I could save myself that if it were clear for some reason that it stinks there or there are other disadvantages because of the oil area...
The refinery and the power plant very likely have no direct impact on the property; in terms of contamination or similar. They are too far away for that. One should not forget that more or less the entire Ruhr area can be problematic; heavy metals and the like are more common there, we do not know the history of the mentioned location (regardless of power plant/refinery).
You will probably see the columns and towers, to what extent that bothers you, you have to decide. And whether there is a realistic option without a view of industry, only you can know (not everyone can build by the coast or at Lake Tegernsee).
Usually the wind comes from the west -> windward side
And because of that, the nicer quarters were originally established west of the industrial areas. Now the air today is much cleaner than in the 1980s (or 1960 or even 1890), only in the event of an accident could (!) it go badly. Realistically, I would worry less here in Central Europe. The safety level in such facilities is already high. But who knows what the next decades will bring?
Now all that remains is the on-site visit! Take your time, walk there, on different weekdays and at different times, in different weather conditions.