One of the first steps toward in eliminating indoor air pollution is identifying its sources. Generally speaking, air-borne pollutants may be biological or chemical.
Biological agents include bacteria, viruses, fungi, pollen, dust mites, and molds, which can trigger allergic reactions and cause disease. Chemical agents include a variety of compounds of an increasing variety of sources.
Carbon monoxide, an odorless gas generated by gasoline combustion, can be a greater hazard inside a building than out: in some office buildings, afternoon levels of carbon monoxide can be 10 to 20 times greater than the EPA's daily standard for outdoor air quality. Carbon monoxide can cause symptoms ranging from headaches and confusion to nausea and, at very high levels, death.
Formaldehyde, a cause of ailments ranging from rashes to cancer, is found in as many as 3,000 different building products.
Radon is a naturally occurring, odorless gas resulting from the decay of uranium in rocks and soils. It enters buildings through cracks in walls and foundation floors, and is a leading cause of lung cancer.
Volatile organic compounds (VOCs), such as benzene, carbon tetrachloride, and styrene, are released at room temperature from materials commonly used in construction and furnishings. Short-term effects of VOCs include eye, nose, and throat irritation, headaches, and nausea. Long-term, high-level exposures can cause damage to the liver, kidney, and central nervous system.
Second-hand tobacco smoke contains more than 4,000 chemicals, including known cancer-causing agents, and has been established as a cause of lung cancer in healthy nonsmokers.
Combating the Growing Threat
Over the past forty or fifty years, exposure to indoor air pollutants has increased. Factors contributing to the problem include construction of more tightly sealed buildings, reduced ventilation rates to save energy, the use of synthetic building materials and furnishings, and the use of chemically-formulated personal care products, pesticides, and cleaning supplies.
A World Health Organization report suggests up to 30 percent of new and remodeled buildings worldwide may generate excessive levels of complaints regarding indoor air quality.
In the United States, a nationwide random sampling of office workers revealed that 24 percent perceived air quality problems in their work environment, with 20 percent reporting problems significant enough to impair productivity.
Selecting Materials and Methods
The Breathe Easy Office is a wood-frame, brick-clad building, with cellulose insulation and a metal roof. These simple materials were chosen for their energy efficiency, ease of maintenance, and lack of toxicity.
Interior finishes include linoleum, ceramic, and wood floorings: natural materials that do not off-gas VOCs or promote the production of mold or other air-borne biological contaminants. Paints and sealants were also chosen for low or no VOC content.
Solid wood cabinetry eliminates formaldehyde-containing particleboard. Furniture is constructed of solid wood and natural materials. Upholstered furnishings were kept to a minimum, and purchased used so their fabric and cushions would have finished off-gassing.
Metal blinds were chosen to avoid VOC off-gassing from fabrics. Even the elevator has a stainless steel interior for easy cleaning and no VOC off-gassing.
Designers also paid attention to the health of construction workers. They chose, for example, insulation and tiles that produce fewer airborne pollutants during installation, drywall sanding vacuum equipment to reduce drywall dust, and a factory-finished wood flooring that requires no in-situ sanding or sealing.
After construction was completed, air filtration and pressure levels were checked using whole-office diagnostic testing. Pressure testing in the delivery area ensures that no vehicle exhaust fumes are leaking into the building.
The heating, ventilation, and air conditioning (HVAC) system uses two-stage electric heat pumps supporting seven zones. Each zone has high efficiency particulate accumulator (HEPA) filtration that captures 99.97 percent of air-borne particles.
The system includes a mechanical ventilation system that humidifies or dehumidifies the office air as needed, recycles conditioned air to provide energy recovery, and slightly pressurizes the building to prevent air entering other than through the filtered ventilation system.
The careful selection of building materials, construction methods, and maintenance procedures is supported by facility operating policies that maintain indoor air quality.
These include regular cleaning of the HVAC system, the use of nontoxic cleaning products and a vacuum cleaner with HEPA filtration, smoke-free and fragrance-free policies, and curtailed use of air fresheners and high-pollinating flowers in staff offices.
Outside, the landscape design uses low-pollen plants, shrubs, and trees. A rock mulch around the building foundation reduces mold growth.
Indoor air problems can be subtle and elusive. They do not always produce easily recognized effects on health, productivity, or physical plant. But as the social and environmental costs of poor indoor air quality become more widely understood, we can expect this issue to have a significant impact on building practice.
The Breathe Easy Office demonstrates specific, cost-effective practices that the ALA hopes will soon become more wide-spread.
Katharine Logan is an assistant editor of ArchitectureWeek.
Project designer and builder: R.E. Collier, Inc.
Energy consultant: Charles Bowles, The Energy Consortium
Interior designer: Hummel-Associates
Linoleum flooring: Forbo Industries, Inc.
Countertops: E.I. Du Pont De Nemours Company, Inc.
Wood flooring: Costen Floors, Inc.
Paints and wall coverings: Duron Paints & Wallcoverings
Windows: MW Manufacturers, Inc.
Paint: Sherwin-Williams Company
Insulation: Applegate Insulation
Sealants: OSI Sealants, Inc.