Cooperative Institute for Research in Environmental Sciences

CIRES & NOAA air-quality research in Colorado*

Every summer along Colorado’s Front Range, ozone pollution periodically spikes to unhealthy levels, despite federal and state efforts to control the lung-damaging chemical. Cars are running cleaner, and power plants are emitting fewer pollutants, so why does ozone still regularly soar above health-based limits?

This July and  August, nearly 200 scientists from several national and regional agencies will focus sophisticated instruments on the Front Range atmosphere, seeking to better understand the sources of emissions and the chemistry that contribute to regional air-quality challenges. Ultimately, the goal is to share discoveries with decision makers seeking to clear the air.

When ozone levels spike, Environmental Protection Agency (EPA) experts recommend that people, especially those in sensitive groups—children, the elderly, and anyone with pre-existing respiratory conditions—limit time outdoors. Seven years ago, Colorado’s Front Range fell out of compliance with federal regulations designed to protect people’s health.

The National Center for Atmospheric Research (NCAR) and NASA are leading the Front Range air-quality missions this summer, and an array of aircraft will make detailed atmospheric measurements, supported by other instruments on the ground. CIRES and NOAA scientists are contributing primarily with ground-, tower-, vehicle-, and balloon-based instruments, as outlined below.

Sun-tracking measurements

CIRES Fellow Rainer Volkamer and colleagues will use a 10-foot-tall mobile laboratory, equipped with innovative, custom-built sensors, to explore variations in the gas column between the vehicle and the sun in space and time. Volkamer’s Multi-Axis Differential Optical Absorption Spectrometer and the novel mobile Solar Occultation-Flux Fourier Transform Infrared Spectrometer rely on sunlight to measure hydrocarbons, ammonia, and nitrogen dioxide molecules located between the van and the sun. These gases are emitted from oil and gas activities, feedlots and dairy farms, and urban sources and undergo chemical reactions in the atmosphere that form unhealthy ozone and aerosols. By combining mobile column measurements with wind patterns, the team’s work will help clarify the contributions of cities, oil and gas activities, and regional weather patterns to regional air-quality challenges.


Towering measurements

At a 985-foot-tall tower in southwest Weld County, Colorado, a research team led by NOAA’s Steve Brown plans to simultaneously measure a suite of chemicals that contribute to ozone pollution; and they also will measure ozone itself. Brown and his colleagues at NOAA, CIRES, and Colorado State University will continuously make chemical and meteorological measurements over the height of the tower, once every 15 minutes. From these data, the scientists should be able to better understand sources of different air pollutants and the efficiency with which they produce ground-level ozone.

Contacts: (Emily Fischer),

Agriculture matters

Scientists and air-quality experts on Colorado’s Front Range know that farming and ranching can degrade regional air quality, and can have other effects on the atmosphere, too, including climate effects. But there are scant reliable data on just what kinds of agricultural activities emit what kinds of airborne chemicals. Crop types, feedlot practices, fertilizer-application techniques, and other factors likely affect those emissions. NOAA scientist Tom Ryerson, CIRES researcher Jeff Peischl, and others will drive an instrumented van around agricultural areas of the Front Range and northeastern Colorado this summer, to collect detailed emissions measurements from specific agricultural sources. The effort should help scientists and decision makers better understand if there are agricultural management practices that minimize negative impacts to the atmosphere.


Methane and more

In 2008, a group of CIRES scientists built a “mobile laboratory” out of a Prius, outfitted it with several instruments, and began driving downwind of oil and gas wells and tanks, wastewater treatment plants, and feedlots in northeastern Colorado, sniffing out air emissions. Gabrielle Petron and her team, based out of NOAA's Earth System Research Laboratory, were especially interested in emissions of methane, a potent greenhouse gas. Since then, they have shifted to a van (more space for instruments and air canister samples) and have deployed their mobile laboratory to oil and gas basins in three states. This summer, their work will continue to focus on methane and other volatile organic compounds, some of which may contribute to air-quality challenges in the region. They will drive downwind of oil and gas facilities, landfills, agricultural operations, cities, and other sites, aiming to identify key sources of methane and other air pollutants, including possible “large emitters” responsible for a disproportionate share of pollutant emissions.


