All you need to do is pull up the transit requirements on Delta.com. Just search "visa" and you'll get a link to TIMATIC which is what all airlines use to determine the rules when you check in. Not rocket science. Assuming the OP is a US citizen, the following rules apply and do allow you to leave the transit area:

TWOV (Transit Without Visa):
Visa required, except for Holders of confirmed onward tickets

for a max. transit For details, click here time of 24 hours. Transit
incl. two stops, with a total transit time of 24 hours, within

China (People's Rep.) is permitted.
Visa required, except for Nationals of USA holding confirmed

onward tickets for a max. transit For details, click here time of 48
hours, provided arriving at and departing from Shanghai

Hongqiao (SHA) or Shanghai Pudong (PVG).
- All transiting passengers are subject to a check by

immigration officials. Passengers in transit are required to

hold passports or passport replacing documents that are
accepted for entry into China (People's Rep.). For more
details on document requirements, please enter China
(People's Rep.) as a destination.

- Leaving the transit area is allowed.