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Pinedale Online > News > May 2008 > VOCs and NOX in Sublette County: Road construction equipment emissions

VOCs and NOX. Photo by Dawn Ballou, Pinedale Online.
VOCs and NOX

Road Work. Photo by Dawn Ballou, Pinedale Online.
Road Work

Heavy Equipment. Photo by Dawn Ballou, Pinedale Online.
Heavy Equipment

Cutslope Work. Photo by Dawn Ballou, Pinedale Online.
Cutslope Work

Grading Cutslope. Photo by Dawn Ballou, Pinedale Online.
Grading Cutslope

Vehicles and Equipment Exhaust. Photo by Dawn Ballou, Pinedale Online.
Vehicles and Equipment Exhaust

Construction Zone. Photo by Dawn Ballou, Pinedale Online.
Construction Zone

Large Equipment Working. Photo by Dawn Ballou, Pinedale Online.
Large Equipment Working

Getting the job done. Photo by Dawn Ballou, Pinedale Online.
Getting the job done

Construction area. Photo by Dawn Ballou, Pinedale Online.
Construction area
VOCs and NOX in Sublette County: Road construction equipment emissions
Highway road construction equipment exhaust emission regulations - WYDOT response
by Dawn Ballou, Pinedale Online!
May 30, 2008 | Updated June 5, 2008

US 191 south of Pinedale is undergoing extensive road construction to put in eleven new much-needed passing lanes. Development of the gas fields in the Jonah Field and Pinedale Anticline have significantly increased the traffic between Pinedale and Rock Springs, prompting the State to allocate money to put in the new passing lanes for better traffic movement and safety of those using the road.

With the recent ozone advisory alerts issued by the Wyoming Department of Environmental Quality this past winter, citizens in Sublette County very much have the topics of VOCs and NOX on their minds.

VOCs, Volatile Organic Compounds, are organic compounds that participate in a photoreaction, generally gas vapors vented from exposed hydrocarbons such as gas, diesel and oil (the fumes you smell when you gas up your car). NOX is nitrogen oxide produced during combustion, generally the by-product of burnt hydrocarbons such as gas, diesel and oil. These are the two components that chemically combine in the air when weather conditions are right, to make ozone. Ozone is typically thought of as an air pollution problem associated with big city smog in the summer. Sublette County had five ozone alerts within a one month period this past February and March, which shocked the local community into a realization that gas development activity in the Upper Green River Valley is creating human health issues and impacting the environment in more serious ways than was expected or modeled by the federal government. This has resulted in the community, industry and government officials scrambling to better understand the contributing factors to the problem and find ways to control and reduce it.

With this setting the stage, many people around Pinedale now look at every puff of black smoke (NOX) with new eyes and questions about how each individual piece is contributing to the overall problem, from our personal vehicles we drive every day to the natural gas field activity taking place in the Upper Green River Valley.

So, getting back to the road construction on US 191, these pictures tell the story of the scene driving through the construction zone on May 17th and made us wonder what regulations apply to this kind of equipment and activity. We sent the pictures to the Governor’s office and asked what the State of Wyoming requires in issuing these big road construction jobs around the state to make sure the contractors they hire for their activities are using “Best Available Technology” and using equipment that is outfitted with pollution control measures. Our question focused on the health safety of the road construction workers on the job who breathe these exhausts for hours and out of concern that the State is sensitive to not excessively contributing to our already compromised air quality in Sublette County.

The Governor’s office forwarded our question about what regulations apply to the black smoke emissions from highway road construction equipment on to Dave Kingham with Wyoming Department of Transportation (WYDOT) Public Affairs.

Below is his reply.

We share your concerns about air quality, and contractors working on our projects are required to meet all applicable particulate emission standards. That would include emissions from the asphalt mixing plants required on many of our projects, and dust created by construction. The asphalt mixing plants are by far the biggest emission source on most road construction projects.

There is no provision specific to exhaust emissions from heavy equipment working on the projects, but WYDOT's specifications require contractors to comply with all federal, state and local laws, which would include any mandated emissions standards.

Wyoming's emission standards state:

The emissions of visible air pollutants from diesel engines as determined by a qualified observer shall be limited to 30 percent opacity below 7500 feet elevation except for periods not exceeding ten consecutive seconds. This limitation shall not apply during a reasonable period of warm-up following a cold start or where undergoing repairs and adjustment following a malfunction.
(e) Unless restricted by more stringent emission limits established elsewhere in the Wyoming Air Quality Standards and Regulations or permit conditions, any single source may discharge for a period or periods aggregating not more than 6 minutes in any hour contaminants;
(i) Having an equivalent opacity of not more than 40 percent as determined by a qualified observer.

Fugitive Dust. Sources operating within the State of Wyoming are required to control fugitive dust emissions. The following control measures or any equivalent method approved by the Division Administrator shall be considered appropriate for minimizing fugitive dust:
(i) Construction/Demolition Activities.
(A) Any person engaged in clearing or leveling of land, earthmoving, excavation, or movement of trucks or construction equipment over access haul roads or cleared land shall take steps to minimize fugitive dust from such activities. Such control measures may include frequent watering and/or chemical stabilization.

As in the enforcement of any law, from speeding to littering, someone authorized to enforce the law has to observe the violation, and in the case of emissions, a "qualified observer" would have to come from the DEQ.

I hope this answers your questions.

Dave Kingham
WYDOT Public Affairs



6/5/08: “I would like to comment on the article and photos by Dawn Ballou for the VOCs and NOX in Sublette County. First of all when you go out and photograph Construction equipment and the black smoke coming out of the exhausts, your picking and choosing when to take the photograph. You have caught all of these pieces of equipment when they are accelerating on the gas to take off and not just driving along the work zone. After they have accelerated and maintain a consistant speed, the black smoke decreases tremendously. Secondly, the equipment you have photographed is some of the "best available technology" and is outfitted with pollution control measures. The D-10 Dozer is new and cost $1,100,000.00 just for this one piece of equipment. I am very much in agreement we need to keep the Ozone clean, but if your going to show a picture or "10 pictures", you ought to show the full picture and keep the camera button pushed to give the real clear picture.”

Editorial Comment: We understand that public officials have to stick with the specifics of the laws in place, but it has become apparent over the past few months that the existing laws do not appear to be enough to keep healthy air quality and ozone levels in the current environment. We believe this is a community problem that will take the serious involvement of everyone, including gas developers, federal agencies, state, county, towns and all the people who live and work here to each do their part and work together to find practical solutions to reduce VOCs and NOX, and not just rely on what is legal or permitted.

Photos by Dawn Ballou, taken on Saturday, May 17, 2008. We welcome comments from our readers. If you wish to comment on this article, or anything else on Pinedale Online, please e-mail:

Related Links
  • Environmental Protection Agency - Organic Gases - (Volatile Organic Compounds - VOCs)
  • Volatile organic compound - Wikipedia
  • Pinedale Online > News > May 2008 > VOCs and NOX in Sublette County: Road construction equipment emissions

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