I measure CO2 at home. When the meter hits ~1000ppm, I open all windows until the level is below 500ppm again. Otherwise they stay closed to keep humidity in.

I measure CO2 at home. When the meter hits ~1000ppm, I open all windows until the level is below 500ppm again. Otherwise they stay closed to keep humidity in. My office has forced ventilation, the level there is usually around 700ppm all day. I'd be interested in measuring NOx levels, sadly I don't have a sensor for that. A few people in the office like to open windows for comfort, our air tends to feel a bit stale, even though it's continuously exchanged. My theory is that by opening the windows we let NOx in, which causes the staleness and in high enough levels irritates eyes and throats.