ozone values fourfold to high

I attached a Gravity Electrochemical Ozone sensor at a RaspPi Zero W.

Unfortunately the values are far to high, indicated is a level of 0.02 ppm (in my home-office situated in the Swiss Mountains), which is far above a acceptable dosis of this hazardous compound.

At 23th of decembre I measured the the fourfold value of ozone, the official station in the capital city measured 6 ug/m3, I measured 120 ug/m3.

Any experiences about that issues around?