The setup was adapted depending on the analyzed r.h. range. Purified air was used as zero gas (ZG) (MCZ Umwelttechnik, NGA 600-25 MD). For measurements in the range of 0-80% r.h., water vapor up to 10000 ppm (∼30% r.h.) was generated using a standard vapor saturation unit (MCZ Umwelttechnick CGM 2000). R.h. levels of 40-80% were generated using humidification modules (MCZ Umwelttechnik). To study changes in r.h. from a baseline r.h., the measurement was performed using the humidification modules for both ZG and analyte gas (AG). Purified air with a constant r.h. of ∼30% was used as ZG, while the r.h. of AG was increased up to ∼80%. Optionally, a commercial humidity sensor (BME680, Bosch SensorTec) was placed in the same test cell and read using a Raspberry Pi. The sensors were exposed to AG for 4 min, followed by ZG for 8 min. The sensors were operated with a bias voltage of 1 V applied by either a Keithley 2601A source meter or an Agilent 4156C semiconductor parameter analyzer, and the resulting current was measured continuously. All timetraces were evaluated using a custom-written python script. The baseline conductance for each sensor was determined by fitting linear functions below each measured transient, taking a ∼30 s interval ∼5 s before r.h. exposure and a ∼30 s interval after ∼7.4 min of ZG exposure into account as linear fitting range.