Ventilation: Indoor Air Pollution

Every room in your home is a chemical warehouse! Your house might resemble a war laboratory much more than you think after just a very quick inventory. If you start your inspection with the living room, you will find formaldehyde coming from the carpets, drapes, furniture, plywood in the subflooring, or paneling. Tobacco and wood smoke from fireplaces and stoves also will help embalm you. Radon radiates from the brick or stone fireplaces. Wood and tobacco smoke also put out nitrogen dioxide. Tobacco smoke alone will put some benzopyrene and carbon monoxide in the room.

Indoor pollution is much worse than anything outdoors! The kitchen a deadly chamber. All those aerosol spray cans invariably contain propane, butane, and /or nitrous oxide. If there is any carpet shampoo among the cleaners, you have some sodium lauryl sulfate, and there is usually some potassium hydroxide in those spray oven cleaners. Most window cleaners have some ammonium hydroxide. Gas stoves give off hydrogen cyanide, nitrogen dioxide, and carbon monoxide. Formaldehyde given off by gas stoves, particle board found in kitchen cabinets, curtains, wallpaper, and plastic appliances.

This chemical warfare list is one of the reasons why Section 6 deals with kitchen ventilation! The spraying, scrubbing, and misting with chemicals never ceases. If your house is exhaling the stuff every few minutes, you are in pretty good shape. If you don’t have the right vents, you have deadly problems.

The laundry room and the basement usually have spot cleaners that contain benzene and carbon tetrachloride. Bleach gives off chlorine fumes while the always-present formaldehyde comes off the soaps, plastics, and plywood. The drain cleaners usually have lye. If the clothes dryer uses gas, you get some carbon monoxide and nitrogen dioxide. Deadly radon is emitted from the concrete walls.

Wood products use more than a third of all the formaldehyde produced annually, and the gases from it found in plywood and particle board can diffuse into the air for months and in some cases for years. If you pass a bedroom coming out of the basement or laundry room while surveying your premises, those moth balls in the clothes closet have naphthalene and paradichlorobenzene—if you want to define the odors in them.

The bathroom might be the smallest room in the house, but it is one of the biggest problems if it isn’t effectively ventilated against the aluminum chloride found in most deodorants. There will be some formaldehyde in the toothpaste, shampoo, and disinfectants as well as in the carpet, curtains, and cabinets. Radon is probably in the water in the sink and the tub. Check the hairspray for vinyl acetate polymer.

The following article appeared in Environment, March 1983. It was adapted with permission from “Behind Closed Doors: Indoor Air Pollution and Government Policy,” published in The Harvard Environmental Law Review 6 (1982): 339-394.

Laurence S. Kirsch, the author of this article, is an attorney with a background in science and environmental studies. He is on the advisory board of the National Indoor Institute. Thanks are extended to him for his excellent work.

BEHIND CLOSED DOORS: THE PROBLEM OF INDOOR POLLUTANTS

The mention of indoor air pollution often provokes reactions of disbelief or humor or both. Although many questions remain to be answered, scientists are becoming increasingly convinced that indoor air pollution is a serious health problem. Articles on indoor air pollution date from the early 1970s.

The indoor air pollutants currently being studied are radon and its decay products, chemical products of combustion such as nitrogen oxides and carbon monoxide, formaldehyde, asbestos, residues from consumer products, allergens and micro-organisms, and tobacco smoke. These pollutants can cause respiratory diseases, cancer, and even death. While many of these pollutants are also found in offices, factories, and public buildings, this article defines “indoor air pollution” as pollution that is found within residential buildings at levels that affect human health. Thus, it does not consider several other serious indoor air pollution problems, such as indoor air pollution in commercial or industrial contexts, or “passive smoking,” although in its consideration of residential air pollution, it uses occupational exposure limits set pursuant to the Occupational Safety and Health Act as guides to safe exposures.

Indoor air pollution may, in fact, pose an even greater threat to health than outdoor air pollution. Contrary to common assumption, air pollutant concentrations behind the closed doors of homes and other buildings are often higher than corresponding concentrations outdoors. This is particularly true of pollutants such as formaldehyde that are released primarily indoors, but it can also be true of pollutants such as nitrogen oxides that are released both indoors and outdoors.

Moreover, most people spend most of their time indoors. Thus, even if pollutant concentrations are lower indoors than outdoors, indoor exposures are more prolonged and frequent. Consequently, health effects may be more severe. Although indoor air pollution affects all groups of people, it particularly threatens the young, the old, and the ill; these groups are both more susceptible to the effects of pollution and more likely to be indoors.

Furthermore, indoor air pollution may be growing worse because of certain recent initiatives to conserve energy. One common way to make buildings more energy efficient is to “weatherize” them by sealing them off, as tightly as possible, from the outside. One experimental energy-efficient house, for example, has been described as a “veritable fortress against the loss of energy. There are leakproof triple-glazed windows, a weather-stripped magnetically sealed front door, and plastic sheets in the walls, floors, and ceilings that keep the home’s living space as airtight as the inside of a sandwich bag.’

Weatherization reduces the ventilation rate—the rate at which outdoor air replaces indoor air. In conventional homes, for example, outdoor air replaces the entire volume of indoor air about once every hour. In some energy-efficient homes, however, outdoor air replaces indoor air only about once every five hours. Preliminary research suggests that concentrations of at least some indoor air pollutants vary proportionately with the ventilation rate; thus, decreasing the ventilation rate by a factor of five may increase concentrations of indoor air pollutants by the same factor. Because of these increased concentrations, the current trend toward sealing off homes to conserve energy may have serious health consequences.

In spite of the accumulating scientific evidence, the legal system has largely ignored the problem of indoor air pollution. Common law remedies for injuries from indoor pollutants are inadequate, and at best serve merely to compensate injury rather than to prevent it. Congress and the federal regulatory agencies have generally not addressed indoor air pollution; their involvement has essentially been limited to funding of research. For example, while public and private expenditures to abate outdoor air pollution amounted to an estimated $25.4 billion in 1979 the total amount spent on indoor air pollution research in the past 10 years has been approximately $5-7 million. Nonetheless, EPA has recently attempted to discontinue funding of all indoor air pollution research.

