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    Meaning of bVOC values (and CO2e)

    Meaning of bVOC values (and CO2e)



    We are a big Scandinavian company using a device with the BME680 to show indoor air quality. It transmitts Temp, Hum, Air pressure, sIAQ, Co2e and bVOC. 


    How should we interprit the bVOC value? What is low/High, Good/Bad? I know it is derived from the sIAQ value but how do we put it in context? Using sIAQ and interprit it is easy due to the fact that there are a lot of guidlines and tables showing what is good indoor air quality. But how do we put the bVOC value in comparison to the sIAQ index?  

    Should we look at the sIAQ index value (e.g a value of 250) and say "Ok the index is high and bVOC is high (but what is high?) so this should mean that the air is bad due to the fact that there are alot of people in this room"?

    Thank you for your time! 

    Kind regards Fredrik

    3 REPLIES 3

    Community Moderator
    Community Moderator

    Hi Fredrik_T, 


    bVOC(eq) = 0.5 ppm when sIAQ = 25 and bVOC(eq) = 15ppm when the sIAQ = 250 in case you have IAQ accuracy reaches to 3. 

    It's closely related, so sIAQ could be enough for IAQ. 

    Yes, you can say that your room is "relatively" dirtier than usual when sIAQ is high. 

    The reason might be complex like so many people or cooking whatever. 

    Thank you. 

    Hi @Minhwan , 

    Thank you for that. 

    So what you are saying is that the bVOCeq is "normal/lowest seen" when at .5 and and "highest/highest seen" when at 15. Yes? 

    How is the sIAQ calculated? Please be as specific as you can on this question/answer. 

    Thank you.

    Kind regards 


    Community Moderator
    Community Moderator

    Hi Fredrik, 


    Yes, you can say that air is relatively clean when bVOCeq =0.5ppm and dirty when bVOCeq = 15ppm. 

    sIAQ is calculated with baseline value and gas resistance + offset value. 

    BME688 is measuring baseline value for your environment. 

    For more details, please visit, use the contact form to submit your request and please make sure you refer to the question posed in the community