There are clothes that have been developed that can keep us warmer. That type of clothing has been around for many years.
We have been less successful at developing clothes that can keep us cool on hot days. The solution has generally been to wear less clothing.
The sun emits a broad spectrum of electromagnetic radiation, including ultraviolet (UV) and near-infrared (NIR). We get sunburned when too much UV radiation falls on our skin and is absorbed. Fabric that reflects UV light helps reduce sun burn and also helps to cool us down.
Fabric that reflects NIR energy doesn’t help keep us cool, as the atmosphere is good at absorbing this type of energy and thus the air around you would warm.
Our bodies also emit electromagnetic energy, some in the form of mid-infrared energy (MIR). The atmosphere is largely transparent to this type of energy, and the MIR we emit goes out to space. When we wear today’s clothes, MIR emitted by our body is absorbed by the cloth and this warms our bodies.
Scientists are developing textiles that transmit MIR. If this could be developed into cloth for summer clothing, MIR energy emitted by our bodies would be transmitted away, helping to keep our bodies cool.
Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) at 11:45 a.m. the last Monday of each month. Send them your questions at stevea@ssec.wisc.edu or jemarti1@wisc.edu.