Several state governments have attempted to deal with this perceived health problem through product bans, ventilation requirements, and ambient air quality standards, but these efforts have been limited in both geographic scope and in the range of pollutants covered. The time has come for a consistent, comprehensive plan for the study and possible regulation of indoor pollutants to emerge from the proverbial smoke-filled rooms of federal policy makers.

This article examines the problem of indoor air pollution and the policy options it presents. Part I discusses the individual pollutants, their known concentrations inside homes, the health problems they pose, and possible methods of controlling them. Part II, which will appear next month in Environment, examines the potential for applying three currently existing federal statutes to the regulation of indoor air pollution. Additionally, it discusses the need for an expanded government role in the control of indoor air pollution, evaluates the possible strategies which Congress might consider, and presents a proposal for federal legislation.

WHAT ARE THE POLLUTANTS?

Although few studies of indoor air pollution are beyond dispute, the scientific literature on several categories of indoor pollutants is surprisingly extensive. This part summarizes the available literature on the identities, concentrations, health effects, and control techniques for these categories of indoor pollutants.

RADON and ITS DECAY PRODUCTS

Radon is a radioactive gas that occurs naturally at trace levels. Like any radioactive element, its atomic structure is unstable, and , thus, it undergoes radioactive decay. Decay is the process by which the atom seeks to reach a more stable structure by emitting subatomic particles or energy rays. These particles are emitted from the atom at high speeds, releasing tremendous amounts of energy. In the process of decay, the atom is transformed into other elements, which are usually also radioactive and thus subject to further decay.

Decay processes follow a predictable course, and radioactive elements are grouped by the decay “family” to which they belong. Radon is an intermediate member of the uranium decay family. It is the gaseous decay product of radium, a solid substance under normal conditions. Radon decays further into polonium, several forms of lead, and bismuth. These decay products are known as the “progeny” of radon.

Radon and its progeny contribute a major portion of the background radiation dosage in the environment. Radon gas is a health threat because it may continue to decay within the lungs after it is inhaled.

There are several sources of the radon found within homes. Radon is present in most soil and may seep up into homes from below. It can diffuse both directly through the foundation and through cracks or penetrations in the foundation. Radon also may be present in the several tons of concrete and brick used to build most homes, because these materials are made from rock and soil. Both water and natural gas used in the house may contain radon if they pass through underground areas that contain the element. Even if the soil in one area is not rich in radon, groundwater flowing through the soil can carry radon with it from adjacent areas. High levels of radon in water have been correlated with indoor levels of the substance. 15 In addition, homes with certain types of solar heating systems may manifest elevated radon concentrations because the rocks used to store heat in such systems contain and emit radon.

Concentrations of radon inside homes can range from the ambient outdoor concentration to several times the outdoor concentration. Indoor concentrations depend on the underlying rock and soil, the building materials, and the rate of ventilation. The extraordinarily complicated set of measurement units that describe radon concentrations and radiation dose exposures, however, make direct comparisons difficult.

Radon concentrations are measured in nano-Curies per cubic meter. A nano-Curie is a set quantity of atoms decaying each second. Because different types of radiation damage the body in different ways, exposure to these various types is expressed in different units. A rad is a unit of the dose of gamma radiation absorbed by human tissue, and a millirad is 0.00 1 rad. For other types of radiation, the dose of radiation, which will have an “estimated biologic effect” equivalent to that of 1 rad of gamma radiation is expressed as 1 rem. Concentrations of radon progeny are expressed in “working levels,” a measure of the concentration of the alpha type radiation that is the primary cause of tissue damage. Working levels may be converted into rems, but only based on a series of inferences about the nature of the radon progeny and a complicated mathematical model.

Levels of outdoor exposure to cosmic radiation vary with location and altitude. Doses can vary from 20 millirads per year at sea level to 50 millirads per year at an altitude similar to that of Denver, Colorado. Terrestrial radiation exposure is approximately 35 millirads per year. Total exposure to radiation from all natural background sources varies from 80 rem for the gastrointestinal tract and bone marrow to 180 rem for the lungs.

Radiation exposures from radon indoors are in addition to radiation exposures outdoors, in the workplace, and from substances within the body. While indoors, however, people are partially shielded from exposure to extraterrestrial and cosmic radiation by the building itself. A survey of New York and New Jersey homes showed average radon concentrations ranging from 0.3 to 3.1 nanoCuries per cubic meter; typical concentrations of radon progeny ranged from 0.004 working levels to 0.02 working levels. The Mine Safety and Health Administration requires that miners not be exposed to over 1 working level at any instant.

Houses built over phosphate deposits or uranium mill tailings have significantly higher radon concentrations than houses in other areas. In one area in Montana, for example, the indoor radiation levels are so high that the United States Department of Housing and Urban Development requires individual homes to be tested for radon levels before the Department approves federal housing loans. Building materials can also affect indoor radon levels; for example, Swedish homes built with alum shale—a type of rock that has a layered structure and contains aluminum sulfate and potassium sulfate, and is often used as a component of concrete—have high levels of radon.

Radon concentrations can be two to five times higher in energy- efficient homes than in conventional homes. Concentrations in these homes are especially high in the first two stories, where residents spend most of their time. The cause of these increased radon concentrations appears to be decreased ventilation rates. Radon is cause for concern in upper stories of dwellings as well. Although radon levels are high in the basement and ground floor levels of apartment buildings, no clear relationship has been found between levels of radon and its progeny and height above the first floor. Thus, apartment dwellers on the tenth floor of a building are not necessarily exposed to lower concentrations of radon than are those living on the third floor.

Like other radioactive materials, radon can cause cancer. The National Academy of Sciences and other groups have found that prolonged exposure to radon concentrations greater than those occurring naturally in the atmosphere elevates the risk of lung cancer in humans. Most of the studies did not consider residential concentrations; their subjects were either laboratory animals or workers in uranium mines who were exposed to high radiation concentrations. Although the radon concentration in mines is likely to be higher than in homes, miners are exposed for shorter periods of time than residents of homes. Moreover, residents exposed to radon include young, old, and sick people who may be more susceptible.

