The first image below, courtesy NOAA HMS, shows the fire locations across the United States. The red dots correspond to active fires, and the grey areas are plumes. The major concentration of fires in northern Texas and the Plains region. Although there is a large concentration of fires, there is little smoke being picked up by HMS. Some of this smoke may have subsided from the recent precipitation. The second image below, courtesy of GASP EAST, shows the retrieved AOD for the country today. You can see that most of these raised values correspond to more optically thick areas, which correspond to the fires and smoke debris throughout the nation. Although there may be small residual smoke layers in the Plains region, most all of the elevated values you are seeing in GASP are not aerosol at all, but rather an artifact of the way GASP is generated. This has been discussed in Ray's post on 9/21. The south eastern seaboard also appears to have an increase in AOD that is most likely due to smoke from isolated fires and light sulfates.
The first image, courtesy EPA AIRNOW, shows most of TX and some of the edges of the surrounding states. The larges AQI value for today was in San Antonio, TX due to high ozone. The next image, courtesy GEOS-5, shows the modeled sulfate only AOD [550 nm] for the eastern half of the country today. These model results show that there has been an increase in sulfate concentrations in the Mid Atlantic region, which may be enhancing PM2.5 production, producing additional code yellows.