Beijing Specified Transit Area

Hi there!

I arrive on flight CA784 from Auckland to Beijing with Air China at 5.10am. I fly out of Beijing to Barcelona on flight CA841 at 1.50am. Therefore, I am in China for less than 24 hours, so I should qualify for the 24 hour direct transit. However, I wish to leave the airport. Above it is specified that I cannot "leave the specified transit area" - do you know what this is for Beijing?

Kind regards, and thank you for the very informative website!