Leaving Toronto Airport during connecting flights?

We are travelling from London to Las Vegas on Air Canada. The flight goes through Calgary on the outbound and Toronto, ontario on the inbound. I have chosen a connecting flight in Toronto with a 16hr gap, during this time will we be able to leave the airport to visit Toronto for the day? I have asked Air Canada staff 3 times and each time I have been given a different answer but no on seems to be certain. Any one know for sure? Thanks