3D Printer Emission Monitor Quantifies The Stench

While we don’t yet know the long-term effects of hanging out around 3D printers, it doesn’t take a in-depth study to figure out that their emissions aren’t healthy. What smells toxic usually is toxic. Still, it’s oh-so-fun to linger and watch prints grow into existence, even when we have hundreds or thousands of hours of printing under our belts.

Most of us would agree that ABS stinks worse than PLA, and that’s probably because it releases formaldehyde when melted. PLA could be viewed as slightly less harmful because it has a lower melting point, and more volatile organic compounds (VOCs) are released at higher temperatures. Though we should probably always open a window when printing, human nature is a strong force. We need something to save us from our stubbornness, and [Gary Peng] has the answer: a smart 3D printer emission monitor.

The monitor continually checks the air quality and collects data about VOC emissions. As the VOCs become elevated during printing, the user is notified with visual, audio, and phone notifications. Green means you’re good, yellow means open a window, red means GTFO. There’s a brief demo after the break that also shows the phone interface.

The heart of this monitor is a CCS811 gas sensor, which provides VOC data to a Particle Photon. [Gary] built a simple Blynk interface to handle the alerts and graph historical VOC readings. He’s got the code and STLs available, so let this be the last time you watch something print in blissful semi-ignorance.

Concerned about air quality in general? Here’s a standalone portable monitor designed to quantify the soul-crushing stuffiness of meetings.

14 thoughts on “3D Printer Emission Monitor Quantifies The Stench

      1. As someone who has worked on respirator filters before, I can say that I very much doubt there are any particles getting through a packed carbon bed.

        Also, and I can’t reiterate this enough, if people at an injection molding facility aren’t dead from the fumes by 40, I’m certain your 3D printer is no significant concern. Sure, there’s bad stuff in the air. However, the dose makes the poison.

    1. But how do you know your filter is effective for all compounds. There’s some VOC’s that are damaging to use puny humans in very low concentrations, which might not all get captured by a carbon filter. It’s not a bad idea to still monitor the air quality in the room

      1. Yeah, just keep in mind that VOCs are really only vaguely air “quality” sensors. They are not air “safety” sensors. There are many completely harmless VOCs that will cause huge spikes in the sensors that aren’t a problem at all. There are also many harmful VOCs that will kill you at concentrations will below the LOD of these sensors, or even just background VOCs in an average house.

        If you’ve ever *actually* tried using one of these sensors in your lab, using some alcohol to wipe off a surface can easily saturate the sensor for quite some time. I’d imagine an open container of vodka would be enough to make the sensors jump as well. You’ll also get spikes from food.

        Some particularly nasty chemicals – most diisocyanates, because I’ve been looking into casting resin chemistry, for example, have exposure limits of only 5ppb. The resolution (not accuracy) of the unit used in this project is 1ppb, and if you’ve ever used a VOC sensor (I have) you’ll be hard pressed to find a indoor room that doesn’t have random background VOCs quite a bit higher than that.

        1. Some more info on typical VOCs from 3D Printers:
          https://ulchemicalsafety.org/wp-content/uploads/2018/12/VOCs_3DP_112018.pdf

          The other proposed problematic emissions come from ultrafine particles, which a PM measurement system *might* be able to capture. To be honest, I have a suspicion that UL is pushing for this so that they can offer more high end testing to companies. If you look at table 1 in the above paper, the UL-supported paper claims that average computer or copy machine emits far more VOCs than a 3D printer!

    1. Or the modern version:

      1. Just print in PLA
      2. Design stuff to not need other materials
      3. Follow ancient version and leave the room if you find you really do need something other than PLA

      As a bonus, your stuff will probably be higher quality anyway.

      1. This is what I was going to say — use PLA. When I found out what hot ABS smells like, I was decided right then and there, and I have been quite happy with PLA. I find it very usable, and anyways I don’t know what I’m missing.

        I use polymax enhanced PLA when I need something particularly strong or sandable, and it has a slight odor but it’s relatively tolerable. *shrug* I trust the smell test, when it comes to hot plastic.

  1. The CCS811 is not the most accurate sensor without careful calibration. Really none are great but it gives you a relative idea. I have a ccs811 next to my printer and it will show the VOCs

  2. After our research with the HSE here in the UK , we advise that every 3d FFF printer should be subject to a risk assessment (based on current H and S legislation) and ideally housed in a BS approved cabinet with suitable air filtration or extraction.
    The VOCs and nano-particles given off should not be taken lightly.

  3. Hum… I’ve placed a webcam on my printer, so I can watch it from far away.

    The printer follows Lufo’s rule itself. Once in a while I have to go there mid-printing, but since it’s well ventilated, there isn’t even a smell.

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