Do I need visa for both the travels while in transit at Beijing airport?

I intend to travel thru China and need to know if I would need visa for both the travels while in transit from China.

Departing: 13:50 Tue Vancouver International Apt, Canada Terminal M Arriving: 16:15 Wed Beijing Capital Apt, China
Terminal 3 Air China CA 992 - Aircraft type - 330 and Connection:
16:15 Wed - 17:40 Wed Stop-over duration: 1h25 Departing: 17:40 Wed
Beijing Capital Apt, China Terminal 3 Arriving:22:20 Wed Dubai International Airport, United Arab Emirates Terminal 1
Air China CA 941 - Aircraft type - 330
Return on Departing: 00:10 Wed Dubai International Airport, United Arab Emirates Terminal 1 Arriving: 11:45 Wed Beijing Capital Apt, China Terminal 3 Air China CA 942 - Aircraft type - 330
Connection: 11:45 Wed - 15:50 Wed Stop-over duration: 4h5 Departing: 15:50 Wed Beijing Capital Apt, China Terminal 3 Arriving: 11:50
Wed Vancouver International Apt, Canada Terminal M
Air China CA 991 - Aircraft type - 330