The difference in smell between laundry that was dried in the sun, in the shade, or in a dryer is primarily due to various factors related to the drying process and environmental conditions. These factors can affect the molecules and microorganisms present in the fabric, leading to distinct odors. Here are some of the reasons for the differences in smell:
Sunlight and UV radiation: Sunlight contains ultraviolet (UV) radiation, which has a sterilizing effect on fabrics. When laundry is dried in the sun, the UV rays can help break down and neutralize odorous compounds and bacteria that might be present in the fabric. This can result in a fresher and cleaner scent compared to shade drying or using a dryer.
Wind exposure: When laundry is hung outside in the sun, it is exposed to natural airflow and wind. This can help remove trapped odors and improve the overall freshness of the laundry compared to when it's dried in still air or a closed space like a dryer.
Evaporation: Sun-drying allows moisture in the fabric to evaporate more efficiently. Faster evaporation means less time for bacteria and mold to grow, reducing the likelihood of musty or mildew smells that might occur when laundry is dried slowly in the shade or a closed environment like a dryer.
Residual detergent: If laundry is dried in the sun, any residual detergent or fabric softener might be further broken down or dispersed by the sunlight and UV radiation. This can contribute to a cleaner and more refreshing smell.
Environmental odors: The surroundings in which laundry is dried can also influence its smell. For example, if laundry is dried in an area with lots of blooming flowers or natural scents, it might pick up some of those pleasant smells.
Dryer and shade drying: When laundry is dried in a shaded area or a dryer, the absence of direct sunlight and slower evaporation may provide a more conducive environment for bacterial growth and the retention of odors, especially if the laundry is not completely dry when removed.
Overall, the combination of sunlight's sterilizing effects, wind exposure, faster evaporation, and the breakdown of residual odors can result in a distinctive, fresher scent when laundry is dried in the sun compared to other drying methods.