term can cause problems, even in healthy patients, but in the short term can trigger inflammatory reactions in patients that are sensitive," Watson said.

Sensitive patients can sometimes feel much worse when air quality is bad.

"Patients with asthma and COPD are more likely to have what we call exacerbations, where they require either increases in doses of medications, or adding medications in the short term, or sometimes would need to be hospitalized if necessary," he said.

But Watson says there are ways to minimize the impact.

"In general just the standard surgical mask is not going to make much of a difference, but an N95 mask is able to filter out the smaller particles that are troublesome," he said. "Patients that are sensitive may want to wear an N95 when they're out and about."

Another way to minimize the impact of these particles is by staying inside when the air quality is poor.