Since the entire gaseous contents of alveoli are not exhausted at each breath (when we are resting, only a tenth of the air is expelled), the air that remains keeps the alveolar sacs inflated and prevents them from collapsing. So, air always resides within us and is as much a part of our bodies as any tissue or organ. We are a part of the air, which in turn is a part of all green plants and every other breathing creature.
After sharing space in a room with others, try a very simplified thought exercise. If you multiply the volume of air (in liters) in the room by Avogadro’s constant (the number of atoms in one mole of substance: 6.022 times (10 to the power of 23), you will get an estimate of the number of atoms in the air in that room. (Assume the air is always mixed completely.) Then divide the number of atoms in the air by volume of air inhaled times the number of breaths per minute times the time spent in the room times the rate at which oxygen and carbon dioxide diffuse across lung cell membranes. Even the crudest calculation reveals that each of us very quickly absorbs atoms into our bodies that were once an integral part of everyone else in the room, and vice versa.
The eminent Harvard astronomer Harlow Shapley once performed another thought exercise about air. He pointed out that while 99 % of the air we breathe is highly active oxygen and mildly reactive nitrogen, about 1% is made up of argon, an inert gas. Because it is inert, it is breathed in and out without becoming a part of our bodies or entering into metabolic transformations. Shapley calculated that each breath contains about 30,000,000,000,000,000,000, or 3.0 times (10 to the power of 19), atoms of argon plus quintillions of molecules of carbon dioxide. Suppose you exhale a single breath and follow those argon atoms. Within minutes, they have diffused through the air far beyond the spot where they were released, traveling into the neighborhood. After a year, those atoms have been mixed up in the atmosphere and spread around the planet in such a way that each breath you take includes at least fifteen atoms of argon released in that one breath a year earlier! All people over the age of 20 have taken at least 100 million breaths and have inhaled argon atoms that were emitted in the first breath of every child born in the world a year before!
According to Shapley: “Your next breath will contain more than 400,000 of the argon atoms that Gandhi breathed in his long life. Argon atoms are here from the conversations at the Last Supper, from the arguments of diplomats at Yalta, and from the recitations of the classic poets. We have argon from the sighs and pledges of ancient lovers, from the battle cries at Waterloo, even from last year’s argonic output by the writer of these lines, who personally has had already more than 300 million breathing experiences.”
Air exits your nose to go right up your neighbor’s nose. In everyday life, we absorb atoms from the air that were once a part of birds and trees and snakes and worms because all aerobic forms of life share that same air (aquatic life also exchanges gases that dissolve back and forth at the interface between air and water).
Air is not a vacuum or empty space – it is a physical substance that embeds within us all and perfuses through us. It is constantly changing as life and geophysical forces add and subtract constituents to the composition of air, and yet over vast stretches of time the basic composition of air has remained in dynamic equilibrium. The longer each of us lives, the greater the likelihood that we will absorb atoms that were once part of Joan of Arc and Jesus Christ, of Neanderthal people and woolly mammoths. As we have breathed in our forebears, so our grandchildren and their grandchildren will take us in with their breath. We are bound up inseparably with the past and the future by the spirit we share.
Every breath is a sacrament, an affirmation of our connection with all other living things, a renewal of our link with our ancestors, and a contribution to generations yet to come. Our breath is a part of life’s breath, the ocean of air that envelopes Earth. Unique in the solar system, the air is both the creator and the creation of life itself.
From the book,
The Sacred Balance
Rediscovering Our Place in Nature
by David Suzuki