Wildfire casualties

Studies have found that wildfires cause far more casualties indirectly than directly.

The indirect causes include inhalation of smoke, even at a distance, poor function of the medical system due to disruption, and depression.

Parts of the article are unclear; when it says that the fire "left one in five people with lung damage", what group of people is that? Maybe I could find and access the paper, though I suspect a paywall will make that impossible. I am curious enough to want to know, but no curious enough to do that much work to find out.