Came across this article about how line drying items outdoors vs. indoors generate a more pleasant long lasting smell.

Also note this week is 4th annual hang dry week.

Silvia’s research analyzed the scents of towels that were dried in the sun compared to towels dried in the shade or dried indoors away from the sun (note that the dryer wasn’t even tested or considered as an option). The team placed towels that were dried in these various methods in plastic bags and then analyzed their odors using gas chromatography coupled with mass spectrometry. The analysis showed that only when towels were dried outside in the sun were substances like carboxylic acids, aldehydes, and ketones detected. These substances are the same ones used in the perfume industry and have aromas like fruit, almonds, or citrus.

The chemistry is complex, but suffice to say that the presence of sunlight and water were necessary to “generate the odorous molecules.” These molecules then “bind with the cotton, which is a linear cellulose polymer, by hydrogen bonds,” and these hydrogen bonds are strong, meaning “the smell of fresh laundry is relatively long-lasting.”