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Huntsville City Schools Add Two HEPA Filters to Every Classroom

Updated: Aug 10, 2023

The ELC-funded HEPA program for schools has ended, according to information we received from its administrators at UAB, but one North Alabama district made sure not to miss the opportunity!

Huntsville City Schools (HCS) recently became the only Alabama school district we know of that used UAB's ELC-funded HEPA program to outfit every classroom in its district with two portable HEPA filters. The email newsletter from HCS can be viewed here.

The MedifyAir MA-112 in-room HEPA air purifiers at HCS are to be operated at fan speed 2, giving Huntsville City Schools the greatest quantifiable engineering controls of any Alabama school district we know of, adding 560 cubic feet per minute (cfm) of equivalent outdoor air in each classroom.

Below is the video shared in a newsletter from Huntsville City Schools on July 20th, 2023:

How Does This Compare with Recommendations and Standards?

Assuming a hypothetical average classroom of 800 square feet and 30 occupants, operating these units would add roughly 18 cfm per person of equivalent clean air, at an air change rate of about 4 air changes per hour. This is in addition to the contribution from school HVAC systems, meaning that these classrooms likely at least meet the WHO recommendation (~21 cfm per person) and the Lancet's lowest-tier recommendation in their good/better/best recommendation (~21 cfm per person or 4 ACH).

Furthermore, in a Huntsville school with code-compliant HVAC, the same hypothetical classroom would likely get >30 cfm/person, meeting Lancet's best recommendation and approaching the rate of 40 cfm/person specified in ASHRAE's new infection control standard, 241-2023.

What Problem Does This Solve?

In October 2022, we wrote about UAB's program offering Free HEPA Air Purifiers for Alabama Schools to help combat the spread of airborne illness. Around that time, CDC added a new color to their US flu-like illness map to represent illness levels in Alabama and a other southeastern states. No information is on-hand about the attendance impact to Huntsville City Schools, but by Halloween, attendance in nearby Madison City Schools had dropped by between 10% - 20%. The record levels of illness caused Alabama pediatric hospitals to struggle, and likely had a significant impact on attendance in most Alabama schools.

Even before that, the most recent School Report Card from the Alabama State Department of Education showed there was a doubling of chronic absenteeism in Alabama schools since the withdrawal of the Department of Education's COVID-19 Reporting Waiver -- jumping from 8.3% in 2021, to 17.9% in 2022.

Even as early as 2021, Alabama ranked the highest in the nation for missed work due to child care issues. Meanwhile, among the reasons for chronic absenteeism in central Alabama was the valid concern from parents about whether schools had adequately addressed the health and safety threats posed by the pandemic.

How do HEPA Filters Specifically Reduce Illness and Increase Attendance?

Portable HEPA filters remove at least 99.97% of particulate contaminants and infectious aerosols from the air that flows through the filter medium:

Even at the particle size where HEPA filters are lowest-performing (0.3 microns), they still capture at least 99.97% of particles.
Graph of HEPA filter particle removal efficiency. Image taken from the Center for Green Schools fact sheet on in-room air cleaners.

Using portable HEPA filters to improve air quality in schools has manifold positive effects that boost the focus and attendance of students and faculty. For example, HEPA filters are capable of:

  • Reducing the airborne burden of infectious bioaerosols that contribute to illness;

  • Reducing the concentration of particulate contaminants occurring from any hypothetical or future wildfire smoke, construction, mold, asbestos, etc.;

  • Reducing irritation from allergies for students and faculty; and,

  • Reducing asthma issues for the 7-10% of asthmatic students in any given classroom.

A 2017 comprehensive review of literature found that increased school air quality could improve health, attendance, cognitive performance, test scores, and grade point averages. Some school districts have seen absenteeism fall by as much as 50% with improved air quality. The US Environmental Protection Agency (EPA) has even found documentary evidence that air quality is a factor in teacher retention, which was already a problem in Alabama prior to the pandemic.

In the video above, Dr. Wilson thanked Indoor Air Care Advocates. One way we supported HCS was by co-authoring a double-sided one-pager with them to educate faculty and staff on how air quality supports the best possible health, focus, performance, and attendance in schools:

Front and back of HCS double-sided one-pager on in-room portable HEPA filters.

We have made a copy of this one-pager available publicly so that it may serve as an informative, evidence-based resource for other air quality advocates.

What Now?

Schools that exercised this opportunity will stand apart from those that failed to take adequate action, in terms of student health, attendance, cognitive performance, and academic success.

Disappointingly, Madison City Schools (MCS) and Madison County School System (MCSS) in particular did not respond to urgings by co-founders to ask to receive two filters per classroom like HCS. Even prior to knowing about the ELC program, we have also asked MCS to use ESSER dollars to purchase HEPA filters for classrooms, which they did not.

On June 6th, 2023, a parent spoke at a Madison City Schools (MCS) board meeting, saying that he and other families have contacted educational attorneys due to the undue burden of sick notes this year, and that they routinely send children to school sick. We've heard other Madison City Schools parents complain that their kids were sick so frequently that MCS called them to ask what the school can do to support them in sending their children to school more regularly. There's a simple answer: follow the example set by Huntsville City Schools.

Parents should hold school administrators accountable who left both filters and money on the table from this public health program. If you want to know if your school participated, check out our next blog post, which will feature the list of all schools that participated based on an an open records request we issued to Alabama Department of Public Health (ADPH).

Meanwhile, in their newsletter, Huntsville City Schools said:

HCS continues to promote school air quality by pursuing ways to continually optimize ventilation in schools across the district.

HCS has followed the science and made good use of the public health resources afforded to them by ADPH's ELC-funded program. This is exactly the kind of effort and care that North Alabama parents have had a right to expect from all schools; it will take nothing less than this for us to enjoy the stability, continuity, productivity, and normalcy we continue to miss after skipping this key step in the "safe return" to most schools.

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