Nearly 600 papers were reviewed regarding the effects of humidity on comfort, health, and indoor environmental quality (IEQ), of which 70 focused on low humidity (RH40%) and were thoroughly analyzed. Low humidity had little effect on thermal comfort, but increased skin dryness, eye irritation, and static electricity. Low humidity increased the survival of some pathogens, e.g. influenza. Low humidity showed non-uniform effects on volatile organic compound emissions and indoor air quality. Temperature, ventilation rates and time were noted as confounding variables. Most studies with adults utilized exposure times of maximum three hours; few studies used children, adolescents or elderly subjects.