Pollution from cooking emissions hangs in air for days

Organic aerosols -- such as those released in cooking -- may stay in the atmosphere for several days, because of nanostructures formed by fatty acids as they are released into the air, finds a study.

These types of aerosols have long been associated with poor air quality in urban areas, but their impact on human-made climate change is hard to gauge. That's because of the diverse range of molecules found within aerosols, and their varying interactions with the environment.

"Cooking aerosols account for up to 10 per cent of particulate matter (PM) emissions. Finding accurate ways to predict their behaviour will give us much more precise ways to also assess their contribution to climate change," said lead author Dr Christian Pfrang, of the University of Birmingham.

Experts at the Universities of Birmingham and Bath probed the behaviour of thin films of oleic acid -- an unsaturated fatty acid commonly released when cooking.

In the study, published in Atmospheric Chemistry and Physics, they used a theoretical model combined with experimental data to predict the amount of time aerosols generated from cooking may hang around in the environment.

"We're increasingly finding out how molecules like these fatty acids from cooking can organise themselves into bilayers and other regular shapes and stacks within aerosol droplets that float in the air, and how this completely changes how fast they degrade, how long they persist in the atmosphere, and how they affect pollution and weather," said co-author Dr Adam Squires, of the University of Bath.

Previous research suggests that gas cooking produces about twice as much PM2.5 as electric. It also produces nitrogen oxides (NOx), including nitrogen oxide (NO) and nitrogen dioxide (NO2), carbon monoxide (CO), and formaldehyde (CH2O or HCHO). All of these pollutants are health risks if not properly managed.