Ozone is a gas found naturally in the Earth’s upper atmosphere. This “good” ozone makes up the ozone layer and is found in the stratosphere where it protects life on Earth from the sun’s harmful ultraviolet rays. Ozone located in the stratosphere forms when one oxygen molecule (O₂) breaks up due to the presence of ultraviolet radiation. The separated atoms combine with an oxygen molecule to produce an ozone molecule (O₃) which will eventually form the ozone layer.
The troposphere is found closest to the Earth’s surface and extends six miles. Ozone found here, at ground level, is considered an air pollutant. This â€œbadâ€ ozone can harm health and the environment. Breathing ozone can trigger or exacerbate health problems such as chest pain, cough, throat irritation, bronchitis, asthma, and emphysema. Ground level ozone also damages vegetation and ecosystems leading to reduced agricultural crops, decreased commercial forest yields, reduced growth and survivability of seedlings, and damage to foliage of trees and other plants.
The EPA has established two measurement sites in our area to monitor ozone levels. Site C1047, at Skylark Field in Killeen, has been operating since 2009. In 2013, a new site, C1045 was set up in the West Temple Park. The data collected from the monitoring sites is reviewed annually to determine compliance with National Ambient Air Quality Standards (NAAQS).
Compliance is determined by this method:
- Measure the highest average 8 hour ozone concentration for each day.
- Find the 4th highest 8-hour reading each year.
- Take 3 years average of the 4th highest concentration.
The 4th highest concentration for each year is shown below for the two monitoring stations.
Temple: Georgia–West Temple Park
- 2014: 67 ppb
- 2015: 72 ppb
- 2016: 64 ppb
- 2017: 72 ppb (year-to-date)
Killeen: Skylark Field
- 2011: 75 ppb
- 2012: 78 ppb
- 2013: 71 ppb
- 2014: 69 ppb
- 2015: 67 ppb
- 2016: 66 ppb
- 2017: 68 ppb (year-to-date)
The latest three year average (2015 – 2017) for the Killeen monitor is 67 ppb (parts per billion) and 69 ppb at the Temple monitor. Under the current standards, the maximum permitted concentration is 70 ppb. If the data shows an average higher than 70 ppb, the area may be designated as “Non-Attainment” for ozone and a plan must be developed to return to compliance within a specified time period. Monthly summaries of the monitoring sites may be viewed on the TCEQ Air Quality data page. This page shows the four highest 8-hour averages for the year-to-date. The fourth-highest value is the number used to determine compliance.
View monthly summaries of the monitoring sites in our region on the TCEQ Air Quality data page..
On October 1, 2016 the State “non-attainment” recommendations for ozone were submitted to the EPA recommending Bell County as ‘in-attainment” status for the years 2014-2016. On November, 6, 2017, the EPA issued final designations for the 2015 National Ambient Air Quality Standards (NAAQS) for ground-level ozone for most areas in the U.S. All seven counties in the CTCOG region are designated as “attainment/unclassifiable”. The final designations will take effect 60 days after the notice is published in the Federal Register. For remaining areas, the EPA is not prepare to issue designations and will address these areas in a separate future action. More information can be found on the EPA website.
To view the Conceptual Model of Ozone Formation in the Killeen-Temple-Fort Hood Area final report, click here.
Taking cars off the road is the most effective way to reduce the harmful emissions from cars that form ground-level ozone. If your trip requires the use of a vehicle, remember to DRIVE CLEAN:
Limit engine idling
When refueling, stop when the pump shuts off
Avoid spilling fuel
Always tighten gas cap securely
Keep your car, boat, and other engines tuned up
Inflate your car’s tires to the recommended pressure
Alternative Fuels Data Center- For locations that offer alternative fuels, please visit www.afdc.energy.gov.