Ventilation and Air Cleaners

 How is the Air Quality in Our Schools?

Simple answer: Not good enough against the new “Delta variant” of SARS-CoV-2.

We have watched with alarm as children have gone back to school across the United States. In just one week, there were more than 180,000 confirmed cases of COVID-19, and 24 deaths. 

COVID-19 is an airborne disease, so to fight it, the focus must be to CLEAN THE AIR!

We call on APS to take the following actions immediately:

Place an additional True HEPA portable filter in every single classroom. APS was given MILLIONS of dollars of federal and state funds to reduce risks in its schools. Spend it to reduce risk, APS! What are you waiting for? Unvaccinated children are going get sick before they even get a chance to be vaccinated if you continue to delay. We have not done everything we could to reduce risks.

Raise the goal of air changes per hour (ACH) to 6, up from 4. The goal of 6 ACH is the minimum required to have an impact on infection control (ASHRAE Standard 170). APS has chosen a minimal target of 4 ACH that falls short (although it better than being below code, where more than a third of APS classrooms started before any mitigations). New guidance published this summer for workspaces starts with 6 ACH as the minimum that is required to protect workers. The head of ASHRAE’s pandemic task force also says 6 ACH is a reasonable goal that schools can reach by adding cleaned air with True HEPA filters. Adding portable HEPA filtration places less strain on mechanical systems, reduces dependency on windows when it’s too cold or too hot, and is cost effective, at $10-$15/student.

Set a secondary standard of providing a MINIMUM of 10 L/s/person of clean air in every school space. Nearly 700 engineers and scientists endorsed this international OCCUPANCY-BASED pandemic standard earlier this year. It is a minimum. Safety is enhanced when you exceed minimums. APS plans to put more kids and teachers in classrooms than they were designed for, as far as the mechanical ventilation (fresh Outdoor Air provided). So this year, a classroom ventilation system designed for occupancy of 25, could wind up serving 30 students and two teachers. Will there be enough ventilation per occupant? We doubt it. APS consultants told facilities managers this in emails last year clearly. APS either needs to de-densify rooms (preferable) or add additional Outdoor Air. If APS cannot meet ventilation code, then class sizes should be lowered. ASHRAE has issued a draft guidance statement telling schools not to count portable units’ filtered air towards occupancy requirements, which APS is doing. True HEPA filters could be used, however, to provide extra uncontaminated air for safety to get to the international minimum 10 L/s/person target.

Deal with the thorny issue that APS purchased ionization machines, the so called “certified air cleaning devices,” which can produce chemical byproducts that are harmful. New draft IAQ (Indoor Air Quality) guidelines for public buildings like schools, in fact, list some of the potential byproducts of ionization as problems that facilities managers need to worry about. In addition, APS’s units did much worse than expected in recent lab tests. They cleaned 19% LESS AIR than expected, according to the REACT project at the Illinois Institute of Technology. Read more here. This means all of APS previous estimates for air quality are incorrect. We have updated our table to reflect the poor performance of APS’ ionization machines in recent tests.

ASHRAE advises using portable True HEPA filters over other technologies. They note in new draft guidelines for IAQ that many cleaning technologies being marketed have not been proven to be effective and may even harm IAQ. ASHRAE notes that True HEPA filters are proven to be effective: Aerosol concentration can be reduced by over 90% within 30 minutes in a classroom with HEPA filter devices, as long as the HEPAS on their own are producing 5.5 clean air changes per hour; drastic particle reductions occur at all particle sizes and evenly throughout the room. This study is specifically cited by ASHRAE experts as important for facilities managers to review.

APS children deserve air equity across our schools. It’s simply wrong to have some in schools with less clean air than others. It’s wrong and it increases some teachers’ and children’s risks of contracting COVID-19. There is a big difference between 4 ACH and 6 ACH.

APS has adopted a “back to normal” mentality, with children switching classes. But APS has not provided enough time between class changes to allow airspaces to clear out particles and must address this. APS must either limit rapid class changes, or it must add more rapid filtration with portable True HEPA units, because the virus that causes COVID-19 will float in a space with 4 ACH for 69 minutes, or many hours longer if the air is not well mixed or there are obstructions, such as decades-old ductwork that isn’t large enough to remove air quickly. In the conditions that APS has set up, children will be able to transmit COVID-19 to each other from the air without ever sitting next to each other in class. Masks that are in use will only block about half the exhaled particles, and APS has made no effort to provide better masks.