Balloon-based measurements

Ozonesondes are weather balloons that can loft ozone-measuring instruments 20 miles into the atmosphere. In support of the NASA and NCAR aircraft missions this summer, NOAA’s Bryan Johnson and colleagues in the Earth System Research Laboratory will make measurements with conventional ozonesondes and also “tethered balloons,” which can be winched up and down from the surface to 1,000 feet high, measuring ozone along the way. Since some aircraft flying in the mission won’t be cruising lower than 1,000 feet, the balloon-based measurements will help scientists understand what’s happening below that, enabling them to create a detailed, four-dimensional picture of how ozone pollution builds up on Colorado's Front Range in the summertime.


Air-quality education and outreach

As part of this summer’s air-quality missions, hikers will measure air pollutants along trails with Boulder Open Space & Mountain Parks naturalists. NCAR interns will monitor air quality on hikes from trailhead to tundra in Rocky Mountain National Park. CIRES is collaborating with other agencies to host an air-quality workshop for educators, August 6 and 7. Members of the public are welcome at an open house at the NCAR Research Aircraft Facility, August 2, and at the Denver Museum of Nature and Science’s free day on July 20.

Learn more: (registration, educator workshop)

*The broader efforts

Support and expertise for the 2014 air-quality work on the Front Range come from NASA, the National Center for Atmospheric Research, the Colorado Department of Public Health and the Environment, the National Science Foundation, the EPA, the National Oceanic and Atmospheric Administration (NOAA), CIRES, CU Boulder, Colorado State University, and many other universities.

For more information on CIRES and NOAA involvement, please contact: 
Kristin Bjornsen, CIRES science writer,, 303-492-1790

The Cooperative Institute for Research in Environmental Sciences (CIRES) is a partnership of NOAA and the University of Colorado Boulder.

As Colorado’s climate continues to warm, those who manage or use water in the state will likely face significant changes in water supply and demand, according to a new report on state climate change released today by the Western Water Assessment and the Colorado Water Conservation Board.

Rising temperatures will tend to reduce the amount of water in many of Colorado’s streams and rivers, melt mountain snowpack earlier in the spring, and increase the water needed by thirsty crops and cities, according to the new report, “Climate Change in Colorado: A Synthesis to Support Water Resources Management and Adaptation,” which updates and expands upon an initial report released in 2008.

The Colorado report comes on the heels of international and national assessments that discuss likely impacts of climate change in broad regions, and it leverages those assessments to provide state-specific information. Because Colorado is located between an area likely to dry further (the U.S. Southwest) and one likely to get wetter (Northern Great Plains), the state's precipitation future is less certain.

“Despite some uncertainties around precipitation, it’s clear that as temperatures rise in Colorado, there will be impacts on our water resources,” said Jeff Lukas, lead author of the new report and a researcher at the Western Water Assessment, a program of the University of Colorado Boulder funded by the National Oceanic and Atmospheric Administration.

“Already, snowmelt and runoff are shifting earlier, our soils are becoming drier, and the growing season has lengthened,” Lukas said. “Wildfires and heat waves have become more common, too. Climate projections suggest those trendsall of which can affect water supply and demandwill continue.”

The newest climate models are split on whether the future will see increasing, decreasing or similar amounts of annual precipitation in Colorado. Even if the future brings more precipitation, the report notes, skiers, farmers and cities may not benefit because a warmer atmosphere will pull more moisture out of our snowpack, soils, crops and other plants.

In producing “Climate Change in Colorado,” the authors sought to provide information that would be useful to people involved in making long-term decisions about Colorado’s water in the face of climate change.

“This report will help to inform critical products like the Statewide Water Supply Initiative (SWSI) and Colorado’s Water Plan,” said James Eklund, Colorado Water Conservation Board director. “This report will add value, just as the 2008 report was widely used by the state and other entities to inform their long-term planning processes such as the Colorado Drought Mitigation and Response Plan and the city of Denver’s Climate Adaptation Plan.”

Read the full report at

The Western Water Assessment (WWA) is part of the Cooperative Institute for Research in Environmental Sciences (CIRES), a joint institute of CU Boulder and the National Oceanic and Atmospheric Administration (NOAA). The Colorado Water Conservation Board (CWCB) is a division of the Colorado Department of Natural Resources and spearheads the state’s climate change adaptation efforts.   

Co-authors of the report are: Joseph Barsugli, of CIRES and NOAA’s Earth System Research Laboratory; Nolan Doesken, of Colorado State University and Colorado Climate Center; Imtiaz Rangwala, of WWA; and Klaus Wolter, of CIRES and ESRL.


