This is a vent for a home-heating furnace (blown-air, gas-heated).
There was some kind of plastic meshing on the outside. It's broken. Now I have to go very high up and fix this somehow. A scary prospect. Any idea if some ordinary meshing (I have some old used window meshing lying around) can be wrapped around this thing to make it work? Or do I need some specialized meshing? Would there be a way to fix this from inside the house (it's very high up from outside and I tried going up a ladder and got scared).