Air quality in the eastern portion of the US improved, as can be seen in today's ozone map (top, left). However in southern California, ozone reached code red once again. PM2.5 levels reached unhealthy levels mainly in Idaho, Montana, Utah, Colorado, Arizona, California and Texas. Smoke is likely to be the main source of the high concentrations observed.
High AOD values were retrieved by MODIS Terra (below) and Aqua (bottom) due to smoke from various sources. According to the HMS team, and as can be also seen in the images below, remnant smoke from Canada and Northwestern US fires are the contributors. Remnant smoke from Siberian fires is also believed to be mixed in.