BY ROALD GUNDERSON
Life on the Inside We Americans spend the vast majority of our lives inside buildings. The 1930 US. census revealed 80% of Americans lived on farms, by 1950, 80% of Americans were in cities. Implicit in this urbanization is a large and rapid shift from working in fields to working indoors. The segregation of humans from the natural environment into artificial, machine operated, fossil fuel run environments. The development of such segregating shells is unprecedented in the history of life on earth. Today, people living in industrialized countries spend over 90% of their lives inside of buildings, that's over 65 years of the average life. The fact is many of us spend more time in our cars than we do outside. So when we're talking about air pollution and air quality and people's health we must talk about indoor air pollution. This is not to say outdoor air quality is unimportant, rather its fate, as we will see, is married with indoor air quality.
The Energy Crisis: Indoor Air's Birth The indoor air story begins with the energy crisis of the seventies. A large increase in building energy efficiency resulted in more air tight construction. An unintended effect of this improved energy efficiency was "sick building syndrome"; by plugging the flow of air, we trapped a pandora's box of airborne toxins inside our buildings. We've since come to the rather inane and humbling realization that fresh air (cleaned complements of the earth's Biosphere) is needed for people to be healthy in buildings. We've also discovered that the things we make buildings out of, and the things we put in and use in buildings could pollute the interior air and effect the inhabitant's health. [Sometimes we humans are kind of slow].
Building A Model of Clean Air: Biosphere 2 Like most architects, in the seventies and eighties, I had not given much thought to the air inside buildings except to keep it a comfortable temperature, humidity and exchange it to keep it from getting stale, (whatever that meant). I came to the issue of indoor air quality while designing and supervising construction on Biosphere 2, near Tucson, Arizona. The Biosphere 2 is conceived as a closed-system experiment modeling some of earth's complex ecological systems as a tool toward understanding them. The 3.5 acre high tech. greenhouse is by far the tightest structure of its size on earth exchanging one atmosphere every 20 years. We went to extreme efforts to make sure building materials, and electro-mechanical equipment, would not adversely effect the plant and animal life inside. When I began working on Bio 2, In 1988, the indoor air field was still in its infancy. Building material sales reps., and even their technical support were perplexed by our rigid non toxic material requirements and the accompanying clean-air-lingo like material off-gassing, MSD Sheets, and low VOCs. Most of their customers were only interested in the latest designer colors and the bottom line costs.
Indoor Air's First Breath: The Birth of Awareness In the late eighties Americans began awakening to the issue of indoor air pollution. Two EPA reports helped with this awareness. In its 1989 Report To Congress On Indoor Air Quality, the EPA study showed that indoor air is often more polluted than outside air and it estimated health and productivity costs to be in the tens of billions of dollars. The second study charged radon gas leaking into buildings from the ground with being the second leading cause of lung cancer in America after cigarettes. In some regions of the country buildings tested with radon levels the equivalent health hazard to smoking twenty packs of cigarettes a day. The EPA recommended that all buildings be tested for radon. Several well publicized cases of sick building syndrome and a Surgeon General's report on second hand cigarette smoke compounded the public's concern for indoor air. Since the late eighties the field of indoor air pollution has exploded: Consultants have become overnight experts in low toxic environments; Manufactures have began producing low toxic building materials. Now that we have yet another culprit to blame and agonize over with regards to our health.; just how concerned should we be? What are the health risks? How do we know if a building is polluted? What can you do If it is? And, if you're planning to build, how can you build clean. I will hope to shed some light on these and other questions with the understanding that this has already become a large and complex field.
Don't Hold Your Breath. Just how concerned should you be about the indoor air you breath? To be sure it is a real problem certainly with regards to the quality of our lives, and it is something we can all do something to improve. But for most of us indoor air pollution is not something to hyperventilate about or to blame our health problems on. The EPA has quantified the problem in the worst cases. But little or nothing has been done to quantify the more subtle long-term changes in our health caused by our artificial indoor air. Chances are we all suffer some minor health effects of indoor air: We are more likely to get colds and flu's in winter when we close buildings up; many of us suffer weakened immune systems; fatigue, headaches and sore eyes as a result of polluted indoor air . But it will be hard to determine these more subtle long-term effects of indoor air because of the vast array of variables, and the difficulty of creating a long term controlled experiment. We have chosen to live inside artificial environments without first understanding how they impact our health. This is a vast experiment with ourselves as guinea pigs. But before you hold your breath, there are things you can do about the indoor air you breath.
