She gave a free concert in the open air, near the Lincoln memorial.

VOA: special.2009.01.25

It's going to take place in there. It's going to be a constant pressure, it might be open to the air, or even if it isn't, there might be plenty of room, and it's a liquid anyway, so the pressure isn't going to change significantly.

也许它是液体，它在这个位置,这是恒压的，它也许是连通大气的，就算不是，它也有，足够的空间，而它是液体,压强不会显著地改变。

麻省理工公开课 - 热力学与动力学课程节选

The World War Two Memorial stands in the open air.

VOA: special.2009.05.25

The seeds float in the air when the pods break open.

VOA: special.2010.04.06

Before the meeting Pope Benedict celebrated a large open-air mass in Valletta, attended by thousands of people.

VOA: standard.2010.04.18

World leaders and dignitaries have gathered to join in the 20th anniversary celebrations, which include open air concerts, fireworks,and the symbolic collapse of a wall of brightly painted oversize dominoes.

VOA: standard.2009.11.09