Well, if it was raining acid clouds... Zeolite is great at removing toxins ranging from acid to radiation.

They could seed the clouds to neutralize any chemical issues pretty easily. This is cheap and simple enough for even some amateur pilots. Literally any skydiving drop zone's Cessna and staff could do this.

That would fall down as dirty rain.

You could also coat the ground itself, so that it has a lesser chance of reaching ground water and runoff.

Well, if it was raining acid clouds... Zeolite is great at removing toxins ranging from acid to radiation.

They could seed the clouds to neutralize any chemical issues pretty easily. This is cheap and simple enough for even some amateur pilots.

That would fall down as dirty rain.

You could also coat the ground itself, so that it has a lesser chance of reaching ground water and runoff.