More information and downloads:

In Las Vegas, air from the naturally ozone-rich stratosphere is sometimes an unwelcome intruder, making it difficult for the region to meet the national ground-level ozone standards in the springtime, according to a new NOAA-led study published online this month in the journal Atmospheric Environment.

“We found that the ozone coming down from the stratosphere is pushing the Clark County area up to and even over the limit,” said Andrew Langford, a research chemist at NOAA’s Earth System Research Laboratory in Boulder, Colorado, and lead author of the new study. “Our finding means that the region would be especially hard pressed to meet the even tougher ozone pollution limits now being considered,” said Langford.

The stratosphere is a region 8-30 miles above Earth that contains over 90 percent of the atmosphere’s ozone. It’s this ozone layer that’s the “good ozone,” filtering harmful ultraviolet radiation from the Sun. But lower down, at Earth’s surface, ozone is a pollutant that’s harmful to human health and other living things.

Areas at higher elevations, particularly in the intermountain western United States, are especially prone to atmospheric events called stratospheric intrusions that bring air from the stratosphere down to Earth’s surface. With background levels of surface ozone gradually rising over the last few decades due to increases in human emissions of pollutants, the “extra” ozone that comes occasionally from the stratosphere now pushes some areas over the ozone standard.

"For air quality managers in Clark County, Nevada, these results explain why they’ve frequently seen ozone values that exceed the national air quality standard in springtime—well before the midsummer peak expected for ozone formed as a result of local pollution. This new study will help them identify when they are being affected by natural events beyond their control."

In different regions of the United States, different factors contribute to elevated ozone levels. In some places, oil and gas activities can release very high levels of chemicals that react to form ozone. In other places, the precursors of ozone sweep in on winds from distant locations, even Asia. This study shows that in the Las Vegas region, at least in the springtime, the stratosphere is the source of some of the ozone at ground level. “Pollution from Los Angeles or Asia, wildfires, and local production are smaller factors,” said Langford.

Researchers used models to analyze the observations they gathered during a roughly 6-week period from May to June 2013, in NOAA’s Las Vegas Ozone Study. A lidar (light detection and ranging) instrument, a remote sensing method, measured ozone from the Earth’s surface to about 1.5 miles overhead, and other instruments measured gases and meteorological parameters at a mountain site about 30 miles northwest of Las Vegas.

“The stratospheric intrusions added at least 30 ppb of ozone in some of the high-ozone events we observed,” said Christoph Senff, a scientist with NOAA’s Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder, who analyzed the lidar observations from the study. “With the normal ‘background’ level of ozone usually at 50-60 ppb, this meant that ozone frequently pushed above 80 ppb."

If the current 8-hour ozone standard of 75 parts per billion (ppb) were lowered to 65 parts per billion, as the Environmental Protection Agency (EPA) is considering, the researchers estimate that the Las Vegas region and other high-elevation sites in the Intermountain West would likely exceed the air quality standard over half of springtime days.

The study’s findings have implications for air quality management in the U.S. Previous studies have shown that several areas of the western U.S. receive pollution from sources that are beyond local control strategies, with some sources—such as transport from Asia and wildfires—on the rise and likely to increase further in the future.

“Our work shows that not only do air quality managers have to contend with pollution coming from across the continent or across the ocean; they also have to consider what’s coming down from far above their heads,” said Langford.


CIRES is a partnership of NOAA and CU Boulder.

Authors of "An overview of the 2013 Las Vegas Transport Study (LVOS): Impact of stratospheric intrusions and long-range transport on surface air quality" include 12 scientists from NOAA’s Earth System Research Laboratory; CIRES; the Laboratoire de l'Atmosphere et des Cyclones; Princeton University; NOAA’s Geophysical Fluid Dynamics Laboratory; and the NOAA/NESDIS Center for Satellite Applications and Research, Cooperative Institute for Meteorological Satellite Studies.



A high-resolution image is available for download on CIRES' Flickr account, News Release album.

CIRES is a partnership of NOAA and CU Boulder.

Recovering the past to understand the future

In 1964, the Beatles took the world by storm, Lyndon Johnson won his second term as President—and NASA launched the first of seven Nimbus spacecraft to study Earth from space.

Fifty years later, experts at the National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder are recovering long-lost images from old Nimbus data tapes and black and white film, and finding treasures in the pictures.

“By extending the satellite record back to the 1960s, we can understand more about the history and natural variability in things like sea ice extent in the Arctic, and the Antarctic,” said David Gallaher, technical services manager at NSIDC. The modern satellite record of sea ice goes back only to 1979.