Predicting the effects of indoor exposure to radon involves “extrapolating beyond the range of exposures for which effects have clearly been documented”.

Conclusions, therefore, are at best sketchy, and those estimates based on the mine studies may be too pessimistic because radon progeny enter the lungs attached to dust particles, and dust levels are far lower in homes than in mines. EPA has said, however, that radon exposure inside buildings may account for as many as ten percent of all deaths from lung cancer in the United States. If this is true, radon “could be one indoor air pollutant with an enormous health effect”.

Because radon occurs naturally in the soil, it is not possible to ban radon or to ban products containing radon. There are, however, several ways to control indoor exposure to radon. One way is to reduce radon levels in building materials from which radon emanates. A third is to use air filters or other means to remove radon from indoor air. Other ways to remove radon include mixing the indoor air to facilitate deposition of the radon progeny on solid substances and introducing charged ions into the air to link up with radon progeny ions, thereby removing them from the atmosphere. Finally, diluting indoor air with fresh air from outside can appreciably reduce indoor radon levels.

WHO CARES ABOUT INDOOR AIR?

Despite greater awareness today about hazardous pollution concentrations in indoor spaces, the public has been slow to demand action on this problem. Probably the main reason is that access to information on indoor air pollution has been limited. Researchers have yet to ascertain the levels of indoor exposure to various pollutants, to clarify the health effects of this exposure, or to explain the biological mechanisms through which these effects are manifested.

As recent energy conservation effects have decreased ventilation rates in buildings, the indoor air pollution problem has worsened. Additionally, evidence of indoor air pollution was discovered after evidences of other types of pollution had been disclosed. Thus, the public’s initial outrage with air pollution had begun to wear off, even as more recent disclosures were being made. and while the dangers of pollution outdoors were dramatically illustrated by several acute “episodes” affecting thousands of people, no similar episodes of broad impact have occurred indoors. Moreover, indoor pollutants are often clear, odorless, and detectable only with scientific instruments; they lack the sensory manifestations which so dramatically informed community members of the existence of an outdoor air problem.

Finally, the public may be reluctant to believe that pollution problems have invaded the home, as the strong financial and emotional ties of a person to his or her home could impede acknowledgment that a problem may exist.

PRODUCTS OF COMBUSTION

Combustion generates carbon monoxide, nitrogen oxides and other gaseous pollutants, and particulates. Combustion within buildings can cause indoor concentrations of these pollutants to exceed both existing outdoor concentrations and health standards established under the Clean Air Act.

Carbon monoxide, nitrogen oxides, and particulates are produced within the home by combustion in gas stoves, water heating, heating furnaces, kerosene space heaters, wood stoves, and gas clothes dryers. Gas stoves and space heaters are usually not vented directly to the outdoors; water heaters, furnaces, and clothes dryers usually are vented directly to the outdoors, but vents sometimes leak or become clogged. Even if vents are functioning properly, they rarely remove all of the combustion products. Thus, combustion fumes are introduced into the houses when appliances are unvented, improperly vented, and even properly vented. Combustion products can also enter the home from wood stoves, fireplaces, and garages adjoining or underneath the living area. Although little information is available on the indoor air pollution contribution from automobiles, one study found that, in a house where automotive emissions could escape from the garage into the living area, the car contributed more to indoor carbon monoxide concentrations than did the gas stove.

Concentrations of combustion products are often higher indoors than outdoors, especially in homes between the time of peak indoor concentrations of combustion products and the time of stove use. Therefore, concentration levels vary substantially with the time of day and the activities of the home occupants. Homes with gas water heaters and clothes dryers also experience combustion product concentrations greater than those outdoors.

The two pollutants whose indoor concentrations far exceed out door concentrations are carbon monoxide and nitrogen dioxide. In houses with gas ranges, for example, indoor nitrogen concentrations are often twice those of outdoor concentrations. In some houses, the long-term nitrogen dioxide concentrations can exceed the Clean Air Act standard of 0.05 part per million, achieving peak concentrations of up to 1 part per million and one-hour average concentrations of between 0.25 and 0.50 part per million in a closed kitchen with no external ventilation.

Indoor carbon monoxide concentrations, especially in homes with gas, coal, or wood heating or cooking stoves, often exceed the health standards under the Clean Air Act. Carbon monoxide concentrations typically vary between 0.5 part per million in homes and 5 parts per million, but peak values often reach 25 parts per million. Homes with gas or coal heating have been found to have carbon monoxide concentrations exceeding 50 parts per million for periods of one hour or longer. Gas stoves are often used for supplemental space heating, which further increases ambient concentrations. Thus, carbon monoxide concentrations in homes often exceed the Clean Air Act standards of 9 parts per million for eight-hour exposure and 35 parts per million for one-hour exposure.

Indoor levels of particulates may also exceed outdoor levels, although they depend heavily on whether a resident is smoking. One study found, for example, that particulate concentrations averaged 40 micrograms per cubic meter when there was no smoking taking place, and ranged from 30 micrograms per cubic meter to almost 700 micrograms per cubic meter when there was smoking. By contrast, the Clean Air Act’s ambient air standard for particulates permits exposure to 60 micrograms per cubic meter on an annual average basis and a maximum exposure of 150 micrograms per cubic meter at any instant. In general, homes with little ventilation have higher indoor concentrations of all these pollutants than do conventional homes.

EPA conducted extensive research on the health effects of combustion products during the 1970s when it set health standards for these pollutants under the Clean Air Act. Carbon monoxide, when inhaled, binds with the hemoglobin in the blood, blocking the distribution of oxygen to the body’s cells. If enough carbon monoxide is inhaled, suffocation results. At lower concentrations, the effects of oxygen deprivation are still present, but more subtle. Because carbon monoxide builds up in the blood, prolonged exposure at low concentrations may also have health effects, such as decreased stamina and coordination.

