In the race to reopen schools, districts across California and the country are beefing up safety measures to limit the spread of the coronavirus — more masks, more sanitizers, new plastic barriers.
As part of the effort, Sacramento City Unified School District purchased more than $6 million worth of classroom air cleaners and replacement parts in November, at a cost of $688 per device.
But several experts have identified potential concerns about the devices, saying the air cleaners that Sacramento City schools purchased are overpriced, inefficient and have unnecessary and unproven technology.
Sac City Unified purchased 6,000 V-PAC SC air cleaners, manufactured by Ultraviolet Devices, Inc., from Johnson Controls. The units, to be deployed in every classroom and common space, have “the best technology for mitigating COVID-19 at a fraction of the cost of other compatible portable filtration devices, such as HEPA filtration devices,” a November school board report stated.
“The COVID-19 virus is destroyed using an Ultraviolet-C light instead of trapping the virus in a filter,” the district report stated.
Industry groups have reported that such claims about UV-C light technology are not backed up with sufficient scientific research. Several studies and researchers also identified concerns about a piece of the device that could potentially create harmful chemicals such as formaldehyde, a known human carcinogen.
“There are many conventional portable HEPA filters that provide more than twice the clean air delivery than the UVDI device and the power consumption is just 100 watts … and for a fraction of the cost,” Bud Offermann, president of Indoor Environmental Engineering, said in an email.
Experts said portable air cleaners with HEPA — high-efficiency particulate air — filters are effective at capturing particles the size of the virus that causes COVID-19, and would have been far more cost-effective.
“There are two things I’m worried about. One is using money wisely to best support school reopening,” said Theresa Pistochini, the engineering manager at the UC Davis Energy Efficiency Institute and Western Cooling Efficiency Center. “The other is creating a false sense of security.”
State and local health authorities have not required upgrades to school air filtration systems as a requirement of reopening. But the district is “committed to going above and beyond the recommendations by federal, state, and county health officials to protect the safety of our students, staff, and community,” district spokeswoman Tara Gallegos said in a statement.
Sac City Unified personnel spent six months reaching out to vendors and reviewing their products and ability to address the virus, Gallegos said in an email. The Sacramento City Unified School District board approved the purchase in November.
The district had to weigh several factors, she said: It needed to purchase devices with CARES Act funding before the end-of-year deadline. Officials also considered, among other things, whether devices were certified by the California Air Resources Board, how many amps they pulled and how soon they could be purchased.
“The longer COVID continues, the more companies are able to meet these requirements,” Gallegos said in an email. “UVDI was the only company at the time that met all of these requirements.”
The district spent $497,500 in CARES Act money last year to hire PBK Architects, a firm that will inspect all classrooms and schools before bringing students back “to assure that our students and staff are in a space that is sufficient to mitigate the spread of COVID-19,” she added.
Because infection rates in Sacramento County remain high, public health and school officials have no clear timeline for when Sacramento City schools may reopen for modified in-person learning.
But when they do, the district will enforce a variety of other methods for reducing the spread: Students’ temperatures will be measured. Plastic barriers will be put up in offices and libraries. Desks will be spread further apart. Disposable masks and hand sanitizer will be abundant. Many teachers and staff will have likely already gotten the vaccine, and rapid COVID-19 tests will be available on-site. When weather permits, doors and windows will be opened to let in fresh outside air.
UVDI declined to comment on its devices. In an email, spokesman Will Gerard said the company deferred to Johnson Controls.
In a statement, Johnson Controls stated that the air cleaners “met a demanding set of requirements to provide an effective solution delivering improved air quality to the Sacramento City Unified School District with minimal infrastructure change, while meeting time requirements.”
V-PAC SC air cleaners inefficient, experts say
Common portable air cleaners, also known as air purifiers, used in homes and offices are often mechanical — meaning, the device pumps air through a physical filter to catch particles, viruses, bacteria and other contaminants. HEPA filters by definition are excellent at removing fine particles in the air, and are widely available on the market.
Portable air cleaners alone are not enough to protect people from COVID-19. Though they can reduce airborne contaminants, including viruses that linger in the air indoors and spread farther than 6 feet, there isn’t direct evidence yet that air cleaners stop transmission from close contact like masks and social distancing have been shown to do.
The Centers for Disease Control and Prevention has recommended opening windows and doors when weather permits to allow for outside air ventilation, and suggests building operators “consider portable high-efficiency particulate air (HEPA) fan/filtration systems to help enhance air cleaning.”
Test data has not been made available by UVDI or Johnson Controls regarding the V-PAC SC air cleaner.
The industry standard for judging how effectively a portable household air purifier cleans the air is its clean air delivery rate. The CADR is measured using the Association of Home Appliance Manufacturers AC-1 test, also known as an AHAM AC-1 test.
The test reveals how efficiently a device is producing clean air for a room. For instance, a device could have a high-quality filter, but if it doesn’t actually push much air through the filter, it might not be an effective air cleaner.
Offermann, an indoor air quality expert with 40 years of experience, helped AHAM develop the CADR test standard in the early 1980s after consulting for the Federal Trade Commission on advertising claims for portable air cleaners. The former staff scientist at Lawrence Berkeley National Laboratory now runs a San Francisco-based research consulting group.
