MONTREAL The Centrale des unions du Québec (CSQ) and its school federations have written to Minister of Education Jean-Francois Roberge and his colleague, Minister of Health Christian Dube to urge them to adopt the precautionary principle in relation to the transmission of COVID-19 by aerosol in schools. In a letter dated Friday and also addressed to the Quebec director of public health Horacio Arruda, the unions said they have been calling for improved ventilation in schools for years. We have been calling for decades for action to be taken to ensure better air quality in our schools and centres, but due to austerity policies, we are now under an obligation to open the classroom windows in the middle of winter, which is completely inconceivable, the unions said in their letter.