I just read your front page article, "San Antonio appears on EPA's radar" and there are a couple of key points I would like to address:
1. Winds were blowing from the NE and East, due to the passage of an early season cool front. That same front ushered in high levels of smoke from forest fires, sulfates (containing NOx) and volatile organic compounds from biogenic and anthropogenic sources to our north and northeast. You can see this on the NAAPS model from yesterday.
2. Background levels of ozone were so high that even Seguin (74 ppb. on the 20th) and San Marcos (81ppb. on the 20th) had high levels of ozone at their reporting sites. When you factor in the high background levels, San Antonio only added 10-15 ppb. of recorded ozone. Austin avoided the high ozone levels due to a constant cloud deck that only parted yesterday afternoon. When it did, their levels also spiked for a few hours. Here is a link to this data: Daily 8hr Ozone Averages
3. The Eagle Ford Shale drilling area is located to the SE of San Antonio and did not play a role in our high ozone on Monday and Tuesday, nor did smoke from Mexico. Our winds were consistently from the NE and East on Monday and Tuesday. This was a dirty "Continental Air" event.
4. These events are rare and can be blamed on the weather, not local pollution. San Antonio has some of the lowest emissions in the country for a city our size and never exceeds the EPA standard unless transported pollution invades our region.
Please check out my website for more information on ozone. I have been studying ozone for over 10 years now.