Unless you’re one of the five or six people currently living in outer space, you probably don’t give a second thought to the air inside your home. After all, air is free and you can pretty much find it everywhere. It’s no wonder we take it for granted. Yet we probably shouldn’t because indoor air is often the kind that’s the most hazardous of all.
The issue of indoor air quality starts with one of the more perverse environmental statistics of modern times: According to EPA research, on average, the air inside the castles we call home typically contains levels of pollutants 2-5 times higher than the air outside and in extreme cases can be 100 times more contaminated. In one study of volatile organic compounds (VOCs), a class of airborne chemical toxin, the Consumer Product Safety Commission found that while outdoor air at sampled sites contained less than 10 VOCs, indoor air at those same sites contained 150 VOCs.
Factor in the essential point that the average American spends about 90% of their time inside and suddenly indoor air quality becomes something we ought to be thinking about. No wonder the EPA ranked indoor air pollution as one of the top five environmental risks to public health. Or that the National Academy of Sciences estimated that indoor air pollution costs our country between $15 and $100 billion each year in related health care costs.
Although the specific types of air pollutants found indoors often vary considerably from home to home, poor indoor air quality has four basic causes:
The chemical substances we use to clean and maintain our homes. Many homeowners use a large number of petrochemical cleaners and other toxic products like pesticides, disinfectants, and air deodorizers liberally around the house. These products produce hazardous fumes when used and leave residues behind that then gradually dissolve into the air over time. The constant application of such a wide variety of chemical compounds throughout the average home greatly increases both the number of dangerous indoor air pollutants and their concentration levels.
The materials we use to build and furnish our homes. Modern residences contain a staggering variety of synthetic materials from carpets and foam cushions to insulation and chemically-treated pressed wood products. These products outgas which means that the chemical compounds they contain break down with age and are slowly released into the air over time in the form of toxic fumes.
Modern construction techniques. Following the oil shocks of the 70s, American homes began to be built with energy efficiency in mind. Today’s homes are better insulated and better sealed than any in the past. This is good for energy conservation. But bad for indoor air quality because without a system that ensures adequate air exchanges to remove hazardous indoor air pollutants or dilute their concentrations, indoor air can quickly reach become unsafe.
Household combustion equipment like furnaces, hot water heaters, and gas stoves. If improperly maintained or vented, these devices can introduce combustion by-products into indoor air that range from particulates like soot to deadly gases like carbon monoxide. In spite of the fact that these basic factors have introduced over 900 identified air pollutants to modern indoor air, the American Lung Association found that 87% of homeowners were not aware that indoor air quality was even an issue. That’s probably because such air pollution can be very difficult to detect. Many pollutants have little or no smell, and those that do smell often go largely unnoticed thanks to olfactory fatigue, a fancy name for the fact that the nose almost immediately adapts to the presence of new odors and effectively removes them from conscious notice. In fact, odors that persist in a house can even lead the nose to develop a semi-permanent fatigue that sometimes even a day away from home can’t overcome.
In her book, Home Safe Home, healthy home expert Debra Lynn Dadd recommends that anyone concerned about their home’s air spend a day away in the best air they can find in order to “rinse out” their nose. Windows and doors at home should be closed to concentrate any odors and a big sniff should be taken immediately upon return. In this way it may be possible to detect odors that indicate problems. Friends whose noses aren’t immune to your home’s smells can also help. More precise results can be obtained by indoor air quality tests. However, these are often costly to conduct. An effective alternative strategy is to examine your home for potential sources of indoor air pollution and then take steps to either remove those sources (as in the case of toxic cleaners or household materials) or assure that they are functioning properly and therefore not producing airborne toxins (as in the case of furnaces and water heaters).
