Hello nathan_swidget,
According to the question, the main point is about the external heating source effect to IAQ. Please find the comments here:
Inside BME680 datahsee, the sensor-to-sensor deviation is listed in table3. the testing condition is under 0-40 degC/ 20-80%. If the environmental temperature is beyond this condition, this spec will not be fulfilled.
But for real case, since IAQ is relative value which quantify the quality of the air, the external heating source would have limited effects to single sensor. Temperature offset setting will not affect IAQ calculation. One recommendation is to set BME sensor away from heating source. If it cannot be placed away from the heating source as description, the heating of 40 degC is acceptable for BME running according to the datasheet.
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