2021 Yes https://doi.org/10.1007/s00405-021-06960-w Patjas, M. Europe Observational Teachers Middle/Jr High (6-8) High School (9-12) Noise Respiratory symptoms Stress/Anxiety Voice Teacher Voice symptoms Distance learning COVID-19 Background noise Air quality Work ability Surveyed 121 Finnish teachers on voice symptoms before and during COVID-19 distance teaching. Symptoms were reduced overall, but worsened for teachers with poor room acoustics, dryness, and noise, suggesting environmental risk factors in home teaching setups.