There were two areas in the US with elevated ozone today, the Lower Mississippi Valley (cities from St. Louis southward) and the Los Angeles basin. One area had moderate to unhealthy for sensitive groups PM2.5 and that was from Dallas south through Houston to Galveston. The PM readings have been elevated all day and there is a chance that the Saharan dust which we have been following is now impacting the Texas coast.
The other area of the globe that has severe aerosol problems is Siberia. The fires in the Kazakhstan region continue to rage and the ECWMF MACC forecast of AOD (right, below) shows that much of that smoke has now entered the high Arctic.
The RGB from LANCE webmapping service shows this extensive area of smoke coming out of southern Siberia.
San Bernadino in the east Los Angeles basin broke 110 ppb for ozone today.
UPDATE: July 29, 2012 10:00 EDT
Today, things remain relatively quiet on the air quality front. Ozone continues to be high in Missouri and this appears to be widespread both in Kansas City and St. Louis. Kansas City ozone readings reached 90 ppb today and did not titrate out over night last night.