In a year marked by record-shattering heat, raging grass fires and ongoing drought conditions, it’s no wonder the citizens of Central Oklahoma weren’t breathing the healthiest air – but the news isn’t all bad.

From May to September, conditions in Central Oklahoma are a hothouse for ground-level ozone. While ozone in the stratosphere helps to absorb harmful ultraviolet light, here in the troposphere ozone has a much more infamous name: smog. Formed by a chemical reaction that relies on a mixture of sunlight and certain emissions like vehicle exhaust, ozone can have a significant impact on public health both short-term and long-term, reducing lung function and irritating the respiratory system.

Ozone levels are measured at sites across Central Oklahoma by the Oklahoma Department of Environmental Quality; you can see the monitoring sites on the map below:

ODEQ Oklahoma Department of Environmental Quality Air Quality Monitoring Sites Central Oklahoma

Air quality is measured using standards established by the Environmental Protection Agency called the National Ambient Air Quality Standards (NAAQS). The current NAAQS for ozone is an eight-hour average of 0.075 parts per million (ppm), a measure that indicates the concentration of a gas per million parts of air. Over the years the standard has been gradually lowered; scientific advances have allowed us to better understand the health risks of poor air quality and technological advances have aided tremendously in reducing emissions. Consider that the University of Michigan’s Transportation Research Institute found the average fuel economy of all new vehicles sold in the U.S. reached an all-time high in 2012, increasing almost 6% from 2011. Or the mid-1990s phase out of leaded automotive gasoline. Or the growth of alternative fuel vehicles powered by compressed natural gas, electricity or ethanol.

Central Oklahoma had 19 Ozone Alert Days in 2012, the most during any single year since 1998. Ozone Alert Days, however, don’t tell the full story. Since 1997, the quality of Central Oklahoma’s air has improved. What’s changed is the NAAQS, which has gradually lowered the bar and made it harder to comply with the standard. Take a look at this chart of the region’s cumulative averages of highest readings from 1997 to 2012:

Cumulative Average Highest Ozone Readings Central Oklahoma Air Quality ACOG

The current 0.075 ppm standard is expected to soon change. A study published in July of 2012 found lowering the NAAQS to 0.070 ppm would save up to 4,130 lives annually, 67% more lives than the existing 0.075 ppm standard.

Such a looming change means it is incumbent upon Central Oklahoma to consider strategies to limit emissions that contribute to the formation of ozone. More than half of those emissions currently come from mobile sources such as cars, trucks and buses; this is symptomatic of Central Oklahoma’s sprawling nature, which emphasizes automobile travel in lieu of meaningful transit, biking or walking. Oklahoma City alone is 627 square miles, the third greatest land mass of all U.S. cities.

In a 2009 report on commuting issued by the U.S. Census Bureau in 2011, Oklahoma City ranked dead last out of the nation’s top 50 cities for public transportation usage.

Central Oklahoma’s air has gotten better but it’s still important we work to improve it. For example, three groups are particularly vulnerable to poor air quality: children, the elderly and those who suffer from respiratory illnesses such as COPD and asthma.

Based on population numbers from the 2010 U.S. Census, here’s what that translates to in just Oklahoma County:

Total Population



Under 18

181, 118


65 & Over



Pediatric Asthma



Adult Asthma



Chronic Bronchitis






Cardiovascular Disease






Considering exposure to ozone has been linked to cardiovascular disease as well as presenting a risk to those with diabetes, a significant base of Oklahoma County’s population is especially vulnerable to poor air quality.

To put this into a wider perspective, a study from the Johns Hopkins Bloomberg School of Public Health’s Environmental Health Sciences department and published in Environmental Health Perspectives last summer concluded that “annual numbers of avoided ozone-related premature deaths would have ranged from 1,410 to 2,480 at 75 ppb to 2,450 to 4,130 at 70 ppb, and 5,210 to 7,990 at 60 ppb”; in other words, the lower the standard, the fewer deaths related to conditions aggravated by ozone.

All but one of the monitoring sites around Central Oklahoma exceeded the 0.075 ppm standard in 2012. The long-term trend shows improvement in Central Oklahoma’s air quality but both 2011 and 2012 have seen standard exceedances that indicate more steps need to be taken to ensure air quality continues to improve:

NAAQS Air Quality Standards ODEQ ACOG Central Oklahoma Ozone O3 Pollution

To learn more about what you can do to contribute to fewer smog-forming emissions, visit or the Oklahoma Department of Environmental Quality’s website. You can also sign up to receive email notifications about Ozone Alert days or monitor air quality in real time via

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