Quarterly Update March 2025
HEI Energy's March 2025 Quarterly Research Updates are now available. You will find the latest progress from each of our 8 exposure studies in communities affected by oil and gas development.
Project Updates
Water Quality Research
Using Geoscientific Analysis and Community Engagement to Analyze Exposures to Potential Groundwater Contamination
The overall goal of this study is to evaluate potential linkages between unconventional oil and gas development (UOGD) and groundwater contamination in a tri-county region of Pennsylvania with many overlapping potential sources of contamination. The analysis will be informed by focus groups in the region to help identify areas of community concern. The team plans to produce a broadly applicable framework to study the relationship between specific UOGD processes and potential groundwater contamination. The investigators will apply the following methods to achieve their goals:
- Combine an existing data set of chemical measurements in groundwater with machine learning to isolate the influences of natural and anthropogenic processes on groundwater chemistry and to identify chemical signatures of UOGD.
- Evaluate linkages between UOGD and potential water contamination.
- Develop an approach to map locations of potential contamination from UOGD activities for application to future investigations of potential human exposures and health effects associated with UOGD.

What's Happened
- Returned all results to study participants in accordance with HEI’s community engagement plan.
- Presented preliminary findings at the League of Women Voters Shale and Public Health Conference, February 27, Pittsburgh, PA.
What's New
- Finalizing survey analysis and literature review.
- Continuing to analyze samples for radium
What's Next
- Present findings in a poster at the May 2025 HEI Annual Conference in Austin, TX.
Upcoming Events
- Allison Fenske, PhD Candidate, Civil and Environmental Engineering @ Penn State, will present a poster at the Penn State Graduate Student Exhibition, March 28, University Park, PA.
- Susan L. Brantley, Co-Investigator, will present an invited talk, How fracking affects our water, at the Pennsylvania Groundwater Symposium in Harrisburg on May 7, 2025.
A Groundwater Modeling Framework for Elucidating Community Exposures Across the Marcellus Region to Contamination Associated with Oil and Gas Development
The research team will build and test a model for understanding residential well water vulnerability to contamination from unconventional oil and gas development (UOGD) across the Marcellus region. This analysis will increase the understanding of risk to groundwater quality using publicly available data describing UOGD spills. The investigators will achieve their goal by:
- Modeling residential drinking water well vulnerability to contamination from UOGD sources over time across the Marcellus region. The model will describe how contaminants move in the subsurface.
- Using the model to understand the likelihood that specific UOGD spills will contaminate the water in residential wells.
- Refining the model and assessing its performance with statistical analyses using the characteristics of documented cases of UOGD spills and known contamination at well locations.

What's Happened
- Calibrated a hydrologic model that simulates groundwater flow patterns across a 300,000 km2 domain covering the Marcellus Shale region in Ohio, Pennsylvania, and West Virginia.
- Coupled the calibrated groundwater flow model to a particle-tracking algorithm to simulate trajectories of contaminant migration away from unconventional oil and gas (UOG) well pads within the region.
- Processed the results of the coupled groundwater flow and particle-tracking simulations to estimate the spatial distribution in hydrologic vulnerability of domestic-water wells to spills at UOG well pads.
- Completed the first iteration of a risk-triage model that estimates domestic-well contamination risk as a function of hydrologic vulnerability and hazard, whereby hazards correspond to documented spills at UOG well pads.
- Developed a logistic regression model to estimate associations between UOG, hydrologic vulnerability, and chemical fingerprints of UOGD spills in domestic well waters.
What's New
Creating year-over-year hazard maps from the particle tracking results and spills data.
Conducting additional logistic regression analyses (i) for different definitions of UOG chemical fingerprints in well-water samples; (ii) with improved definitions of spill hazards; and (iii) to account for repeated well-water measurements.
What's Next
- Present findings in a poster at the May 2025 HEI Annual Conference in Austin, TX.
Air Quality and Noise Research
Measuring and Modeling Air Pollution and Noise Exposure Near Unconventional Oil and Gas Development in Colorado
The goal of this study is to develop community exposure profiles in the Colorado North Front Range for chemicals in the air as well as noise over the UOGD lifecycle, from site preparation through production of multi-well pads. This study will assess potential exposure pathways connecting UOGD chemical emissions to nearby communities and use the results to better understand the public health implications. The investigators will apply the following methods to achieve these goals:
- Use a combination of existing air quality data, innovative air quality measurements, and source apportionment models to quantify potential exposures.
- Collect noise measurements from UOGD operations to quantify potential exposures.
- In collaboration with the Hildebrandt Ruiz team, develop the "TRAcking Community Exposures and Releases" (TRACER) model for use in the Denver-Julesburg region to predict chemical emissions from specific UOGD processes. The teams will combine the predicted emissions with an air quality model to estimate concentrations of chemicals in the air.
- Evaluate model performance by comparing air quality monitoring data collected by this and the Franklin team with model predictions in the Denver-Julesburg region.

