At a Glance
- Researchers unexpectedly made the first real-time atmospheric measurements of toxic medium-chain chlorinated paraffins while conducting unrelated air quality research in rural Oklahoma.
- These potentially harmful industrial chemicals are thought to be increasingly used as unregulated replacements for a similar class of toxic compounds banned by international regulations.
- The scientific team suspects the toxic pollutants became airborne after being released from biosolid fertilizers, a wastewater treatment product applied to nearby agricultural fields.
- Using a specialized mass spectrometer, the team found that the pollutants’ levels change daily, which affects how they are transported long distances through the atmosphere.
- This breakthrough provides a critical new technique for monitoring these persistent pollutants, paving the way for future research into their environmental behavior and potential health impacts.
In an unexpected discovery, scientists have performed the first real-time atmospheric measurements of a toxic class of industrial pollutants in the Western Hemisphere. While studying air quality in an agricultural region of Oklahoma, a research team from the University of Colorado Boulder stumbled upon medium-chain chlorinated paraffins (MCCPs). These synthetic chemicals, used in products ranging from metalworking fluids to PVC plastics, are known to be persistent in the environment and are currently under consideration for global regulation. The findings, published in ACS Environmental Au, open a new door to understanding how these potentially harmful compounds travel through our atmosphere.
The presence of MCCPs in the environment is a growing concern, partly due to what scientists call the “unintended consequences of regulation.” A similar class of chemicals, short-chain chlorinated paraffins (SCCPs), has been regulated for over a decade by the U.S. Environmental Protection Agency (EPA) and the international Stockholm Convention due to their toxicity. Researchers theorize that as industries phased out SCCPs, they increased their use of MCCPs as replacements. Using a highly sensitive instrument called a nitrate ion chemical ionization mass spectrometer, the CU Boulder team could detect MCCPs in the air around the clock for a month, estimating their concentration to be in the range of single-digit nanograms per cubic meter.
Researchers suspect the MCCPs they detected originated from biosolid fertilizer spread on nearby fields. Biosolids, also known as sewage sludge, are a byproduct of wastewater treatment and can contain chemicals flushed down the drain. When applied to land, these compounds can be released into the air. The team also observed that MCCP levels fluctuated daily, which they attributed to gas-particle partitioning. This means the chemicals can switch between a gaseous state and clinging to tiny airborne particles, a behavior that significantly impacts how they are transported through the atmosphere and how long they can last before breaking down.
This accidental finding provides a crucial method for monitoring MCCPs, which, like the infamous “forever chemicals” known as PFAS, are slow to degrade. Now that a technique for real-time detection exists, future research can explore how MCCP levels change with the seasons and further investigate their environmental and health impacts. While many unknowns remain, this work underscores the importance of ongoing scientific research and regulatory evaluation to identify and manage potentially hazardous chemicals in the environment to protect public health and safety.
References
- Katz, D. J., Dobson, B., Alton, M., Stark, H., Worsnop, D. R., Canagaratna, M. R., & Browne, E. C. (2025). Real-time measurements of gas-phase medium-chain chlorinated paraffins reveal daily changes in gas-particle partitioning controlled by ambient temperature. ACS Environmental Au, acsenvironau.5c00038. https://doi.org/10.1021/acsenvironau.5c00038
- University of Colorado at Boulder. (2025, June 6). First-ever airborne toxic chemical detected in Western Hemisphere. Phys.Org; University of Colorado at Boulder. https://phys.org/news/2025-06-airborne-toxin-western-hemisphere.html
