The airborne spread of COVID-19 is one of several reasons Visalia Unified School District teachers are concerned about resuming in-person instruction at the end of the month.
That’s why it was a step in the right direction when the district spent more than $1.4 million to buy 1,700 HEPA air purifiers and carbon filters for all of its classrooms, according to Greg Price, who leads the teachers’ union, Visalia Unified Teachers Association.
“We’ve been bargaining, saying you have got to do something better than the status quo,” Price said. “They have gone the direction we were hoping they would go, but we had to do a lot of bargaining to get there.”
Many teachers in Visalia and across the country are concerned about ventilation (air movement) and filtration (air cleaning) within their classrooms.
About 41% of school districts nationwide need to update or replace heating, ventilation and air conditioning systems, according to the federal oversight agency, the U.S. Government Accountability Office, which surveyed 50 states and the District of Columbia. GAO staffers visited 16 school districts in six states, including California.
There is no statewide assessment of school buildings in California due to the large number of educational institutions and the cost, according to GAO, which added that “school districts are primarily responsible” for this task.
Erik Kehrer, the new chief operations officer at VUSD, assured Times-Delta the district’s HVAC systems “are operating at an acceptable level, following all the guidelines and standards,” he said.
It isn’t likely VUSD students in grades 7-12 will be back in school to use the district’s new air purifiers due to rising COVID-19 cases in Tulare County. But about 14,600 elementary school students will return to campus on Nov. 30 and Dec. 7 after getting state approval.
The HEPA air purifiers are expected to arrive before the reopening — barring any shipment delays — and will address some of the pressing concerns of teachers, Kehrer added.
“The air purifiers are to supplement our existing HVAC systems and provide an extra layer of protection,” Kehrer said. “They will cover every nurses’ office and some of our kitchens” in addition to every elementary, middle and high school classroom.
Are HEPA air purifiers effective?
The effectiveness of certain types of air purifiers has been up for debate among experts, but VUSD plans to use a type recommended by public health experts.
High-efficiency particulate air filters — commonly called HEPA — “can theoretically remove at least 99.97% of dust, pollen, mold, bacteria, and any airborne particles with a size of 0.3 microns,” according to the Environmental Protection Agency.
Though it isn’t clear “how much practical impact the machines could have for COVID-19,” HEPA filters “capture with extraordinary efficiency: 0.01 micron (10 nanometers) and above,” according to the New York Times. “The virus that causes COVID-19 is approximately 0.125 micron (125 nanometers) in diameter,” the New York Times added.
To help prevent COVID-19 from lingering in the air for up to three hours, the district will be using medical-grade HEPA-13 filters in the Alen BreatheSmart 75i air purifiers it’s purchasing. The district also purchased carbon filters, which will help during wildfire season, according to Kehrer.
VUSD will use more than $1.4 million of the $30 million in CARES funds it received from the federal government to buy the air purifiers and filters, according to Kehrer.
The HEPA air purifiers are designed to last at least 12 months in 1,300-square-foot rooms, according to a custom specifications sheet given to VUSD by its vendor, Cerritos-based Supply Solutions.
The average size of a VUSD classroom is between 960 square feet and 1,000 square feet, according to Kehrer.
As part of an online tool they built, public health experts with Harvard University and University of Colorado Boulder show that ceiling height must be considered when buying air purifiers.
The ceilings within VUSD schools vary, Kehrer said.
“Some of our new sites have a little bit higher classroom, but that does take into account the volume,” he said. “We don’t have any classrooms that are such a ceiling height that the capacity wouldn’t be enough to support that classroom.”
VUSD leaders see the air purifiers as part of a combination of precautions, including the continuous running of HVAC system fans two hours before a classroom is occupied and an hour after. The district also recommends VUSD staff open windows and doors to ensure ventilation, which isn’t required, Kehrer said.
The district’s HVAC systems and its chosen air purifiers are designed to change air about three times per hour in a typical classroom. This means the number of people inside a classroom must be considered.
How many people will be inside each elementary school classroom depends on each site and how many families signed up for in-person instruction, according to Kehrer.
“Principals are still working on those numbers right now,” he said.
Why VUSD isn’t retrofitting its HVAC systems
The district is also planning to order a type of filter called Minimum Efficiency Reporting Values 13, or MERV-13, which can capture larger particles between 0.3 and 10 microns, according to the Environmental Protection Agency.
MERV-13 has among the highest capturing capabilities of its kind. Many school mechanical systems aren’t able to support them, including an unspecified number of HVAC units within VUSD. The district currently uses MERV-8 filters.
VUSD isn’t retrofitting all of its HVAC systems to accept MERV-13 filters, Kehrer said.
“That’s on our list of things to think about going forward,” he said. “As it stands right now, that’s site and unit specific. It would be very hard to go through and say this is what it will take.”
“We are operating the way we are supposed to with the regulations right now,” he added.
Kehrer wasn’t sure which classrooms would have the filters installed into their HVAC units, which may be a single wall unit hanging from a window, he said.
“There will be some units at older sites that will not be able to handle (the filters),” Kehrer said. “The supplemental purifiers we’re putting in there will help to offset that.”
“As those (MERV-13) filters arrive, we will — through trial and error — place them where we can and where the units can support a heavier filter,” he added. “We will keep them in place, and that will be the standard for those units.”
The filters won’t be purchased using CARES dollars, according to Kehrer.
“They’re part of our normal routine maintenance,” Kehrer explained, “so that’s something we’d have to buy anyway.” He added he didn’t know the cost of the MERV-13s the district would be purchasing.
VUSD’s MERV-13 shipment is backordered until January because of high demand for the filter, which has been recommended to U.S. school districts by the Centers for Disease Control and Prevention and the American Society of Heating, Refrigerating and Air-Conditioning Engineers.
“It’s not just us,” Kehrer said. “It the entire country that’s trying to update this.”
The top 7 concerns from VUSD teachers
Some VUSD teachers are still concerned about resuming in-person instruction, according to Price.
Price surveyed at least 600 teachers from Nov. 6-9, and he found seven common reasons teachers feared returning to school:
- Flu season will be in full swing upon return
- Four major holidays will occur that will generate gatherings
- Not much time to prepare in-between teaching and parent-teacher conferences.
- Strongly opposed to returning while Tulare County is in the purple tier of the state’s COVID-19 monitoring system
- Cleaning and disinfecting concerns at school sites
- Air ventilation and filtration worries about “outdated” HVAC systems and opening classroom windows amid inclement weather
- 85% of teachers want to wait until after winter break and return on Jan. 11
VUSD has bought equipment to sanitize buildings and purchased other health and safety essentials, which it is storing in its warehouses.
District leaders said they have done walk-throughs at elementary schools to prepare for the reopening of schools and plan to train teachers regarding health and safety protocols.
But teachers don’t know what that training is, according to Price.
“They are building the plane in the air,” Price said. “There are no engines. No propeller. We are heading down.”
“VUTA wants kids to come back, too,” he added. “It just needs to be safe, and the teachers need to feel ready.”
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This article originally appeared on Visalia Times-Delta: Concerned about COVID-19 infection in classrooms? What to know about VUSD’s air purifiers and HVAC systems