This guide is intended as a tool to reduce the potential spread of the SARS-CoV-2 virus through aerosol transmission. Strategies and possible solutions for ventilation in classrooms are provided, alongside tools to evaluate the implemented ventilation strategies. • This guide has two parts. Part I focuses on how to maintain healthy indoor air in classrooms to reduce the risk of transmission of SARS-CoV-2 via aerosols, including ventilation and air cleaning, and how to check if the ventilation is sufficient to reduce risk using CO2 as a tracer. Part II focuses on simulations of risk of infection under different scenarios (tackled in Part I) in a classroom. • This guide is based on the Harvard University Guide (https://schools.forhealth.org) and other experimental studies on ventilation and filtration, as well as on modelling work by SCOEH (https://scoeh.ch). • The guide can be applied to other types of indoor spaces, such as offices or other public buildings, though some adjustments may be needed for physical characteristics (e.g. area and volume). • The use of masks, maintaining physical distance, and upholding hygiene measures, as recommended by governments and health experts, must be adhered to in conjunction with the strategies described here. • The measures described here aim to reduce the risk of contagion, but they do not eliminate the risk entirely.

Promoted by the COST Action CA17136 INDAIRPOLLNET, the Government of Valencia and the Spanish Ministry of Science and Innovation. Authors of this report are members of INDAIRPOLLNET (INDoor AIR POLLution NETwork), a network of ~200 scientists from 36 countries, mainly around Europe. INDAIRPOLLNET aims to significantly advance the field of indoor air pollution science, to highlight future research areas, and to bridge the gap between research and business to identify appropriate mitigation strategies that optimise indoor air quality. This report will provide guidance to schools around Europe (and beyond) on best practice around ventilating their school buildings to minimise exposure to COVID-19 indoors. It aims to enable school managers to understand how the virus can accumulate and be transmitted in school buildings, and also suggests practical measures for reducing the viral load and hence transmission between occupants of school buildings. COST (European Cooperation in Science and Technology) is a funding agency for research and innovation networks. Our Actions help connect research initiatives across Europe and enable scientists to grow their ideas by sharing them with their peers. This boosts their research, career and innovation.

Spanish version: http://dx.doi.org/10.20350/digitalCSIC/12677

Peer reviewed