Problems with stagnant classroom air in PPS

Airflow reports that did not account for air purifiers only being usable at half speed.

Rooms with substandard ventilation that were overlooked entirely for getting an air purifier, and still remain with no air purifier.

Elementary schools like Rosa Parks, Hayhurst, Woodmere, and more being left with the majority of their classrooms letting kids’ viruses linger in the air for over an hour, even with air purifiers running.

The district not publishing final airflow reports for 21 schools – until our public records requests prompted them to.

We’re advocating to solve problems with indoor air quality in PPS.

PPS’s problems with poor air quality and what we’re doing about it


PPS’s airflow reports are a wealth of quality information about airflow in nearly every room of the district, but the reports contain gaps and errors in the measurements and calculations of effective air changes per hour

What we’re doing about it:

We have completed appropriate and QA’d analyses of every elementary, middle school, and K-8 school that had an airflow report completed, and have that data available and at the ready for sharing with parents and staff. We also have an analysis demonstrating the major error in the high school airflow reports, and we are working on a comprehensive re-analysis of high schools where the airflow report still apply.

Read more about Addressing gaps in PPS ACHe measurements and calculations


Information about air quality and ventilation in PPS schools is disorganized and hard to find on the district website


We have a running history of air quality documents, links, reporting, meetings, and testimony for advocates who want to dig deep and put their hands on relevant documents and claims from the district. We will strive to continually add relevant memos, district communications, and meetings as there are more developments.

Find articles, memos, district reports, former SOPs, etc in Full history of documents and links

Look through HVAC work orders for the 2022-2023 school year through spring

Addressing gaps in PPS ACHe measurements and calculations

Before resuming in-person learning in 2021, PPS had airflow testing conducted in every room of every PPS building, yielding two different types of total effective air changes per hour (ACH_e) measurements for each room. One measurement of ACH_e was for the HVAC system only. The other measurement was total ACH_e if Intellipure air purifiers are run at full speed.

We have done a base analysis for each elementary, middle school, and K-8 school that corrects for three basic gaps in these airflow reports as originally published by the district:

  1. Intellipure air purifiers that were purchased by PPS cannot be run at full speed in classrooms and classroom-like settings. Half speed is the setting at which noise from the unit does not compromise learning. PPS teachers do not run their Intellipures at full speed. Our corrected calculations use specifications obtained from the manufacturer for clean air delivery rate at different speed settings to calculate a Total ACH_e with the Intellipure run at half speed.
  2. In 16 schools, airflow reports were done prior to the school being upgraded to MERV 13 filters, and calculations used the old MERV 8 efficiency factor in PPS’s reports. The district has now stated that all classrooms have been upgraded to MERV 13’s. For schools that were not upgraded at the time of airflow measurements, we have run a set of calculations of ACH_e’s that use the MERV 13 efficiency factor, to estimate the room’s current airflow.
  3. There are haphazard errors in the district’s reports, and many rooms that were excluded from measurements because of the room type (storage rooms, electrical rooms, mechanical rooms, etc) were marked as having a zero for airflow, rather than an appropriate marking of a hyphen. Our calculations note and correct for errors as we find them, and we worked to try to be consistent about excluding rooms such as storage, closets, electrical, etc.

Converting and correcting the PDF’s of the district’s airflow reports into Google Sheets also allows us to do analysis – summary statistics, graphs, calculations of how much different air purifiers would improve airflow, and other options for looking at what the district has or has not accomplished.

Currently, we’ve made public our base analysis, a preliminary plan for ordering additional air purifiers through OHA’s program, and what that plan would accomplish for airflow in a selection of PPS schools. PPS schools have great need for additional filters – 597* kindergarten through 8th grade classrooms grossly lack adequate fresh air from outside, and even with the Intellipure air purifiers the district added, these classrooms remain under 2 or 3 air changes per hour, while another 1111* kindergarten through 8th grade classrooms are only 3 to 6 air changes per hour. See the analyses we’ve shared here.

*597 / 1111 classrooms and counting …

As we do deeper dives into different schools when parents join our group and reach out to us for details about their school, we continue to discover schools in which PPS’s airflow report has an error for one or more classrooms.

Storage closets incorrectly designated as classrooms. Classrooms that PPS skipped entirely for any measurements whatsoever. PPS getting the room dimensions for a classroom wrong.

Both of these totals have creeped up by one or two from our original estimate for the March 21 school board meeting of 595 classrooms below 3 air changes per hour and 1110 classrooms below 6 air changes per hour. These total numbers may very well continue to change by one or two up and down as parents identify errors that PPS made in the report for their school. However, 597 / 1111 is our best estimate today, and we are confident that we have it very close to the total numbers.

These totals for elementary, middle school, and K-8 classrooms under 3 and between 3 and 6 air changes also does not include ACCESS Academy. ACCESS lacks a current airflow report, and that is one of the gaps in data that the district needs to fix.