How do I Calibrate Gravity: IIC Ozone Sensor?

so I've bought the Gravity: IIC Ozone Sensor for my final project related to Ozone Gas Concentration. But what I want to know is do I have to calibrate the sensor before I use it or is it automatically calibrated from itself? moreover, when I test it with the program, the result that is shown from Arduino IDE serial monitor are significantly increase by a resolution of 1 pbb, however the resolution shown from the datasheet is 10 ppb, is there anyone who could explain it?