The AirNow Map image above shows that on September 18th the there was a high concentration of Ozone near Las Vegas Nevada. The AirNow Tech graph below reports that the air quality in Lincoln Nevada reached a Yellow AQI (Moderate, 60-75 ppb).
The NRL/Monterey Aerosol images above show that sand from the Sahara has been moving West from the Sahara towards South America. However, due to Hurricane Humberto, the sand is also being pulled toward the East of the United States. The NASA Worldview image below shows a large concentration of sand off the coast of Morroco.