In the Arctic, sea ice extent was larger in the 1960s than it is these days, on average. “It was colder, so we expected that,” Gallaher said. What the researchers didn’t expect were “enormous holes” in the sea ice, currently under investigation. “We can’t explain them yet,” Gallaher said.

“And the Antarctic blew us away,” he said. In 1964, sea ice extent in the Antarctic was the largest ever recorded, according to Nimbus image analysis. Two years later, there was a record low for sea ice in the Antarctic, and in 1969 Nimbus imagery, sea ice appears to have reached its maximum extent earliest on record.

When NASA launched Nimbus-1 50 years ago, the agency’s key goals were to test instruments that could capture images of clouds and other meteorological features, Gallaher said.

The Nimbus satellites dished up such excellent observations, NASA eventually handed over key technologies to the National Oceanic and Atmospheric Administration (NOAA), for use in weather forecasting, including hurricane forecasts.

But even with such success, data tapes and film that recorded Nimbus observations slipped through the cracks.

“At the time, the satellites’ real-time observations, including clouds, for example, were what people wanted most of all, for weather forecasting,” Gallaher said.

He and colleagues with NASA Goddard Space Flight Center in Greenbelt, Maryland, tracked down old Nimbus film to a NOAA facility in Suitland Maryland, where they were stored for about 25 years, and then Asheville, North Carolina. There, hundreds of 35-millimeter film reels lay in an old storage facility.

With funding from NASA, the researchers located and made operational an old film reader that could digitize the images. The team figured out how to determine geographic location for each image, given the orbit of the satellite. And they’ve now made more than 250,000 images public.

NSIDC, the world’s leading source of information on sea-ice changes at Earth’s poles, is part of CIRES, the Cooperative Institute for Research in Environmental Sciences

CIRES is a partnership of NOAA and CU Boulder.

Download the first image from Nimbus-1, captured August 31, 1964.
Watch a short video about the Nimbus data rescue project at NSIDC.
Check out and download Nimbus data.
Learn more about the data rescue project.

David Gallaher, technical services manager, NSIDC: 720-878-8448,
Garrett Campbell, data specialist, NSIDC: 303-492-5194
Katy Human, CIRES communications: 303-735-0196

CIRES is a partnership of NOAA and CU Boulder.

NOAA-led study says September 2013 floods not due to climate change

Last September’s widespread flooding in northeast Colorado, which saw just over 17 inches of rain in one week in the city of Boulder, was not made more likely or more intense by the effects of human-induced climate change, according to a new NOAA-led study published today in the Bulletin of the American Meteorological Society.

"There’s clear evidence that overall, our greenhouse gas emissions are making the planet warmer and moister, but we found such climate factors had little appreciable effect on the frequency of heavy 5-day rainfall events in this area during September," said Martin Hoerling, a research meteorologist at NOAA’s Earth System Research Laboratory in Boulder, Colorado, and lead author of the new study, which also included researchers from the Cooperative Institute for Research in Environmental Sciences (CIRES) and NASA. In fact, the study suggests that in this region, the likelihood of heavy rainfall events may have slightly decreased because of human-induced climate change.

2013 Colorado Floods - Total Storm Precipitation for the Region. Map created with Storm Precipitation Analysis Software (SPAS) through a collaborative effort by Applied Weather Associates, LLC, MetStat, Inc. and the Colorado Climate Center. Radar data supplied by Weather Decision Technologies, Inc.

Last summer’s extreme rainfall—17 inches is close to the city’s typical total for the entire year—was very unusual, but it wasn’t the first time Colorado experienced such heavy rains. Widespread flooding rains fell over the Front Range during several days in September 1938, before human-caused climate change was detectable. The two events were similar in many ways: they happened over a large area, lasted a long time, and were characterized by a slow-moving weather system that pulled lots of moisture into the region.

To tease out the impact of climate change on the 2013 floods, Hoerling and his colleagues used a climate model, developed by NASA, that contained detailed information on how various climate factors—such as greenhouse gas levels, ocean temperatures, and sea ice extent—have varied since the late 19th Century. Run many times, the model produced occasional heavy September rain events both at the end of the 19th Century (1870-1900) and in a recent 30-year period (1983-2012). Comparing those two time periods, the researchers found that the extra greenhouse gases, warmer oceans and lower amounts of sea ice of recent decades did not increase the likelihood of rains as heavy as those in September 2013.