Nitrogen oxides also bind with hemoglobin, producing effects similar to those of carbon monoxide. Exposure to nitrogen dioxide may impair breathing, damage airways and tissue, and lead to chronic bronchitis and emphysema. Nitrogen oxides may also have behavioral and psychological effects, such as lengthening reaction times or causing depression. Carbon monoxide and nitrogen oxides may affect the young, the old, and the sick more severely than other groups.

A number of studies have revealed dramatic health differences between residents of homes with gas and electric cooking facilities. Children living in homes with gas stoves have been found to have significantly lower lung capabilities than children living in all-electric homes, even when socioeconomic status and parental smoking habits were taken into account. Moreover, these studies provide some evidence that the effects of peak concentrations could be as serious as lower-level, long-term exposure.

Particulates cause coughing, headaches, nausea, and irritation of the eyes, nose, and throat. They are small enough to be inhaled and deposited deep in the lung. In addition, several epidemiological studies have found a link between particulate matter and increased death rates.

There are several ways to control concentrations of combustion products in residential buildings. One obvious way is to remove sources of these products. Indeed, based on existing evidence of respiratory impairment in children, some researchers have proposed the complete elimination of gas stoves from the home. A second way is to design sources of combustion products to operate more efficiently so that they create less pollution. Finally, general ventilation can reduce overall pollutant levels, and direct ventilation of individual combustion sources can serve to reduce both overall levels and peak concentrations.

FORMALDEHYDE

Formaldehyde is both a by-product of combustion and a widely used chemical present in many manufactured products. It is one of the few indoor air pollutants that have received attention from the mass media and the federal and state governments. Formaldehyde is a serious respiratory and skin irritant, and perhaps a carcinogen.

A surprising number of household items contain formaldehyde. The main sources of formaldehyde in indoor air appear to be urea formaldehyde insulation, particle board, and plywood. Urea formaldehyde foam insulation is popular because it can simply be sprayed into walls to augment existing insulation. Formaldehyde is also found in synthetic resins that serve as adhesives in particle board, fiberboard and plywood, and furniture. In addition, formaldehyde gas is released indoors from combustion appliances, cigarettes, paper products, floor coverings, and textiles (to which the chemical is added to reduce creasing, crushing and shrinkage, and flammability). Other consumer products that may contain formaldehyde include grocery bags, waxed paper, facial tissues, paper towels, disinfectants, toothpaste, shampoos, cosmetics, and some medicines, to which formaldehyde is added because the chemical kills bacteria, fungi and viruses.

Indoor formaldehyde concentrations tend to be higher than out door concentrations. Studies have shown that indoor concentrations often exceed I part per million and even the 3 parts per million occupational exposure limit. Levels are particularly high in energy-efficient residences and in mobile homes, which often have low ventilation rates and walls of particle board or plywood. In fact, early health evidence on the ill effects of formaldehyde resulted from complaints received from residents of these small, tightly enclosed homes.

Concentrations in homes containing urea formaldehyde insulation are much higher than outdoor concentrations. The Consumer Products Safety Commission cites evidence that average formaldehyde levels in homes with urea formaldehyde foam insulation are four times the levels in homes insulated with other kinds of materials. One study found that the addition of furniture to previously empty residences tripled the concentration of formaldehyde, possibly because of formaldehyde in the furniture’s wood or fabrics.

Even low concentrations of formaldehyde affect human health. Formaldehyde is an irritant, and scientists learned of its health effects from complaints of affected individuals as well as from tests on laboratory animals. The National Academy of Sciences has estimated that “on the basis of laboratory tests and various kinds of population surveys, … perhaps 10-20% of the general population may be susceptible to the irritant properties of formaldehyde at extremely low concentrations.” At levels ranging upward from 0.05, formaldehyde exposure leads to rashes, irritation of the respiratory tract, nausea, headaches, dizziness, and lethargy. Formaldehyde also aggravates bronchial asthma. All of these effects appear at lower concentrations in people who have been exposed to the substance for long periods of time.

The greatest concern, however, is that formaldehyde may cause cancer. Studies have found that formaldehyde is a carcinogen at exposure levels as low as 6 parts per million. The Consumer Product Safety Commission has stated that concentrations of formaldehyde causing cancer in laboratory animals are not greatly different from concentrations to which humans are exposed. The National Academy of Sciences committee that investigated indoor air pollution indicated that it was “especially concerned with long- term and essentially continuous indoor exposures to low concentrations of formaldehyde.’ ‘61

Because most formaldehyde in the indoor air appears to originate from products used in homes, one way to reduce formaldehyde concentrations is to eliminate these products. Elimination is relatively simple for housing not already containing urea formaldehyde insulation. However, removal of existing urea formaldehyde foam from houses can cost up to $15,000 per house. A less drastic measure than elimination of formaldehyde-bearing products is to manufacture them more carefully to minimize the release of formaldehyde. Improving quality control standards may be possible for particle board or other factory-made items, but would be more difficult for urea formaldehyde foam insulation because the insulation is actually “manufactured” at each home as it is installed. Other control measures include ventilation and air cleaning.

ASBESTOS

Asbestos is not, as commonly thought, a particular chemical substance. Rather, it is the name of a group of substances that are fibrous, flexible, incombustible, and durable. Substances called asbestos have different chemical formulae, but are usually naturally occurring mineral fibers of relatively small diameter and long length. Asbestos materials in common use include serpentine chrysotile, amosite, crocidolite, anthophyllite, and actinolite-tremolite. This article refers to these materials collectively as asbestos. Additionally, other fibrous substances such as glass wool sometimes found in the indoor environment also may affect health, but the details of these effects remain to be documented.

Asbestos fibers remain airborne for long periods of time, are small enough to be inhaled deep into the lungs, and are durable even within human tissue. Asbestos causes several forms of cancer, yet an estimated 2,000 to 3,000 products contain asbestos. Many of these products, such as roofing and flooring materials, textiles, papers, filters and gaskets, cement, pipes, coating materials, and thermal and acoustic insulation, are found in homes.

