Looking at the NOAA HMS Smoke and Fire Product (top left), the small red dots indicate groups of fires while the grey areas are smoke plumes. The persisting Northwest Territories wildfires are feeding the large plume spanning into the North Atlantic Ocean, as new and remnant smoke is mixing together as it has been for a couple of weeks. The HMS also saw a plume of unknown origin in the Great Lakes migrating north, as both remnant smoke from Northern Canada or wildfires from Arkansas near the Mississippi River could be contributing factors. In addition, a plume comprised of mostly dust particles was found over Texas, Oklahoma, and Kansas. While the plume's direction of motion is uncertain, the MODIS Aqua AOD image (top right) is showing elevated AODs in New Mexico and Arizona, just west of where the HMS picked up the dust.
To take a look at the surrounding area, the webcam photo to the left is from Joshua Tree National Park, CA at 4:15 PDT looking southeast. As noted by comparing it to the photos to the right, bad air visibility is obvious in the area, which coincides with the elevated AODs seen by MODIS.
Furthermore, the NAAPS Aerosol Model (bottom left image) predicted high concentrations of dust for much of the West for 0:00 UTC on June 28, implying that the dust plume in the HMS could be moving to the west and affecting air quality and air visibility. The EPA AIRNow combined AQI loop (bottom right), on the other hand, shows mostly good AQIs in this region, with only the typical moderate AQIs for southern California. Moderate AQIs were also prevalent in the Great Lakes and Mid-Atlantic, and recently the northern peninsula of Michigan saw an extreme spike in AQI, as the Eastern Upper Peninsula station is currently reading a value of 188, comprising of mostly PM2.5. As this AQI is popping up quite rapidly, it could be an anomaly, but it could be a result of the aforementioned aerosol plume seen by the HMS migrating north from Illinois and Indiana as well.