Association between Elevated Airborne Radioactivity and Natural Gas Emissions Downwind of a Colorado Oil Refinery 

D. Helmig¹, J. Nobel², D. Caputi³, D. Brown⁴, R. Daly⁵, L. Darby⁶, P.T. Doe⁷, O. Gonzalez⁸, G. Greenberg⁹, J. Hueber¹⁰, K. Potter¹¹, G. Schade¹², S. Simoncic¹³, M. Stahli¹⁴ and W. Subra¹⁵

¹Boulder A.I.R. LLC, Boulder, CO 80305; 303-499-3174, E-mail: dh.bouldair@gmail.com
²Rolling Stone Magazine, New York, NY, 10017
³Planet Ozone Meteorological Consulting, Concord, CA 94521
⁴Environment and Human Health Inc., Westport, CT 06880
⁵Boulder AIR LLC, Boulder, CO 80305
⁶LDWX LLC, Boulder, CO 80301
⁷Be the Change – Colorado, Littleton, CO 80218
⁸Cultivando, Commerce City, CO 80614
⁹Private Citizen, Boulder, CO 80303
¹⁰JH Atmospheric Instrumentation Design, Boulder, CO 80301
¹¹Kateric Ltd, Longmont, CO 80501
¹²Texas A&M University, Department of Atmospheric Sciences, College Station, TX 77843
¹³Pitch Roll and Yaw LLC, Boulder, CO 80302
¹⁴Fort Collins, CO 80525
¹⁵Subra Company, New Iberia, LA 70562

Air pollution monitoring was conducted over a full year near the Suncor Refinery in Commerce City, CO. The study included continuous real-time monitoring of airborne radioactivity from both radon gas and radon progenies attached to particulates downwind of an oil refinery. Radon causes an estimated 21,100 annual lung cancer deaths in the United States. Despite radon emissions being well-established in industrial, government, and academic literature, as of 2024, they are not regulated. The monitoring site was located in an environmental justice community with a disproportionately higher percentage of Hispanic residents (≈ 65.8% of the city population). Gas and particle-associated airborne radioactivity contribute nearly evenly to the total alpha radioactivity. Total radioactivity levels of 30-40 Bq m -3 were 2-3 times higher when winds were light and southwesterly than the 10-15 Bq m -3 background, which suggests the refinery as the geographic origin. Further, elevated radioactivity measurements tracked most closely with the light hydrocarbon and natural gas tracer ethane. These findings suggest that emissions from oil and natural gas processing contribute to the atmospheric burden of radioactive radon and its progenies.

Figure 1. Conditional probability analysis of the 90th to 100th percentile occurrences of gas (left) and particulate (right) radioactivity for 8/30/2022 – 8/2/2023, with a satellite image (Google Earth) showing the Commerce City footprint (bottom). Both plots use a wind speed of  > 1 m s-1. The star shows the location of the monitoring shelter, the bounds of the sector with the high radioactivity occurrences is indicated by the yellow lines.  The location of the Suncor Refinery is within the red circle.