The researchers also explored what the future may hold for such rain events in this area, as greenhouse gases continue to rise. The team examined climate projections used in the Intergovernmental Panel on Climate Change (IPCC) assessments and found no significant changes in the risk of summer heavy 5-day rainfall events over the High Plains region, including Colorado.

Hoerling and colleagues stressed, however, that with further increases in water vapor in a warmer world, many parts of the world are likely to see more frequent episodes of very heavy rains. They said that what happens globally doesn’t necessarily explain what happens in one particular place, where local to regional processes may trump global ones. To figure out why that is, the researchers are doing further studies with other models.

This study is part of a Bulletin of the American Meteorological Society special report on 2013 extreme weather events.If climate change didn’t cause the 2013 floods, then what did? “For this event, the weather pattern was much more important than climate change, or other climate factors such as ocean temperature variations and changes in Arctic sea ice,” Hoerling said. In this case, a slow-moving low pressure system pulled up moisture from the south and essentially stalled at the Front Range, dropping that moisture as heavy rains.

Authors of "Northeast Colorado Extreme Rains Interpreted in a Climate Change Context" include Martin Hoerling and Randall Dole from NOAA’s Earth System Research Laboratory; Klaus Wolter, Judith Perlwitz, Xiaowei Quan, Jon Eischeid, and Henry Diaz from CIRES; and Hailan Wang and Siegfried Schubert from NASA’s Goddard Space Flight Center.

CIRES is a partnership of NOAA and CU Boulder.



Area of Research

Recent Stories

Chemicals released into the air by oil and gas exploration, extraction and related activities can spark reactions that lead to high levels of ozone in wintertime, high enough to exceed federal health standards, according to new NOAA-led research, published today in Nature.

The study comes at a time when new technologies are helping to accelerate oil and gas development in Utah’s Uintah Basin, elsewhere in the United States and in many other countries, and its findings may help air quality managers determine how to best minimize the impact of ozone pollution. When ozone levels spike, Environmental Protection Agency experts recommend that people, especially those in sensitive groups—children, the elderly, and anyone with pre-existing respiratory conditions—limit time outdoors.

Winter ozone pollution is surprising because normally, the more intense sunlight of the summer season can spark the chemical reaction that creates ozone pollution, said lead author Peter Edwards, a scientist with NOAA’s Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder at the time of the study, and now with University of York in England.

However, Edwards and his colleagues showed that in winter in northeastern Utah, levels of volatile organic compounds (VOCs) build high enough that they can trigger pollution-forming reactions, themselves.

“This is not the usual spark for ozone formation, but it’s a potent one,” Edwards said. “Under certain wintertime conditions, it can cause extreme levels of ozone pollution.”

In winter, warm air aloft can trap cold air below, creating an "inversion" that traps and concentrates air pollutants. The presence of snow increases light reflection and accelerates ozone production.

For instance, in 2013, ozone in Ouray, Utah, exceeded the national air quality standards 49 times. By contrast, in the densely populated, urban area of Riverside, California, the standards were exceeded about half as often that same year, but during the summer.

“So it’s the same starting ingredients, nitrogen oxides and VOCs, that form ozone in Riverside, but it’s a different spark in Utah in winter,” said coauthor Steven Brown, a scientist with NOAA’s Earth System Research Laboratory (ESRL) in Boulder, Colorado. “Under wintertime conditions, the much higher VOCs in Utah break down to make carbonyl compounds, which set off the ozone production.”

The research is based on data collected during a series of wintertime studies in Uintah Basin, led by scientist James Roberts, also with NOAA ESRL. “We encountered a range of conditions during the three winters, from snowy in 2013 and 2014, to virtually no snow in 2012,” Roberts said. “Oil and gas emissions of VOCs were high in all three years, but high ozone occurred only in the cold, snowy, stagnant periods.”

Researchers from NOAA, CIRES, and other institutions made detailed measurements of ozone and the chemical ingredients, such as VOCs and nitrogen oxides, that “cook up” into the pollutant, and they used chemical models to better understand the system.

“These studies in Utah have caused us to think about air pollution chemistry a little differently,” said coauthor Joost de Gouw, a researcher with CIRES working at NOAA ESRL. “Our findings could help state and local air quality managers who are faced with ozone episodes to design policies, and industry representatives to meet air quality standards in the regions where they operate.”

