“If it is safe to do this, open the windows and doors,” advises the CDC. “Even opening a window or door helps to increase the flow of outside air, which helps to reduce the potential concentration of virus particles in the air. If it gets too cold or too hot, adjust the thermostat.”
It is important to make sure that open windows are not dangerous, noted the CDC. “Do not open windows or doors if it poses a health or safety risk (such as falling, exposure to extreme temperatures or triggering asthma symptoms),” the document said.
The same goes for buses.
“Open the windows on the transport vehicles.” The more windows that can be opened, the better, but even opening windows helps, said the CDC.
The use of masks can prevent the virus from airing in the first place, said the CDC on the new web page. But good ventilation is also important.
“Use child-safe fans to increase the effectiveness of open windows. Securely attach fans to a window to blow potentially contaminated air out and pull fresh air through other open windows and doors,” he adds. “Consider having activities, classes or lunches outdoors when circumstances permit.”
The new guidance also addresses heating, ventilation and air conditioning (HVAC) systems. “Configure HVAC systems to bring as much outside air as your system safely allows,” he suggests. “Increase the total airflow supply of the HVAC system to occupied spaces when possible. More airflow encourages air mixing and ensures that any recirculated air passes through the filter more often.”
Filtration is also important, but filters should not reduce airflow.
Certain air filters can also be useful, said the CDC.
“Consider portable air purifiers that use high-efficiency particulate air filters (HEPA) to improve air cleanliness whenever possible, especially in high-risk areas, such as the infirmary or infirmary / isolation room,” he recommended.
Likewise, correctly installed ultraviolet lights – they should be high, at the ceiling level – can help, said the CDC.
“Consider using ultraviolet germicidal irradiation (UVGI) in schools and non-home child care programs as a supplemental treatment to inactivate the virus that causes COVID-19, especially if the options for increasing ventilation and filtration are limited. Consult a professional qualified to help design and install any UVGI system, “said the CDC.
With insufficient ventilation, viral particles can accumulate in the air in a classroom, cafeteria, or corridor.
“If you look at all the high-profile outbreaks – same underlying factors – no masks, low ventilation. It doesn’t matter if it’s spinning class, ice hockey, camping, classrooms, choir practice or restaurants, (it is) same underlying factors, “said Joseph Allen, who directs the Healthy Buildings Program at the Harvard TH Chan School of Public Health, to CNN earlier this month.
Ventilation experts have been asking the CDC to say more about the importance of clean air in schools.
“The state of school ventilation in the United States at the moment is terribly inadequate,” said Richard Corsi, dean of Portland State University School of Engineering and Computer Science, at a forum organized by the Johns Hopkins Center for Health Security at Bloomberg School of Public Health this week.
But they said schools should avoid falling for misleading products whose promoters say they clean or disinfect the air.
Most importantly, experts agree, is fresh air.