So often there is not too much difference in the accuracy of the monitors. I wrote about this some time ago [1].
However when it comes to data ownership, API access, costs and repairability that's where there are big differences. In many reviews these aspects are in my opinion not enough covered.
[1] https://www.airgradient.com/blog/most-aq-monitors-use-same-p...
It’s got the PMSA003 which doesn’t seem to be used by anything else on that list, though I’m guessing from a quick glance at the spec sheet is substantially similar.
Part of why I went with this one was because it was relatively open. They do offer a cloud service and things most people would expect, but the device will work out of the box with no account or internet connection. Mobile app works too. It stores some historical data on the device so you still get nice graphs and charts.
If you punch the device’s IP in a browser it gives you a page back where it dumps all the data back at you. There’s an actively maintained Home Assistant integration.
All the sensors are replaceable. Or swappable if you decide you would really rather measure something else later. (Don’t know about buying the component and soldering it on yourself, but they sell the sensors on the little daughter boards that can be swapped.)
Only real downside I can think of is… it’s not particularly cheap.
Mostly just mentioning it in case it ends up on some of those charts later. ;) Biggest challenge with any of these measurement devices is… I have no reference to compare to or any way to evaluate the accuracy. (Lemme tell you about the time I tried to measure the humidity around here… I now own a psychrometer as a reference device since I figured that’d be pretty hard for any manufacturer to fuck up _too_ badly.) I’d definitely be curious to see how it stacks up.
That said, I have definitely considered an airgradient and the esphome firmware.
They are open source, and provide the code source of their software as well as for the hardware, which is very rare. I have plan one day to build my own outdoor monitor based on their plans (as a project I don't have the usage)