CIRES is a partnership of NOAA and CU Boulder.

Authors of “High winter ozone pollution from carbonyl photolysis in an oil and gas basin” are: Peter M. Edwards (CIRES and NOAA), Steven S. Brown (NOAA), James M. Roberts (NOAA), Ravan Ahmadov (CIRES and NOAA), Robert M. Banta (NOAA), Joost A. deGouw (CIRES and NOAA), William P. Dube´ (CIRES and NOAA), Robert A. Field (University of Wyoming), James H. Flynn (University of Houston), Jessica B. Gilman (CIRES and NOAA), Martin Graus (CIRES and NOAA), Detlev Helmig (University of Colorado), Abigail Koss (CIRES and NOAA), Andrew O. Langford (NOAA), Barry L. Lefer (University of Houston), Brian M. Lerner (CIRES and NOAA), Rui Li (CIRES and NOAA), Shao-Meng Li (Environment Canada), Stuart A. McKeen (CIRES and NOAA), Shane M. Murphy (University of Wyoming), David D. Parrish (NOAA), Christoph J. Senff (CIRES and NOAA), Jeffrey Soltis (University of Wyoming), Jochen Stutz (University of California, Los Angeles), Colm Sweeney (CIRES and NOAA), Chelsea R. Thompson (University of Colorado), Michael K. Trainer (NOAA), Catalina Tsai (University of California, Los Angeles), Patrick R. Veres (CIRES and NOAA), Rebecca A. Washenfelder (CIRES and NOAA), Carsten Warneke (CIRES and NOAA), Robert J. Wild (CIRES and NOAA), Cora J. Young (CIRES and NOAA), Bin Yuan (CIRES and NOAA), and Robert Zamora (NOAA).


High-resolution images are available for download on CIRES’ Flickr account, News release album:

  • Towering measurements NOAA and CIRES scientists installed instruments on a tower....
  • Drilling rig in Uintah Basin, Utah.
  • Sunset over a field in Uintah Basin where natural gas and oil development has increased.
  • more

Oil and natural gas production fields can emit large amounts of air pollutants that affect climate and air quality—but tackling the issue has been difficult  because little is known about what aspects of complex production operations leak what kinds of pollutants, and how much. Now a CIRES-led study in the journal Atmospheric Chemistry and Physics sheds light on just that, pinpointing sources of airborne pollutants.

The results have important implications for mitigation strategies in the nation’s oil and natural gas production.

“Before you can stop a leak, you have to know where it is,” said lead author Carsten Warneke, an atmospheric chemist with NOAA’s Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder. “This study tells us where the largest emissions are coming from, and that, in turn, helps industry identify what they can do to reduce emissions as cheaply and effectively as possible.”

Oil and gas production fields emit the greenhouse gas methane and also other air pollutants called volatile organic compounds (VOCs), which include the air toxics benzene, a carcinogen, and toluene. VOCs, present naturally in oil and natural gas, are chemical precursors for ozone pollution, which, at high levels, can harm people’s lungs. The new study focuses on the emissions of VOCs in the oil and gas fields of the Uintah Basin in Utah, where the landscape is dotted with 8,000 gas wells and 2,000 oil wells in operation, and about 1,000 new wells are added each year.

The study shows that in the Uintah Basin, equipment located on well pads—such as condensate tanks, dehydrators, and pumps—are key sources of pollutants. It also found that well operations frequently emit high levels of benzene and toluene, and that emissions vary by production method.
The study is one of the first to use fast-response and highly sensitive instruments to measure VOCs from individual gas and oil well pads and other point sources. To collect the data, Warneke and his team, in February 2012, drove an instrumented van downwind of 38 gas wells, 12 oil wells, one newly producing well, one refractured well with a flowback pond and 17 other point sources such as evaporation ponds, storage tanks and compressor stations. The mobile laboratory approached closer than 300 feet of most sources, measuring the VOCs in the air.

