BME680 VOC Scale Change on the PurpleAir Map

Recently, the scale for the BME680 VOC sensor readings changed on the PurpleAir map. The colors of the scale now transition from white to blue, and the levels do not have any health information associated with them. We have made this change because the BME680 sensor is still experimental, and many users were getting very concerned over the readings their sensors were reporting. We do not feel confident enough in the VOC readings yet, and we are still taking steps to understand and improve the sensors’ readings.

We are actively working on new firmware for the PurpleAir sensors that will use more memory to store variables that the BME680 sensor creates during its calibration. The sensor will then consider these variables when reporting VOC data.


Hello. I am a resident of Louisville that was impacted by the Marshall fire. As you are likely aware, many people in the community have installed PA with the VOC monitoring. I understand that it is in beta but do you have any indication as to how to interpret the results? My concern is PM 2.5 shows “0” / green but surround VOC monitors show 300-500.

The city, the public health department, and the school district, are not taking into account the VOC readings because they are in beta. Therefore, our children located at schools near the burn sites, have recess outside, play sports outside, etc. because the air is considered safe. Given the proximity of Coal Creek elementary to the fire and the fact that lots are being cleared with giant excavators, I highly doubt the air is safe.

I would love some guidance on how to approach thinking about the VOC numbers.

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Is there an eta when this may transition off experimental status?
Formaldehyde would be nice to include as well.