Judging Our Risks For most people in industrial countries there are two buildings we spend nearly 90% of our lives in: our homes and our work places. These are the two buildings we need to focus on since the health risks of indoor air pollution is most dependent on the duration of our exposure. There are exceptional obvious risks of exposures to intense toxins, but these cases are regulated by OSHA the EPA and other agencies and exclude the vast majority of us. We are looking for the insidious common place offenders which degrade the dailey quality of life and through years of exposure can kill. We've surrounded ourselves with these offenders. ,in our homes and work places and, fortunately, these are the two places we have some power to improve indoor air quality. Here is some basic criteria to judge your own risks:
1) Are the buildings you are in, most of the time, relatively air tight? Drafty buildings, while energy inefficient and more polluting of the general environment, obviously provide lots of air changes and are not as prone to indoor air problems. Tight buildings have been built or remodeled since the late 1970's and pose a substantial increased risk of having polluted air. 2) Do the buildings you're in have inadequate ventilation.? In poorly ventilated buildings the air may seem stale and uncomfortable to breath. Humidity may build up and contribute to the growth of molds and mildew. If your workplace has special venting needs such as with dry cleaners, printers, garages, laboratories, a wide range of manufacturing and industries even restaurants and bakeries, they need to follow local codes, and OSHA workplace guidelines. 3) Are strong cleaners, glues, sprays, paints, or solvents being used frequently? Any number of toxic substances may be a regular part of your indoor environment particularly at work. OSHA has set stringent guidelines to govern exposures to workplace toxins. 4) Do you notice any symptoms: burning eyes, headaches, or a feeling of malaise associated with a building? A stressful job or one you don't like can cause these symptoms but so can bad indoor air. 5) Do you smell things burning? Poorly vented furnaces, wood stoves, and gas appliances can usually be sniffed out. If they are frequently used they should be serviced at least once a year. 6) Is your area at high risk for radon? Its a good idea to get your buildings tested anyway and especially if your county health department knows the area to be at great risk. 7) Does your building have that fresh built smell? Newly built or remodeled buildings are more likely to have polluted air at least for a period after construction. 8) Do you notice an odor of mold or mildew? Moisture condensing on windows and walls can cause the growth of microbes and pose a health hazard. 9) Do you live with already polluted outside air? People in urban areas may need to clean the air coming into buildings. If you have answered yes to any of the preceding questions it would be worth your health to investigate the situation further.
Indoor Pollution Apart from external pollutants like smog and radon leaking into buildings, the other big factors affecting indoor air quality are internal to the building. These sources fall into categories: 1) Off-gassing building materials. 2) Pollution from electro-mechanical equipment and appliances ( air conditioners, copiers, computers, 3) Biological sources (molds, mildew, microbes, pet dandruff, 4) Combustion ( Furnaces, Fireplaces, cigarettes, cooking) 5) Cleaning, and maintenance compound
1) Off-gassing building materials. New buildings often have the worst air. Not only are they tightly constructed but they have the latest, freshest and worst offenders with regards to material off-gassing,, that is unless the owners want to pay for a clean building. Paying for a clean building can be expensive depending on the extent to which it is done as with hypo-allergenic building materials. But it doesn't have to be an elitist's pursuit. Most frequently the cleanest building materials tend to be organic, and as with food the less processed materials tend to be better for you: solid untreated woods, straw (as in straw bale construction), wool and cotton rugs and carpets, cellulose insulation, gypsum wall board, plaster, tile, glass, concrete and stone to name the most common. Some stones, used in masonry and aggregates for concrete, like granite may be a source of radon gas and its progeny. Metals as a whole are not an off-gassing concern but rather can be a water quality concern as with copper which can kill aquatic systems at parts per billion., and aluminum off pots and pans which may play a role in some forms of arthritis and senility. The problems we most frequently had with selecting materials on the Biosphere 2 Project were of four types: 1) Materials containing binders: fiber glass insulation, chip board, plywood, particle board, 2) Materials made from petrol-chemicals: foam insulation, gaskets, furniture padding, carpet pads, softer plastics 3) Paints and Coatings: oil based paints, oil based stains, solvents 4) Glues, Adhesives, and solvents: PVC and CPVC glues, vinyl tile adhesives, caulks, A good rule of thumb is if you can smell it, its off-gassing Get on your knees and sniff your Dupont Dacronª carpet with 3M Scotch Guardª anti stain protection and you'll know what material off-gassing is. Ever wonder why you get a headache and burning eyes shopping in Home Despot? Construction materials are loaded with a chemical candy store of compounds. You need not learn a litany of chemical names to master the basic concerns. How much of a toxic material has been or is being used in a building? Often this will govern one's primary focus. For instance formaldehyde and mobile homes; practically everything in a mobile home except the kitchen sink has formaldehyde in it. Another criteria is a toxic chemicals duration of off gassing. Again, formaldehyde can off-gas for years, whereas a more toxic compound like xylene, a solvent, might be 99% gone in a few days. Where a material is used in relation with the indoor environment will also determine its interaction and off-gassing. For instance if a properly installed vapor barrier is between you and your fiberglass insulation, little if any formaldehyde or particulates will enter your environment. By focusing ones efforts on the primary culprits to clean indoor air one will not get bogged down with numerous minor offenders.
