Visa in Shenzhen bao'an international airport?

I've booked a flight Bangkok- Moscow with a 23h layover in Shenzhen (SZX) airport. I'm the citizen of the EU and holding Latvian passport, can I leave the airport during my layover without an entry permit? Information on this matter is very controversial: the Chinese embassy in Latvia says that there is a 72 hour transit in Shenzhen, the other sources say that SZX airport is an exception and I need an entry permit. Please advise.
Thank you,