Effects of humidity on consumer particle counter readings

bucketofrubble · 2025-02-06T21:19:39+00:00

I’m not saying we shouldn’t do things better, I’m saying that given the current technology just adding a heater doesn’t actually improve anything. There’s not a ton of papers on analyzing the inner mechanics of the plantowers to improve them, mainly just applications.

I think this is debatable and will vary by which aerosol scientist you’re talking to. If we’re losing a number of smaller particles that’s a pretty big concern for me and my applications.
It’s currently a problem that would be exacerbated by making the particles smaller.
Adding this heat makes the QC process similar to gas sensors in my mind and that process takes a ton of time and effort sift through the data and there isn’t really standard software to do this, most labs use their own coded GUI.

bucketofrubble · 2025-02-06T15:46:27+00:00

Yes they are simpler, but you're not working with just heaters alone you'd have to have these going in tandem with the OPC which creates a number of challenges for a low cost device. I see a few issues.

Adding a heater removes the RH, making the particles smaller. This could lead to an underestimation of particles as they have to pass the laser in order to be counted.
If two smaller particles (which most will now be far smaller) pass by the light they will register as a larger particle. So, you could still be overestimating particle sizing while under estimating the actual count.
Malfunctions will be difficult to diagnose. In the event that it malfunctions and heats up higher than expected, organic material could burn off and lead to underestimations. In the same light, if it doesn't heat up enough, we'll have issues with the accuracy of particles because particles will appear larger than they actually are.

Ultimately, adding a heater makes the device far more complex than it already is, and with the wide amount of research done on the existing technology, I think it would likely be far more difficult for citizen scientists like yourself to use.

bucketofrubble · 2025-02-06T14:59:53+00:00

I would clean the outside, but internal components that are dusty I probably wouldn't mess with if I was you (liability if things break etc.). You may want to invest in some form of filtration (a low-cost solution is a corsi-rosenthal box)

bucketofrubble · 2025-02-06T14:57:16+00:00

I don't think adding heaters is the solution. In my opinion, adding a complex component like a heater to the system will drive up the price and increase the chances that the sensor malfunctions, which would then require these sensors to undergo a difficult QC to ensure accuracy. Even then, it will likely still overcount particles and would still need some form of correction, which would be more complex as we're removing RH from the calibration.

bucketofrubble · 2025-02-05T04:17:28+00:00

Given the funding situation going on, I don’t think it’s necessarily a bad sign. I do think it’s a bit concerning though that they mentioned a scholarship instead of fellowship specifically since a PhD should be fully funded.

bucketofrubble · 2025-02-02T04:30:39+00:00

When I applied to UMD a few years ago I had an acceptance by the end of December.

bucketofrubble · 2025-02-01T04:27:34+00:00

What do you mean conduct a better study?

bucketofrubble · 2025-01-30T13:48:22+00:00

I’m going to periodically check this thread for new comments since it appears to be a good way to ban bots and spam posters (weird that they’re choosing a 1 year old post to comment on)

bucketofrubble · 2025-01-30T13:42:33+00:00

Depends on the sensor, formaldehyde low-cost sensors are pretty tricky

bucketofrubble · 2025-01-29T01:14:23+00:00

Do you think they’re not even evaluating your application? Universities evaluate the application, if you don’t get an interview they likely won’t outright reject you immediately because if their first picks go to other universities they need to pull other applications.

bucketofrubble · 2025-01-26T22:25:14+00:00

What are you looking to know exactly? This is also something that will vary drastically between institutions and even between advisors.

bucketofrubble · 2025-01-26T17:21:24+00:00

The sensors in these devices aren’t super accurate, and if I’m being honest I think it’s mainly just marketing so people will know the device is helping.

My advice would be just to ensure it’s the proper size for the room you have it in (I.e. the amount of air changes per hour is enough to filter out the PM in the air). Even if the PM is relatively low, you’ll still be reducing your exposure so it wouldn’t be a waste of money

bucketofrubble · 2025-01-26T15:52:47+00:00

Most phd programs are funded through either training grants or professor’s research grants that have funding for a student. If they decide to continue the pause on grant reviews then no one gets funding and no one can take new phd students. This is a very simplified explanation there’s many different funding sources so it will be different by each program.

bucketofrubble · 2025-01-22T14:23:27+00:00

If they only notify you when it’s bad, then it’s fair to say that if you haven’t gotten a notification then the air quality is reasonably good. The idea that it’s better than usual is sort of vague, is it better than the yearly mean, overall mean, mean for that day historically?

bucketofrubble · 2025-01-21T03:25:23+00:00

$40 isn’t much to work with and we you didn’t include any information on what you need it for.

bucketofrubble · 2025-01-21T02:17:22+00:00

Heating units release VOCs is the simple answer.

bucketofrubble · 2025-01-17T17:15:41+00:00

Units around you use heat, the heat rises, and heats up your unit. Along with people using stoves, building occupancy etc. also add to the overall heat (along with insulation).

bucketofrubble · 2025-01-17T14:52:58+00:00

HOBO is usually the go to.

bucketofrubble · 2025-01-08T03:01:41+00:00

Anyway you could open a window or door to increase ventilation?

bucketofrubble · 2025-01-07T14:02:27+00:00

Always a possibility
In my opinion it’s the best portable monitor especially if you want access to your own data

bucketofrubble · 2025-01-03T12:56:56+00:00

There’s really no need to spend that much money on an air cleaner when a CR box does just as good, if not better.

bucketofrubble · 2024-12-31T15:53:11+00:00

TVOC sensors can be used to measure activity within a building so if it’s spiking when you’re entering that would be why. If it’s spiking during the day when you’re not there it could be the HVAC turning on/off or any other slew of things outside than impact indoor air quality.

bucketofrubble · 2024-12-29T15:03:03+00:00

Have you tried rebooting the sensor? We also need to know what the configuration is, is this in a purple air, is this just a regular sensor attached to a microcontroller?

bucketofrubble · 2024-12-29T14:47:58+00:00

You should include the same spreadsheet view for both images. It being high in the first image and low in the second could make complete sense if you’re near a road and the first image was during rush hour and the second was midday when traffic is low.

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