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pimoroni / enviroplus-python

Python library for the Enviro+ environmental monitoring board
https://shop.pimoroni.com/products/enviro-plus
MIT License
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Please clarify the PMS output #43

Closed ferazambuja closed 1 year ago

ferazambuja commented 4 years ago

The current output erroneously gives the impression that the first 3 values are the actual amount of particles read by the sensor with the names like combustion particles, organic compounds, metals. Those values are actually the standard value, which is a calculation off the concentration "corrected" to the "standard atmosphere", and not the real values of the sensor. https://www.aqmd.gov/docs/default-source/aq-spec/resources-page/plantower-pms5003-manual_v2-3.pdf

PM1.0 ug/m3 (ultrafine particles): 88 PM2.5 ug/m3 (combustion particles, organic compounds, metals): 129 PM10 ug/m3 (dust, pollen, mould spores): 148 PM1.0 ug/m3 (atmos env): 58 PM2.5 ug/m3 (atmos env): 85 PM10 ug/m3 (atmos env): 98

There is more info here: https://publiclab.org/questions/samr/04-07-2019/how-to-interpret-pms5003-sensor-values#c23772

At least for me, this is how different this values are comparing to other similar devices side by side reporting in "under atmospheric environment" : https://imgur.com/a/NbRluZU

ADEidos commented 4 years ago

Hi @ferazambuja , I am interesting in what you are poiting out about this. I am using the PMS5003 sensor and I have some dubts about values I am getting with it. They are too hight to be considered true. I am also trying to find a way to verify the values but I didn't get a good answer so far. N.b. I am using it outdoor.

nophead commented 4 years ago

I don't think the PMS5003 measures temperature and pressure so I think all it can do is make assumptions for fan flow rate, air density and particle density to produce those "corrected" readings.