Indoor Air Contaminants

Americans spend 80 to 90 percent of their time indoors. As our buildings become more tightly controlled environments, the quality of indoor air and its effects on our health becomes an increasingly critical issue. There are over 80,000 synthetic chemicals in use today, most of which have not been tested individually or in combination for their effects on human health. Materials used in building, furnishing, and maintaining a building potentially contain many toxic chemicals.

According to the U.S. Environmental Protection Agency (EPA), indoor air in the United States is now on average two to ten times more contaminated than the air outside. The World Health Organization (WHO) asserts that 40 percent of all buildings pose significant health hazards from indoor pollution, and WHO experts have observed unusually high rates of health and comfort complaints that could be related to indoor air quality (IAQ) from occupants in up to 30 percent of new or remodeled commercial buildings.

Twenty percent of all workers report building-related irritations or illnesses. The EPA has declared poor IAQ the number one environmental health problem in the United States. According to the American Medical Association, a third of our total national health expenditure is spent on ailments directly attributable to indoor air pollution. The EPA cites an 18 percent decrease in overall worker productivity due to poor IAQ.

Three major reasons for poor IAQ in office buildings are the presence of indoor air pollution sources; poorly designed, maintained, or operated ventilation systems; and uses of the building that were unanticipated or poorly planned for when the building was designed or renovated. Interior designers play a significant role in specifying materials that may contribute to indoor air pollution. We also are key players in the renovation of buildings to new uses and to accommodate new ways of working.

Air pollution problems can start with the building's materials and finishes and/or with the construction methods used to build or renovate the building. Indoor air quality is compromised when inadequate ventilation fails to provide enough outside air. Chemicals used in cleaning and office products thus get trapped inside the building, and outdoor pollutants that enter get caught inside, adding to the problem. Mold or other microorganisms that grow, multiply, and disperse particles through heating, ventilating and air-conditioning (HVAC) systems are a significant source of IAQ problems as well. Poor design and maintenance of the HVAC system supports the growth of microorganisms.

People contribute skin scales, carbon dioxide that we exhale, and airborne particles, vapors, and gases. Cleaning, cooking, broiling, gas and oil burning, personal hygiene, and smoking all add pollutants to indoor air. Pesticides from pest management practices can also pollute the building's air. Indoor air pollutants can be circulated from portions of the building used for specialized purposes, such as restaurants, print shops, and dry-cleaning stores, into offices in the same building.

Prior to 1973, energy for buildings was relatively inexpensive, and large quantities of outdoor air were used to ventilate buildings. During the oil embargo of 1973, Americans became more aware of the limited supply of fossil fuels for energy. New energy-conserving designs were developed that often limited the amount of outdoor air entering the building, thereby saving the cost of heating or cooling this fresh air. Insulation was increased, air leakage through the building envelope was reduced, and mechanical ventilation rates were decreased. Heat exchangers were introduced to recover the heat of exhaust air.

Air quality was originally ignored in the quest to produce energy-efficient buildings, leading to concentration of contaminants at levels that threatened public health. Scientists developed new chemical compounds for use in the manufacture of synthetic building materials, in equipment inside the building, and in cleaning and maintenance products. With the decrease in fresh air entering the building, these potential air pollutants became concentrated in the indoor environment of some buildings. Some chemicals were concentrated at levels 100 times higher than would ever occur in the open air. Because updating codes takes years, and ventilation standards have changed, the code in force when an HVAC system was designed may have permitted a lower ventilation rate than the current standards.

Contaminants in buildings are so widespread that virtually every building contains one or more recognized contaminants. Asbestos and lead have been used in building products for many years in the past. Heating systems can give off carbon monoxide. Interior finishes and building materials often contain formaldehyde. Benzene and chlordane are both petroleum products found in detergents, insecticides, and motor fuels. Mercury, ozone, and radon can contaminate buildings as well. Paper copying and inks produce irritating fumes, and dust and tobacco smoke contain particles that irritate the respiratory system. Plastics can give off offensive gases. Fabrics treated with fire-retardant chemicals can cause problems for some people.

