@FotoFieber how goes the testing? The BME680 and the SGP30 both correlate in their readings with temperature. This means when the temperature goes up and down, i've seen the TVOC reading go up and down as well. Hardly useful for a sensor that is supposed to tell you if your air is bad or not. Take a look at the screenshot below: You can see that both sensors react wildly to temperature. Whereas the CCS811 has a bump but not significantly. If I go by the scales in the data sheets for the BME680 and SGP30, the room that these sensors are in require immediate venting. Even right now, the SGP30 sensor is half way to the danger zone. Danger zone! While testing that, I also threw everything together into an enclosure. Even added GPS: So it sits up in the kitchen and chirps at me when I burn my food. I switch on my air purifier and the particulate level goes down pretty quick!