Asbestos, which is found in residences principally in wall and pipe insulation, spackling compounds, and decorative and acoustic tiles, does not present a health problem until the fibers become detached and float freely through the air. Asbestos that is sprayed or troweled onto materials as insulation is easily dislodged. Asbestos used in solid materials, however, is generally tightly bound until the materials are disrupted by vibration, abrasion, cutting, grinding, sanding, or aging. Such disturbances might be caused by house keeping, maintenance, renovations, redecoration, or vandalism. Releases of asbestos thus tend to depend on occupant activity and to be confined to particular times and places. Asbestos fibers settle to the floor like dust after they are released into the indoor atmosphere; like dust, however, they are easily re-suspended.

There have been no systematic studies of asbestos levels in homes. Studies of schools and office buildings, however, indicate relatively low exposure to asbestos unless renovations or other activities dislodge the asbestos. The National Academy of Sciences has estimated that exposure in homes may be greater than in schools because the building materials that contain asbestos may be in poorer condition in homes than in schools.

Asbestos concentrations are close to zero even in buildings that contain asbestos, unless disruptive activities are occurring. Asbestos concentrations can rise, however, to 0.3 fibers per milliliter of air for a bystander in a room being cleaned, to 1.6 for a person sweeping the floor, and to 4.0 for a person dusting near his or her face. A person repairing a ceiling that contains asbestos can be exposed to about 18 fibers per milliliter, and a person stripping the ceiling can be exposed to over 80 fibers per milliliter. Thus, exposures to asbestos in homes can greatly exceed the current OSHA standards of 2 fibers per milliliter on an eight-hour average basis and 10 fibers per milliliter on an instantaneous basis.

The health affects of asbestos have been studied extensively. Although the mechanisms through which these pollutants do their damage are only poorly understood, we know that asbestos can adversely affect human health when it comes into contact with the skin, when it is inhaled, and when it is ingested. Asbestos fibers which enter the body through the lungs or gastrointestinal tract can be transported through the blood or lymphatic systems to other parts of the body.

The most common way for asbestos to enter the body is inhalation, which can lead to lung cancer and mesothelioma, a cancer of the cells lining the lung and heart cavities. In addition, asbestos can cause asbestosis, a form of pulmonary fibrosis that involves the scarring of the lungs with fibrous tissue, and to fibrosis of the heart cavity. Asbestos can also cause severe irritation when it comes in contact with the skin.

The lack of information regarding exposure concentrations has kept the relationship between asbestos concentrations and disease incidence unclear. It is, however, known to take 15 to 40 years after exposure for asbestos related diseases to develop; this long latency period exacerbates the problems of quantifying the relationship between exposures and disease. Additionally, even short exposures may induce disease, further complicating efforts to understand the health effects of asbestos. Moreover, asbestos exposure and cigarette smoking appear to work synergistically. Studies have found that smoking increases the risk of asbestosis death by a factor of two to three. Risks of lung cancer among smoking asbestos workers also were found to be eight times greater than among the smokers in the general population, and 92 times greater than for non-smokers in the general population.

One way of reducing asbestos concentrations in indoor air is to eliminate products containing asbestos from buildings. Removing building materials that contain asbestos from existing buildings, however, may itself release large amounts of asbestos fibers unless complicated precautions are taken. Alternative means of limiting exposure to asbestos include preventing the disturbance of materials that contain asbestos—the approach adopted by Congress and EPA in dealing with asbestos in schools sealing asbestos into its current location.

CHEMICAL FUMES and PARTICLES

Many of the consumer products used in residences release particles or chemical fumes. Like other indoor air pollutants, these particles or fumes may be trapped indoors and concentrated to the extent that they adversely affect human health.

The numerous aerosol spray products found in most homes contain indoor air pollutants. The average residence contains an estimated 45 aerosol spray products. These aerosol items include hair spray, frying-pan spray, room freshener, insect repellent, furniture polish, and bathroom cleaner, among others. The active substances in aerosols include sodium or potassium hydroxide (oven cleaners), ammonium hydroxide (window cleaners), morpholine (furniture polish), tetracholoroethylene (spot removers), toluene, xylene, methylchloride and pigments (paints), hydrated aluminum chloride (deodorants), vinyl acetate copolymer resins (hair sprays), and chlordane (pesticides). Aerosol propellants include dichlorodifluoromethane and trichlorofluoromethane (commonly known as fluorocarbons), vinyl chloride, propane, butane, nitrous oxide, and methylene chloride. Fluorocarbon and vinyl chloride propellants, however, have now been banned from consumer products.

Grinding, sanding, cleaning, and other activities also release potentially hazardous chemicals into the air. Plastics, paints, solvents, artificial fiber textiles, cleaners, bleaches, disinfectants, deodorizers, and other substances all emit pollutants either through evaporation or “outgassing”—that is, the release of gaseous chemicals from solid substance, such as methylene chloride from paint remover, mercury compounds in latex paints, and various breakdown products from pesticides. Dust and particles, which may be by-products of hobby and craft materials and processes (for example, lead glazes, solder and flux from stained glass and jewelry making, and woodworking), are resuspended whenever the area is cleaned.

Concentrations of pollutants from consumer products vary with the product and the rate of ventilation. Many products release fumes even when used as directed; still more products can present danger when misused. Some products release pollutants only when in use, and others pollute the air even when not in use. The National Academy of Sciences reported that “measurements of actual concentrations of chemicals associated with household products are scarce; where they are reported, they can be very high.”

Evidence of health effects is scant for most substances found in consumer products, and existing reports tend to be anecdotal. Most products, when properly used, do not produce immediate acute effects, but the long term effects of the substances found in such products are largely unknown. Analysis of health effects is often hampered by labels that do not identify individual chemical ingredients.

The health effects of these consumer products are as diverse as the products themselves. For example, one study has associated respiratory effects with aerosol use, but other studies have shown no such effects. Repeated inhalation of wood dust on the job has been linked with nasal cancer; wood dust in the home may present a similar hazard. One study found a statistical link between the use of spray adhesives and birth defects.

