Moderate (Code Yellow AQI) ozone (EPA Airnow animation) concentrations were experienced along Arizona, Texas, and Southern California, due to stagnation, limited vertical mixing, high temperatures associated with a high pressure over this region. Tropospheric NO2 retrievals from OMI (courtesy of KNMI) show that concentrations were highest in northern Wisconsin, southern California and New York metro area.
NOAA Hazard Mapping System Fire and Smoke Product reported the presence of remnant smoke was drifting off the Mid-Atlantic coast of the US, as shown below in the NASA Terra MODIS sensor "true color/rgb and AOD images. This area of remnant smoke was the result of numerous fires in the eastern US over the past few days. Also smoke was reported over northwestern Mexico along the Mexican states of Durango, Sinaloa, and Chihuahua.