Does Frying Cause Indoor Air Pollution?

Consuming too many fried foods has long been known to be detrimental to be your health – but the method in which you cook them could also be contributing to health problems, as well, according to a new study.

Researchers at Texas Tech and Utah State in the United States have demonstrated that when mixed with oil above a certain temperature, water droplets of a miniscule size can leap into the air and become ingested by humans, thus endangering their health.

Indoor pollution worse than outdoor

It might be tempting to think of air pollution as an issue confined to the great outdoors; when we consider rules and regulations put in place to limit poor air quality, what often springs to mind are the industrial directives aimed at power plants and the suchlike.

But while poor outdoor air quality is a serious concern which affects 92% of the Earth’s population (according to figures compiled by the World Health Organisation), indoor air quality could be a far greater concern. Indeed, it has been found that indoor air pollution is up to three times more noxious than on the streets, meaning we should concentrate just as much on the air in our homes as that outside them.

The pitfalls of frying

One major contributing factor to indoor air pollution could be frying foods in improperly ventilated kitchens, according to a new study from the US. The researchers were able to demonstrate through slow-motion video how water reacts with very hot oil to create “oil jet forests”, which spit particles of oil less than 300nm in size into the air – which is small enough to be inhaled and cause harm to the body.

The phenomenon did not occur with oil less than 150°C in temperature – but above that threshold, the droplets leap into the air and remain suspended there, where they could be potentially breathed in by people. Since many vegetables and meats contain large quantities of water, traditional fry-ups and stir-fries could be worse for human health than previously thought.

“We've discovered that a very large number of small oil droplets are released when even a single, small droplet of water comes into contact with hot oil,” explained Jeremy Marston, assistant professor at Texas Tech. “You can see the explosive release when the water, trapped under the oil, vaporizes all of a sudden. This causes the oil film to rupture and sends oil droplets flying.”

What can be done

In order to minimise the risk of ingesting such tiny oil particles, it’s essential that you only ever fry your foods in a properly ventilated kitchen. This means opening windows and turning on extractor fans before you begin and keeping them open / on throughout the process.

Additionally, there are plenty of other things you can do to reduce indoor air pollution, including removing shoes, smoking outside and getting an air purifier.