In many cases, proper use of consumer products reduces or eliminates the dangers associated with the products. Adequate ventilation can also pay an important role in lowering pollutant concentrations, but ventilation may not provide sufficient protection against some pollutants, especially if the products releasing the pollutants are misused. Product restrictions or bans may be the only way to control the danger created by products that are hazardous even when used properly.

OTHER INDOOR POLLUTANTS

In addition to the pollutants discussed above, others not now thought to present a major threat to indoor air quality should not be ignored. Airborne bacteria, viruses, and fungi found in indoor air may present a health threat. Many of these microorganisms carry infectious diseases, such as influenza, Legionnaire’s disease, tuberculosis, measles, mumps, chicken pox, and rubella. Air-cleaning filters, heat exchangers, humidifying systems, and air conditioners perhaps also indirectly cause infections.

Ozone, the effects of which may include respiratory irritation and drowsiness, is also found indoors, but usually in concentrations less than those prevalent outdoors. Yet if sources of ozone, such as electrostatic air filters, are located indoors, indoor concentrations can exceed outdoor concentrations.

WHAT CAN WE DO ABOUT THEM?

The current statutory and common law mechanisms for dealing with the potential health hazards associated with indoor air pollution are uncertain and inadequate. State and local laws have been used to a certain extent as means of controlling indoor air pollution. Some states have forbidden the use of certain building materials, mandated minimum acceptable ventilation rates, and set standards for indoor pollution concentrations. Many more state and local governments have building code legislation that they could use to deal with the indoor pollution problem.

Federal involvement with indoor air pollution, chiefly limited to funding research, has been haphazard at best. Programs affecting indoor air pollution have been redundant in some instances, and contradictory in others. Conflicts and duplication, in turn, have led to agency squabbles and inaction. Unlike many other interagency disputes to claim jurisdiction, federal agencies have argued that indoor air pollution does not fall under their statutory mandates.

Federal agencies have been reluctant to act on indoor air pollution for several reasons:

+ Regulators have lacked extensive scientific information on which to base their actions.

+ Some regulators fear that recognition of an indoor air pollution problem would increase pressure to weaken outdoor air quality standards.

+ Regulators are reluctant to intrude into private homes.

+ Regulators have not shown great concern because they have not been subject to public pressure to regulate indoor pollution.

+ Most importantly, regulators have been reluctant to act without unequivocal statutory authority.

There are a number of federal laws that could be used to address indoor air pollution, particularly the Clean Air Act, the Toxic Substances Control Act, and the Consumer Product Safety Act. Part II of this article, which will appear next month in Environment, will discuss the need for, as well as the range of existing and possible forms of, federal intervention Congress might consider in addressing the indoor pollution problem.

NOTES

1. In 1981, the National Academy of Sciences performed a major review of research on indoor air pollutant concentrations, health effects, and control techniques. Committee on Indoor Pollutants, Board on Toxicology and Environmental Health Hazards, Assembly of Life Sciences, National Academy of Sciences/National Research Council, INDOOR POLLU TANTS (Washington, D.C., 1981) (hereinafter cited as NAS/ NRC REPORT). In the same year, scientists from around the globe presented over 100 technical papers on the subject at an international Symposium on Indoor Air Pollution, Health and Energy Conservation jointly presented by the Energy and Environment Policy Center of the John F. Kennedy School of Government at Harvard University and the Harvard School of Public Health. The Council on Environmental Quality (CEOJ recognized the problem of indoor air pollution by summarizing the available information on the subject in its 1980 Annual Report.

2. Occupational Safety and Health Act, 29 U.S.C. pp. 651-678, 655 (1976 and Supp. III 1979).

3. NAS/NRC REPORT, note 1 above pp. 23-24.

4. Pollutants of the latter variety are not necessarily released in greater quantities indoors than outdoors. Because of the smaller air volume indoors, however, concentrations of these pollutants are higher indoors.

5. M. Gold, “Indoor Air Pollution,” SCIENCE-80. March! April 1980. p. 30.

6. Ibid., p. 33.

7. Ibid.

8. NAS/NRC REPORT, note 1 above, p. 62 (radon concentrations inversely proportional to the air exchange rate which is, by definition, inversely proportional to the time for a complete air exchange); C. Hollowell, J. Berk, S. Brown, J. Dillworth, J. Koonce, and R. Young, INDOOR AIR QUALITY IN NEW ENERGY-EFFICIENT HOUSES and RETROFITTED HOUSES (abstract of paper presented at the International Symposium on Indoor Air Pollution, Health and Energy Conservation, Harvard University, October 13-16, 1981). Substantial uncertainties still exist, however.

9. R. Stewart and J. Krier, ENVIRONMENTAL LAW and POLICY, 2d ed. (Charlottesville, Va: Miche-Bobbs, 1978), pp. 255-324.

10. U.S. Council on Environmental Quality, ENVIRONMENTAL QUALITY-1980 (Washington, D.C., 1980), p. 397.

11. Telephone interview with James L. Repace, Office of Policy Analysis, U.S. EPA. February 8, 1982.

12. Letter from Anne Gorsuch, administrator, U.S. EPA, to Toby Moffett, U.S. House of Representatives (September 22, 1981), cited in ENVIRONMENT REPORTER (BNA) 797 (October 23, 1981). Supposedly, Administrator Gorsuch attempted to end all EPA funding of indoor air pollution research because of a lack of statutory authority. EPA’s authority over indoor air research will be discussed in Part II of “Behind Closed Doors,” to be published in ENVIRONMENT, April 1983.

13. K. Krauskopf and A. Beiser, THE PHYSICAL UNIVERSE (New York: McGraw-Hill, 1973), pp. 272-277.

14.. R. Bruno, SOURCES OF INDOOR RADON IN HOUSES (abstract of paper presented at the International Symposium of Indoor Air Pollution, Health and Energy Conservation,

Harvard University, October 13-16, 1981).

