I have a bunch of sensors from Plantower and Honeywell, I will post some examples in September (I'm away on holidays now) using those sensors and displaying AQI on LCD.
The point I was trying to make in my previous message is you cannot really make this sensor work. With no fan and no decent factory calibration you cannot have reliable data. Look at the data sheet, the curves for min/max value are somewhere around +/-60% from real value. As air flow is generated from heating resistor results will also depend a lot on the temperature.