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Taking Stock of Emissions in Utah

On a typical winter weekday in 2019, air pollution along the Wasatch Front is measured coming from the following sources. Click to enlarge.

June 10, 2019

By: Nic Sells

Anyone who has spent much time along the Wasatch Front is all too familiar with the infamous brown haze that hangs over the valley during the wintertime. But it’s not only the winter inversions that impact the valley’s air quality. High temperatures and sunlight bring elevated levels of ground-level ozone. And that can be as harmful to human health as winter inversions.

If all of this information causes unbearable levels of doom and gloom, or if spending every day, all day indoors sounds like the best option, just relax. The Utah Department of Environmental Quality’s Division of Air Quality (DAQ) works deliberately and tirelessly to understand the sources of air-quality-deteriorating-emissions and how to reduce them to improve air quality.

And their efforts aren’t without merit. According to a report by the Environmental Protection Agency, Salt Lake City’s bad air days have steadily declined since 2000. There were 52 days during 2000 that reached unhealthy levels for sensitive groups on the Air Quality Index for combined ozone and PM2.5. But only 28 of those days occurred during 2016.

But Salt Lake City’s population grew during this period. And it continues to grow. So how is air quality improving along the Wasatch Front while its population is expanding? Well, there’s a lot of reasons:

  • There’s the thousands of residents who leave their cars at home every day and take public transit to school or work instead.
  • There’s those that don’t idle their vehicles when possible.
  • There’s those who plan ahead and trip chain. And then there’s the emissions inventory team at the DAQ.

The emissions inventory is one method used by the state to assess the level of pollutants released into the air from various sources. There are three sources the state summarize emissions for the EPA’s criteria pollutants (more on what those are later):

  • Point Sources: Stationary, commercial or industrial sources that emit more than 100 tons per year of a criteria pollutant—again, more on what criteria pollutants are later. Examples of point sources include oil refineries, power stations and chemical processing plants.
  • Area Sources: Stationary, like point sources, but are too small or numerous to be treated as individuals. Agricultural dust, outdoor grilling, residential wood combustion and solvent use are all categories confined within the area source inventory. Area sources also include emissions from “events” like wildfires.
  • Mobile Sources: You guessed it: emissions from mobile sources. These include both on-road and non-road sources. Emissions from passenger cars and trucks to locomotives and airplanes are considered mobile sources.

At this point, we need to take a step back and look at what criteria pollutants are. The EPA regulates a group of common air pollutants, determined based on their health and/or environmental effects. Some of these you’ve likely heard of, others maybe not. These are the EPA’s criteria air pollutants:

  • Carbon Monoxide (CO): Can be lethal in high concentrations. High levels of CO can have acute health effects on humans by reducing the supply of oxygen in the bloodstream.
  • Nitrogen Oxides (NOx): Oxides of nitrogen are poisonous, highly reactive gases. These gases form when fuel is burned at high temperatures. Sources include automobiles and non-road vehicles, as well as industrial sources such as power plants, boilers and turbines. When NOx reacts with volatile organic compounds (VOCs) near ground level on hot summer days, it produces ozone.
  • Particulate Matter (PM10 and PM2.5): The main source of Utah’s wintertime air pollution is PM2.5. Its name refers to microscopic particles, particulate matter (PM), that have a diameter of less than 2.5 micrometers. Mobile sources are the largest contributor to PM2.5 levels, thus the importance of limiting automobile use, especially during wintertime inversions. PM10 are larger particles in our air. These are things like dust and coal particles from power plants. But PM10 can also come from combustion from car engines, home heating and industrial sources.
  • Sulfur Oxides (SO2): Gases produced by burning sulfur. All fuels used by humans (oil, coal, natural gas and wood) contain some sulfur. During the combustion process, sulfur reacts with oxygen to form SO2. Acid rain is one product of SO2 as it combines with particles and moisture in the air and transforms into sulfuric acid in the atmosphere. Acid rain can damage lakes and aquatic life, building materials and plant life.
  • Volatile Organic Compounds (VOCs): Released into the air mostly during the manufacture or use of everyday products and materials. Common sources of VOCs may include fumes from fuels, personal hygiene products, cleaning agents and paints. When VOCs mix with sunlight and NOx, ozone is formed. Breathing ozone can damage lung tissue and lead to chest pain, coughing, shortness of breath and throat irritation. Ozone may also worsen chronic respiratory conditions and compromise the body’s ability to fight infections.

So, while the DAQ is waging a war against our valley’s poor air–like helping pass legislation in 2018 mandating new water heaters sold in the state include the latest ultra-low NOx technology, reducing those emissions by 75 percent compared to conventional water heaters and aiding in the passing of state and federal requirements of large industry that has reduced emissions by 47 percent since 1995—there’s some things you can do to help.

While you may not be able to do anything about emissions from point sources, there are some actions you can take today to reduce your contribution from mobile and area sources. There are the seemingly small things that can have big impacts, like trading your gas lawn mower in for an electric model. It’s worth knowing that running a gas-powered lawn mower for one hour emits as much pollution as driving a car 196 miles!

And there are some larger steps you may consider, like asking your employer about teleworking opportunities. By working from home, teleworking can have a big impact on reducing emissions from Mobile Sources. And it can save money. Working from home can save $30 a week on gas with a 50-mile round trip commute. If teleworking isn’t an option, consider all the ways to rethink your commute.

Nic Sells

I am a recent graduate of Weber State University with a degree in communication. When I’m not tending to my chickens and garden at home, you can find me biking, hiking or fishing with my wife and two-year-old son. A Utah native, I love this place we are all lucky enough to call home.

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