People in Southern California with relatively high exposures to wildfire smoke over a decade also had significantly higher risks for dementia, a new study warns. In fact, the fine-particle pollution created by these fires seems more closely tied to brain trouble than similar pollutants from factories and car exhaust, the researchers noted. Advertisement Over the long-term, every one-microgram-per-square-meter increase of wildfire-generated air pollution "was associated with an 18% increase in