Quirks & Quarks

Fried foods are creating fat clouds in London

Fat particles - mostly from cooking up greasy foods - make their way into the atmosphere where they collect water molecules and help form clouds.
Cooking fat droplets from foods like fish and chips in the air over London may be contributing to cloud formation. (Phil Noble/Reuters)

The fat

It was known that fat molecules make their way into the atmosphere in a couple of ways. One is from cooking up greasy foods, and the other is a more natural process.

Fat from decomposing organic material, such as plankton, forms a layer on the surface of an ocean.

Ocean spray then propels the fat molecules into the atmosphere. It is estimated that 10 per cent of all molecules in the air above the city of London are fat. What scientists did not understand prior to this study was what happens to the fat molecules when they are in the atmosphere.

What they found

Dr. Adam Squires, an associate professor in the department of chemistry at the University of Bath in England, found that the fat molecules in the atmosphere arrange themselves in complex structures similar to the way that fatty acid soap molecules form in water.

In a lab experiment, they discovered that the fat molecule structures act like a sponge and absorb moisture from the air around them, as they would in the atmosphere. This process increases the lifetime of the molecules and slows down the chemical process within them.

Fat and clouds

The researchers believe that it is very likely that this process encourages the formation of clouds. It is known that clouds can have a cooling effect on the climate — but it's a stretch to suggest the cooking up fatty foods could in turn cool the planet. It is possible, however, that the subsequent formation of clouds could have a local impact on the weather at best.  


Dr. Joel Ducoste, a professor in the department of civil, construction, and environmental engineering at North Carolina State University explains that so-called 'fatbergs' are not unique to London. In fact cities all over the world have had to deal with them, though none were quite the size of the 130-tonne monstrosity in London.


Educating people about what they can and cannot flush, or put down the drain is key to solving the problem of blocked sewers. When fatbergs do occur, once solution may be to use the fat — or brown grease — to create biofuels.