There is another step beyond just running the 3.1.9 firmware. You have to enable the correction in the web app, if you haven’t done that yet
@Achim_AirGradient, I will try it with that function disabled for a few days. It doesn’t seem to have an effect if it’s disabled overnight (the “sleep” mode on the air purifier does that automatically) but I don’t think I’ve kept it off for more than 24 hours. Will report back!
@MallocArray, I actually did enable the setting in the web app. That’s when I noticed that the strange errors from my PM0.3 sensor affected the PM2.5 readings.
Without the correction enabled, it would almost always be at 0 to 1 unless the air quality outside was particularly bad and got into my home (e.g., regional forest fires). With the correction enabled, I was getting random spikes up to 50 (and I have a hard time believing that the actual PM2.5 level in my room would go from 0 to 50 to 0 within a span of 20 seconds).
I have the same issue with the pm0.3 count jumping to a very high number, often above the number registered on the outside monitor. Weird given that there is no movement in the room, the windows are closed and the air purifier is off.
@eugene @rpirsc could you please share the serial number on your PM sensor (not the AirGradient monitor). Especially the date stamp on the serial number.
Then we can have a closer look in our test lab to see if we can reproduce this.
Hi @Achim_AirGradient, the serial number on my PM sensor is PMS5003-2023121807159. I can also report that disabling the ionization function on my air purifier ~2 days ago doesn’t seem to be changing the behavior.
Hi Achim
My serial number is PMS5003-2023121807827
Once I apply the correction, should I expect the correct PM2.5 values to appear on the display of my AirGradient? I’m currently just seeing 0 on it, but the dashboard shows the actual correction.
Yes, but it needs a firmware update that we currently finalize.
I’m also wondering there exists batches that are also uncharacteristically accurate. In the computer world there exists (or used to exist) companies that “binned” chips for enthusiast customers to buy - buying and testing chips to see which ones could be pushed the furthest to resell.
I wonder if there is any value in binning these sensors. Does there exist a significant difference between the most and least accurate batches? Do some batches have better PM0.3 or PM1 than others?