15. Ibid., pp. 2-3. NAS/NRC REPORT, note I above, p. 69.

16. NAS/NRC REPORT, note 1 above, p. 66.

17. Ibid., p. 70.

18. Ibid., pp. 58-60.

19. Ibid., pp. 62, 70, 30-31.

20. 30 C.F.R. pp. 57.5-38 to 57.6-39 (1981).

21. Uranium mill tailings are the “sand-like radioactive by products of the (uranium) milling process.” Flax, “Radio active Waste Management,” HARVARD ENVIRON MENTAL LAW REVIEW 5 (1981): 259, 261 note 12. From 1950 through 1966, piles of uranium mill tailings in Grand Junction, Colorado, were given to builders, who used the tailings as a substitute for fill dirt. The interiors of the homes, schools, and other buildings constructed on top of these tailings were found, as early as 1966, to have radon levels (“significantly higher than background levels.” See Metzger, “Dear Sir: Your House is Built on Radioactive Uranium Waste,” N.Y. TIMES, October 31, 1971, V. 6(Magazine), pp. 14, and 62. According to Metzger, in at least one classroom and several homes, for example, levels of radioactivity exceeded the federal exposure limits for uranium mines. These discoveries prompted some of the earliest research on indoor air pollution from radon. The Atomic Energy Commission conducted one such study in areas of Tennessee and Florida known to have high radioactivity levels from naturally occur ring uranium in the surface soil. Even in these areas, indoor radon and radon progeny concentrations were only 1 percent of the high indoor concentrations found in the Colorado buildings over mine tailings.

22. U.S. General Accounting Office, INDOOR AIR POLLUTION: AN EMERGING HEALTH PROBLEM, Pub. No. CED-80-111 (Washington, D.C., 1980), p. 5.

23. 0. Hildingson, MEASUREMENT OF RADON DAUGH TERS IN 5600 SWEDISH HOMES (abstract of paper presented at the International Symposium on Indoor Air Pollution, Health and Energy Conservation, Harvard University, October 13-16, 1981). The Swedish government has imposed a radon daughter concentration standard for residences.

24. R. Fleicher, A. Mogro-Campero, and L. Turner, INDOOR RADON LEVELS: EFFECTS OF ENERGY-EFFICIENCY IN HOMES (abstract of paper presented at the International Symposium on Indoor Air Pollution, Health and Energy Conservation, Harvard University, October 13-16, 1981).

25. Ibid, p. 2.

26. F. Abu-Jarad and F. Fremlin, THE ACTIVITY OF RADON DAUGHTERS IN HIGH RISE BUILDINGS and THE INFLUENCE OF SOIL EMANATION (abstract of paper presented at the International Symposium on Indoor Air Pollution, Health and Energy Conservation, Harvard University, October 13-16, 1981).

27. NAS/NRC REPORT, note 1 above, pp. 307-308; U.S. General Accounting Office, note 22 above, p. 4.

28. Miners are exposed to radiation concentrations on the order of 1-20 working levels; concentrations inside homes are usually about 0.01 working level, but they can range up to the exposure levels in mines. NASINRC REPORT, note I above, p. 310.

29. Ibid., p. 317.

30. Ibid., p. 39, 307.

31. U.S. Council on Environmental Quality, note 10 above, pp.

186-197. Typical indoor concentrations have been argued to cause as many as 2,000 to 20,000 lung cancers per year in the United States. A. Rosenfield and C. Hollowell, MEASUREMENT and CONTROL OF INDOOR AIR QUAL ITY IN EXISTING and NEW HOMES (testimony presented before the Subcommittee on 1 Development and Applications, of the House Committee on Science and Technology, May 28, 1981), p. 3. The risk of lung cancer in creases for individuals who live in homes with higher than nor mal radon concentrations. Ibid.

32. Gold, note 5 above, p. 33.

33. U.S. Council on Environmental Quality, note 10 above, p. 184. For a discussion of the Clean Air Act and its applicability to indoor pollution, see Part II of “Behind Closed Doors,” to be published in ENVIRONMENT, April 1983.

34. Dryers are not always vented directly outside. One energy conservation gadget on the market is advertised as a device for recapturing residual heat from the exhaust of clothes dryers. It consists of a simple lint filter in a frame. The homeowner detaches the outdoor vent from the clothes dryer, attaches the filter to the end of the exhaust hose, and allows the hot air exhaust to blow directly into the house instead of outdoors. See, for example, CHRISTIAN SCIENCE MONITOR, October 26, 1979, p. 7 col. 2. Because the lint filter is not completely effective, excess lint and other particles are blown into the home. When gas dryers are used, all of the gaseous combustion fumes, which would have been blown outdoors, are introduced into the air that the inhabitants breathe indoors.

35. NAS/NRC REPORT, note 1 above, p. 145.

36. Wade, Cote, and Yocum, “A Study of Indoor Air Quality,” JOURNAL OF THE AIR POLLUTION CONTROL ASSOCIATION 25 (1975): 933, 939. Peak concentrations are important because time-averaged exposures do not reflect the different ways in which different pollutants harm the body. See NAS/NRC REPORT, note 1 above, pp. 20, 51. Certain health effects result only from peak exposures which “may be encountered only during specific activities or in locations occupied only infrequently,” Ibid. For example, exposure to a high concentration of carbon monoxide, even for a short time, can be fatal. If the same total exposure to the pollutant were averaged over a lifetime, effects would probably be minimal. Thus, where peak concentrations are important, studying average concentrations may be misleading because “short-term peak concentrations may contribute only a small proportion of a person’s total (average) exposure.” Ibid., p. 20. Conversely, pollutants may manifest certain health effects principally over long periods of exposure because “substances that accumulate within the body (will) have the opportunity to accumulate to toxic levels (and) substances that cause relatively little tissue damage by single exposure, such as some volatile chemicals (will) have the opportunity to cause cumulative tissue damage by repeated exposure.” Hinkle and Murray, “The Importance of the Quality of Indoor air,” BULLETIN OF THE N.Y. ACADEMY OF MEDICINE 57 (1981): 829.

