Ventilation is a key factor in reducing the spread of coronavirus (COVID-19) and other respiratory infections, such as the flu. It is the process of introducing fresh air into indoor spaces and removing stale air. Good ventilation has been linked to improved sleep, focus, and fewer sick days off from work or school. A potential benchmark for good ventilation is CO2 readings below 800 parts per million (ppm).
There are ways to measure or calculate if the ventilation methods you are using in a room are working properly. Ventilation improvements have been associated with lower infection rates in Georgia elementary schools, among other sites. Air cleaning devices are not a substitute for good ventilation, however, when good ventilation cannot be maintained, air cleaning units using HEPA filters or UV technologies could be a useful alternative to reduce airborne virus transmission. If you're not sure, consult your heating, ventilation, and air conditioning (HVAC) engineer or consultant.
Implementing multiple tools at the same time is consistent with CDC's tiered approach and will increase the overall effectiveness of ventilation interventions. Traditionally, CO2 monitoring systems are expensive, require extensive knowledge to install and configure them accurately, and require sophisticated control programs to effectively interact with building HVAC systems in real time. When used for infection control, the barrier is designed to prevent someone on one side of the barrier from exposing a person on the other side of the barrier to infectious fluids, droplets, and particles. It also recommends that building managers leave ventilation systems running until night if people are using the building, rather than routinely rejecting them.
Renowned UVGI manufacturers or experienced UVGI system designers will take the necessary steps and make the necessary adjustments to avoid harmful UV exposure of people in space. The risk of spreading SARS-CoV-2, the virus that causes COVID-19, through ventilation systems is not clear at this time. However, CO2 concentrations cannot predict who has SARS-CoV-2 infection and could be spreading the virus, the amount of viral particles in the air produced by infected people, or whether the HVAC system is effective in diluting and eliminating viral concentrations near its point of generation. In poorly ventilated rooms, the amount of virus in the air can accumulate, which increases the risk of spreading, especially if there are many infected people in the room. Proper ventilation also reduces surface contamination by removing some virus particles before they can fall out of the air and fall onto surfaces.
However, increasing ventilation alone isn't enough to protect people from COVID-19. The CDC recommends that building managers use a tiered approach to improve ventilation in buildings where people may be at risk for COVID-19 transmission. This includes increasing outdoor air supply through mechanical systems or opening windows; improving air filtration; increasing air circulation; and using physical barriers such as plastic sheeting or plexiglass shields. Overall, good ventilation is an important tool for reducing the spread of COVID-19 and other respiratory infections. It can help eliminate air that contains virus particles and prevent transmission from person to person. Ventilation to reduce the spread of respiratory infections, including COVID-19 (Gujarati) (PDF, 180 KB, 6 pages).
