https://www.sciencedaily.com/releases/2020/04/200410162450.htm

Among the simplest suggestions for healthier buildings: opening windows to improve air circulation and opening blinds to admit natural daylight.

While more research needs to be done on the effect of sunlight on SARS-CoV-2 indoors, "Daylight exists as a free, widely available resource to building occupants with little downside to its use and many documented positive human health benefits," the authors write.