BME680 - What temp. offset should I use with Pi Zero & breakout garden

I am using a Pi Zero W with the pibow case and a breakout garden pHAT on top. I do not have a room temperature thermometer to take baseline readings but based on this setup I am not sure if the BME680 will experience much temperature offset due to the heat from the RPI0’s CPU temp.

What temperature offset should I use in Celsius if any? I am currently using a wonderful python script that uses a C program linked with the official Bosch library:
I updated the code to use the latest BSEC library version The default temp offset in there is 5C. I also removed the MQTT stuff for now.

After running for a few hours, I am getting numbers like this:

{‘IAQ_Accuracy’: 1.0, ‘IAQ’: 120.6, ‘Temperature’: 28.4, ‘Humidity’: 51.3, ‘Pressure’: 1012.7, ‘Gas’: 230498.0, ‘Status’: 0.0}

Although initially the IAQ was lower at around 30-40. It seemed to ramp up suddenly after a while. Though the sensor readings seem to be staying steady with a bit of variation as I opened the window and let cold air in. Is that weird?