Wildfires burning in the West affect not only the areas burned, but the wider regions covered by smoke. Recent years have seen hazy skies and hazardous air quality become regular features of the late summer weather. Many factors are causing Western wildfires to grow bigger and to generate larger, longer-lasting smoke plumes that can stretch across the continent. An analysis led by the University of Washington looks at the most detailed observations to date from the interiors of West Coast wildfire smoke plumes.