The researchers detected high amounts of VOCs at almost all the locations, but large differences existed among sources. Specifically, they found:

  1. On well pads, some equipment leaks more VOCs than others. The main emitters include separators, dehydrators, and oil and natural gas liquid (condensate) tanks. Separators divide natural gas into its liquid and gas fractions, and dehydrators remove water from natural gas.
  2. Different production techniques result in different emissions. For example, dehydrating gas on-site (at the well pad) leads to higher emissions of VOCs than dehydration carried out off-site at a centralized facility.
  3. The scientists found high ambient levels of benzene and toluene (another air toxic) at specific sites in the basin, with measurements reaching up to 1,000 parts per billion (1 part per million) by volume. “In urban areas, values are closer to 0.1 to 0.2 parts per billion by volume,” Warneke said. One such site was a recently re-fractured well with a flow-back pond. Evaporation ponds were also a large source of VOCs. 
  4. In Rangely, Colorado, where the team also took measurements, they found fewer emissions, probably because of two key factors: Rangely’s gas field is drier than Uintah Basin’s, and most wells have electric power. Both factors lessen the need for production equipment, such as dehydrators and storage tanks. “Less equipment means fewer opportunities for leaks,” Warneke said.

The new findings are qualitatively similar to emissions "inventories," which are estimates of emissions based primarily on well counts and production data. Like the measurements, inventories identify well heads themselves, dehydrators and tanks as major VOC emission sources.

The researchers’ measurements were part of a larger experiment to unravel the mystery of why the sparsely populated Uintah Basin experiences frequent wintertime exceedances of ozone air quality standards.  The research shows that these exceedances trace back to oil and gas activities—and to the VOCs that Warneke and his colleagues have now detailed in the new study.

“To understand ozone pollution, we need to understand both the chemistry behind it and the major sources that start this chemistry, and we went right to the source of the emissions to study them,” Warneke said.

CIRES is a partnership of NOAA and CU Boulder.

More on the Web:

  1. Paper Link 
  2. OSHA / NIOSH standards for benzene exposure:
  3. High-resolution graphics available on the CIRES Flickr page, News Release album

Authors of “Volatile organic compound emissions from the oil and natural gas industry in the Uintah Basin, Utah: Point sources compared to ambient air composition,” published in Atmospheric Chemistry and Physics, are Carsten Warneke (CIRES and NOAA’s Earth System Research Laboratory, ESRL), Felix Geiger (Karlsruhe Institute of Technology), Peter M. Edwards (CIRES and NOAA ESRL), William Dubé (CIRES and NOAA ESRL), Gabrielle Pétron (CIRES and NOAA ESRL), Jonathan Kofler (CIRES and NOAA ESRL), Andreas Zahn (Karlsruhe Institute of Technology), Steven S. Brown (NOAA ESRL), Martin Graus (CIRES and NOAA ESRL),  Jessica Gilman (CIRES and NOAA ESRL), Brian Lerner (CIRES and NOAA ESRL), Jeff Peischl (CIRES and NOAA ESRL), Thomas B. Ryerson (NOAA ESRL), Joost A. de Gouw (CIRES and NOAA ESRL) and James M. Roberts (NOAA ESRL).


New study shows that false-negative errors may be just as important as false-positives

Understating the effects of climate change could be as costly and dangerous to human well-being and economics as overstating the impacts, according to the authors of a new analysis published today in the Bulletin of the American Meteorological Society.

“Scientific papers and assessments such as the Intergovernmental Panel on Climate Change (IPCC) may err too much on the side of caution,” said lead author William Anderegg, a postdoctoral researcher at Princeton University in New Jersey. “Such hedging can prevent decision makers and the public from understanding the full range of risks.”

Anderegg and his co-authors, including Cooperative Institute for Research in Environmental Science (CIRES) Fellow Max Boykoff, evaluated “type 1” and “type 2” errors related to IPCC reports released in 2007. Type 1 errors are false positives. These would include, for example, a case in which scientists accidentally identify a stronger relationship between a certain type of weather pattern and climate change, than exists in reality. In a type 2 or false-negative error, scientists might inadvertently fail to identify a real relationship, concluding that none exist.

Boykoff is also an associate professor in the University of Colorado Boulder Environmental Studies Program.

Anderegg, Boykoff and their colleagues examined two scientific topics widely covered by the media during 2007: The IPCC’s estimates of future sea level rise, which were relatively low compared to other sea level rise estimates; and a well-publicized typo in Himalayan glacier melt rates, which amounted to an overstatement. The researchers described the latter as a possible “type 1” error.

“Climate scientists are very aware of type 1 errors, and are very averse to them,” Boykoff said. “No one wants to make a mistake like reporting a too-high figure for Himalayan glacier melt rates. But in an attempt to avoid these kinds of errors, scientists may accidentally make more type 2 errors.”