Binders are often nasty and are of course used to hold materials together. Phenyl Formaldehyde is used in most chip board, plywood, wall paneling, and fiberglass insulation to name a few. When you walk into a building center that sickly sweet odor is formaldehyde. Its the most notorious due to its abundance and longevity of off gassing. Glues and adhesives used to set vinyl tiles or carpeting contain long term Solvents used as vehicles in oil based paints, stains, and caulks are often extremely toxic. Most evaporate a few weeks after their use contributing to atmospheric pollution. Water based latex paints avoid most of these VOCs and have special environmentally friendly formulations by Gildon and other manufacturers to reduce VOC contents.
In constructing the Biosphere most of the common palette of building materials had to be eliminated on their toxicity alone. If a paint had a heavy metal in its pigment, as most do, we couldn't use it for fear it might leach into the marine systems and wreak havoc on algae, or if a material, like carpeting, gave off too much of a volatile organic compound it might build-up and make the crew sick. Now granted Bio 2 is an extreme indoor air case but it illustrates the problems with creating an atmosphere inside buildings which is something all modern buildings do to some extent.
Before a sales rep. got past the front door on the site of Biosphere 2 they had better be equipped with MSD Sheets on their products. Material Safety Data Sheets list a litany of aspects of a product: its flammability, handling, chemical contents... From this EPA required registrar of information we could deduce its compatibility with our delicate mini-world. Few reps even new what MSD Sheets were. Today they probably do, and so do many architects. Are We Wired? 2)Pollution from electro-mechanical equipment and appliances A very real presence in our artifical indoor worlds are the hums, buzzes, lights, whills, flashes, and beeps of electronic-machines. These companions of comfort, convienience, entertainment and information are indespensible in our lives today All these techno-species: telephones, refrigerators, computers, entertainment centers, washing machines, hot water heaters, air conditioners, even lights did'nt exist in buildings a hundred years ago. Today, with their niches well established, how are these new inhabitants affecting our health? This Technosphere, as we called in the Biosphere 2, keeps our fragile flesh and nurons content and firing even if its just being a couch potatoe eatting microwave popcorn, channel surfing infront of the airconditioner. With the advent of personnel computers, tens of millions of people now work or entertain themselves for hours every day two feet in front of an electron ray tube. The Electro Magnetic Force or EMF has been linked to a wide range of health effects. Its an electro magnetic field generated by all electical equipment including wires. High voltage power lines have long been suspected for a wide range of health disorders by those living near by. now we have virtual suspects in our laptops. While alarm is inappropriate, caution is well advized for the effects our electro-mechanical gienies may have over a long run
3) Biological sources (molds, mildew, spores, microbes, pet dandruff)
What's Smoking? A Burning Issue 4) Combustion ( Furnaces, Fireplaces, cigarettes, cooking) For many of us the path to energy independence in the late seventies was buying a wood stove. While still a viable renewable heat source for many, burning wood produces its share of pollution, and more than its share of smoke and dust. Any form of combustion whether smoking a cigarette or burning toast will produce unhealthy by products like carbon monoxide, and nitric oxide. Again we're after the biggest household offenders usually a wood stove, poorly maintained furnace, or a leaky chimney. Generally the more complete the combustion the cleaner the burning so regular annual maintenance is a good indoor air and planet friendly habit. A Carbon Monoxide (CO) detector which detects below ten parts per million or less is a good investment for anyone who burns things. Carbon Monoxide is the most lethal product of poor combustion and poor venting. CO detection equipment is reasonably affordable.
