Air Dispersion Modeling, Exposure Pathway Characterization, and Health Risk Assessment for Unconventional Natural Gas Operations
RoseyFields conducted a comprehensive environmental evaluation and health risk assessment for a multi-well unconventional natural gas development project. Our team evaluated the environmental impacts associated with various phases of extraction and production, including drilling, hydraulic fracturing, flowback operations, and long-term gas processing. We analyzed a complex mixture of chemicals of concern emitted during these processes, focusing heavily on volatile organic compounds (VOCs) such as benzene, toluene, ethylbenzene, and xylenes (BTEX), as well as formaldehyde, hydrogen sulfide, and particulate matter. The assessment comprehensively addressed potential atmospheric releases from a variety of on-site infrastructure, including compressor engines, residual waste storage tanks, and open-air impoundment lagoons used to temporarily hold produced water and fracing fluids.
To accurately quantify the release and transport of these contaminants, our team performed rigorous environmental modeling and fate and transport analysis. Our experts developed site-specific emission factors utilizing established regulatory methodologies, applying mass transfer equations to estimate the volatilization of toxic organic compounds from liquid waste storage systems and working losses from production tanks. Subsequently, RoseyFields utilized advanced regulatory air dispersion modeling systems, incorporating hourly meteorological data, complex terrain algorithms, and building downwash parameters, to simulate the atmospheric transport of these emissions. This multi-tiered modeling approach allowed us to accurately map both peak short-term and chronic long-term ambient air concentrations of hazardous air pollutants across the surrounding area.
Leveraging the outputs from our air dispersion models, RoseyFields characterized the primary inhalation exposure pathways and systematically identified the potential exposure class within the vicinity of the industrial operations. By evaluating the spatial footprints of modeled pollutant plumes against local topography and prevailing wind patterns, our team delineated specific geographic zones where the surrounding population was most likely to be impacted by episodic emission spikes and continuous baseline exposures. We then compared these modeled ambient air concentrations against established toxicological benchmarks, minimal risk levels, and excess lifetime cancer risk thresholds to provide a robust, scientifically sound health risk assessment for the affected area.
This investigation was conducted under the direction of Dr. Paul Rosenfeld, an environmental scientist and environmental forensic expert with extensive experience in environmental exposure assessment, toxicology, air quality, environmental fate and transport, risk assessment, and environmental forensics. Through RoseyFields LLC, Dr. Rosenfeld provides scientific consulting, environmental forensic analysis, regulatory support, and expert witness services involving environmental contamination, human exposure, and public health. His technical oversight helped ensure that the methodologies, scientific interpretations, and conclusions presented in this case study are consistent with accepted scientific principles and current best practices.