1.   If you open the valve on the tyre, air flows out until the pressure inside the tyre equals that outside.

2.   If the windows are shut, air cannot flow freely through the building.

3.   As a result, the exhaled air flows backward, away from the smell.

4.   A band of heavier showers will occur in the interior Southeast where humid air will flow north from the Gulf of Mexico.

5.   Air flows up over the wingtip from the high-pressure area under the wing to the low-pressure area above the wing.

6.   Air would flow in.

7.   But a tracheotomy in the emergency room allowed air to flow into her lungs.

8.   Cooler air will flow into the Northern Plains on northerly winds.

9.   Cooler replacement air flows in through the lower vents to help push the hot air out.

10.   Cool air will flow into the Northwest in the wake of a cold front.