Improving The Quality Of Indoor Air Five ways to manage indoor air pollution are listed in what is often easiest to accomplish, first. 1) increase ventilation. 2) clean or condition the air. 3) protect against the polluting source 4) remove the polluting source. 5) build clean
Ventilating Pollutants: A Building's Breath Like people buildings too must breath. This is achieved actively by windows doors, fans, vents, and passively by infiltration of air through walls , roofs, and floors. Most people have good control over ventilation at home but little if any control over ventilation at work. By code buildings are required to have multiple air changes every day, one air change being a turnover of air equivalent to the building's volume. The number of air changes varies depending on the building's use (house, factory, school, etc.), and local codes. A widely accepted value is half an air change per hour. That's twelve times the size of your building daily. The Biosphere 2 has one air change in 20 years. Tight energy efficient homes or office buildings can achieve as few as two or three air changes a day. Local codes may require such buildings to exchange additional volumes of air. Implied in these codes is that outdoor air is fresher and healthier than indoor air. A penalty to exchanging this air is we need to heat or cool the so-called fresh incoming air. This usually requires burning fossil fuels further polluting the outside air. Its a positive feedback loop with a very negative outcome. Over 50 major cities in the US have dirty air, failing EPA standards particularly on ozone levels. We are exchanging dirty indoor air with dirty outdoor air. So how do we get out of this pervasive urban smog? The conventional wisdom is to add some more machines to our increasingly electro-mechanical environments we've come to depend upon. Air to air heat exchangers can recapture over 80% of the heat, and filters can take out particulate, but each add initial expense, and require energy and regular maintenance to operate. Even with these techno-fixes we haven't addressed the deadliest urban offenders. Ozone, nitrous oxide, and volatile organic compounds which pose the greatest health hazards in urban indoor air. Clearly we need tight energy efficient buildings, made with clean materials and ways of internally refreshing the air inside. This is where the Biosphere 2 has some proven applications.
Cleaning and Conditioning the Air: The Biosphere Within The conventional way to clean and ventilate indoor air are the air to air heat exchangers and the use of filters like electrostatic filters. Besides the drawback mentioned above Neither eliminates VOCs the most noxious pollutants which are abundant in most urban "fresh" incoming air. A promising alternative to cleaner indoor air which Biosphere 2 depends on is using plants and soils to clean and freshen indoor air. We don't need a rocket scientist to tell us that plants and their symbiotic bacteria in soils are good companions for us animals. In A Study of Interior Landscape Plants, Dr. Roy Wolverton under a grant from NASA looked at quantifying different plant's effectiveness at air cleaning. NASA was interested in alternatives to cleaning space station air on planned long durations in space. The Spaces Shuttles have extremely polluted air but on these short durations NASA isn't as concerned about polluted air's effects on the astronaut's health (although I'd bet their performance suffers). NASA wanted to see if plants could be designed into the space station to perform multiple roles of air cleaning, oxygen production, and a small amount of food production. Wolverton's group tested ten varieties of house plant for their various abilities to remove commonly used chemicals such as Trichloroethylene (TCE), Benzene, and Formaldehyde. The results of the study were impressive. Plants species varied in their uptake of different chemicals, but were found to be, as a whole, very effective at uptake of each of these VOCs. The report also calculated the number of plants required in an average 1800 square foot, energy efficient home with 0.2 air changes per hour for the cleaning of Formaldehyde. They estimated fifteen average sized Mother's-in-law Tongue (Sansevieria laurentii) or six large Bamboo Palms (Chamaedorea seifritzii) would maintain a Formaldehyde free air. So a surprisingly small number plants can perform a huge service. We used Wolverton as a consultant to design Biosphere 2's biological air cleaning systems. Apart from the passive benefit of the plants and soils inside Bio 2, we had designed a so called "Soil Bed Reactor" which drew air off the Human Habitat and pushed it through the soil bed of the Intensive Agriculture Building. This simple technology can be used in solar greenhouses to force air through soil beds, serving to store heat and clean the air at the same time. If building codes reflected health and well-being realities, they should require an established number of plants per square foot of building. If we embraced plants and soils as we have mechanical systems as a regular component of clean indoor air we could reduce the number of air exchanges, reduce energy consumption and its resulting pollution while substantially improving indoor air quality. Most would agree, the esthetics of plants are a tad more appealing than mechanical equipment. The cost of plants and their care while time consuming and expensive could be well offset by energy savings alone, let alone the potential productivity improvements of their human companions. Like mechanical systems, plants require room. Building could be retrofit or designed from the start with attached greenhouses, solariums, atriums, or greenways which if properly designed could provide solar heat, food, even organic waste and waste water cleaning, along with air cleaning. Added together the result could be large cost savings and environmental benefits. The wholesale embracing of living systems inside our buildings would revolutionize our inside and outside environments for the better. by cleaning indoor air with plants our buildings can be tighter saving energy, money and the pollution of the environment while keeping us healthier.
