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Front Range Air Quality 2020: How Now Brown Cloud?




Image via 9News



There are days when the state of air quality along the Front Range can be viewed with the naked eye. The brown cloud that blocks our mountain views is the result of particulate matter made by the reactions of sunlight with a variety of human produced emissions including nitrogen oxides (NOx), volatile organic chemicals (VOCs). In addition, residents are breathing other pollutants that can’t be seen as easily.

Together, all of it can cause asthma, respiratory issues, and other illnesses. Experts believe the pollution is caused by myriad sources that include exhaust from cars, exhaust from other combustion engines, and the full range of oil and gas operations. This fact has been brought into sharp relief – across the nation – as pictures of skylines before and after lockdown have gone viral.

While it is one thing to visually detect poor air quality on the Front Range, it is another thing to understand exactly what’s going on and what’s happening to mitigate problems. The EPA’s Air Quality Index (AQI) provides some of this information. It offers air quality data that is based on observations collected by strategically placed monitors. On any given day, the AQI reports on both the air quality levels and exactly which types of harmful pollutants are present.

An array of actions has been put in place to mitigate issues identified through AQI readings and other research points. These remediations include fines, monitoring programs for polluters, and supportive programs like increased public transportation, carpool incentives, and pollution control device mandates for automobiles and industrial equipment.

In addition to these actions, something entirely new is helping to reduce human created pollution: the statewide COVID-19 stay-at-home order that was issued on March 26th. Though schools and businesses began to change operations or close in mid-March, the stay at home order dramatically lowered human activity. Notably, the rush hour traffic that’s a huge contributor to pollution has slowed to a near-trickle.

Are the typical responses to air quality issues working? Will the decrease in human activity due to the stay-at-home order make a difference? To answer these questions, we’ll look at what has happened so far on the Front Range, and then speak with experts who have been tracking the issue.

Where Air Quality Stood at The First Part of The Year

The Front Range didn’t enter 2020 on a high note in terms of air quality. On December 16th, 2019, the EPA announced through a press release that it reclassified and downgraded the Denver Metro/North Front Range ozone nonattainment area from a moderate level offender to a serious one. “A nonattainment area is one in which air quality does not meet the ozone standards set by the federal government,” according to Colorado.gov.

As a result, the state has been required to reduce its pollution by 2021; at the same time it increased the threshold for issuing permits. The stricter standards will require permits for industries that emit more than 50 tons of pollution a year instead of the previous 100-ton level.

In January of 2020, Environment Colorado released a report that was based on air quality data from the EPA. The report placed Colorado within the top ten high-population cities for poor air quality. According to Hannah Collazo, State Director for Environment Colorado, “often air quality can be out of sight, out of mind, but when you really dig into the data you can see how big of a threat it is to public health.”

At the end of March, the bad news about Front Range air quality continued. The EPA provided preliminary findings for its AQI numbers for 2019. These numbers showed that throughout the entire year, the Front Range experienced just 100 days of acceptable air. Details show that 243 days were found to be in the range of 51 to 100, which reflects higher levels of environmental damage and lower air quality. Finally, 20 days came in at 101-150, which is considered unhealthy for sensitive groups, with two days coming in at 150 to 200 which is considered unhealthy for all.


Causes of Current Air Quality Levels

Right now, there appear to be a few reasons why Colorado is losing ground in the effort to keep air quality high. One of them is that while vehicles are being made more cleanly, the state’s population is increasing. That leads to increased traffic congestion that offsets pollution reductions per vehicle.

At the same time, oil and gas production on the front range was large enough to affect air quality, though with impact from decrease in oil demands due to COVID-19 restrictions, and with dramatic global business impacts on the oil industry, this may change. With the level of industrial activity that took place until recently, substantially more VOCs are in the air from multiple parts of the production process. In addition to requiring permits for these companies so that they’re mandated to operate more cleanly, other remediations include requiring specific mechanical controls on buildings or industrial processes. These include wet scrubbers and condensers to remove pollutants from the exhaust stream.

A third contributor to poor air quality is the warmer temperatures that are being seen along the Front Range throughout the year. Both the sunlight and heat that are present on hotter days accelerate the presence of pollutants.

While the major categories of pollutants might be what you’d expect, we were curious about unexpected sources of pollution. Some of the state’s largest breweries play a role in pollution. Exhaust from flights (there are 79 public airports in Colorado. DIA is the second largest airport in the world and the activity from general airport operations at DIA contribute to problems, as do landfill activities.

According to Jeremy Nichols, Client and Energy Program Director at Wild Earth Guardians, these sources contribute, though they don’t approach, the impact of what the larger polluters and permit holders can do. He says that in the analysis he’s seen, “Fossil fuel production and consumption rises to the top on all fronts, whether its refining oil, or fueling jets or cars.”


Do Actions to Reduce Spread of COVID-19 Highlight the Role Personal Use In Finding Solutions?

As this human activity has slowed with the recent stay-at-home order, the Front Range may be feeling the effects in terms of improved air quality. Frank Flocke, a researcher from the Atmospheric Chemistry Observations and Modeling Laboratory at NCAR, reminded us that this is a unique chance to study what having people required to stay at home and reduce commuting times will do.

