As the DFW area reaches the end of the 2016 ozone season on the last day of this month, it is likely that we will have enjoyed the best air quality that we’ve experienced in modern times.
Among the 20 air quality monitors scattered throughout the region that measure conditions that can potentially harm our lungs and respiratory system, only one is recording levels that exceed current health standards.
Last year half of those monitors registered non-attainment readings and the year before that there were just two showing violations.
The major emissions that lead to ozone formation are volatile organic compounds and nitrogen oxides. They are produced from mobile vehicles and stationary sources such as power plants and cement kilns.
Both of these pollutants have been significantly reduced by state and federal regulatory measures. Emissions of NOx are 70 percent below where they were 20 years ago and VOC levels have been cut by more than half during that same time period.
The wide fluctuations in ozone levels such as we have experienced during the past three years can be explained by one thing: the weather.
High summer temperatures, bright sunlight, cloudless skies and little air movement create the perfect circumstances for forming ozone.
Even with the continued downward trend in what science calls precursors to harmful air conditions, the principal cause of high readings at those 20 monitors is the one thing government hasn’t figured out how to control.
Nevertheless, the Clean Air Act requires an ongoing scientific and medical review of the level of ozone present in the atmosphere that could lead to health problems.
Currently that level is set at 75 parts per billion of air concentration. Any area of any state that exceeds that standard is required to develop a plan to reduce ozone-forming emissions, regardless of weather conditions.
The Texas Commission on Environmental Quality is our agency charged with formulating such a plan.
TCEQ describes its success over time: “Texas’ air quality has made huge strides in the past few decades. The state has devoted significant resources for air monitoring and research to advance the science and find innovative ways to improve air quality.”
To determine whether any community is in violation, the average readings of the three most recent years must be below the federal standard at all the area monitors .
If even one of them exceeds the limit, then the entire non-attainment area is considered to be in violation. There are only two monitors exceeding that average standard in North Texas.
We are certainly not alone in dealing with the stubborn problem, as 43 regions of the country are classified as being in violation of ozone limits. About 120 million people live in these areas.
Our area’s challenge to reach compliance is significantly increased by our rapid population growth and the even greater escalation in vehicle miles traveled every year.
If all of this isn’t complicated enough for most to keep up with, the future promises us even more perplexity.
The EPA has declared the ozone standard will be lowered to 70 parts per billion as soon as legal challenges and congressional actions potentially effecting that decision have run their courses.
That will take a while longer.
If that lower requirement were applied today, 11 of the area monitors would fail the three-year averaging test. Only five of them are showing readings above the new level this year.
What this means to the average North Texan can be summed up this way: Our air is cleaner, emissions that lead to unhealthy air conditions continue to decline, and new standards will inspire more progress.
Richard Greene is a former Arlington mayor and served as an appointee of President George W. Bush as regional administrator for the Environmental Protection Agency.