2020-2021 Classroom Analysis

(Updates in Progress for 2021-22 School Year) 

We used the Harvard T.F. Chan School of Public Health’s Ventilation Guide for school classrooms as a starting point to analyze how much clean air there was in APS classrooms and show where there was room for improvement.

We thought that APS would want to shoot for 6 ACH everywhere, since this is the minimum standard for any kind of infection control per ASHRAE. APS instead adopted 4 ACH as its goal, which primarily affects children stuck in older school facilities, where APS needs for system upgrades have not kept up. 

The purpose of this analysis is to help APS implement targets for clean air fairly and correctly across all schools, and to make sure the rooms with low amounts of clean air — and larger volumes of air to clean —receive one or two air cleaners during the pandemic.

This is not intended to be a complicated mathematical modeling of variable outdoor air exchange rates in specific rooms, nor a complex engineering exercise. This is an estimation of need and intended to empower advocacy by school communities to speak up and ask for better air quality in all our schools.

APS has similar graphics up on its website, but you might notice that the number of classrooms analyzed is different. APS has not released (or does not have) a list of air quality data for about 14% of its spaces, according to records provided to Smart Restart APS. We assessed needs for every classroom space we could find that was being occupied and marked the ones without data as unknown. Most of this analysis is also done from paper documents, and not from actual testing in spaces, which is critical to truly understand how ventilation is working.

Every room needs to have True HEPA filter added. And the rooms with the very worst air quality — and the lowest amount of fresh Outdoor Air — need two True HEPA filters, to make sure those students have the same amount of virus-free air to breathe as those at newer school buildings. APS would only commit to place second air cleaners in 22 classrooms in the spring, and chose to promote the idea that 4 ACH was the same as 6 ACH instead.

The disparities between the amount of new, Outdoor Air that is brought into our buildings across APS is stark. For example, a student at Thomas Jefferson or Swanson middle schools can have 75% LESS fresh air being brought into their classroom than a student who gets to be inside H.B. Woodlawn’s new $100-million Heights building, because they won a lottery. This also means the TJ student in that poorly ventilated room takes on a greater risk of catching COVID-19 in their classroom, compared to a student at the Heights. APS could put a second air cleaner in these rooms at schools such as TJ, Barcroft, Wakefield, or others, to address this. 

If any of this changes, we will update this page.

Here is a list of schools where APS has decided to allow students to have the WORST air quality during the pandemic — about 450 total rooms that need a SECOND air cleaner to reach more than 5 air changes per hour of effective clean air, hopefully 6+ ACH. These are also the rooms that do not have as much Outdoor Air being brought into them.

In addition: 

• Teachers and staff share office spaces in many buildings that are not be designed to have the same ventilation as classrooms. They have requested at least 10 extra air cleaners to position in such spaces. That would require about 380 more units. Office spaces may — by design — have about one sixth of the fresh air coming in as classroom spaces in our schools. Since APS won’t provide such units, we know of many staff members who are purchasing their own. This is where APS is penny-wise and pound foolish. If someone in a shared office space gets sick or exposed, they may be out for two weeks. That’s a much higher cost than the $300 air cleaner unit that could have helped prevent people in that shared space from getting sick.
• Teachers have also suggested that extra portable air cleaning units should be on hand at schools for days when HVAC systems have completely stopped working, so there may be little or no airflow at all to a room, until maintenance can arrive to fix the problem. And schools should have a plan to move students from a room with non-functional airflow, if necessary.

At a cost of about $300 each, adding portable air cleaners to classrooms is a cost effective way to reduce risks and give kids more super clean air to breathe. In addition, this is easier to implement than major HVAC improvements that APS is planning for 19 schools, after its internal review of HVAC systems last summer and fall.

Arlington Public Schools Air Quality Data

Search for your classroom by typing your school name. You can add the room number or grade level if you know it.
For example, type “Jefferson 224” or “Fleet kindergarten” and click the green + sign for more details.