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- Because of its impacts on health (see below), EPA regulates ozone in ambient air.
Current EPA standards limit ambient ozone to 70 ppb (calculated as the daily maximum 8-hour average).
- Ozone concentrations have exceeded the EPA standard during some winters in the Uintah Basin.
The number of ozone exceedance days and concentrations of ozone that occur each year are closely
tied to meteorology. Years with persistent snow cover and high barometric pressure tend to have
more days with strong winter inversions and high ozone.
- During inversion episodes, ozone concentrations tend to be higher at lower elevations where
inversion conditions are stronger and last longer. For example, during an inversion episode in
February 2017, Ouray (4803 ft. above sea level) registered 10 exceedance days and up to 111 ppb of
ozone, while Vernal (5268 ft. above sea level) had no exceedance days and a maximum of 69 ppb.
- Ozone is formed from chemical reactions involving pollutants emited to the atmosphere. Winter
inversions are extremely effective at trapping locally emited pollution within the Uintah Basin,
making external sources of pollution less important. The Basin has about 10,000 oil and gas wells,
and the oil and gas industry is the largest local contributor of ozone-forming emissions.
- In the absence of winter inversions, ozone concentrations in the Basin are similar to those in other
rural, high-elevation locations around the western United States.
- Portions of the Uintah Basin below an elevation of 6,250 feet have been declared in non-atainment
of the EPA ozone standard, which will likely lead to increased regulation and emissions control
requirements, especially for the oil and natural gas industry.
- Exceedances of the EPA standard for particulate mater (i.e., PM2.5) have occasionally been observed
in the Uintah Basin during winter inversions. Particulate mater exceedances are infrequent enough,
however, that the region is not in danger of becoming a non-atainment area for particulate mater.
- Ozone negatively impacts respiratory health, especially for those with lung diseases. Children, the
elderly, and those with respiratory diseases are most vulnerable. For detailed information about
the health impacts of impaired air quality, see EPA's documents at here
- USU and other groups have measured concentrations of organic compounds in the Uintah Basin
atmosphere for several years. Oil and natural gas consist of organic compounds, and volatile
organic compounds are emited into the air during processes related to oil and gas exploration and
production. Concentrations of many organic compounds in the Basin are higher than in areas
distant from oil and gas activity.
- Benzene, toluene, ethylbenzene, and xylenes are toxic organic compounds. Concentrations of these
compounds are higher in the Basin than in remote environments. Concentrations of benzene in the
Uintah Basin, including in some populated areas, are higher than EPA’s one-in-a-million benchmark
for elevated cancer risk, which means that the risk of a resident contracting cancer as the result of
benzene exposure is greater than one in a million. For perspective, the level of cancer risk from
benzene in the Uintah Basin is similar to some large urban areas in the United States.
- The Utah Department of Health conducted a study of stillbirths and infant mortality in the Uintah
Basin. This study found that the rates of several adverse birth outcomes in the Uintah Basin were
not different from the rest of the state and were lower than the national rate. The study also stated
that “the low amount of [adverse birth outcome] risk that can be atributed to air pollution
exposure, compared to intrinsic, extrinsic, and medical risk factors suggests that these
environmental risk factors are not likely to be very important to overall community health with
respect to [adverse birth outcome] rates.”
- Wintertime ozone in rural areas like the Uintah Basin has only been known to science since 2006,
and the Uintah Basin is one of only two areas in the world where wintertime ozone is known to
occur (the other is Wyoming’s Upper Green River Basin). Because of this, many aspects of the
meteorology, chemistry, and emissions that allow ozone to form during winter are still poorly
- Federal and state agencies are required by law to promulgate regulations that reduce ozoneforming
emissions in the Uintah Basin. These regulations will mostly target the local oil and gas
industry, which is the basis for the majority of the Basin’s economy.
- Scientific research to beter elucidate the causes and characteristics of winter ozone formation can
help industry and regulators craft emissions reductions that maximize effectiveness and minimizecosts to the local industry and economy
- Utah State University is carrying out a comprehensive research program to understand and provide
solutions for the Basin’s air quality problems. This is a cooperative effort with Uintah and Duchesne
Counties, local industry, the Utah Department of Environmental Quality and Division of Air Quality,
the Ute Indian Tribe, the TriCounty Health Department, research teams at other Utah universities
and around the nation, and several federal agencies (BLM, EPA, DOE).
- Government agencies and industry have enacted a number of science-based environmental
controls to reduce the amount of air pollution in the Uintah Basin. These include:
- New regulations by the Utah Division of Air Quality and EPA to reduce emissions from the
oil and gas industry.
- Increased focus on air quality in oil and gas permiting processes carried out by land management agencies.
- Increased focus on air quality by the Ute Indian Tribe.
- Voluntary efforts by industry to install equipment and adopt practices that reduce emissions to the atmosphere.
Actions that all Oil & Gas operators should consider implementing
- Prior to the winter season, train staff about the importance of minimizing VOC and NOx
emissions during winter inversion episodes, and about ways to reduce emissions.
See DEQ's suggestions here.
- Each time high ozone is forecast, remind staff about how to reduce emissions
- Inspection and maintenance that can be performed each time a facility is visited:
- Check that thief hatches on tanks are properly sealed and closed.
- Perform leak checks to ensure valves, fittings, etc., are not leaking, and repair leaks if found.
Options for leak checks include:
- AVO inspections (least effective)
- Natural gas detectors (more effective). We use
which is priced at under $1500.
- Optical gas imaging cameras (most effective). These are expensive, but you can borrow one from the
DEQ-sponsored ULend program. See
- Vehicle use:
- Delay refilling methanol or other chemical tanks when possible.
- Only use paints, chemicals, and cleaning products that have low VOC emissions.
Actions that may be more difficult to implement
- Postpone liquids hauling until after an ozone episode.
- Postpone or avoid maintenance activities that could lead to emissions, such as liquids unloadings/blowdowns, venting lines, line pigging, etc.
- Postpone well completions or recompletions.
- Postpone or avoid gas releases associated with startups and shutdowns of compressors.
- Reduce circulation rates of glycol dehydrators.
- Capture/control emissions from equipment, such as dehydration units, pneumatic devices, engines, heaters, etc.