Hi neldorling,
it most likely works. But it creates "pollution sinks". I described the behaviour in the FAQ on the mod page in the forums:
Q: How does it work?
A: The air filter machines (afm) reduce the pollution in the Chunk where they are build. You can see the chunk borders, by activating the "Tile grid" option in the debug menu (press F4 in game). Every Tick, they will reduce the pollution by 40. So, for your example, you would need 5 afm to equilize the pollution. As a rule of thumb, you should place the afms in a circle around your pollution producing factories, the avoid the spread of pollution.
To answer the "radius" question: Directly, the afms reduce the pollution only in their chunk. But you have to concider the way pollution works. Pollution will spread from chunk to chunk. It will "flatten" across the land. So if you have a chunk with many afms, this chunk will act like a "pollution sink". Not all pollution will get cleaned though. (Numbers are outdated, but you get the point)
Hope this helps.
Greetings,
Schorty
