Opinion: COVID risk is only one reason to improve air in classrooms Most classrooms have ventilation rates much lower than those required to reduce infectious disease transmission, even with open windows. Author of the article: Jill Baumgartner and Scott Weichenthal • Special to Montreal Gazette Publishing date: May 13, 2021 • May 13, 2021 • 3 minute read • The EMSB showed off their newly installed air purifiers at Pierre Elliott Trudeau elementary school in Montreal on Monday January 11, 2021. The HEPA filter hangs from the wall in the background while principal Tanya Alvarez takes over a class at the elementary school. More schools should have such air filters, Jill Baumgartner and Scott Weichenthal suggest. Photo by Dave Sidaway /Montreal Gazette