N95 masks protect against dangerous fine particulate matter, including from wildfire smoke, according to federal environmental authorities. When worn correctly, certified N95 masks block 95% of airborne particulates from entering the respiratory system. The masks are certified by the National Institute for Occupational Safety and Health, which is responsible for approving respirators for U.S. workplaces. N95 masks do not protect against gases or vapors, including formaldehyde, benzene, ethylene oxide sulfur dioxide and hydrogen sulfide. Short-term exposure to wildfire smoke can lead to difficulty breathing and more serious respiratory and cardiovascular conditions.