The air element is matter in its gaseous form. The particles move faster and spread out making it less dense than the heavy elements of earth and water and giving it a quality of lightness. The most direct way to experience the air element is through the breath. We take air in and breathe air out, feeding our bodies with up to 30,000 cycles per day. And yet, we often don't recognize this element as nourishment. Consider however, that you can go 3 weeks without food (earth) and 3 days without water, but you can only go 3 minutes without air.
Air resides inside the heart chakra, anahata, which is where our true nature resides and in our most natural state, we are joyful. When meditating on the air element, I am reminded of Danielle Laporte's perfect analogy:
Happiness is like rising [champagne] bubbles -- delightful and inevitably fleeting. Joy is the oxygen -- ever present.