For giggles, I dipped the CO2 gadget into a bowl that had just fizzed up some bicarb soda + vinegar. But I'm not doing this again because I had to delete the day's data in order for the graph to show a more useful y-axis range. The app is quite good actually - you can tell it to delete data older than x days, etc; but since today is day 0, I deleted everything to fix the graph's scale.
There seems to be good responsiveness and range. Low value appears close enough to background CO2 levels. But it's the relative changes that matters more in day-to-day use anyway. Either way, I'll see if it "auto calibrates" lower in the coming days.
The LED has a few different colour states (green/yellow/red, as well as white for initialising and I think blue for updating settings). The brightness level can be changed in 10% increments from 0 all the way up to 100. Data is stored until logging interval is changed or power is removed.
I finally own a CO2 monitor! After seeing Naomi Wu's recommendation, I chose the Sensirion SCD4X CO2 Gadget. I ordered it from Mouser Electronics 8 days ago and after UPS pretended to card me yesterday, they finally delivered it today (next time I'll try FedEx first and hope for better).
I'll try to repeat my survey in the future with the looming bushfire season and work to count more comprehensively - perhaps video on tripod near the mall at a pedestrian crossing will be a more rigorous method. But I don't think it requires genius to notice that very few people mask when it's a good idea to do so.
This video is good too: https://www.youtube.com/watch?v=TRCZ8Qnf0Z0
You don't even need to bother with the hood if you want a test that's better than doing nothing.
How to do a DIY mask fit test
Pro tip: if you haven't done a mask fit test already, using bushfire smoke is better than nothing. At least it's better than breathing the smoke in without a mask or respirator. With a well-fitting P2 respirator, you shouldn't be able to smell any bushfire smoke.
More on DIY mask fit tests: https://twitter.com/michael_hoerger/status/1604020083189219330
Mike Hoerger, PhD MSCR MBA on X
THREAD: 19 Tips for a DIY mask fit test to reduce your risk of #COVID19.
H/t @amandalhu & @__philipn__
What did I miss?
