There really is nothing quite like opening a window or door and breathing clean, fresh air. As humans we need oxygen for life. And although we are somewhat finicky about what we eat, most people give very little thought to what they breathe.
Thankfully, clean outside air contains about 21% oxygen. That leaves 78% nitrogen (N) and a 1% mixture of mostly argon (Ar ~ 0.90%) a trace of carbon dioxide (CO2), neon (Ne), helium (He), methane (CH4), krypton (Kr) hydrogen (H), and xenon (Xe).
But the air inside our homes can be radically different than the air outside. The EPA says it can be 2 to 5 and occasionally more than 100 times more polluted than the outside air
What caused this conumdrum?
There are a number of contributors.
(1) Our homes have dramatically changed over the last 30 to 40 years.
(2) Our expectations and the way we live in our homes has changed.
(3) We have a passionate love affair with chemicals.
Since the oil shock of 70’s, houses have been built with improved insulation and are increasingly airtight to save energy. Today’s new house can be 2-3 times more airtight than a home built just 25 years ago. Thousands of homeowners have made their own improvements to save energy that usually included air tightening.
The good news is tightening a leaky home will definitely cut the heating bill. AIr sealing reduces the heat lost through holes and cracks. The bad news is, many of these holes brought in fresh air that flushed out indoor pollutants. Sealing the holes leaves pollutants and moisture trapped inside where concentrations can build up and cause serious health problems.
Benjamin Franklin commented on this topic in an essay first published in 1786. He offered his advice on "preserving health";
“It has been a great mistake, the sleeping in rooms exactly closed and the beds surrounded by curtains. No outward air that may come in to you is so unwholesome as the unchanged air, often breathed, of a close chamber.”
It’s obvious that Ben was a big proponent of fresh air. He went on to state,
“Another means of preserving health to be attended to is the having a constant supply of fresh air in your bedchamber.” He further proposed a theory that “air in a closed room becomes saturated and prevents people’s pores from expelling putrid particles.”
Yuck! Nobody likes breathing “putrid particles”.
Another aggravting factor is that most homes have centeral heating and cooling systems. So very few people see the benefit of opening windows.
Essentially, we live in substantially airtight bubbles with little to no fresh air exchange. The question is, what are we breathing in our bubble?
Amercians have a passionate love affair with chemicals
We have found or made over 50 million different chemicals in our world, the vast majority of them over the last few decades. The rate new chemicals are being produced and isolated is astounding.
“A novel substance is either isolated or synthesized every 2.6 seconds on the average during the past 12 months, day and night, seven days a week in the world,”
Dr. Hideaki Chihara, Ph.D. chemist and former president of Japan Association for International Chemical Information
The Chemical Abstracts Service (CAS) registry is the most comprehensive list of chemcials available in the world. It contains more than 94,000,000 substances. It took 33 years to get the first 10 million chemicals registered and a mere 9 months to get the last 10 million. Most experts agree there are more that remain off the books that we know little about.
“The EPA has data on some 8,000 to 10,000 chemicals. And we know how most of them affect our health and safety. But when you mix 2 or 3 together, we have no clue."
David Lee, Air Quality Division, U.S. EPA
Most homes have more chemicals under the kitchen sink than what were found in a chemistry lab 30 years ago.
We spend 80% to 90% of our time indoors. Our homes are substantially airtight and poorly ventilated. We don't open windows and we love chemicals. Sounds like the perfect storm for some unintended consequences.