Why do I get gouged on air travel costs compared to US travellers?

I live in Atlantic Canada, let's say near Halifax, since that's the only semi-large airport in the region. But, let's say that I want to purchase a round-trip ticket (any time of the year) from Asia back home, back to Asia. I will end up paying approx. four times what someone whose home is in N.Y. or Boston would pay (roughly the same region). What gives? What can I do to stop Air Canada from extorting money from me? Expert air travellers' advice needed.