Johnson Controls, a global company with $22.3 billion in sales last year, and UVDI did not publish the device’s clean air delivery rate. But the Sacramento Bee received a copy of the report from Offermann, who requested it from UVDI.
The test shows that the average clean air delivery rate for the V-PAC SC purchased by the district is 88 CFM, meaning that’s how many cubic feet of clean air per minute is produced by the device.
The Association of Home Appliance Manufacturers recommends having a clean air delivery rate that translates to about two-thirds of a floor area. For example, if a room is 600 square feet, a device’s CADR should be 400 CFM.
Gallegos, the district spokeswoman, said in an email that the one V-PAC SC air cleaner could purify the air for a space of up to 1,000 square feet. In fact, the air cleaners the school purchased would be sufficient for a room roughly 130 square feet, based on industry standards and Offermann’s assessment.
The district would need to use at least eight devices per 1,000 square foot classroom to effectively clean the air. Given how inefficiently it cleans the air, the devices are “10 times more expensive than something you could buy on Amazon,” Offermann said.
The Bee had requested a copy of the device’s AHAM AC-1 report from the school district. The district initially declined, stating it didn’t exist for the air cleaner because it is a “commercial” device. After presenting a copy of the obtained report, both the district and Johnson Controls confirmed that the report and its findings are accurate.
Though not stated on the device’s technical specifications, Gallegos said that the devices use a HEPA-level filter. Even if that’s the case, “there’s hardly any air going through it,” Offermann said.
“If the unit performance does not meet our district’s needs, we will explore other options,” Gallegos said in an email.
Issues with unproven technology
Unlike more common household air cleaners with just a mechanical filter, the V-PAC SC devices have ultraviolet-C light and photocatalytic oxidation reactor. While UV-C light can effectively kill bacteria and viruses, it’s most effective for sanitizing objects, surfaces or spaces over an extended period of time. UV-C light may be able to inactivate the virus that causes COVID-19, according to the U.S. Food and Drug Administration, but there is currently limited research.
There is not enough scientific data to prove how effective it is for reducing viruses passed through an air cleaner device, Offermann said.
“The concern I have is that the UV-C device packaged inside an air filter is unlikely to have a significant impact, because the air is moving quickly and is in contact with UV-C for a short period of time,” Pistochini said.
The V-PAC SC air cleaners were certified by the California Air Resources Board in April, which requires testing for electrical safety and ozone emissions.
CARB certification does not assess how effective an air cleaner is, according to spokeswoman Melanie Turner.
“There is not enough information to assess (UV-C technology’s) effectiveness for virus reduction when it is contained within an air cleaner device,” Turner said in a statement. “The addition of UV-C does not add any functionality for particle removal.”
In an email response, Johnson Controls spokesman Charles Bickers said it would be more accurate to say “that the UV-C filtering is in addition to the filtering.”
The devices also have a photocatalytic oxidation, or PCO, grid, which is activated by the UV-C light and is intended to breakdown pollutants through an oxidizing process. But studies have also raised concerns about PCO technology.
“There is also the potential for an incomplete oxidizing process, which produces by-products of reaction that can be more toxic or harmful than the original constituents (e.g., formaldehyde),” according to the American Society of Heating, Refrigerating and Air-Conditioning Engineers.
Shelly Miller, a mechanical engineering professor at the University of Colorado Boulder, said the manufacturer would need to release testing data on the device to rule out the formation of harmful chemicals.
In general, Miller said she doesn’t recommend school districts on a limited budget purchase air cleaners with “bells and whistles” since it will cost significantly more than straightforward HEPA filters that produce clean air efficiently.
She emphasized it is better to buy more air cleaners and better masks, rather than invest in air cleaners with untested add-ons.
In a statement, Johnson Controls said that “the airstream purification and disinfection solution provide a combination of technologies to enable improved air quality and will be complemented by other mitigation procedures (mask wearing, washing hands, etc.) in place to address the risk of COVID-19 infection.”
Returning to classes
HEPA air cleaners and filter replacements for large rooms can easily be purchased online for a couple of hundred dollars on sites like Amazon, and be plugged into normal home wall sockets without issue.
The district “did not entertain the idea” of purchasing cleaners marketed for residential use, since the district is made up of commercial buildings and those units “would not stand the test of time in the long run” operating 24/7, Gallegos said.
Residential units are designed to be run constantly, however. Both Pistochini and Offermann said there’s nothing that makes the V-PAC SC devices “commercial,” such as having a higher CADR or stainless steel covering. The presence of an industry-standard AHAM AC-1 report for the device — a test conducted on portable household air cleaners — suggests it is not a commercial device.
The district stated that the commercial HEPA air cleaners it considered purchasing would have required significant and costly electrical upgrades to school sites to power, or they otherwise overload most circuits.
The manufacturer states the V-PAC SC air cleaners draw .89 amps and don’t require any electrical upgrades, according to Gallegos. The district considered the Carrier OptiClean, a mechanical HEPA air cleaner, but the units cost about $2,000 each and draw 5 amps.
“We’ve continued to express and demonstrate that we are willing to go above and beyond,” Gallegos said in an email. “These are not empty words, but the reality of the extensive work of our district to protect our staff, students, and community.”
This story was originally published January 24, 2021 5:00 AM.