This sounds like a standard separatist appeal in any country (just insert what you want instead of Toronto and the province - for example: QC and Canada, UK and Scotland, Ukraine and Eastern Ukraine and so on):cool:
I believe you are totally right, the prevailing wind chart is called "Wind rose" (http://en.wikipedia.org/wiki/Wind_rose) and usual wind in TO is from West - this means that west TO air will usually be cleaner