“Now there’s a natural experiment that’s taking place. It is an experiment that we normally can’t do,” Flocke said. It reminded him of what happened the week after 9/11, ”when there were no aircrafts in the air. People did look at satellite data then, though they couldn’t fly to certain areas for research.”

Anecdotally, individuals in major cities including LA (number one for poor air quality on the Environment Colorado report) and Denver are joyfully reporting on the views of their skylines. Some have remarked that the air is as clear as they’ve ever seen it in recent memory.

Is there hard data to support what people believe they are seeing visually? Some believe that there is. In Los Angeles, where commuter traffic has dramatically dropped, groups that regularly track and advocate for better air quality have made note of the fact that their AQI numbers have been regularly green since February. NASA satellites have observed the lessening of the pollution cloud over major cities in China, Italy, and France. Those kinds of images have been seen for Denver, too.


Easy to Visualize Elements May Not Tell the Whole Story

Flocke agrees that the stay-at-home order’s reduction on traffic is having a positive effect on air quality, but he’s careful to quantify what that impact is. That’s understandable as collecting and analyzing data never has been a straightforward endeavor. Even now, just as with 9/11, scientists are confined to their homes and restricted from doing too much field research.

In addition, researchers are contending with other barriers to their work – just has they always have. For example, Dr. Detlev Hemig, an associate researcher at CU Boulder’s Institute of Alpine and Arctic Research was let go from the university. He was relied upon to provide a ton of data for researchers to use and his presence will be missed.

Flocke does note that traffic counts, and corresponding levels of the pollutant nitrogen dioxide, are lower. At the same time, he cautions that people refrain from jumping to conclusions, saying that, “right now, everyone wants to know about air quality, but you can’t just do that over lunch or on the back of an envelope. It’s just not going to be meaningful.”

Part of the problem is that Front Range weather patterns pose a challenge to connecting the true causes of any changes in air quality at any given time. Detecting improvement in air quality numbers is tricky at this time of year, when cooler spring weather supports good air anyway. Typically, the higher numbers happen in the summer as longer days and hotter temperature are around to convert emissions into pollutants .

However, weather variables, which can occur at any time, make things trickier. For example, thanks to a warm weather temperature inversion, Denver’s brown cloud made a rare springtime appearance and on March 6th the AQI reached 151. In that case, better numbers seen this year rather than last year could simply be because last year was atypical.

In addition, researchers caution their colleagues and the public to reserve judgement about drawing a strong connection between NASA satellite images and improved air quality. They caution that these images may be the result of varying cloud formations rather than of gains in air quality. To get a better sense of what’s happening researchers would need to filter these images through more complete data analysis processes and observe them over longer periods of time.

True Benefits May Be Felt Over Time

Just because it is difficult to make a connection between air quality improvements and reduced human activity doesn’t mean there isn’t one. The complicated connection may just take time to establish. It’s important to allow for the ability to compare an appropriate data set over months or years and to consider all impacts on air quality.

It is also true that the longer the stay-at-home order lasts, the more data researchers will have on the order’s impact on air quality. For example, if less commuting traffic took place during the middle of summer, the AQI showed a string of green days representing cleaner air, the connection between traffic and pollution would be easier to prove.

Maintaining Air Quality Gains

If researchers can make a more direct connection between the statewide stay-at-home order and air quality gains, that’s important information for the public to have. It is possible, though, that understanding how we could improve air quality wasn’t ever the hard part. Maybe the biggest challenge was figuring out how to achieve and maintain fundamental behavior and regulatory change that results in healthier air for the long term.

Once quarantine is lifted, communities are likely to return to life as it was before. This isn’t surprising considering that even in the face of immediately impactful, life-threatening illness, it took weeks of communication from a variety of outlets and trusted public figures to encourage people to stay home. Behavioral change also required alterations in how school and business are conducted, and it came at the expense of many individuals’ livelihoods. At the time of this writing, in spite of all the information we had on mortality and infection rates, protests and marches for the freedom to go back to normal were spreading across the nation, including in Denver.

The toughest question may be how to motivate permanent change that is less restrictive but brings healthier outcomes. Encouraging more work from home flexibility or doing greater amounts of business locally would reduce the number of cars on the road, which could be a start. Other solutions could also include making ongoing improvements to emissions controls for industrial processes and stricter regulation across the range of industrial operations in Colorado.

Change isn’t ever easy but in the case of air quality it may be required to maintain community health.


Deborah Cameron
Deb brings a passion for community journalism and for the local food scene. She started out as an intern and over the years grew into our current Cuisine Editor. She has appeared in multiple publications including the Longmont Leader, The Left Hand Valley Courier, Ms. Mayhem, Finance101, and Ask.com. When not writing she's eating, road tripping, dog-parking, or watching high school softball. She moved to Colorado from Seattle in the early 2000s after spending a year traveling the U.S. in a teal Ford Escort hatchback. She lives with her husband, two teenagers, and a rescue dog named Charlie.