Article
Environmental Sciences
Congmeng Lyu, Shannon L. Capps, Kent Kurashima, Daven K. Henze, Gordon Pierce, Amir Hakami, Shunliu Zhao, Jaroslav Resler, Gregory R. Carmichael, Adrian Sandu, Armistead G. Russell, Tianfeng Chai, Jana Milford
Summary: Recent expansion of oil and natural gas production activities in the Denver-Julesburg Basin have led to significant increase in nonmethane hydrocarbon (NMHC) emissions, contributing to ground-level ozone formation. Using different methods, it was estimated that O&NG activities in Platteville and Denver have different contributions to NMHC mixing ratios. Vehicle emissions in Denver have a larger impact on NMHC levels compared to O&NG activities.
ATMOSPHERIC ENVIRONMENT
(2021)
Article
Environmental Sciences
Samuel Rossabi, Jacques Hueber, Wei Wang, Pam Milmoe, Detlev Helmig
Summary: The study monitored methane and nonmethane volatile organic compounds near Boulder in the Northern Colorado Front Range to investigate their spatial distribution and sources, with a focus on the impact of oil and gas operations on regional air quality. Findings showed that light alkane petroleum hydrocarbons were the dominant VOCs analyzed, while longer-lived VOCs like ethane and propane decreased with increasing elevation. This study also revealed elevated levels of VOCs at mountain sites due to upslope transport of plumes from the plains, and increasing VOC concentrations closer to oil and gas development sites in suburban East Boulder County.
ELEMENTA-SCIENCE OF THE ANTHROPOCENE
(2021)
Article
Environmental Sciences
James L. Crooks, Rachel Licker, Adrienne L. Hollis, Brenda Ekwurzel
Summary: The study found that the ozone climate penalty in the Denver Metro North Front Range region is most pronounced around major urban centers and is positively associated with factors such as the percentage of Hispanic/Latino residents and children living within 100-200% of the federal poverty level.
JOURNAL OF EXPOSURE SCIENCE AND ENVIRONMENTAL EPIDEMIOLOGY
(2022)
Article
Environmental Sciences
Samuel J. Oltmans, Lucy C. Cheadle, Detlev Helmig, Helene Angot, Gabrielle Petron, Stephen A. Montzka, Edward J. Dlugokencky, Benjamin Miller, Bradley Hall, Russell C. Schnell, Jonathan Kofler, Sonja Wolter, Molly Crotwell, Carolina Siso, Pieter Tans, Arlyn Andrews
Summary: Research conducted in the Colorado Denver-Julesburg Basin (DJB) from 2008 to mid-2016 using air samples collected at the Boulder Atmospheric Observatory (BAO) found that emissions from oil and natural gas (O&NG) have remained relatively constant, despite significant production increases. Elevated mole fractions of O&NG tracers such as methane and propane were observed in air transported from the northeast sector, while emissions from the south (urban) sector showed lower concentrations. These results contrast with projections from VOC emissions inventory, indicating a discrepancy between actual emissions and predicted reductions.
ELEMENTA-SCIENCE OF THE ANTHROPOCENE
(2021)
Article
Engineering, Environmental
Pamela S. Rickly, Matthew M. Coggon, Kenneth C. Aikin, Raul J. Alvarez II, Sunil Baidar, Jessica B. Gilman, Georgios I. Gkatzelis, Colin Harkins, Jian He, Aaron Lamplugh, Andrew O. Langford, Brian C. McDonald, Jeff Peischl, Michael A. Robinson, Andrew W. Rollins, Rebecca H. Schwantes, Christoph J. Senff, Carsten Warneke, Steven S. Brown
Summary: Increasing trends in biomass burning emissions significantly impact air quality in North America. The transport of smoke from local and long-range fires has been found to increase the mixing ratios of ozone (O3) in urban areas. This is primarily due to the transport of pyrogenic volatile organic compounds (PVOCs) and the influence of O3 produced within the smoke. Detailed chemical measurements have shown that both local and long-range smoke periods lead to increases in carbon monoxide, background O3, OH reactivity, and total VOCs, while the NOx mixing ratios remain constant. Box-model calculations indicate that local O3 production is in the NOx-sensitive regime, with PVOCs substantially increasing O3 production in the transition and NOx-saturated regimes.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Environmental Sciences
Ruth C. Heindel, Sheila F. Murphy, Deborah A. Repert, Gregory A. Wetherbee, Alexander E. Liethen, David W. Clow, Toby A. Halamka
Summary: As human activities increasingly dominate the nitrogen cycle, ammonium deposition, one of the main components of nitrogen deposition, remains high in the Rocky Mountains, despite efforts to reduce emissions. Previous spatial models have underestimated the contribution of urban and agricultural emissions to ammonium deposition in adjacent ecosystems. Through field measurements, this study found elevated wet ammonium deposition in urban and foothill areas, and lower deposition in montane and subalpine regions. Ammonium accounted for the majority of nitrogen deposition, particularly in spring when air masses from the plains transport ammonium to the mountains. The results highlight the importance of considering urban and agricultural sources in nitrogen deposition models and suggest that fire-prone forested foothills receive even greater ammonium deposition than higher elevations, posing a risk to water supplies and ecosystems.
