Hello Cane,

Sorry to hear about your health issues.

The BME680 is a mems sensor, but for detecting VOC it operates on the same principle like any other semiconductor / metal oxide sensor. Read on that here: http://www.edaphic.com.au/gas-detection-encyclopedia/semiconductor-sensors/
The sensor initiates REDOX chemical reactions on a heated filament, resulting in ionised local air and as a result modified electrical resistance. A cleaner air will produce less such reactions, resulting in poor conductivity and increased resistance, while a polluted air will increase conductivity resulting in lower resistance.

Given the existence of many different gases / vapours / chemicals, any ppm would be an approximation for a particular class of substances. Their molar mass / burn rate / ionising resulting compounds and multiple other properties and complicated chemistry, make it impossible to compute an absolute ppm level, or to identify the substances.

On the other hand it offers a clear indication of changes in the air composition, and since the uRADMonitor records all data online, you have access to a history chart and you can correlate that to your condition. It will help you link the numbers to various emissions and their effect on your health.

Please have a look on the uRADMonitor A3, here. There is also the uRADMonitor INDUSTRIAL, that has 4 slots where we can install 4 sensors for 4 different gases, there’s a big list at the bottom, see it here.