Facts and Quotes

Americans are indoor creatures.  On average, we live to be 79 years old and spend over 69 of those 79 years inside buildings.  We spend 54 of those years inside of our own homes, and over 26 years lying in a bed.  If we care about our exposure to toxic air pollutants, allergens, and other pollutants, we should focus on our own homes, including our bedrooms.

Most of the air pollution that we breathe during our lifetimes, even pollution of outdoor origin, we breathe inside buildings.  This excites me, as it means that we can redesign and operate buildings in such a way to both dramatically reduce our exposure to outdoor air pollution and to pollution generated inside buildings.

The most intimate contact that you have with any surface during your lifetime is with your pillow.  Think about your pillow and the contact that it has with your breathing zone for one-third of your life.  The foam in pillows may contain and slowly release chemicals such as toluene diisocyanate – https://www.atsdr.cdc.gov/phs/phs.asp?id=1450&tid=245, as well as endocrine disrupting flame retardants.

Physical barriers do not work to protect you from aerosols.  You put up a fence to keep your neighbor’s dog out, not your neighbor’s bird.

House plants do NOT purify indoor air any more than an old baseball cap nailed to a wall.  One would need on the order of a thousand plants to make a noticeable difference in, for example, indoor volatile organic compound concentrations.  This would add to your water bill and indoor moisture loads!

Portable ionizers can emit appreciable amounts of ozone and are largely ineffective at removing particles from indoor air.  This is particularly true relative to good HEPA-based portable air purifiers. Why? The effectiveness of a portable air purifier is best measured as a clean air delivery rate (CADR), which is the product of single-pass removal efficiency (fraction of particles removed in a pass through device) and the volumetric flow rate through the device.  The latter tends to be very low for portable ion generators, which is the reason that they are quiet.  Don’t get confused by efficiency versus effectiveness.  Efficiency means nothing if there is low flow through the device.

Polystyrene foam in furniture and carpet cushion is a repository of chemicals that are or were present in indoor air.  It is a significant sorptive sink in buildings, adsorbing a wide range of organic compounds and releasing them slowly over time when sources are removed or source strengths decline. 

Quotes by Others

 “If there is a pile of manure in a space, do not try to remove the odor by ventilation. Remove the pile of manure.”  Max von Pettenkofer (1858)

 “Most civilized men and women are unwilling to put on underclothing that has just been taken off by another person or to put into their mouths articles of food or drink that have recently been in other peoples mouths but they take without hesitation into their lungs air that has just come from other people’s mouths and lungs or from close contact with their soiled clothing or bodies.” John Shaw Billings (1893)

“I am persuaded that no common Air from without, is so unwholesome as the Air within a close Room, that has been often breath’d and not changed.” Benjamin Franklin (1785)

Note that Franklin advocated for as much exposure to fresh air as possible.  He frequently slept with an open window, and enjoyed and promoted a daily air bath to cleanse his skin. An air bath involved sitting naked in his chambers with the windows open, perhaps much to the chagrin of his neighbors.

“Stagnant, musty, and corrupt as it can by possibility be made and it is quite ripe to breed small-pox, scarlet-fever, diphtheria, or anything else you please.” Florence Nightingale (mid-1800s).

“Over the 20-year life cycle of a prototypical 100,000 sf building, 5% of the cost is spent on design and construction, 10% on o & m, and 85% on salaries of personnel working in the building. Even a 1% increase in productivity would increase the bottom line exponentially.”
Summary report of the national workshops on Design Excellence in HVAC for Federal Buildings