Article
Environmental Sciences
Lisa S. Darby, Christoph J. Senff, Raul J. I. I. I. I. Alvarez, Robert M. Banta, Laura Bianco, Detlev Helmig, Allen B. White
Summary: The study conducted in the vicinity of Denver in the summer of 2008 revealed the transport of pollution into wilderness areas of the Rocky Mountains. Findings demonstrated that under specific conditions, ozone-enriched air can be advected into high-elevation mountain sites, highlighting a potentially important ozone transport mechanism in mountainous terrain.
ELEMENTA-SCIENCE OF THE ANTHROPOCENE
(2021)
Article
Astronomy & Astrophysics
Patrick J. Reddy
Summary: The Denver Metro/Northern Front Range area is severely nonattainment for O-3. Previous research indicates north-south gradients in oil and gas (O&G) impacts on O-3, with greater contributions in the north. Recent analysis shows reductions in methane and ethane emissions in the area from 2013 to 2020, consistent with reductions in O&G volatile organic compound (VOC) emissions. The gradient in trends suggests significant O&G emissions reductions have benefited locations in the central and northern portions of the nonattainment area (NAA).
EARTH AND SPACE SCIENCE
(2023)
Article
Engineering, Civil
Isaac S. Bukoski, Sheila F. Murphy, Andrew L. Birch, Holly R. Barnard
Summary: By analyzing water samples from small foothill catchments and a larger catchment extending from foothills to subalpine regions, this study investigated the impact of land use and precipitation changes on hydrologic flowpaths. Findings showed that lithogenic constituents increased and dissolved organic carbon decreased with decreasing seasonal runoff, indicating a transition in flowpaths, and suggested that anthropogenic activities can influence local stream and groundwater chemistry. Additionally, the study highlighted the influence of anthropogenic land use on runoff generation during storm events.
JOURNAL OF HYDROLOGY
(2021)
Article
Geosciences, Multidisciplinary
Yi-Shin Jang, Sheng-Feng Shen, Jehn-Yih Juang, Cho-ying Huang, Min-Hui Lo
Summary: Research has shown that in montane cloud forests in central Taiwan, the diurnal temperature range increases with altitude, while it is larger in low-altitude and high-altitude areas. This highlights the importance of montane cloud forests for the mountain ecosystem.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Environmental Sciences
Yansen Xu, Kazuhiko Kobayashi, Zhaozhong Feng
Summary: Ground-level ozone concentration is increasing in Asia, which poses a major threat to global wheat supply as wheat is highly sensitive to ozone. Comparing China, India, Europe, and North America, China has the highest estimated yield loss followed by India, Europe, and North America. The reduction in single grain weight contributes to yield loss in China, Europe, and North America, while the reduction in the number of grains contributes more in India. The difference in cultivars used among regions may explain the differential yield response. It is important to quantify ozone-induced yield loss for each region, taking into account the effects of seasonal ozone concentration changes, cultivars, and climate.
SCIENCE OF THE TOTAL ENVIRONMENT
(2024)
Article
Forestry
Ariel B. Demarest, Paula J. Fornwalt, Brett H. Wolk, Kyle C. Rodman, Miranda D. Redmond
Summary: Mechanical restoration treatments in dry conifer forests of the Colorado Front Range have been found to significantly increase native understory plant cover and richness, while limiting invasion from non-native species. The cover and richness of native plants in treated areas were associated with 19th-century forest structural conditions and were better predicted by spring moisture availability rather than long-term water deficit. These findings highlight the importance of ongoing restoration activities in dry conifer forests.
FOREST ECOLOGY AND MANAGEMENT
(2023)
Article
Environmental Sciences
Guo Yu, Daniel B. Wright, Kathleen D. Holman
Summary: This study employs a process-based approach to simulate the probabilities of rare floods in mountainous watersheds, using different techniques to understand the hydrometeorological drivers of flood frequencies. The results highlight the significance of storm transposition and physics-based modeling in elucidating the relationships between flood drivers and frequencies.
WATER RESOURCES RESEARCH
(2021)
Article
Engineering, Environmental
Ilana B. Pollack, Megan E. McCabe, Dana R. Caulton, Emily Fischer
Summary: Quantifying the enhancement ratios of ammonia (NH3) to methane (CH4) from agricultural sources is crucial for understanding air pollution and nitrogen deposition. A study conducted in northeastern Colorado Front Range reveals that concentrated animal feeding operations (CAFOs) in the region emit significant amounts of NH3 and CH4, which is further complicated by the presence of oil and natural gas extraction activities. Utilizing measurements from a research aircraft, the study demonstrates that NH3 and ethane (C2H6) can be used together to distinguish between near-source enhancements of CH4 from agriculture and oil and gas activities.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2022)
Article
Environmental Sciences
I. Ortega, J. W. Hannigan, R. R. Buchholz, G. Pfister
Summary: This study analyzed multiple tropospheric gases in the Colorado Northern Front Range using high-resolution ground-based solar absorption FTIR instrument over ten years. The research showed seasonal variations and trends of gases related to oil and gas extraction, cattle feedlot activities, urban emissions, biomass burning, and volatile organic compounds. The study also included simulations of gases using CAM-chem within the CESM framework and compared them with observations, revealing agreement for most gases except NH3, which was underestimated.
ATMOSPHERIC ENVIRONMENT
(2021)