Better Ventilation Systems Are Crucial

By Lizzie Rothwell

Good evening everyone. I testified at the September Action Meeting about measurements of carbon dioxide concentration that my son took in his school. These measurements are a proxy for direct measurements of the airflow rate of a ventilation system. They give us a rough indication of the total air changes per hour in an enclosed space. A healthy classroom would have about 5 air changes per hour. 3 should be the bare minimum. In my son’s classroom, we estimated that there are 1.5.

Dr. Hite — at the September meeting, you asked me where my son attends school, and I was reluctant to answer because I knew this was a problem throughout the district, not just in one particular school where a parent who is a building professional was concerned about indoor air quality and able to afford a $200 CO2 monitor. I’ll tell you now that my child attends Lea Elementary.

I’ll also tell you that at Kearny Elementary, the CO2 concentration regularly reaches 1500 parts per million in a 780 square foot classroom with 32 students. This indicates about 1.8 air changes per hour.

It’s better at Richmond Elementary, where our measurements top out around 1000 parts per million, suggesting a range of 3-4 air changes per hour.

Students at Henry found that their specials rooms had up to 1800 parts per million of CO2, indicating about 1.2 air changes per hour in a room that serves multiple groups of students each day.

At Southwark, we are measuring at least 4 air changes per hour when the windows are open, but one afternoon when they were closed, the rate dropped to 2.6.

And at Strawberry Mansion High School, our peak data point is 2088 parts per million, but as long as there are people in the room, the numbers keep going up. They do not level off or decrease until the room is vacant. This classroom has well under 1 air change per hour.

Let me repeat that a healthy classroom should have 5.

I can come back in January to give you numbers in more schools, but I would rather see the School District develop a transparent and comprehensive master plan for monitoring and improving indoor air quality in every building. I’m grateful for the District’s mask requirement and relieved that 5-11 year-olds can now be vaccinated, but even with these mitigations in place, we are likely to see a seasonal increase in covid rates. Any principal who has lost an afternoon to contact tracing and any parent who has scrambled to accommodate their child’s sudden return to virtual school during quarantine will tell you that this situation is untenable.

We will be living with covid for the foreseeable future, and institutional commitments to better ventilation systems are crucial to any return to “normal.”