In the case of sea level rise, for example, scientists involved in the IPCC report of 2007 chose to be extremely conservative in estimating future likely sea level rise, because of some uncertainty regarding how major land ice sheets, such as on Greenland and Antarctica, will behave in a warmer world. The IPCC report carefully noted the fact that such land ice was not included in the 2007 analysis, and was a reason for the low estimate. However, only about 30 percent of media reports mentioned that important caveat.  

“Type 2 errors can hinder communication of the full range of possible climate risks,” the paper concluded.

The authors argue that climate scientists, and those in other policy relevant fields such as medicine, must better recognize both type 1 and type 2 errors. They urge that scientists accurately report the full range of possible outcomes, even if improbable, controversial or poorly understood.

“Climate change is fundamentally a problem of managing risk,” Anderegg said. “In order to do that as a society, we have to know the full range of possible futures from the science. The available evidence suggests that in many crucial areas climate science likely understates these risks.”  

CIRES is a partnership of CU Boulder and NOAA.

Authors of “Awarness of Both Type 1 and Type 2 Errors in Climate Science and Assessment,” published in the Bulletin of the American Meteorological Society October 30, include William Anderegg (Princeton University), Elizabeth Callaway (University of California, Santa Barbara), Maxwell Boykoff (CIRES and CU Boulder), Gary Yohe (Wesleyan University), and Terry Root (Woods Institute for the Environment, Stanford University).


Bill Anderegg, lead author and Princeton University postdoc,, 970- 739-4954
Max Boykoff, co-author and CIRES Fellow, available by email only,
Katy Human, CIRES communications, 303-735-0196 and

CIRES is a partnership of NOAA and CU Boulder.

Politicians and others often overstate the role of climate change in the growing toll of natural disasters, according to a new book by Roger Pielke Jr.: The Rightful Place of Science: Disasters and Climate Change.

Pielke—director of the Center for Science and Technology Policy Research (CSTPR) and a Fellow of the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder—writes  that the increasing costs of hurricanes, floods, tornadoes or droughts cannot yet be pinned on more frequent or extreme events, according to a broad scientific consensus. Saying otherwise can undermine public and policy makers trust in the science of climate change, Pielke said.

“Science tells us that humans are influencing the climate system and that there are very real risks,” he said. “But if advocates for action go beyond what science can support, then they risk their credibility on the climate issue more generally.”

Disasters and Climate Change, which is written for the general public without technical jargon, will be available tomorrow, November 1. The book is part of a series titled The Rightful Place of Science, edited by Gregg Zachary at Arizona State University’ Consortium for Science Policy and Outcomes.

Pielke said he was motivated to write the book after hearing President Obama state in a June, 2013 Weekly Address that drought, floods and hurricanes have all become more common.

“That’s not the case,” Pielke said, referencing a recent climate report by Obama Administration and recent reports by the Intergovernmental Panel on Climate Change. For example, these reports found very little evidence that tropical cyclones or hurricanes have become more frequent or intense. The reports, however, did find a link between accumulating greenhouse gas concentrations in the atmosphere and more frequent extreme heat waves around the world. Pielke’s book summarizes the state of science with respect to climate trends for various types of extreme weather.

“For those wishing to maintain credibility in public debates over the long term, it’s important to play it straight with the science,” Pielke said.

CIRES is a partnership of NOAA and the University of Colorado Boulder.

Roger Pielke Jr., book author, CIRES Fellow, Director of CSTPR,, 303-735-0451
Katy Human, CIRES Communications,, 303-735-0196

Roger Pielke Jr. is a Professor in the Environmental Studies Program and a Fellow of the Cooperative Institute for Research in Environmental Sciences (CIRES) where he is Director of the Center for Science and Technology Policy Research. He is also author of The Climate Fix: What Scientists and Politicians Won't Tell you About Global Warming (2011, Basic Books).

CIRES is a partnership of NOAA and CU Boulder.

The University of Colorado Boulder was ranked second in the world in geosciences by U.S. News & World Report last week.

CU Boulder trailed only the California Institute of Technology. Rounding out the top five are the Swiss Federal Institute of Technology Zurich, Harvard University and the University of Washington. U.S. News & World Report ranked the top 100 universities in geosciences in 2014 based primarily on their research and reputation.

Geosciences is considered the study of Earth, from its structure to the history of its formation. Studies in the field of geosciences include geology, geophysics, geochemistry, climatology, oceanography and petroleum geology.

Check out CU Boulder's news release here. And learn more about:

CIRES is a partnership of NOAA and CU Boulder.