What makes wildfire smoke a health hazard? Wildfire smoke is different than a smoke you would inhale from a close fire because of the particulate matter in the smoke. We see most health effects in patients with a predisposition to respiratory problems, in the young and in the elderly. Of those that have respiratory problems, patients with asthma are most common, and can have more symptoms if exposed to the particulate matter. In this case, they need to use their rescue medications more frequently. Wildfire smoke can persist for days or even months, depending on the extent of the wildfire. Although the air may look clear, it may have particulate matter that can make asthma worse or trigger an attack.