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AirGradient Forum

CO2 report from outdoor monitor

#1

Hi,
I’ve seen recent comms from Achim on global CO2 map. Unfortunately my monitor does not provide CO2 levels, therefore not visible on map. I thought that was due to the reason there are no readings necessary outdoor, but now I’m confused.

Serial Number: ecda3b1c2ff0
Monitor Maker: AirGradient
Firmware Version: 3.1.3
Model: O-1PP
Monitor Commissioning Date: Jun 1, 2024

#2

The O-1PP model you have contains two PM modules but no CO2. You can replace one of the PM modules with a CO2 module that’s available in our online shop under spare parts.

#3

Ok, thanks. That makes sense. Are there any downsides taking out one PM module?

#4

I’m guessing by this statement, you meant that CO2 is not a concern on an outdoor monitor?

If that is the case, you’re partially right, yes. Outdoor CO2 concentrations won’t impact you much, and there isn’t a need to monitor them in regards to how they impact you or your health, as even elevated CO2 levels outdoors (such as near a busy road) won’t often exceed 500ppm, let alone 600ppm (see the example here). On the other hand, indoor levels can easily reach 2000ppm or beyond, which will have a direct and significant impact on your cognitive performance and also impacts other factors, such as how long viruses can live in that environment.

The importance of monitoring CO2 levels outdoors is related to climate change and identifying local emission sources and their impact, not to health effects (as it is indoors). I believe this might be where your confusion comes from!

Regarding your second question:

The second module is installed for redundancy and reliability. In most cases, the second sensor isn’t needed, as it will provide similar readings to the first. However, having two sensors allows us to know if one is failing. Suppose the readings from both sensors match or are within a close range, confidence in the accuracy of the data increases. If there is a discrepancy, it can indicate the need for maintenance or a sensor replacement. However, these sensors tend to perform well for years, and that is why we opted for a more useful CO2 sensor instead.

Since you already have a second PM module, you could occasionally use it to test the first sensor. For example, in most cases, run 1x PM module and 1x CO2, but every six months or so, insert the second PM module for a day to ensure the readings are consistent with the first. It might be too much work, but it’s just an idea! At worst, you’ll have a PM module replacement if needed.

I hope this helps answer your questions!

1 Like
Outdoor Temperature and humidity reading correction
#5

The sensor is autocalibrated to 400 ppm every 8 days. So, what will it show outdoors? The difference between day and night, weekday and weekend?
How is that related to climate change? May be, there is some article on that?

#6

Yes. I wrote exactly about this and below article gives some real example.

1 Like
#7

Thanks for the article!

Did I understand correctly one can switch Open Air device between “PMS5003T + PMS5003T”, “PMS5003T + Sensair S8” and “single PMS5003T” as easy as plugging in one sensor or another, and everything will work with the latest firmware?

#8

Yes. The firmware will auto detect the different models.

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#9

May be a stupid question.

I have read in the forum (for example here) that ONE unit works well if SGP41 and SHT40 are placed one instead another (the only issue is the temperature is shown a little bit high as it is warmed by PM sensor).

Can I place SHT40 unit instead of SGP41 to Open Air? Will the firmware recognize that and work?

#10

I am not sure it will work. I will ask our firmware developer.

However, the problem is the ventilation of the outdoor unit compared to the indoor unit. So I believe the SHT40 would also be affected by internal heat built up.

#11

Answering myself: no, it will not work.

boardInit function begins with the code:

  if (ag->isOne()) {
    oneIndoorInit();
  } else {
    openAirInit();
  }

oneIndoorInit contains SHT sensor initialization, openAirInit does not.