What's Happened
- Submitted final report to HEI Energy.
- Shared monitoring and modeling results in a 2-part HEI Energy webinar series.
- Introduced and demonstrated the TRACER preproduction model for Oil and Gas Staff of Broomfield, CO.
- Presented findings at the January 2025 American Meteorological Society Annual Conference in New Orlean, LA.
What's New
- Organizing a public event in the study location to share study results with communities in the Denver-Julesburg region.
What's Next
- Host a public event in the study location on April 7, 2025 in Longmont, Colorado.
- Present findings in three posters and during a TRACER dedicated session at the May 2025 HEI Annual Conference in Austin, TX.
Upcoming Events
- Two presentations are scheduled for the April 2025 Air & Waste Management Association Air Quality Measurement Methods and Technology Conference:
- Collett, J.L. Jr. et al (2025) Air Toxics Concentrations and Acute Exposure Potential near Oil and Gas Well Pads During Well Drilling, Completions, and Production, to be presented at the Air & Waste Management Association Air Quality Measurement Methods and Technology Conference, Aurora, CO, April 23-25, 2025.
- Ku, I.-T. et al. (2025) Synthetic Drilling Mud Emissions: Characterization and Implications for Regional Air Quality, to be presented at the Air & Waste Management Association Air Quality Measurement Methods and Technology Conference, Aurora, CO, April 23-25, 2025.
Assessing Source Contributions to Air Quality and Noise in Unconventional Oil Shale Plays
The goal of this study is to understand potential community exposure to UOGD-associated chemicals and radioactivity in air as well as noise. The investigators will apply the following methods to achieve their goals:
- Monitor air quality and noise in the Permian region of New Mexico and the Eagle Ford region of Texas to understand how potential exposures vary across the regions and over different time scales.
- Combine existing air monitoring data in the Denver-Julesburg region of Colorado and original data collected in the Permian and Eagle Ford regions with statistical models to distinguish UOGD from other sources of chemicals in the air and noise sources.
- Leverage satellite data to examine the association between natural gas flaring and air quality.
Collaborate with the Collett and Hildebrandt Ruiz teams to evaluate the "TRAcking Community Exposures and Releases" (TRACER) model performance in the Denver-Julesburg and Eagle Ford regions.
Online database with preliminary air concentration data collected by Dr. Franklin’s team. The data have not yet undergone HEI Energy’s rigorous peer review.

What's Happened
- Submitted final report to HEI Energy.
- Shared monitoring results in part one of a 2-part HEI Energy webinar series
What's New
- Developing a summary report of Carlsbad Community Open house, where the team shared back findings of the study with people in the Carlsbad area.
What's Next
- Participate in a virtual public event with the Hildebrandt Ruiz team in March 2025.
- Present findings in two posters and during a TRACER dedicated session at the May 2025 HEI Annual Conference in Austin, TX.
What's Happened
- Submitted final report to HEI Energy.
- Shared monitoring and modeling results in a 2-part HEI Energy webinar series.
- Submitted two manuscripts to peer reviewed publications, one of which is in review, and another which was published: https://doi.org/10.1021/acsestair.4c00077
What's New
- Organizing a virtual public event to share study results in collaboration with the Franklin team in March.
What's Next
- Host a virtual public event in March 2025
- Present findings in 5 posters and during a TRACER dedicated session at the May 2025 HEI Annual Conference in Austin, TX.
Air Quality Trends
Long-term criteria and toxic pollutants trends and community exposures over the Marcellus Shale in the U.S.
This study aims to assess trends in air quality and community exposures in the Marcellus Shale region and whether any might be explained by changes in oil and gas development-related operations or governance. The analysis will focus on local and regional exposures to criteria and hazardous air pollutants from 2002-2021, with special attention toward historically disadvantaged communities. The investigators are achieving their research aims with the following steps:
- Perform a long-term emissions trend analysis by integrating bottom-up oil and gas emissions and ambient measurements of criteria and select hazardous air pollutant concentrations.
- Conduct a long-term air quality trend analysis by applying a chemical transport model to simulate the criteria and select hazardous air pollutant concentrations over the region.
- Use a more advanced chemical transport model that employs machine-learning to investigate sources of and control strategies for oil and gas emissions.
- Apply a county-level community health vulnerability index approach to identify disproportionately exposed communities.

