u/djMedd

Went to see Devil Wears Prada 2 with my wife. Got there 50 minutes early, so we waited by the popcorn counter — crowded Friday night, people everywhere.

Set up my air quality monitor on the counter and let it run. The CO₂ climbed steadily the whole time we waited. By the time we walked into the actual theater (which was almost empty), the air in there was way better than the lobby.

I designed the monitor — it’s called the Aeris View, made it in Montreal: getaeris.ca

Ok so I've been wondering for a while why I feel so gassed at the gym. Lightheaded between sets, out of breath way faster than I should be, weirdly exhausted after easy sessions. I just figured I was out of shape.

Then I brought a CO₂ monitor.

Set it down, did my workout, checked back — the reading was stuck between 3,500 and 3,700 ppm the whole time. Not climbing, not spiking. Just sitting there. Which means the air was already that bad before I even walked in.

Quick context on what those numbers mean:

• Outdoor air is around 420 ppm
• Healthy indoor air should be under 1,000
• Above 1,400 your focus drops and breathing rate goes up
• Above 2,000 you get into headache / fatigue / dizziness territory

My gym was basically 9x outdoor levels. Almost double the headache zone. Wild.

It's a low-cost gym and I'm 90% sure they're running ventilation at the bare minimum to cut energy costs. So everyone in there is basically breathing recycled exhale for their entire session.

The monitor I used is one I actually built — getaeris.ca if anyone's curious. But honestly any decent CO₂ meter will do the job. Just check your gym. If you've been feeling gassed for no reason, it might not be you.