Ventilation in university classrooms during the COVID-19 pandemic

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus has caused a pandemic, forcing schools and universities to stop in-person classes. For universities to allow students into a classroom environment, they need to evaluate each classroom’s ventilation quality to reduce the risk of airborne viral transmission. Organizations have provided recommendations on reducing the risk of spreading COVID-19, however there was little and conflicting information for institution who may lack the resources needed to evaluate and update their ventilation systems. The aim of this study was to evaluate building design and ventilation expert knowledge to determine an “acceptable room ventilation” based on COVID-19 recommendations from the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) and the American Conference of Governmental Industrial Hygienists (ACGIH). The end goal was to provide guidance for managers of educational buildings for assessing classroom ventilation. The ventilation in university classrooms ventilation was assessed with carbon dioxide (CO2) decay to measure air changes per hour (ACH). The study used two CO2 monitors to assess 12 lecture-based classrooms with a mix of thought to be adequate/inadequate ventilation as well as mix of mechanical and natural ventilation classrooms. A data analysis of monitor location determined there was no significant difference between the ACH in front and back of classrooms. The classrooms designed to ASHRAE 62.1 2004 standards did not meet ACGIH COVID-19 recommendations. Half of the classrooms met the used ASHRAE criteria. However, a classroom that was anticipated to fail based on expert knowledge, met the ASHRAE and ACGIH criteria. Only three classrooms passed ACGIH recommendations. None of the classroom that passed ACIGH criteria were originally expected to pass. From these results, classroom design criteria and expert knowledge alone should not be used to assess building and classroom ventilation. A proper assessment of classroom ventilation should include collecting classroom ventilation data as well as ventilation experts who are familiar with the system. and collected classroom ventilation data.