What's Happened
- Calculated 4-km gridded VOC and BTEX pollutant emissions for abandoned wells from 2002 through 2022 for Ohio, Pennsylvania, and West Virginia.
- Set up the CAMx simulation system to study long-term trends in select criteria and toxic pollutants over the Marcellus Shale.
- Evaluated the CAMx model performance for various air pollutants for 2008, 2014, and 2019.
- Trained a deep-learning chemical transport model (Deep CTM) to mimic CAMx modeling of HAPs.
- Developed a community health vulnerability index (CHVI) based on exposure, sensitivity and adaptive capacity and explored the relationship between air quality and demographic and socioeconomic data.
- Completed generating all 20 years CAMx-ready meteorology and emissions inputs from 2002 to 2021.
- Mapped spatial patterns of PM2.5 and ozone data to recognize any significant changes in spatial patterns across the research area for 2008, 2014, and 2019.
- Created time series and density plots of PM2.5 and ozone to analyze any significant changes in temporal patterns.
What's New
- Training the DeepCTM model for ozone based on 2008, 2014 and 2019 CAMx annual simulations inputs.
- Finalizing the spatial and temporal linkages between the 20+ years of emissions, ambient monitoring, meteorological, production, exploration, and regulatory datasets for Marcellus area wells in Ohio, Pennsylvania, and West Virginia.
- Evaluating impacts of federal regulations and general permit updates on emissions.
- Generating the long-term concentrations of Benzene, Toluene, Ethylbenzene, Xylenes, and Naphthalene the trained DeepCTM.
What's Next
- Present findings in four posters at the May 2025 HEI Annual Conference in Austin, TX.
Trends in Marcellus-Utica Shale Regional Air Quality due to Unconventional Oil and Gas Development (TriMAQs)
This study aims to understand how oil and gas development might contribute to any local or regional trends in air quality and associated population exposure across the Marcellus-Utica Shale region from 2004-2023. The team is assessing whether changes in operations or governance may have contributed to any observed trends. The investigators are achieving their research aims with the following steps:
- Organize daily air quality monitoring data for criteria air pollutants and volatile organic compounds into a single dataset for the study region from 2004-2023.
- Develop a dataset of daily oil and gas operational activity (including drilling, fracturing, transport, and gas compression) and an inventory of expected emissions across the study region for the same period as the air quality dataset (2004-2023).
- Estimate population exposure to the criteria air pollutants and volatile organic compounds, including exposures experienced by economically disadvantaged areas using the US Census American Community Survey data.
- Estimate the fraction of emissions in the region that come from oil and gas development and how changes in industry practice and governance might have led to changes in air quality.

What's Happened
- Refined dispersion models over the 2004-2023 time period and validated input data on air emissions from UOGD
What's New
- Completing dispersion and machine learning modeling efforts to characterize exposure across the study region and period.
- Developing visualizations to communicate the findings of these models.
What's Next
- Present findings in two posters at the May 2025 HEI Annual Conference in Austin, TX.
Upcoming Events
- Presenting "Air Pollutant Exposure from Unconventional Oil and Gas Activities in the Marcellus and Utica Shale Region: Insights from Dispersion Modeling and Satellite Data" at the 2025 AEESP Research and Education Conference, May 20-22, 2025.
Air Quality Trends in Texas and Colorado Associated with Unconventional Oil and Gas Development
The overall goal of this study is to determine trends in the atmospheric concentrations of methane and non-methane hydrocarbons at eleven locations in the Haynesville, Eagle Ford, Barnett, and Permian regions of Texas and six locations in the Denver-Julesburg region of Colorado. The research team is using air quality monitoring data that date back as far as 1997 at one of the Texas locations, including:
- Texas Commission on Environmental Quality ambient air quality data collected in proximity and downwind of oil and gas production.
- Air quality data from the Colorado Department of Public Health & Environmental, the National Oceanic and Atmospheric
- Administration, and from a Northern Colorado Front Range Regional Government Coalition.
- Satellite-based measurements of formaldehyde above the Permian basin as a proxy for non-methane hydrocarbon emissions in the last 10 years.
The research team is separating long-term trends from seasonal and other short-term variations and is seeking to understand whether any observed trends are the result of changes in oil and gas operations or significant disruptions such as the COVID-19 pandemic shutdowns in 2020.

What's Happened
- Completed data downloads for all air monitoring sites in Texas and Colorado and multi-site comparisons were initiated.
- Began conducting trend analyses of the air monitoring data on ethane which is being studied as an indicator of oil and gas development, for both Texas and Colorado.
- Used NOAA HYSPLIT trajectories to select and validate wind sector classifications to understand the effect of wind on emissions from oil and gas operations vs. non-oil and gas related emissions and compared trajectories with wind direction measurement methods at oil and gas sites.
What's New
- Completing trend analysis of air monitoring data in Texas and Colorado with a focus on ethane, propane, benzene, and nitrous oxides (NOx).
- Completing quality control for NOx data to account for negative data
- Comparing trend analyses for all sites.
What's Next
- Complete satellite data analyses.
- Complete statistical and trend analyses.
- Compare air quality trends with regional oil and gas production data.
- Share methods, results, and study conclusions in a final report with the HEI Energy Research Committee.
- Present findings in a poster at the May 2025 HEI Annual Conference in Austin, TX.
Figure 1: Comparative abundance of ethane across all Colorado sites except BAO. State data (PLV) have a longer record, and are taken closer to oil&gas production areas inside the DJB.