I'm using the BME680 or 688 together with the BSEC library to obtain an IAQ value, everything appears to work as I expect, the index starts low at a steady 25/27 and then after some time starts to report a varying IAQ, apparently with the changing enviroment.
However, I noticed that when an SCD41 measuring CO2 besides the BME680 starts to detect an increased value of CO2, the BSEC IAQ falls, this does not make any sense to me, surely when in an enviroment with high or increasing CO2 levels, should the IAQ increase and not decrease as it does at present?
My logic is the IAQ should climb as CO2 concentrations climb...
The graph on the left is the BME680 CO2 ppm, on the right is BME680 IAQ and at the bottom is the SCD41 CO2 variations in the same environment.
You can observe that as the SCD41 reports rising CO2, the IQA falls as does the BME680 CO2 equivalent?
What am I missing here?
Has the BSEC library been validated and are there any results of the validation?