University of Birmingham Researchers Reveal Air Frying as Cleanest Cooking Option

The University of Birmingham has once again made headlines in environmental science with groundbreaking research demonstrating that air frying produces significantly fewer airborne pollutants than traditional cooking methods like shallow frying and deep-fat frying. This latest study, published on January 27, 2026, in the American Chemical Society's journal ES&T Air, expands on the university's prior work by testing a wider variety of foods, including high-fat options such as bacon and pork sausages. Led by Professor Christian Pfrang and PhD student Ruijie Tang from the School of Geography, Earth and Environmental Sciences, the findings underscore air frying's potential to improve indoor air quality in UK homes, where cooking is a major source of everyday pollution.

Indoor environments account for over 80% of the time people spend daily, making kitchen emissions a critical focus for public health. Volatile organic compounds (VOCs)—gases released from oils, fats, and browning reactions during cooking—and ultrafine particles (UFPs), tiny airborne solids smaller than 100 nanometers, can linger in the air long after meals are prepared. These pollutants have been linked to respiratory irritation, cardiovascular risks, and other health concerns, yet they receive less attention than outdoor smog.

Inside the Experimental Setup: Custom Chambers and Real-World Simulations

To isolate cooking emissions precisely, the Birmingham team constructed bespoke 0.15 cubic meter Perspex chambers equipped with state-of-the-art sensors. A standard 4.7-liter COSORI air fryer operated at 175 degrees Celsius, cooking 12 diverse dishes in triplicate for reliability. These included frozen pre-fried items like onion rings and smiley hash browns, oiled low-fat fresh chicken breast, and high-fat staples such as smoked bacon, unsmoked bacon, and pork sausages.

Pollutants were monitored using proton transfer reaction quadrupole interface time-of-flight mass spectrometry (PTR-QiTOF-MS) for VOCs, a scanning mobility particle sizer (SMPS) for UFPs (14.6–637.8 nm range), and chemiluminescence analyzers for nitrogen oxides (NOx). Emission rates were calculated via mass balance equations accounting for air exchange and deposition. Blank runs with empty trays assessed baseline emissions, while scaling models simulated a typical 15 cubic meter UK kitchen with one air change per hour. This rigorous, controlled approach allowed separation of cooking-specific contributions from background noise, providing the most detailed spectrum of air fryer pollutants to date.

For those pursuing careers in atmospheric chemistry or environmental monitoring, the University of Birmingham offers exciting opportunities—explore research jobs in higher education to contribute to such innovative lab work.

Key Emission Data: VOCs, UFPs, and NOx Quantified Across Food Types

Air frying emission rates varied by food: total VOCs ranged from 17.8 to 184 micrograms per minute, NOx from 24.6 to 37.9 micrograms per minute (only in nitrate-rich foods like bacon and hash browns), and UFPs from 0.1 to 17.4 × 10¹² particles per minute. High-fat foods drove peaks—pork sausages hit 17.4 × 10¹² UFPs/min and 346 × 10¹² particles per cubic meter in the chamber—due to lipid thermal decomposition and Maillard browning reactions producing alkenes, aldehydes, and ketones.

Crucially, kitchen-scaled peaks remained low: VOCs 0.011–0.17 mg/m³ (below 0.3 mg/m³ TVOC guideline), UFPs 0.2–34.8 × 10¹² #/m³. Ozone formation potential (OFP), driven by alkenes, reached up to 1.24 mg/m³ scaled—still safer than alternatives.

Air Frying Outperforms Traditional Methods in Head-to-Head Tests

• Vs. Deep-Fat Frying: 10–100 times higher VOCs; UFPs comparable only for high-fat air frying but vastly lower overall.
• Vs. Shallow/Pan Frying: November 2024 study showed air frying VOCs at 20 ppb vs. 260 ppb pan-frying chicken; PM 0.6 μg/m³ vs. 92.9 μg/m³.
• Vs. Boiling/Steaming: Similar low VOCs/UFPs for low-fat foods.

Deep-fat frying beef/vegetables emitted 2.3 mg/min VOCs—over tenfold air frying highs. These comparisons affirm air frying as the cleanest for fatty staples common in UK diets.Full study paper

Cleaning Matters: Residue Build-Up Increases Emissions Over Time

After 70+ uses without deep cleaning, empty air fryer runs showed 23% more VOCs and 236% more UFPs from inaccessible residues. While still below frying levels, this highlights maintenance's role. Professor Pfrang advocates redesigns for better cleanability: "Repeated use without cleaning inaccessible surfaces can negate benefits... a case for air fryer design that allows deep cleans."

Practical step-by-step: 1) Unplug and cool; 2) Wipe basket/heating element; 3) Soak removable parts in hot soapy water; 4) Use vinegar for grease; 5) Dry fully to prevent mold.

Health Risks of Cooking Pollutants and Why Indoor Air Matters in the UK

UFPs penetrate deep into lungs, entering bloodstream and linking to heart disease, stroke, and dementia. VOCs irritate eyes/throat, exacerbate asthma, and form secondary pollutants like ozone. UK stats: Cooking contributes up to 10% urban organic aerosols; gas hobs exceed WHO limits frequently. Birmingham's work reveals overlooked household risks, empowering better habits.

PhD student Ruijie Tang notes: "Foods with high fat produce more emissions in air fryers, but only a fraction versus shallow or deep-fat frying."University press release

Spotlight on the Research Team and Birmingham's Environmental Expertise

Professor Christian Pfrang, expert in atmospheric chemistry, leads efforts tracing pollutants from kitchen to climate. His team—Ruijie Tang, Yizhou Su, William Acton, Lara Dunn—combines lab precision with real-world scaling. The School of Geography, Earth and Environmental Sciences fosters such interdisciplinary research, training future leaders. Aspiring lecturers in atmospheric science? View lecturer jobs across UK universities.

Building on Legacy: Birmingham's Track Record in Cooking Emission Studies

This 2026 paper follows the 2024 Indoor Air study on chicken and earlier work showing cooking oils persist days in air. UoB's contributions position it as a hub for indoor pollution research, influencing policy and consumer choices.

Broader Implications for UK Households, Policy, and Appliance Design

With air fryers surging in popularity amid energy crises, this validates healthier, greener cooking. Policymakers could incentivize low-emission appliances; manufacturers, cleaner designs. For families, pair air frying with ventilation—open windows or run extractors 30+ minutes post-cook.

Explore academic career advice if inspired to join env science research driving such changes.

Photo by Trnava University on Unsplash

Future Outlook: Ventilation, Tech Innovations, and Ongoing Research

Birmingham plans expanded tests on ovens, microwaves, and long-term health cohorts. Smart vents and HEPA kitchen filters loom as solutions. Professor Pfrang emphasizes: "Air quality in homes is increasingly vital—our work helps households understand kitchen impacts." Stay tuned for more from this pivotal UK research powerhouse.

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