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BIRMINGHAM, England — In kitchens worldwide, cooking oils sizzle and splash, releasing invisible particles into the air. While many of us rely on extractor fans to whisk away these cooking fumes, new research suggests these airborne particles don’t just disappear into thin air. Instead, scientists say they reorganize themselves into complex architectural structures that could influence both air quality and climate.
The new study published in Atmospheric Chemistry and Physics reveals how these airborne cooking fats reorganize themselves at the molecular level, potentially protecting harmful urban emissions and affecting cloud formation.
Scientists from multiple British universities, led by researchers at the University of Birmingham, investigated how fatty acids — particularly oleic acid, a common component in cooking oils and sea spray — behave when released into the atmosphere. Their findings suggest that these compounds don’t simply float around as individual molecules but instead form complex structures that can trap water and resist chemical breakdown.
Picture building blocks that can arrange themselves in different patterns. These fatty acid molecules can stack like plates, form cylindrical tubes, or cluster into spherical shapes depending on environmental conditions. The research team discovered that adding sugar (specifically fructose) to these fatty substances caused them to adopt different architectural arrangements at the molecular scale.
Working at Diamond Light Source’s I22 beamline, alongside experts from the Central Laser Facility at the Rutherford Appleton Laboratory, researchers observed these molecular arrangements in real time. Using sophisticated X-ray techniques, they tracked how the structures changed under varying humidity levels and exposure to ozone, a common atmospheric oxidant.
This approach revealed something surprising: these particles could absorb substantially more water than simple models had previously suggested. Scientists say that as these droplets take on more water, they become heavier, eventually falling as rain and being removed from the atmosphere. However, the study revealed a complex dynamic where particles can reform into different three-dimensional structures even as they break down, each with varying abilities to absorb water and react with other chemicals.
Perhaps most intriguingly, certain molecular arrangements made the fatty acids more resistant to chemical breakdown by ozone, which typically destroys these compounds in the atmosphere. This finding helps explain a long-standing mystery: why cooking-related fatty acids persist longer in real urban environments than laboratory studies would predict.
The implications extend beyond just understanding atmospheric chemistry. For city planners and public health officials, this research highlights the importance of proper ventilation in urban environments. “To reduce exposure to pollutants from cooking, people should consider making more use of extractor fans and ensuring that kitchens are well ventilated to allow aerosol particles to escape rapidly,” says lead researcher Christian Pfrang in a statement.
The research also emphasizes the dynamic nature of these atmospheric particles.
“Our results show that aerosols exist in a really dynamic state, with complex structures being formed as well as being destroyed. Each of these states allows polluting molecules to linger in the atmosphere for longer,” explains Pfrang.
From sizzling pan to atmospheric particle, the journey of cooking fats shows how sometimes the most mundane substances harbor the most sophisticated secrets. Each pan sends forth not just the aroma of dinner, but participants in an atmospheric journey that could influence our environment in ways both subtle and profound.
Paper Summary
Methodology
The researchers created thin films of fatty acid mixtures containing oleic acid, sodium oleate, and varying amounts of fructose. These films were studied using small-angle X-ray scattering (SAXS) and Raman microscopy, allowing simultaneous observation of molecular structure and chemical composition. Samples were exposed to controlled humidity levels and ozone concentrations while measurements tracked structural changes and chemical reactions in real-time.
Results
Different fructose concentrations led to distinct molecular arrangements, ranging from simple spherical clusters to more complex geometric patterns. These structures showed varying abilities to absorb water and resist ozone degradation. The most disordered arrangements proved most reactive with ozone, while more ordered structures showed greater resistance to chemical breakdown.
Limitations
The study focused on simplified mixtures rather than the complex combinations found in real atmospheric particles. Additionally, experiments were conducted on relatively thick films compared to typical atmospheric particle sizes. While the researchers argue that the fundamental molecular arrangements should remain similar at smaller scales, this represents an important caveat to their findings.
Discussion and Takeaways
This research helps explain why fatty acids from cooking last longer in urban environments than laboratory studies would suggest. The ability of these compounds to self-organize into protective structures could enable long-range transport of urban pollutants. While their water-absorbing properties might influence cloud formation, the researchers emphasize that other atmospheric components likely play more significant roles in this process.
Funding and Disclosures
The research was supported by the Natural Environment Research Council (NERC) and conducted using facilities at the Diamond Light Source, a UK national science facility. The authors declared no competing interests.
