I got sensor a week ago and have noticed for past couple of nights aqi has been zero. On latest firmware air gradient one.
The drops-to-zero don’t seem like data artifacts - no “40ug one second and 0 the next”. If I saw that data I’d just assume the sensor was experiencing a bit of particle-free time.
Is your sensor mounted high above the ground? Has it been windy at night, or calm?
Currently, i have it on a bedside table. It would have made more sense if it were gradual, but it drops to zero, making me wonder if the sensor has some issue. I got the assembled one.
Do you have an HVAC system at your house with hepa filters and fresh air intake?
The pattern looks very similar to my house where I can reach consistently 0 PM with a filtered fresh air that creates positive pressure.
The way it drops does not look like a sensor issue to me but real measurements.
There is no HVAC in the building, so the heating is provided by old water radiators. My windows are generally closed at night, so maybe that’s when I see low AQL. The red bars are probably due to the humidifier running.
I am getting an external unit, so that will probably help in checking as well by running inside when this one is zero. I understand the calculation model won’t be correct, but it will give an idea.
Try and use distilled water for the humidifier. Some of them create a lot of particles.
Yes, ultrasonic humidifiers put all of the minerals into the air.
Traditional wick or heated humidifiers do not.