37. Spengler, Ferris, Dockery, and Speizer, “Sulfur Dioxide and Nitrogen Dioxide Levels Inside and Outside Homes and the

Implications on Health Effects Research,” ENVIRON MENTAL SCIENCE and TECHNOLOGY 13 (1979): 1276, 1278.

38. NAS/NRC REPORT, note 1 above, p. 41.

39. Ibid., p. 139.

40. Ibid., p. 32.

41. Ibid., p. 135.

42. Reocade and Lowery, “Indoor Air Pollution, Tobacco Smoke, and Public Health,” Science 208 (1980): 469.

43. 40 C.F.R., 50.7 (1981).

44. Melia, Florey, Altman, and Swan, “Association Between Gas Cooking and Respiratory Disease in Children,” British Medical Journal (1977-2): 149-152; Spengler et al., note 37 above.

45. See generally, NAS/NRC Report, note I above, pp. 359-361.

46. See U.S. Council on Environmental Quality, note 10 above, p. 187.

47. For example, T. Sterling, J. Weinkam, and E. Sterling, The Case for Entirely Removing the Gas Range from Indoors (abstract from paper presented at the International Symposium of Indoor Air Pollution, Health and Energy Conservation, Harvard University, October 13-16, 1981).

48. NAS/NRC Report, note 1 above, pp. 0-41.

49. Ibid, pp. 83-84.

50. Department of Public Health, State of Minnesota, “In the Matter of Proposed New Rules Relating to Formaldehyde.”.

51. NAS/NRC Report, note 1 above, pp. 83, 86, 29 C.F.R., 1901.1 (1981).

52. Committee on Aldehydes, Board on Toxicology and Environmental Health Hazards, Assembly of Life Sciences, National Academy of Science/National Research Council, Formaldehyde and Other Aldehydes Washington, DC, 1981 (hereinafter cited as “Formaldehyde Report”), pp. 47-51, 200-202.

53. U.S. Consumer Product Safety Commission, “Decision Briefing Package on Urea-Formaldehyde Foam Insulation”

(1982), p. 4.

54. “Formaldehyde Report,” note 52 above, pp. 50, 53.

55. NAS/NRC Report, note 1 above, p. 40. At a consideration as low as 0.05 per million, for example, formaldehyde can irritate the eyes, note 52 above, pp. 187-189.

56. NAS/NRC Report, note I above, p. 40, 323-331: “Form aldehyde Report,” note 52 above. pp. 187-189, 190-192, 194-197.

57. “Formaldehyde Report, note 52 above, pp. 190-193, NAS/ NRC Report, note 1 above, p. 40.

58. NAS/NRC Report, note I above, p. 6.

59. Nasal cancer developed in one group of rats exposed to 6 parts per million and another group exposed to 15 parts per million. Swenborg, Kerns, Itchell, Gralla, and Parkov, “Induction of Squamous Cell Carcinas of the Rat Nasal cavity by Inhalation Exposure to Urea Formaldehyde Vapor,” Cancer Research 40 (1980): 3398.

60. See 47 Fed. Reg. 14,366, 14,370 (1982).

61. NASINRC Report, note I above, p. 6.

62. Washington Post, Feb. 23, 1982, P. Al, col. 1.

63. NAS/NRC Report, note 1 above, p. 339.

64. U.S. General Accounting Office, note 22 above, p. 8. Approximately 600,000 tons of asbestos were consumed in the United States in 1979; worldwide production is approaching 5 million tons per year. NAS/NRC Report, note 1 above, p. 112.

65. NAS/NRC Report, note 1 above, pp. 31-32.

66. Ibid., pp. 6-7.

67. Ibid., pp. 118-119.

68. 29 C.F.R., 1910.1001 (1980).

69. U.S. Council on Environmental Quality, note 10 above, p. 224.

70. See Asbestos School Hazard Decision and Control Act, 20 U.S.C., 3601-3611 (Supp. 1V 1980).

71. NAS/NRC Report, note 1 above, pp. 12, 102; Gold, note 5 above, p. 33.

72. See NAS/NRC Report, note 1 above, p. 102. 21 C.F.R.,

300.10, 700.14, 700.23 (1981). 26 C.F.R., 1500.17 (a) (10) (1981).

73. Ibid., pp. 100-101, 104-106.

74. For example, the known carcinogen chlordane, a termite pesticide, remains in the atmosphere as long as 14 years after application. J. Repace, “Indoor Air Pollution,” (paper pre sented at the International Symposium on Indoor Air Pollution, Health, and Energy Conservation, Harvard Univer sity, October 13-16, 1981) P. 13.

75. NAS/NRC Report, note 1 above, p. 104.

76. Ibid., pp. 102-103.

77. Acheson, Cowdell, Hadfield, and Macbeth, “Nasal Cancer in Woodworkers in the Furniture Industry,” British Medical Journal (1968-2): 587.

78. NAS/NRC Report, note I above, p. 103.

79. See ibid., p. 54.

80. Colligari, “The Psychological Effects of Indoor Air Pollution,” Bulletin of the N. Y. Academy of Medicine 57 (1981): 1015-1016.

81. NAS/NRC Report, note 1 above, p. 34.

INDOOR POLLUTION TESTING

Some of the most deadly pollutants are extremely difficult to detect. They are silent menaces that are usually colorless and odorless. Children, the elderly, and housewives tend to be the most suscepti ble victims to indoor dangers because they spend so much more time at home than men and women who work.

The least expensive home testing device to see if carbon monox ide is being given off by gas appliances, fireplaces, and wood-burning stoves is a small $10 adhesive strip that has some resin in it.

More and more firms are offering some type of formaldehyde detectors. The detectors might sometimes be purchased separately, and you have to have a laboratory analysis done on them after they have been used.

Radon is one of the most vicious radioactive killers, and it is hard to detect. It is even difficult for technology at this point to target it quickly. Some of the devices on the market must be attached to a wall in a house or building for three months. After that time, they are sent to a lab for analysis. The detectors run from $60 or so to $200 in some cases.

Homes that are very tight and have poor ventilation tend to have a much higher radon concentration than those which have less energy efficiency. The geographical location is a factor.

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