Air Quality (PM2.5) Monitors

[Basso53]

I have two Phillips AC2887 air purifiers (PM2.5), and three of the local CM ones. Both of the Phillips have new filters and display the PM2.5 reading also; the local ones don't but I do have two Chinese Air Quality monitors for inside the house.

The situation is the Phillips purifier/monitors give a vastly different reading from the stand alone monitors. I have attached two photos taken in my computer room which show two vastly different reading with the devices whilst standing two metres apart. The same goes in my living room with the other Phillips and stand alone monitor. As I'm in the at risk group so would like to know the current true reading of the PM2.5 particles so I can either put another purifier in the occupied space or not. At the moment I am running an air purifier 24/7 in the room I occupy.

I chose to live here so please no lectures....I am just trying to adjust to the situation and am seeking advice on a way to get a true PM2.5 reading...perhaps a good monitor...not sure.

[KannikaP]

11 minutes ago, bbas3008 said:

which show two vastly different reading with the devices.....................

Slightly off topic but I have been in a hospital where the blood pressure and weight measurements are completely different on different machines.

Edited March 3, 2023 by KannikaP

[Don Chance]

Where a n95 mask indoors, when you are sleeping too.

[VocalNeal]

9 minutes ago, KannikaP said:

Slightly off topic but I have been in a hospital where the blood pressure and weight measurements are completely different on different machines.

Use three machines and take the average????

[tomazbodner]

Is it possible that sensor might have some particles stuck in it? I know Xiaomi warned that you should clean the sensor and small fan that feeds it regularly and that if you see strange readings, it's likely that sensor has some dust particle blocking laser.

 

Of course it could be quality issue of the sensor as well, but above one is quick to do and see results. I usually just vacuum the vents.

[brommers]

Firstly you need to know which monitor is using which measurement system. The Chinese system uses an average spread over time to give a smoothed reading, the US system uses real time measurements to give readings which fluctuate more than the Chinese but is a more accurate measure of reality. Then you need to measure your air at the same locations. The instrument with the purifier is measuring air in the close proximity to the machine, so place your mobile readers in exactly the same location. And finally you need to be sure of the type of measurement technology being used by the various devices as they have varying accuracy rates. The best measurement monitor is possibly the AirVisual that is sold via the IQAir app site, but others might prefer a different device.

[trevoromgh]

Just a thought, but as you are in an 'at-risk' group it might be worth investing in a water misting system on the exterior doorways and windows you open on a regular basis. Have heard they not only cool the air but trap the particulates as well before they can get inside via those routes anyway.