The overall result of these pollutants can be sick building syndrome (SBS), which is diagnosed when more than 20 percent of the building's occupants complain of symptoms such as headaches, upper respiratory irritation, or eye irritation, and when these symptoms disappear after leaving the building on weekends. Symp toms may also include irritation of mucous membranes, dizziness, nausea, throat irritation, and fatigue. Although the specific causes aren't identified, the symptoms coincide with time spent in a particular building and disappear once the sufferer leaves. The related term "building related illness" (BRI) is also used to describe the same range of ailments, from mild allergic reactions to more serious infections such as pneumonia; the difference is that BRI is applied to those cases where the specific cause of the ailment is known. Both SBS and BRI are largely the result of poor IAQ.

The EPA conservatively estimates the potential economic impact of employee illness and loss of productivity due to indoor air pollution to total $4.4 to $5.4 billion per year. The most susceptible people, who are also those who spend the most time indoors, include children, elderly people, and people with chronic illnesses. Contamination by multiple chemicals has an effect greater than the sum of the same chemicals individually. Allergies and asthma are rising dramatically, and may be caused by contaminants in a sick building.

Symptoms that appear suddenly after a change in the building, such as painting or pesticide application, are another indication of IAQ problems. Some individuals may be affected by IAQ problems, while others sharing the same space are not.

Frequently, IAQ problems in large commercial buildings cannot be effectively identified or remedied without a comprehensive building investigation. Diagnosing symptoms that relate to IAQ can be difficult, time consuming, and expensive. If a professional company is hired to conduct an investigation of a commercial building, the building's owner should select a company on the basis of its experience in identifying and solving IAQ problems in nonindustrial buildings, as the methodology and standards are different for industrial settings.

These investigations may start with written questionnaires and telephone consultations in which building investigators assess the history of occupant symptoms and building operation procedures. In some cases, these inquiries may quickly uncover the problem and on-site visits are unnecessary. More often, investigators will need to come to the building to conduct personal interviews with occupants, to look for possible sources of problems, and to inspect the design and operation of the ventilation system and other building features. Taking measurements of pollutants at the very low levels often found in office buildings is expensive and may not yield information readily useful in identifying problem sources. The process of solving IAQ problems that result in health and comfort complaints can be a slow one, involving several trial solutions before successful remedial actions are identified.

Unusual odors, too hot an indoor environment, improper lighting, noise, vibration, overcrowding, ergonomie stressors, and job-related psychosocial problems can all produce symptoms that are similar to those associated with poor air quality, but IAQ may not be the culprit. Because of the complexity of IAQ problems and building dynamics, as well as the potential for serious human health effects, building owners or managers who suspect IAQ problems should seek the help of competent, qualified IAQ specialists to investigate, diagnose, and mitigate problems.

In order to improve IAQ and prevent contamination by pollutants, the building's architect, engineers, and interior designer must work together. The interior designer can specify appropriate materials, products, and equipment. You should evaluate the amount and toxicity of emissions given off during installation or use, especially where surfaces of possibly polluting materials are exposed to the air and to people. Review maintenance requirements for cleaning processes, stain resistant treatments, and waxing that emit pollutants. When the construction is complete, the interior designer should provide the building's management, users, and owners with appropriate information about maintenance requirements.

Many of the problems people have with reactions to building contaminants begin with new or renovation construction. Renovations in occupied buildings are especially likely to introduce pollutants into the building's interior. Construction can be compartmentalized using partitions and doors with closers, and connecting plenums can be blocked. The work area must be securely isolated from other occupied spaces, and supplied with extra ventilation via window- or door-mounted fans. Keeping the construction area under negative pressure prevents contaminants from spreading throughout the building. Plugging up air-conditioning returns so that contamination from a construction area can't spread throughout the building also helps. If appropriate, construction workers should use organic vapor respirators with charcoal filters. Emphasize that complying with IAQ requirements also protects construction workers.

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