Flying from Seoul, Korea to Toronto, Canada with a layover in Shanghai, but having to switch airport

I am looking at booking a flight from Seoul Korea, to Toronto Canada. The route would be Seoul - Shanghai (hongqiao), with an 18 hour layover. Then I'd have to switch airports to Shanghai Pudong to get my flight to Toronto.

Going to:
Seoul - Hongqiao
Pudong - Toronto

Coming back:

Toronto - Pudong
Hongqiao - Seoul

Would I qualify for the 72 hour visa?