Why do clothes that naturally dry in the sun smell fresh?

Naturally dried clothes have a special aroma, there are even poems about it, or manufacturers are trying to create similar scents to be added to candles and room aromatic items.

Researchers have studied thoroughly the natural drying towels to each molecule that makes them to see where they have such a special aroma.

Hang laundry by Lake Atter in Austria.

This is the research project of graduate student Silvia Pugliese at the University of Copenhagen, Denmark. Ms. Pugliese said that when she was young, she saw her mother drying clothes in the sun and she grew up doing so whenever she could, 'because the fresh fragrance of clothes reminds me of home' - she to speak. And she has studied this fragrance to make her master's thesis.

Ms. Pugliese and two colleagues tried drying the laboratory towels in the office, on the balcony under a plastic roof and on the balcony with direct sunlight from the sun. After the towels were dry, they put the towels in sealed bags for 15 hours. During this time, they sampled chemical compounds that emitted air from these bags. They sampled that way with empty bags and non-washable towels and also the air around the towel drying area.

The only drying process in the sun that produces some aldehydes (aldehydes) and ketones (ketones) that other processes don't have, are the organic molecules that their noses are on. You can smell it from plants and perfumes. For example, after exposure to the sun, towels give off pentanal , which is found in cardamom seeds, octanal , an aromatic compound of citrus, and nonanal , which smells like rose.

Practice the towel drying experiment on the balcony of the University of Copenhagen.

Why is that? It may be due to exposure to ozone , a chemical in the atmosphere that converts certain common chemicals into these aldehydes and ketones.

Another possible cause is the sun itself . When exposed to ultraviolet light, some molecules become 'activated' and form active compounds called free radicals. These free radicals then recombine with nearby molecules, which often produces aldehydes and ketones.

Another reason is that the water in a wet towel contains many of these easily activated molecules and then the water acts as a 'magnifying glass' , converging the sun and speeding up the reactions. this.

Similar processes occur on any natural outdoor surface, including bare land and individual grass leaves, possibly in part because the sun after heavy rain makes everything smell fresh. (Although the smell on clothes seems to last longer, it's likely that the aldehyde clings to the fabric.)

Chemist Ricardo López of the Aroma Analysis and Wine Processing Laboratory of the University of Zaragoza, Spain, thinks that the cool aroma is not just due to aldehydes and ketones. He said that when testing the main scent compounds, sometimes some of the lower concentrations are just as important as the ones at high concentrations. More testing is needed to fully understand this problem.