Classroom Air Quality Needs Improvement, Now!

Testimony of Lizzie Rothwell to the Board of Education, September 23, 2021

Last year, the school district shared room-by-room ventilation reports on their website. Parents learned that many classrooms throughout the district had no fresh air supply at all and many more fell short of ASHRAE’s standard supply rate of 15 cubic feet of fresh air per minute per student. This is a pre-pandemic standard; in an airborne pandemic, the fresh air supply should obviously be higher.

The data shared last fall was updated in the spring to reflect ventilation improvements. The latest report (see charts below) for my son’s school shows that 22 classrooms in his building, including his own, still do not have any supply of fresh air. However, his classroom was deemed acceptable for occupancy because an air purifier was placed in the room. Based on the specifications provided by the district, these purifiers supply only 60 cubic feet per minute of purified air. As Dr. Michael Waring, a Drexel aerosol scientist has already pointed out, these are the wrong air cleaners for the job.

In current temperatures, teachers can leave the classroom windows open for fresh air, but based on measurements that my third-grade son has taken of the carbon dioxide concentration in his classroom, we’ve determined that the outdoor air supply through open windows and building leakage provides only 1.5 air changes per hour in the room. The air purifier is providing an additional .4 air changes per hour, but that’s still less than 2 air changes per hour total, meaning that exhaled viral particles can linger for over 30 minutes.

By comparison, in a classroom downstairs that has functional mechanical ventilation, my son’s friend recorded CO2 measurements indicating that the air in the room is fully replaced every 13 minutes. Every student needs to be in a classroom like this.

The cafeteria has a mechanical air supply of 490 cubic feet per minute, but with 50 students in it, that’s not enough. This graph shows the CO2 concentration in the cafeteria — a measure of how much air has been in someone’s lungs — spiking over the lunch period. This is deeply concerning in a space where students are removing their masks to eat lunch. At Penn Alexander and Greenfield, students are eating lunch outside to mitigate this risk, but my son’s school doesn’t have the resources or staffing to do the same.

How does the school district plan to support outdoor lunch across the district and why hasn’t it happened yet? And does the district have a science-backed plan for monitoring and improving indoor air quality in every classroom? It should not be up to 8 year olds with CO2 monitors to figure out which classrooms are unsafe, but we will do it if you don’t.