My Comment to the EPA Response to the Designation Recommendation From Texas for the San Antonio Area for the 2015 Ozone National Ambient Air Quality Standards

To whom it may concern:

My name is Mark Langford and I have been studying meteorology and ground level ozone for over twenty years. Although I hold no degree in either subject, I have spent many hours and days researching both sciences and consider myself very knowledgeable on how ground level ozone forms and the many factors that impact high and low ozone readings throughout a region. I am a past member of the Alamo Area Council of Governments (AACOG) Air Advisory Committee and the owner and editor of the website, https://ozoneinformation.com/. I have also written many posts on my ozone blog, https://ozoneinformation.com/my-ozone-blog  . After reading my response, feel free to check out both sites for additional information on this important subject. Lastly, and probably most important, I am a lifelong asthmatic who has been on anti-asthma medications since I was two years old…I just turned sixty at the end of 2017.

As you consider whether San Antonio and surrounding cities should be labeled as “non-attainment” for our three year ozone average, please consider the following points:

       1.   Local (AACOG) and EPA modeling show that when San Antonio has a high ozone event, our local contributions are only between 20-30% of the recorded ozone. This means that unless we were to almost completely shut down our entire city during a high ozone event, there is no way we can keep our ozone from going over 70ppb as an eight hour average. This also means that 70-80% of the ozone being recorded in our area is from other sources. These come from transported anthropogenic sources from Mexico, Asia, nearby states and cities. They also come from biogenic sources like oak trees, pine trees and invasive plant species like Kudzu.

         2. Our local emissions are trending down. Although high ozone events are fairly random, our local emissions are not. San Antonio and other cities in the USA are lowering their NO2 emissions every year, thanks to vehicles and point sources becoming cleaner due to current regulations. In fact, as of 2018, vehicle emissions in San Antonio will now be second to point sources for the first time in our history of studying ground level ozone. I imagine that San Antonio is not alone.
    
3  Health studies on ozone are “iffy” at best. I have read many scientific papers on the impacts of ozone on humans and most do not include very important factors such as daily allergy reports, how long the people were actually outside during a high ozone event and whether they are smokers, etc. I have never been negatively impacted by any of the San Antonio high ozone events. My challenge in breathing comes during high pollen events, smoke from agricultural burning in Mexico and Central America and Saharan dust.Cities in the south are unfairly labeled “non-attainment “, due to our geographic location. 

4.  Since most high ozone events occur during hot days with clear skies, cities in the south should be allowed more high ozone event days than those in the north. There many more days of 80 degrees plus temperatures in southern states than northern states. Our odds of having a high ozone event are greater, even if we have the same emissions as cities to our north.

          5.  There is concern about the accuracy of measurements by all EPA-approved ozone analyzers, for scientific studies by the EPA and others since 1999 have clearly established that conventional ozone analyzers that employ ultraviolet wavelengths to measure ozone are biased by interference from mercury vapor and sulfur dioxide, both of which are emitted by coal burning power plants. See, for example, "Laboratory Study to Explore Potential Interferences to Air Quality Monitors" (United States Office of Air Quality, EPA-454/C-00-002, Environmental Protection Planning and Standards, December 1999.)" This is a very important concern. If our monitors are not giving us the proper readings, how can know whether any cities are really exceeding the eight hour ozone standard?

         6.  Part of the reason we are even discussing this issue is because the EPA has lowered the eight hour

      average ozone standard to a point where almost every city and many national parks will be unable to achieve such a low reading, despite continued lowering of emissions. My research has found that on many days of the year, several national parks in the west and east go over the eight hour ozone average, even though very few people live in these areas. Their problem as well as ours is due to transport. Here is a link to ozone exceedances for our national parks.   https://www.nature.nps.gov/air/monitoring/exceed.cfm  Will the EPA be considering the parks listed on this page as “non-attainment” areas?

        7.  High ozone events are weather driven. In San Antonio, high ozone events (which are rare) only occur under unusual weather conditions. For us, high ozone events almost always occur when late or early season cool fronts (continental air) push into south central Texas, switching our winds and circulation into the NE or east. We never have high ozone events in the middle of summer, despite temperatures reaching or exceeding one hundred degrees. Were it not for low pressure systems in the Gulf or cool fronts switching our winds into the NE and east, we would never have high ozone events in San Antonio. When the same early and late season cool fronts cause clouds and rain to form instead of clearing our skies, we don’t see high ozone. We cannot control the weather, nor can we control high ozone events.

Please consider high ozone events as a weather driven phenomenon that should be treated as we do any impending storm or severe weather.  Continue to issue health alerts on high ozone days just as NOAA would issue a tornado warning, but don’t penalize cities like San Antonio, who’s air quality is normally very good unless impacted by rare weather events.  Unless a city is dramatically increasing their emissions and is clearly causing an increase in high ozone events, they should not be put onto the “non-attainment” list.