One of the environmental condition in Altivar ATV650 datasheet deals with chemical pollution resistance.
For ATV reference it is possible to find
Chemical pollution resistance : class 3C3 EN/IEC 60721-3-3
The standard defines the levels of chemical active substances. For 3C3 class, max concentration of chlorine can achieve 0.3mg/m3 (average) or 1mg/m3 peak value.
Average value is expected long-term value. Peak value can occur over a period of time of not more than 30 minutes per day.