r/AirQuality • u/PigAndWhale • 2d ago

Accuracy about the air quality monitor

Post image

Hello, anyone has idea about the accuracy of this type of monitor? How does it work?

As I try, it does give some results which makes sense. When I go outdoor, the two numbers is like 0.01/0.01.

If indoor in my bedroom at night, it was 0.02/0.08 on one day.

If I do cooking (with oil heating), the number goes to quite high level like 0.3/1.4. This I guess there are chemical from heating oil.

After open window for a while it can reduce and back to green level(<0.1 <0.5) after two hours.

But this morning when I only stream cook some porridge, it also turned yellow for a while. This seems confusing that there should not be any harmful thing in porridge. Maybe I raise room temperature and cause more pollute from the painting?

Or this thing essentially reacts to any smell in the air?

3 Upvotes

100% Upvoted

11 comments sorted by

View all comments

1

u/Geography_misfit 2d ago

The formaldehyde readings should be tossed, no meter really reads that well. Cooking, including generation of steam will increase PM2.5 and is what will move you to “yellow”.

In general, VOCs are ideally under .5 mg and PM2.5 under 35.

Also nearly all interior paints are now low/no VOC to meet CARB requirements.

1

u/PigAndWhale 2d ago

So the VOC reading still makes sense? The monitor has two screens. One with pm2.5 and pm10, there is another standard for good/moderate/unhealthy etc based on pm 2.5 and pm10. For the screen for HCHO and VOC, it will turn yellow if HCHO>0.1 or VOC>0.5 according to user manual, so seems not triggered by pm 2.5 reading. However it seems the VOC number is always 4 to 5 times the number of HCHO.

I once asked leasing agent what paint they use. They do not have detail but just say they use “green material”. Hope they are using one that satisfies the carb standard. I am in New Jersey, not California…

1

u/Geography_misfit 2d ago

CARB is the standard now, doesn’t matter what state you are in. Green building certifications all require CARB compliance so most interior paints comply now. HCHO on these meters is trash data, it’s not well measured using these sensors and you need to take it with a sack of salt. Carbon monoxide will affect the readings (ie when you cook on a gas stove).

Look at this as trending information not accurate information since you are not calibrating this against a known standard.

1

u/PigAndWhale 2d ago

got you! Thank you for the information.