Thread by @DavidElfstrom

Uh oh @GEDSB. My daughter's classroom was doing well in the fall with CO₂ levels below 800 ppm, so I stopped sending the logger. After my presentation last night with @DFisman, I decided to check it again. #COVIDCO2 /1

This is a school with full mechanical ventilation. This room is centrally provided so air is shared with other classrooms.
Filters have NOT been upgraded to MERV-13 or better.
HEPA is only in the rooms required by the province. Not in this classroom. /2

https://twitter.com/normsworld/status/1468021363172642817?s=20

The relative humidity is low.
The entire school day it was 25%–28%. WHO & CDC recommend 40%-60% for SARS-CoV-2, Health Canada recommends 30%–50% on account of our climate & buildings. /3

I'm a strong proponent of mechanical ventilation. However, it needs monitoring. When it fails, it can REALLY fail: /4

https://twitter.com/jeremychrysler/status/1433913160273178629?s=20

GEDSB didn't follow ASHRAE & Ontario Ministry of Education recommendation to upgrade to better filters in my children's school.
Instead, GEDSB purchased and installed equipment that creates and releases reactive peroxides into the breathing air. /5

https://twitter.com/marwa_zaatari/status/1371955683256590337?s=20

I'd like to address this escape clause "some measures may not be feasible within the context of a facility & related building systems".
Yes, some systems can't handle an upgrade from MERV-8 to MERV-13. But every single mechanically ventilated school in the district? No. /6

Worse today. 2167 ppm peak = 4.6% rebreathed fraction; 1 in 22 breaths fully shared. Better humidity of between 35-44% but I'd rather have the ventilation! A good decline near the end of today before dismissal. /7

Happy to report it's much better today, like what it was like back in the fall. Yesterday had me worried. #COVIDCO2 /8