What sources should you be looking for? Here’s an alphabetical list of the most common kinds of indoor air pollutants and the places they come from. If you have any of the source materials or devices listed below in your home it’s advisable to either remove them or have a knowledgeable professional verify that no contaminants like these are being emitted:
Carbon Monoxide: An invisible, odorless, and tasteless gas produced by the incomplete burning of carbon-based fuels like gas and oil in devices like furnaces, gas ranges, and non-electric space and hot water heaters.
Combustion by-products (CBPs): Gases and particles created by cigarette smoking, fireplaces, woodstoves, furnaces, gas ranges, and non-electric space and hot water heaters.
Dust: Believe it or not, the average 6-room home accumulates roughly 40 pounds of dust each year, and there’s not much we can do about it because dust is being made around us all the time as the materials we use in our daily lives breakdown and shed microscopic particles. Household dust can contain tiny pieces of textiles, wood, and food; mold spores; pollens; insect fragments; furs and hairs; and particles of smoke, paint, nylon, rubber, fiberglass, plastic, and paper.
Formaldehyde: A chemical used in everything from carpet and pressed wood products like plywood to bed linens. Formaldehyde is a volatile organic compound (VOC) but it’s so common that some experts believe it to be the single most important indoor air pollutant. For this reason, it warrants a separate mention among the many hundreds of VOCs that can exist in indoor air. Formaldehyde is colorless gas with a sharp odor, although at the concentrations typically found in indoor air, it is undetectable by the nose.
Composite or pressed-wood products are a common source of indoor formaldehyde. Wood resins and glues containing it are found in particleboard, plywood, paneling, furniture, wallboard and ceiling panels. Other sources include carpets, decorative wallpapers, and fabrics in which formaldehyde is used as a finish to create permanent press, flame-resistant, water-repellant, and shrink-proof materials. Formaldehyde can also come from gas stoves, glues, room deodorizers, cosmetics, personal care products, paper grocery bags, waxed paper, paper tissues and towels, and even feminine protection products.
Nitric Oxide and Nitrogen Dioxide (Nitrogen Oxides): Colorless, odorless and tasteless gases produced by gas ranges.
Ozone: A gas created by the breakdown of volatile compounds found in solvents; reactions between sunlight and chemicals that are produced by burning fossil fuels; and reactions between chemicals found in materials like paint and hair spray. Most ozone in the home comes from outside and results predominantly from automobile exhaust which is why this pollutant is more problematic in urban and suburban homes than rural homes. Ozone can also come from copy machines, laser printers, and ultraviolet lights.
Particulates: Tiny particles of soot and other materials. The biggest sources of indoor particulates are windblown dust, house dust, and tobacco smoke. Secondary sources include wood stoves and appliances like furnaces and non-electric heaters.
Pesticides: The mere act of applying these toxic materials spreads them around the house and introduces them to indoor air. Residues that remain continue to pollute the home and its occupants.
Radon: A natural radioactive gas that seeps from the rocks and soil surrounding certain homes. Radon is odorless, colorless, and tasteless and largely a problem only in basements in regions where soils have a large radon content.
Tobacco smoke: A mixture of over 4,700 different chemical compounds and the single most preventable indoor air pollutant on this list.
Volatile Organic Compounds (VOCs): Chemical compounds that exist in a gaseous form at room temperature. In the home, the presence of these chemicals in the air comes predominantly from two sources: the outgassing of synthetic materials like foams and plastics and the use of toxic cleaning products and other household chemicals.
Common VOCs include benzene, toluene, xylene, vinyl chloride, naphthalene, methylene chloride, and perchloroethylene.
But such materials are just the tip of the indoor air/VOC iceberg. There are hundreds of VOCs capable of causing everything from neurological and organ damage to cancer. Interestingly, many victims of Multiple Chemical Sensitivities think their troubles began with an exposure to VOCs.
Because of this high toxicity, VOCs are a major indoor air concern. That ends our look at common indoor air pollutants and their sources. As to what to do about them-stay tuned. In our next issue, we’ll have a complete look at the strategies you can use to help your family breathe a little easier.