Air Quality Awareness Week - Part 2 - Air Emissions Trends and Oklahoma

National Trends

Thanks to the Clean Air Act and other air quality regulations (such as vehicle fuel standards), the overall air quality in the United States has actually improved in many ways since the onset of air science and air regulation in the 1950’s. I know it sounds hard to believe, but we have learned a lot as a country in the past 60 years of air control, and it shows. EPA's recent Air Trends Report describes the progress: Based on historical data, levels of every major Criteria Pollutant have decreased both in ambient levels (the level we are exposed to) and in amount of emissions.

Example Graph from Air Trends Report

This becomes more evident if you think back to the tragic events in Pennsylvania and London, where poor air quality resulted in the deaths of many perfectly fine, otherwise-healthy individuals (and these events were not isolated; there were others less note-worthy).

Nowadays, except for very extreme and rare circumstances, most healthy American citizens have less to worry about in terms of air. Some people are extra sensitive to air pollution and they still have to keep vigilant on air quality to protect themselves. These categories of folks are young people (who breathe more quickly than adults and whose lungs are still developing), older people (who are sometimes less physically resilient), and people with cardiovascular and pulmonary disorders (such as asthmatics and heart patients).

Ozone in Oklahoma

In Oklahoma, our major air pollutant of concern is ground-level Ozone. Ozone is a lung irritant, and especially problematic for asthmatics. Ozone is a secondary pollutant, meaning that it is not directly emitted, but is created as chemicals in the air react with each other. It is a summertime pollutant because the weather affects the rate of these reactions and the amount of ozone created. Oklahoma experiences higher levels of this pollutant for a variety of reasons. Some of these include:
  • Interstate transport - ozone and ozone precursors blowing in from other states
  • Weather - Hot, bright, still summers allow for more creation of ozone and allow the pollutant to linger for longer periods
  • Urban sprawl and long commutes - Automobiles produce chemicals that react in the sun to create ozone (Nitrous oxides and volatile organic compounds), and Okies love to drive. Our state is designed for vehicle transport.
Every summer in recent years, Oklahoma has had several days which exceed the NAAQS for ozone. It is possible that areas of Oklahoma - such as OKC and Tulsa - are on the verge of being designated as nonattainment for this pollutant; watch for this in the news in upcoming years.

PM2.5 in Oklahoma

The second pollutant that Oklahoma is sometimes concerned with is fine particulate matter. This is any thing in the air at all that is teeny tiny... less than 2.5 micrometers in diameter. This can be tiny bits of dust, tiny bits of pollen, tiny bits of soot, even tiny vapor droplets. Particles of this size can be breathed in and travel deep into the lungs - penetrating farther due to their size - and our bodies have a difficult time cleaning them out. Oklahoma's major contributors for fine particulates are:
  • Blowing dust
  • Smoke from wildfires


Oklahoma Trends

Oklahoma's Department of Environmental Quality produces Air Data Reports each year so you can see what the monitored levels of various pollutants were in the state. The Air Data Report from 2012 is here. An example graph for Ozone is below.

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