New ventilation guidelines from Lancet COVID-19 Commission

Ventilation with clean air is essential for maintaining healthy indoor spaces. Insufficient ventilation increases the risk of transmitting airborne pathogens such as SARS-CoV-2 and also can lead to the buildup of indoor air pollution. The Lancet COVID-19 Commission on Safe Work, Safe School, and Safe Travel released recommendations November 18, 2022 for the minimum rates of ventilation with clean air for a workplace, classroom, or public transportation. These recommendations expand on the ASHRAE recommendations for minimum outdoor air ventilation and explicitly considers the combination of outdoor air ventilation with air filtration and air disinfection.

Table 1. from: Lancet COVID Commission Proposed Non-Infectious Air Delivery Rates for Reducing Exposure to Airborne Infectious Respiratory Diseases. November 2022.

The continued drumbeat of attention surrounding ventilation and healthy indoor air is without question a positive thing. However, a central problem is: How do schools and businesses meet these guidelines? Issues of funding aside, even knowing the ventilation rate on a room by room basis (“are we meeting guidlines or not?”) is a big technical hurdle for many organizations. This recent open-access study by McNeill et al. discusses approaches that were used in universities and schools across the country to assess ventilation needs and discusses best practices.