Protecting Against the Polluting Source Another effective way of improving your indoor air is to isolate or segregate the offending sources from exposure to interior air. The most common way this is done is with a vapor barrier at the time of construction or during a major interior remodeling. A vapor barrier is most often a 6 mil polyethylene plastic sheet. If properly designed and installed a vapor barrier can protect indoor air from the vast majority of formaldehyde used as binders in fiberglass insulation, oriented strand board (chipboard) and plywood. Used outside foundations and below poured concrete floors one can almost eliminate radon gas problems. Other less effective methods are using coatings, sealers, and caulks over the offending surfaces and cracks preventing some of the off-gassing while creating a temporary problem with the off-gassing of the applied product.
Removing the Polluting Sources: Remodeling Your Air One can improve indoor air quality by removing the biggest offending materials and selecting clean replacement materials. Suspect materials might be carpets and carpet pads, wall paneling, chipboard cabinets, and foam padded furniture to name a few. A significant quantity of any given material must be present before it poses a potential health hazard. However, you may have a little paneling, chipboard, and plywood which all use Phenyl Formaldehyde as a binder, when added together constitute a harm. If you live in a mobile home, it may be impractical to remove all the offending sources. If one has an allergy to an indoor pollutant, careful scrutiny of suspects is important before remodeling time and dollars are spent ineffectually and perhaps making things worse. Furniture, while usually a small indoor air polluted is easily replaced. Asbestos is still found in buildings and should be carefully removed by a licensed professional. Another technique for removal of short lived off-gassing toxins in new buildings (usually solvents used in paints, and adhesives) is the so called "bake-off". This is not a bake sale but it might involve turning on your oven. The idea is to get the new building as hot as possible which accelerates the release of gases from materials. This works well with short term pollutants. The best way is to avoid indoor air pollution all together, and if you are fortunate to be in the position, is to build clean.
Building Clean: Organic Buildings As I have already mentioned and it perhaps comes as no surprise, organic building materials tend to be safe for indoor air. In our strenuous pursuit to find acceptable building materials and interior finishes to use in Bio 2, two distint catagories emerged: high tech materials coatings and finishes, and low tech organic materials The high tech finishes we used were specialty stainless steels and coated glass, epoxy coatings and caulking, silicon foams. The organic materials we used were solid woods in furniture, finish trim, doors and cabinetry, wool carpeting, and wool streached fabric walls and ceilings, wool upholstry and crimped wool batting,, jute carpet pads, ceramic tile floorings, stone pavers. We did use materials which are quite conventional and safe such as gypsum wall board (sheet rock), concrete (without any heavy metal fly ash), and hard plastics like PVC, CPVC. Coatings presented one of our largest stumbling blocks. With the advent of low VOC paints since building Bio 2 our job would have been much easier. Today you can find several brands marketed as safer for the environment or low VOC coatings. Two good manufacturers with a wide range of coatings are American Formulating and Manufacturing (619)239-0565, and Miller Paint Co. (503) 233-4021. If you can afford the extra cost hiring a indoor air specialist is a good idea which will pay off in the long run. If you're in my position , however, you'll build organic. One organic approach which is gaining acceptance is straw bale construction. The use of straw for insulating and increasingly load berring is gaining acceptance. And unless the bales get wet and turn to mold it is environmentally very safe. Since indoor air pollution is particularly bad in cold climates, straw is particularaly atractive for its high insulative characteristics(R3 per inch). My wife and I have built perhaps the first "A" framed staw bale house using straw in the roofs, walls, and floor as insulation. Most straw bale homes still have a conventional roof with conventional insulation. . We have used a minimum of fiberglass and foam insulation, and our other finishes are solid wood, plaster, gypsum board with latex paint, stone and glass. While we've had a very stressful nine month adjustment to our new home, and a new baby, we've each only gotten sick once, with a cold, while our family and friends cycle through numerous illnesses. We have some major culprits yet to contend with (i.e. wood stove, propane refrig. and range) and we look forward to our new attached solar greenhouse to reduce some of these emmisions.Home