With over 800 wildfires raging across Canada, thick smoke has drifted into the United States, affecting regions such as the Midwest and the Northeast.
As of Thursday, air quality alerts were issued across several states, including Minnesota, Illinois, Pennsylvania, and New York, urging residents to take precautions.
People who work outdoors, those sensitive to smoky conditions, or in vulnerable groups should consider wearing masks for protection. However, selecting the appropriate mask is crucial.
Kai Chen, an associate professor of epidemiology at Yale School of Public Health, informed ABC News that an N95 mask, designed to filter out at least 95% of airborne particles, offers the best protection.
Chen noted that wildfire smoke consists of a mixture of gases, solid particles, and fine particulates, with the fine particulates posing the greatest health risk.
Fine particulate matter, known as PM2.5, is 30 times smaller in diameter than a human hair. Because these particles are too small to be seen with the naked eye, they can easily enter the nose and throat and can travel to the lungs. These tiny particles get trapped in the lungs,
Chen said surgical masks can block the majority of respiratory droplets from a cough or a sneeze but are not effective at filtering PM2.5. Similarly, paper dust masks, cloth masks, wet cloths and bandanas are not effective at filtering out fine particulate matter, he said.
Chen said people should make sure their N95 mask is certified by the National Institute of Occupational Safety and Health. The N95 should have two straps that go around the head and fit over the nose and under the chin, creating a tight seal.
N95 masks will not work properly without a tight seal, so children or people with facial hair might get reduced protection. Most healthy people can wear them safely, but some may notice it takes more effort to breathe due to the snug seal.
If you develop significant shortness of breath, dizziness while wearing an N95 mask, remove it once you are in a safe cleaner-air environment, and seek medical attention if symptoms do not improve.
At least one city is offering free masks to protect residents. New York City Mayor Zohran Mamdani