Comparing to ISO cleanroom thresholds, although this isn't a certified/traceable meter so I can't officially say I qualify, I'm comfortably below the ISO 7 (class 10000) thresholds at the moment (outside air intake fan off, me not actively in there stirring up dust):
* > 0.5um: measurement 46K, threshold 352K
* >1um: measurement 1K, threshold 83.2K
* >5um: measurement 0, threshold 2.93K
This generally tracks with the rough data I made with my older, cheaper Plantower sensor but the data was a lot noisier there due to low count values and poor sensitivity. The Sensirion seems to be more consistent although it's too soon to make firm judgments.
I'll let it sit overnight to get a good baseline then spend some time working in the lab tomorrow with the ventilation fan on and see how much worse it gets when I'm sucking in outside air and moving around using equipment rather than just recirculating through the filters over and over. If past data is any hint, I will probably end up in the ISO 8 range under those conditions.
Andrew Zonenberg
npub1cd…z9vpd
2026-07-20 05:30:03 UTC
in reply to nevent1q…qf2l
Author Public Key
npub1cddglts94qutscms0qpmk87lel9m8xku7q0wr20u2th5fxvvunqqxz9vpdSeen on
wss://relay.ditto.pubPublished at
2026-07-20 05:30:03 UTCEvent JSON
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"content": "Comparing to ISO cleanroom thresholds, although this isn't a certified/traceable meter so I can't officially say I qualify, I'm comfortably below the ISO 7 (class 10000) thresholds at the moment (outside air intake fan off, me not actively in there stirring up dust):\n\n* \u003e 0.5um: measurement 46K, threshold 352K\n* \u003e1um: measurement 1K, threshold 83.2K\n* \u003e5um: measurement 0, threshold 2.93K\n\nThis generally tracks with the rough data I made with my older, cheaper Plantower sensor but the data was a lot noisier there due to low count values and poor sensitivity. The Sensirion seems to be more consistent although it's too soon to make firm judgments.\n\nI'll let it sit overnight to get a good baseline then spend some time working in the lab tomorrow with the ventilation fan on and see how much worse it gets when I'm sucking in outside air and moving around using equipment rather than just recirculating through the filters over and over. If past data is any hint, I will probably end up in the ISO 8 range under those conditions.",
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