Mounting instructions - indoor and outdoor?

[Guilherme]

Hello all,

I’ve found these mounting guidelines on the AG website: Mounting and Installation Instructions

I would like to ask if these apply for both indoor and outdoor monitors. Reasons I’m asking are below:

• Minimum height of 100cm on the wall: in most pictures I see from the mounted indoor monitor (users, website, reviews), it is rather placed directly on a desk by means of standing clips that are provided in the kit. Could this however potentially affect monitor readings (e.g. PM due to dust in the surface)? I started to wonder whether my indoor PM readings might be off due to this.

• Maximum height of 300cm and “unobstructed air flow at the bottom and top of the monitor”: I understand that the outdoor monitor enclosure is closed on the top, so would maximum height and/or obstructed airflow on top be an issue for outdoor monitors too?

For the latter, I was even considering mounting my outdoor monitor directly on the balcony ceiling. This would have two advantages for me: (a) avoid direct sunlight on the wall; (b) it would be closer to power source - I have no power outlet in the balcony, but do have a ceiling light there.

[Guilherme]

Hi, any thoughts on the questions above?

Today I managed to install my outdoor monitor directly on the balcony ceiling next to the lamp I have there, it looks like this (photo is rotated 90°).

And this is how I have my indoor monitor standing directly on some desk.

Do you foresee any issues with these mounting options?

[Achim_AirGradient]

Does the lamp emit hear? It might influence the temperature (and thus RH) readings.
Also, I think it will be better if the monitor is not mounted horizontally. I can imagine this would also impact the heat distribution in the enclosure and thus distrurb any standard compensations we develop.

[Guilherme]

The lamp now is always off as I’ve simply redirected the power to the AirGradient. But interesting point on the horizontal position. My initial goal was to keep it vertical, but the hole on the enclosure didn’t let me align with the screw on the lamp (due to the ceiling) unless the monitor was in the horizontal position.

What about the close contact with the desk for the indoor unit? Could dust or other particulates on the desk potentially affect the readings?

Asking as for a while now I’ve observing the PM values to always fluctuate around 0-30, unless pollution outside is high (and then the indoor monitor will exhibit higher values as well). Maybe with averaging they wouldn’t fluctuate that much all the time, but still, I’m under the impression that on the first weeks it behaved differently.

So I started to wonder why I’m unable just to see very low levels, even if there could be something wrong with my sensor (if the desk position wouldn’t explain that). Could it be that there is some dirt stuck inside the sensor, which would lead to never have very low stable values?

[Guilherme]

@Achim_AirGradient, To further illustrate my concern with the indoor monitor standing directly on some surface (or whether it’s the PM sensor not working), here is a screenshot from last 24h of readings as using the stock firmware 3.1.7 (as released in the Arduino IDE)

Between 8AM and 10PM, I sometimes had the windows open, but no air purifier running.

So what least I observe there is: when outdoor PM level increases, the indoor does accordingly. But when it gets to lower values, then the indoor keeps fluctuating around some baseline value between 15-25 ug/m3.

And the same seems to be the cast after 10PM, when. I turn on the air purifier for sleeping. One can see the immediate response on the PM level to be lower than outdoors. But then it doesn’t get below that baseline level aforementioned.

One could think that the air purifier is not working properly, or even that windows are not sealed (and indeed I leave one window slightly open so CO2 doesn’t explode either). But at some point it is clear that outdoor level becomes better than indoor, whereas the latter still keeps fluctuating around that baseline level.

What would be your thoughts on this?

[Achim_AirGradient]

Can you post your humidity levels for the same period? High humidity overstates the PM measurement. So if you have a higher humidity inside that could cause it.

[Guilherme]

Hi @Achim_AirGradient , here the indoor RH for the last 48 hours here. I would say it’s not that high, and under similar conditions in the first weeks that I had the sensor it would still be able to record lower PM values though.

If there is some dust stuck inside the sensor, would it explain that baseline level and yet the ability to still pick up higher PM values? Or even the former hypothesis of the monitor to be standing on a surface?