Hi, I'm going from Germany to Thailand with a 9-hour connection in PEK.

Sorry to tell you that all smoking areas are outside the terminal building now.

During your layover, it is worth to have a general look at the city center - Tiananmen Square. Several attractions like the Forbidden City, Tiananmen Tower and Memorial Hall of Chairman Mao are within walking distance. You may see from outside. If there is time left, roam around the Qianmemn Street for simple shopping & dining.

Thank you so much for such precious tips. Just one more question, is it faster get to Beijing center by taxi or the Airport Express train + subway?

Considering the traffic jam, subway is always faster, which may take 1h to the Tiananmen Square.