An Ocean of Air

I inhale. Exhale.

Ah, essential air. Rare air. Barely there air.

The first and last thing I will ever know.

Air may be light, but it is not empty. Even the cleanest air is filled with microscopic organisms: bacteria, viruses, spores, fungi, rusts, molds, yeasts, amoebae and pollen. Twenty-five million tons of air fill every square mile on this planet. Your average lungful of clean air contains about 200,000 particles; on any given day in the most polluted cities of the world, the count may be as high as 375 million.

The sky that begins miles above my head reaches its fingers all the way down past the roots of grass and into the earth. Molecule by molecule, oxygen, nitrogen and hydrogen sift into the smallest spaces, into the burrows of snakes and earthworms, into the spaces between grains of sand.

Eighty percent of the atmosphere huddles within ten miles of the earth’s surface. If the earth were the size of an apple, the air around it would be a single layer of wax. That thin skin of sky, a biofilm just fifteen miles thick, that ocean of air, holds most of the earth’s weather and most of earth’s water – just enough of both to protect us from the lethal vacuum of the universe.

The earth is our space suit. Think about that each time you breathe.