Air Quality Index analysis while dumping beans

Roasting on the Bullet R1
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Hi Roasters. I’m providing some air quality index (AQI) information that I think will interest you. I recently acquired an AQI analyzer because I was curious about exposures while roasting.
First some information about my setup: I use an in-line fan exhaust system that vents to the outside. I roast in my garage so I always have a big floor fan circulating a lot of air for my own comfort (it’s hot in Florida in the summers!) I am including a picture of my setup.
In short, the AQI meter indicates that everything is A-OK while roasting with my setup (see the still photo of the meter)

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. What really surprised me was what the meter indicated during dumping of the roasted beans; the air quality deteriorated rapidly well beyond the point where the analyzer went into alarm. I have included a photo showing the meter at its highest reading.
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In the photo you will see that the bottom/center number is the AQI, the bottom/right number on the meter indicates Particle Matter less than 10 microns (PM10), and the number right above PM10 is the PM2.5 indicator (Particle Matter less than 2.5 microns. Particles this small can enter the lungs and even the blood stream. This photo was shot with the meter sitting within a foot of the cooling bowl.
I repeated the measurement on a subsequent dump with the meter closer to my body, or within 2-2,5 feet. The photo of that dump will show that the AQI near me was still not good but the analyzer did not go into alarm.
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In the future, I will keep as much distance as I can between myself and the cooling bowl while still being able to stir the beans, and will wear a mask like those we’ve all worn during the Covid pandemic.
Finally, I found an article regarding a study performed by an environmental agency at a coffee roasting and packaging facility. (https://www.cdc.gov/niosh/hhe/reports/pdfs/2016-0080-3324.pdf In short, all employees involved in the process showed above acceptable exposure limits for various compounds related to coffee roasting and packaging. What I gather from this is that I should do my best to limit my exposure while enjoying my craft! Maybe you will come to the same conclusion.

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Do you have a vent hose from the back of your cooling tray to vent out? If not, I wonder what the AQI would read if you have a hose that directs the fumes outside. In my setup I have a hose from the cooling tray to direct the fumes to my range hood vent that is on during roasting. I think many of us have a hose to vent out the cooling tray fumes.

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Hi blacklabs. No I do not, but a hose at the cooling tray exhaust is now on my list of improvement. Thanks.

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Let us know how that AQI reading changes after that improvement… I’m curious! :slight_smile:

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I have an exhaust tube on my cooling tray, and I also see out of healthy region AQI levels when dumping beans, but all good when roasting. I don’t have as fancy of an AQI meter, but I do have a meter that is connected to my air purifier that lets me know when things are out of healthy region. Currently I’m using an inline 6 inch AC Infinity, which adapted to pull from 4 inch ducting and split 50/50 between the cooling tray and exhaust area of the roaster. I think it would be possible to create some sort of adapter that could pull some air from just under the exit of beans from the roaster and also from the normal exit from cooling tray and then y-into a 4 inch male exit. I have a picture in my head, but that’s hard to explain. Think of something like a hardwood floor vacuum cleaner attachment, that might have a curve around the roaster exit to get as close to the exit as possible, which would then meet up with the 4 inch coming out of the cooling tray.

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Big concerns definitely for long term health.

Not only the smoke from the beans, but the plastics can heat up significantly enough that I wonder about fumes from those. Though if you smell plastic burning, it is probably a sign that your roaster is not working properly.

Thanks for sharing about the air quality and it is a good reminder to make sure ventilation is a priority.