Ventilation is the intentional introduction of fresh air into a space while the stale air is removed. It is done to maintain the quality of air in that space.
WHO has contributed to guidance on ventilation and air-conditioning systems in the context of COVID-19, available here.
WHO works closely with the World Meteorological Organization Joint Office for Climate and Health and the United States National Oceanic and Atmospheric Administration (NOAA) through the Global Heat Health Information Network to develop and update this guidance.
Ventilation is an important factor in preventing the virus that causes COVID-19 from spreading indoors. Below are steps to consider which can improve indoor ventilation. These steps should be considered in consultation with a heating, ventilation and air conditioning (HVAC) professional.
In all workplaces, schools and tourist accommodations, there should be fresh, clean air. WHO recommends an increased ventilation rate through natural or mechanical means, preferably without recirculation of the air. In case of air recirculation, filters should be cleaned regularly, especially for jobs that place an individual at a medium or high risk of exposure to COVID-19. Examples of such jobs may include frontline workers in retail, tourist accommodation and domestic workers.
This Q&A is intended for people who manage public spaces and buildings. For general advice on ventilation and air conditioning, go to Coronavirus disease (COVID-19): Ventilation and air conditioning.