The more I think about the this case, the more strange it gets, assuming the decay life being mentioned was between 30-45 minutes. The radiation levels are very high and the radiation emitted is mostly alpha radiation. As the half life is very short then the production of the element (assumed to be Radon, being an intermediate element in the decay chain of U235, U238 and heavier elements) must essentially be being produced nearby near the north of Toronto.

Assuming that it is Radon or another radioactive gas, which is naturally occurring, that is being washed out at low atmospheric altitudes then it might be a precursor to a very large earthquake (if there is little Uranium or Phosphate mining in the area), but again this has been measured on a continual basis since the Fukishima event by the video producer but at much lower levels and occurs during heavy downpours.

I can see why the video maker may have come to the conclusion that the radiation is due to atmospheric seeding from a nearby man made source. Perhaps venting the buildup of underground Radon from an industrial source within a radius of 10-20 miles. If so it still represents a major health hazard to the local area.

Of course it could still be a fake, but because of the video producers explanation of what is being observed I don't think that it is. It certainly needs investigation by the relevant regulating nuclear authorities.