- Sean Cayton
- Wildfires like Waldo Canyon in 2012 can contribute to ozone production.
Denver’s been in and out of compliance with the federal Environmental Protection Agency’s Air Quality Standards for decades.
The Colorado Springs metro area tells a different story. Thus far, ozone levels in El Paso and Teller counties have stayed just under the maximum allowable measure.
But that may not be true for long, according to state and local officials who are hoping to avoid triggering a “nonattainment” designation for the area, which could force the region to implement new regulations on industries and consumer products to improve air quality.
And besides the economic consequences of a “nonattainment” designation, high ozone causes health problems.
“It’s a public health issue, especially for our more vulnerable population folks with under underlying health conditions — folks with asthma, respiratory conditions,” says Andy Gunning, executive director of the Pikes Peak Area Council of Governments.
Peak ozone levels usually occur between June and August due to higher temperatures and weather patterns. In Colorado, EPA modeling shows that only about 30 to 40 percent of ozone is caused by emissions from human activity, such as driving motor vehicles, manufacturing, producing energy and extracting oil and gas. Natural contributors include weather patterns, wildfire smoke and vegetation.
Electrical generating units — such as the Martin Drake and Ray Nixon power plants — are the second-ranked cause of nitrogen oxide emissions in El Paso County, after highway vehicles.
Nitrogen oxide, or NOx, and volatile organic compounds from natural sources or pollutants combine to produce ozone with the addition of sunlight.
“We have drastically reduced our NOx emissions [at coal-fired-power plants] by more than 77% since 1995,” writes Colorado Springs Utilities spokesperson Amy Trinidad. “...In 2018, our power plant emissions were lower than ever before. This trend will continue downward as we expand our renewable energy portfolio.”
While air quality along the Southern Front Range has trended upward since 2000, it’s not enough to stay comfortably within the EPA’s ozone standards. The max in 2008 was 75 part per billion. The limit decreased to 70 ppb in 2015.
“The [EPA] standards have gotten lower, which makes things look worse,” says Gordon Pierce, technical services program manager for the state’s Air Pollution Control Division. “So our air is getting cleaner but just not as quickly as we would like it.”
Ozone levels are calculated by taking the fourth highest measurement from each of the last three years, and averaging those numbers. By that calculation, the Air Force Academy came in at 70 ppb between 2016 and 2018, and Manitou Springs came in at 69 ppb. (The state only operates those two monitoring sites in El Paso County.)
That means that the fourth-highest ozone measurement for both locations cannot exceed 70 ppb this summer — which seems like a tough target to meet, since those monitors reached 73 and 72, respectively, last year.
While Pierce says most of the man-made emissions contributing to high ozone in El Paso County come from activity in that area, Denver and Weld County pollution also sometimes plays a role in high monitor readings. In certain conditions, winds can blow pollutants from oil and gas extraction in Weld County, through the Denver metro area, and finally southwest into Colorado Springs and Manitou — causing what forecasters assign the ominous label of “Denver cyclone.”
On days when wind patterns look ripe for a Denver cyclone, or when certain other factors are present — such as clear skies and temperatures in the mid 80s to upper 90s — the state’s Air Pollution Control Division may issue a “voluntary emission reduction” request asking oil and gas extractors and other industries to take steps to cut down on emissions. Colorado Springs Utilities is also exploring ways to reduce emissions on days when high ozone levels are predicted.
Weather conditions likely to exist this summer offer a glimmer of hope for air quality in Colorado, says Scott Landes, a state meteorologist.
“I am encouraged by the forecast for increased precipitation, lower wildfire threat here in Colorado,” Landes says. “Those are good things. We didn’t have those things in the forecast this time last spring.”
But a couple of weeks of dry weather, or even smoke from a California wildfire drifting into Colorado could upset that balance, Landes cautions.
How to help
In hopes of avoiding a “nonattainment” designation this summer, the Pikes Peak Area Council of Governments wants residents to take steps to reduce emissions on days when forecasters predict high ozone levels. Here’s a few ideas from Denver’s Regional Air Quality Council:
1. Reduce driving time. “Replacing two vehicle trips each week by walking, riding a bike, or taking public transportation can keep 14 pounds of ozone-causing emissions out of our air,” the RAQC’s website notes.
2. Wait until after 5 p.m. to mow the lawn. Sunlight is necessary for ozone production, so when you wait until later in the day to complete emission-causing activities, “you’re getting outside of that ozone production window,” Pierce says. “Those emissions aren’t going to go towards the ozone formation as much.”
3. Fill up your tank in the evening. Refueling can also cause emissions by releasing pollutants into the atmosphere, so it’s better to wait.
4. Don’t let your car idle for more than 30 seconds. And, if you can, reduce driving during the middle of the day.
Local officials are working on a public outreach campaign to let people know when there’s a risk of high ozone and low air quality (which may also mean vulnerable populations should stay inside). In the meantime, you can sign up for air quality forecasts at enviroflash.info or at colorado.gov/airquality.