2016 No https://doi.org/10.1007/s00420-016-1111-0 Angelon‑Gaetz, Kim A. North America Observational Epidemiology Study Teachers Elementary (K-5) Middle/Jr High (6-8) High School (9-12) Humidity Respiratory symptoms Teachers Asthma Allergies Longitudinal study Workplace Classroom humidity Longitudinal study in North Carolina schools linked classroom humidity levels with respiratory symptoms in teachers. Data suggest prolonged high or low humidity may modestly increase asthma-like or allergy symptoms.