Posted by: Li Ling Young | January 31, 2013

Air quality, #1 priority

Americans spend 90% of our time indoors…  An indoors that has evolved greatly since the cave, the tipi, the yurt, the igloo, the sod house, the wattle and daub hut, the log cabin, the stone cottage, and the wood-framed house.  We have not always lived as we do now, and our buildings have not always been constructed and configured as they are now.  But now we spend a lot of time in our buildings and now we have building-related illness.

Housing has long been linked to the rapid increase in asthma, particularly among children, and particularly among those living in low-quality housing.(1)  Bad housing causes asthma, among other things.  Good housing is the result of intelligent, careful, hard work, and very hard to come by.  A house that does everything it should is a good house, a high performance house.

A good house…

  • Is comfortable (here I’m mostly talking about the senses rather than the architecture)
  • Creates a healthy environment
  • Is safe (here I’m talking about life issues like fire prevention, but in some places security is also an important concern)
  • Is durable (needs few repairs, maintains high performance characteristics for a long time, keeps it’s value)
  • Stays affordable to operate (mostly an issue of energy bills, but also strongly related to maintenance and durability)

In my opinion, none of these attributes are dispensable.  This is what we should strive for in all our housing.  How to achieve this isn’t well-understood and, very sadly, is widely ignored by everyone from architects to builders to occupants.  The stakes are pretty high.  Get it wrong and one could lose the biggest investment most of us will ever make.  Get it wrong and one’s children could spend a childhood being admitted to the hospital and missing school.

A healthy indoor environment can be built.  It’s not chance and it’s not just a matter of making sure there are enough leaks that nasties have a chance to float away before we notice them.  In many parts of the world where indoor wood cooking is prevalent, lung disease, especially among children, is rampant.  These are wide open houses, but even this does not make good indoor air quality.  A home built for good air quality is…

  • Clean and cleansable: designed to contain contaminants; built with materials that can be cleaned
  • Dry: dampness and humidity support the growth of mold and dust mites
  • Without pollutants: don’t bring bad stuff into the house
  • Mechanically ventilated: all homes need ventilation and natural leakage is no substitute

There should be little- to no tolerance for anything that worsens air quality.  Lots of things that we regularly do in our homes make bad air quality.  We willfully ignore the consequences, but the they are real and they affect us and our families.   Here are some very common things that are bad for indoor air quality:

  • Air freshener
  • Harsh cleaning chemicals
  • Humidifier
  • Crawlspace with dirt floor
  • Litter box
  • Self-cleaning oven
  • Scented candles
  • Improperly vented gas water heater
  • Upholstery, especially that containing fire retardents
  • Insecticides
  • Perfume

Add to this list construction flaws that allow the building to get and stay wet and that admit soil gases including radon, and if you have developed an image of the modern house as a toxic environment you’re not too far off, at least for some homes.  The most egregious are rental housing where the occupants have no control over building maintenance and the owner has no interest in creating a healthy environment for others.  But bad air quality knows no bounds.  One of the ickiest cases of unacknowledged bad, bad air quality I’ve seen was an 11,000 sq. ft. house on Lake Champlain.  The duct system was completely riddled with mold, which the owners treated by wiping down the air registers, never considering the miles of moldy ductwork through which their air was circulated 24 hours a day.

Start your own healthy indoor environment today.  Most of what you can do to create good air quality in your home is easy.  The difficult, expensive stuff, like fixing bad flashing that makes the windows leak rain, well, I’d argue it’s not ok to leave the house like that whether or not you care about air quality: it’s just something that needs to be fixed.  So start with the free, cheap, easy stuff.  Find out what the expensive stuff is and make a plan to repair it.  You’ll be on your way to a high performance house, starting with the most important part: your own health.

Here are some specific things you can do to improve and maintain good air quality:

  • Do not add anything to the air in the house.
  • Don’t spray stuff in your house.
  • Don’t let smelly stuff evaporate in your house.
  • Let new furnishings off gas (unwrapped) for a month before bringing them into the house.
  • Do not add moisture to the air in your house; allow wet things to dry as quickly as possible.
  • Don’t wear your shoes in the house, and make a place where guests can take their shoes off.
  • Do not use anything poisonous in or around your house.  I recommend Seventh Generation for cleaning products and boric acid for insecticide.
  • Zero tolerance for mold.  If you have mold in your home use this guide to clean it.
  • Get rid of anything that is moldy and cannot be cleaned.
  • Fix anything that allows any part of your house to get wet: plumbing leaks, roof leaks, siding leaks, foundation leaks.
  • Do not use an unvented gas heater.
  • Fix circumstances that support an insect or rodent population.  Cockroaches need water, so don’t leave wet sponges or spills if you have roaches.  Become a super good housekeeper if you have mice or rats.  Work with your neighbors to make your building pest-free.
  • Use your bath fans and your range hood.
  • Pets… Well, that’s your call, but don’t underestimate the impact they, their dander, the dirt they track in and their feces can have on your air quality.
  • Never, ever let a gas engine operate in an attached garage.
  • Don’t store gas or solvents in the house or in any space attached to the house
  • No smoking
  • Don’t use the self-cleaning function of your oven
  • Pretty much anything with a smell, even a nice one, is bad to breathe.  Keep that stuff out.
  • Cover any dirt floors with heavy plastic, carefully installed.  Even dry-looking dirt introduces a lot of moisture into the air.
  • Ventilate.  This whole, boring blog post is a prelude to a post on our ventilation system, why we wanted it, what it does and how.  After you read it, maybe you’ll ventilate too.

(1) Clearing the Air: Asthma and Indoor Air Exposures, Institute of Medicine, Committee on the Assessment of Asthma and Indoor Air


  1. I didn’t find it boring at all! I love this stuff! Thanks for the information.

  2. […] Ventilation – lots when it’s mild out, but almost none when it’s wickedly hot or cold […]

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