BME680 - How do I convert the IAQ value to ug/m3?

[Sascha29]

Hey all,

I want to measure VOC with the BME680 but I have to convert it into the unit ug/m3. I couldn't find something about a conversion from the Indoor air quality index to the physical unit.

Is it possible?

Many thanks in advance for you help.

Regards

//Sascha

[Vincent]

No,  BME680 is measure the relative changes of TVOC and we define the IAQ value to repsentive it.

So, the IAQ is not able to conver to ug/m3 units.

[Sascha29]

Thanks for your quick reply.

Is it possible to exlpain it in more detail how the sensors works and calculate the IAQ index?

Currently I am not sure, if your component is comparable with customer requirements we have to fulfill.

Thanks in advance.

//Sascha

[Vincent · Accepted solution]

More detail can be found in datasheet from BST website.  I put one link here.

BME680 datasheet 

In general,  BME680 is detect the TVOC component and the register value is changing based on the concentration of those component.    BSEC lib will be used to integrated the output of gas resgister value and convert it to IAQ index which defined as 0 - 500.   BSEC lib will track the baseline of the VOC value and set the cleanest environment as IAQ 0. 

So BME680 is an relative gas sensor, it will able to shows the VOC concentration change but not the exact value like ug/m3

[Sascha29]

Thank you so much for your help!