As Ray mentioned yesterday, there haven't been many air quality events in the last couple of days and the trend continues. Today California was the only state to record unhealthy levels of ozone for sensitive groups (code orange), Moderate levels were also observed in Texas. The areas of code yellow (moderate AQI) in the South and Midwest in today's AQI animation from AIRNow were due to PM2.5. Below is the animated loop of combined AQI (PM2.5 + O3) in California, and in the entire US.
OMI retrievals of tropospheric NO2 (left) over California shows higher concentration over the areas that experienced poor air quality. AOD retrievals from MODIS Aqua (right) shows sightly elevated values only over Nevada today.