According to experts, the CDC needs to promote better ventilation to prevent the spread of the coronavirus in schools.

According to ventilation experts, the US Centers for Disease Control and Prevention needs to do more to guide and promote improved air circulation in buildings, especially schools, to prevent the spread of the coronavirus.

They say that the CDC does not pay enough attention to the role that ventilation can play in helping or reducing the spread of the coronavirus.

According to experts, schools use HVAC systems, stand-alone HEPA air filter systems, or just open the window if students, teachers and staff are safe to return to school in the fall, time and money. It is necessary to improve the air flow.

“Currently, US schools are terribly inadequately ventilated,” said Richard Corsi, dean of Portland State University’s Faculty of Engineering and School of Computer Science. Forum hosted by Johns Hopkins Center for Health Security This week at Bloomberg Public Health School.

“Currently, schools are looking at the CDC and aren’t getting the answer to the kind of things we’re talking about,” Corsi added. “All of them are looking at the CDC.” Corsi said he advised the school that ventilation needed to be improved, and the CDC website responded that there was no specific guidance.

The CDC suggests that schools think about improving ventilation.

“Consider upgrading or improving the ventilation system and other procedures to increase the supply of clean air and dilute potential pollutants in the school. Experience when considering changes to HVAC systems and equipment. Talk to a wealth of heating, ventilation, and air conditioning (HVAC) experts. ” Say in that guidance..

Also, Guidance posted by the American Society of Heating, Refrigering, and Air-Conditioning Engineers..

But that’s not enough, experts agreed.

Why ventilation is important

Poor ventilation can cause viral particles to accumulate in the air in the classroom, cafeteria, or hallway.

“Looking at all the attention-grabbing outbreaks (the same underlying factor), there is no mask and less ventilation. It doesn’t matter if it’s spin class, ice hockey, camp, classroom, choral practice or restaurant.” Said Joseph Allen, who directs the Healthy Building Program at Harvard School of Public Health. I told CNN earlier this month.

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The pandemic has revealed the role that our buildings, including schools, can play a role in the transmission of infectious diseases, “Penn State University’s professor of architectural engineering William Burnfres told the forum.

It’s a simple enough concept. People constantly cough, sneeze, or simply spit out particles. If a person is infected with a virus, including a coronavirus, the virus particles can run on droplets that can float in the air. In a closed room, those particles accumulate and others inhale them.

The solution can be simple — air exchange. Replacing particulate air with fresh, clean air reduces the risk of infection.

The problem arises when the ventilation system of a closed building is also inadequate. The problem is exacerbated in cold weather, as windows and doors can be tightly closed against the cold.

According to Baan Fres, infectious particles can be removed by completely changing the air in the room three times. A high-performance air purifier or ventilation system can do this in 20 minutes, he said.

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With a clean air supply rate of 300 cubic feet per minute in a typical classroom, a portable HEPA system is equivalent to 3-4 air changes per hour. That’s up to 50%, 60%, and 70% reductions in inhaled doses in many classrooms, “Corsi added.

However, principals, boards of education, and teachers often know very little about this concept.

“There isn’t much awareness about indoor air,” said Claire Barnett, founder of the Healthy Schools Network. She said the problem has been exacerbated since the US Environmental Protection Agency stopped funding indoor air programs for schools 10 years ago. Neither the CDC nor the Ministry of Education currently has expertise in school indoor air, she said.

And, like many others, it’s a problem to have more impact on poor communities.

“It has been well documented for decades that the poorest communities often have the poorest school facilities: clean air, ventilation, poor plumbing, hygiene. This means that it is less prone to leaks and mold, “says Burnett.

B
ahnfleth pointed to 2020 Government Accountability Office (GAO) SurveyThe 54% of school districts found required multiple system updates. “Approximately half of the districts had to update or replace multiple systems such as heating, ventilation, air conditioning (HVAC) and plumbing,” the report said. “Estimated one-third of schools needed updates to their HVAC system.”

It’s expensive in advance, but it’s worth it, Burn Fres said. “Yes, it can be quite costly in some cases, but it’s not as high as some people think, and the cost of not making that investment is much higher,” he said.

So who should pay?

“We only need to invest in the filtration of classroom air purification systems, which should be provided by the federal government,” Dr. Donald Milton, a professor of environmental health at the University of Maryland, told CNN.

President Joe Biden’s School Has Money $ 1.9 trillion rescue planHowever, nothing is assigned to the school’s ventilation system.

And the CDC said he needed to do more to help people think about where the virus was — and it’s in the air.

“If it’s in small particles floating in the air and you inhale them-it doesn’t matter how much it travels in the air-the problem is the same. The solution is the same. Ventilation, filtration. , And source control is needed, and a snug mask with good filters and breathability is needed, “he said.

Something you can not do

Experts advised using unproven techniques to “purify” air, stating that some approaches can result in polluted air. The important thing is to replace all the air in the room with fresh air several times an hour.

At the Johns Hopkins forum, Corsi said, “I want to encourage everyone not to challenge unproven technologies that are cleverly marketed.”

This includes cloudy and fog systems, “robot” disinfection, or in-situ UV systems.

“Fogger and Mr. work ideally in certain settings,” Burnett said. They include laboratories and hospitals. It does not include schools or office buildings where untrained workers do not know how to use dangerous chemicals.

A UV system that sits high on the ceiling and has an air circulation to suck in the exhaled air works well, Burnfres said. However, it can be expensive and is more suitable for large shared spaces such as gyms and cafeterias than small classrooms.

Some low-tech approaches do more harm than good, according to Burnett. For example, a plastic shield can concentrate polluted air and stop large droplets for a short period of time (think grocery checkout), but over time the air It is not useful in settings such as classrooms where there is a possibility of circulation.

“If you smell cigarette smoke from the other side of the plexiglass, you’re also inhaling the virus,” Burnett said.

All experts were critical of the CDC’s focus on cleaning desks and other surfaces at the expense of the concept of clean air. Delphine Farmer, an aerosol expert at Colorado State University, said: “Surface cleaning doesn’t help much in terms of Covid-19’s cost-effectiveness. If nothing else, the cleaning solution can fill the air with a complex cocktail of toxic chemicals, she said. ..

“There are very realistic consequences of over-cleaning,” Farmer told the Johns Hopkins Symposium.

The same applies to systems that use oxidative chemical processes to break down virus-containing particles.

“But in doing so, they produce a series of organic compounds,” she said — including toxins like formaldehyde.

“What we know is ventilation and filtration,” Farmer said.

This story has been updated to show that Claire Burnett intended to say the Ministry of Education instead of the EPA when talking about school ventilation expertise.