Over time, there has been user interest in painting the outside of the sensors for various reasons. We do not advise you paint your sensor.
Depending on the sensor you are using, you may cause data quality issues caused by the off-gassing of VOCs. VOCs can (a) clog the pre-filter of the electrochemical sensors within the MODULAIR and (b) can interfere with the sensors themselves. We have not completed extensive experimentation to determine if any paints are acceptable, so we generally advise against it.