The AirNow Map image above shows that there is an increased level of ozone along the Mississippi River. It increases to Unhealthy levels in Illinois.
The Windy image above shows that in this region is an increased level of heat. While heat does not correlate to an increased level of surface ozone, the two are found in the same region. Loretta J. Mickley, a Senior Research Fellow in Chemistry-Climate Interactions at Harvard University, “Ozone production accelerates at high temperatures, and emissions of the natural components of ozone increase. High temperatures are also accompanied by weak winds, causing the atmosphere to stagnate. So the air just cooks and ozone levels can build up.”
The NASA Worldview image above shows that there is an increased level of dust being transported off of the Western side of the Sahara Desert.
The NRL/Monterey Aerosol image above shows that much of the concentration of this dust has reached levels of 180-320 ug/m**3 (shown in dark green). Off of the coast Africa, much of the concentration reach 640-1280 ug/m**3 (shown in yellow).