Glossary

Small thin-walled air-containing compartments of the lung that are typically arranged in saclike clusters that give the tissue a honeycomb appearance and expand its surface area for the purpose of air exchange.

Chronic inflammatory disease of the airways. Asthma attacks are often triggered by exposure to allergens, and during an attack the airways spasm, alternatively swelling and narrowing, causing the individual to wheeze or gasp for air.

Any disease that is persistent or has long-lasting health effects.

Internal clock that keeps the body's hormones and bodily processes on a roughly 24-hour cycle, even in continuous darkness.

Photosensitive cells in the eye used to differentiate colors and brightness in moderate and high levels of illumination.

Quantified environmental data for a product with pre-set categories of parameters based on the International Organization of Standards (ISO) 14040 series of standards, but not excluding additional environmental information.

A physical area within a building that encourages concentration and attentiveness to a task among occupants though its strategic layout and design.

Any of a group of unicellular, multicellular or syncytial spore-producing organisms feeding on organic materials.

A standard format for reporting product content and associated health information for building products and materials.

Equipment, distribution systems and terminals that provide the processes of heating, ventilating or air conditioning.

Surfaces that are frequently touched by building users and occupants such as door knobs, hand rails and tables. See Table A1.

The integrated body system of organs, tissues, cells and cell products such as antibodies that differentiates self from non-self and neutralizes potentially harmful organisms or substances.

Localized protective reaction of tissue to irritation, injury or infection, characterized by pain, redness, swelling and sometimes loss of function.

An organ that plays a vital role in a range of important metabolic processes including detoxification, protein synthesis and glycogen storage.

Any biochemical process that occurs within an organism that is necessary to sustain life.

Different spectral distributions of light which produce the same response on the cones and are therefore visually identical.

A personal dedicated resting space optimized to offer a short but regenerative sleep.

Diseases of the brain and nervous system.

Outlines current indoor air quality guidelines for the workplace.

Achieved when you combine UV light rays with a TiO2-coated filter.

The energy and particles which are released during the decomposition process of atomic nuclei is called radiation.

Inadequate gas exchange by the respiratory system, with the result that oxygen and/or carbon dioxide levels leaving the heart cannot be maintained within their normal ranges.

Photosensitive cells in the eye used to discern peripheral vision in low levels of illumination.

Personal habits and practices that help maximize sleep quality.

Extent to which a substance is harmful to a living thing.

A sterilization method that uses ultraviolet (UV) light to break down microorganisms by destroying their DNA. Often used in a variety of applications, such as food, air and water purification.

Rate of exchange of outside air, as well as the circulation of air within the building.

A sheet, spray- or trowel-applied membrane or material layer that prevents the passage of liquid water even after long or continuous exposure to moisture.

A major herbicide that is very susceptible to running off or leaching into ground and surface water sources.

Substances consisting of very fine particles of a liquid or solid suspended in a gas. For example, mist which consists of very fine droplets of water in air.

Proteins generally found in the blood that detect and rid the body of potentially damaging organisms, such as bacteria and viruses.

An element found in the earth's crust that has applications in various industrial processes, however runoff from factories, agricultural practices and natural deposits can lead to high concentrations in water.

Among the most widely used pesticides in the United States and among the most commonly detected pesticide in drinking water.

Any of a group of organic compounds that includes sugars, starches, celluloses and gums and serves as a major energy source to support bodily functions and physical activity. Easily digestible carbohydrates found in white bread, pastries and soda may contribute to weight gain and promote diabetes and heart disease.

A compound that increases the risk of developing cancer.

A highly irritating, greenish-yellow gaseous halogen, capable of combining with nearly all other elements, produced principally by electrolysis of sodium chloride and used widely to purify water, as a disinfectant and bleaching agent.

Metallic element that enters water sources through natural deposits, but contamination most commonly occurs through corrosion of copper or brass.

Coating on window surfaces purely for aesthetic purposes with no other functionality.

Particulate matter 2.5 micrometers in diameter or smaller. Can be directly emitted from combustion sources such as forest fires or can form when gases emitted from power plants, industries and automobiles react in the air. Also called PM₂.₅

Substances typically added to processed foods to enhance or preserve flavor or appearance.

A simple sugar that is found naturally in small amounts in fruits and vegetables, but which occurs in extremely large quantities in many modern foods. High fructose intake has been implicated in liver disease, inflammation, metabolic syndrome, diabetes, heart disease and cancer.

A simple sugar that occurs widely in most plant and animal tissue. It is the principal circulating sugar in the blood and the major energy source of the body. Once eaten, carbohydrates break down immediately into glucose. Elevated blood glucose levels are one of the distinguishing elements of diabetes.

When chlorine and chloramine are added to water and react with other organic matter to produce haloacetic acids known as a disinfectant byproduct (DBP), these can damage internal organs and the nervous system in elevated concentrations and can lead to can

A chemical released by a cell, gland or organ that transmits a signal to another part of the body.

Refers to a chemical compound that is not "organic". Broadly, compounds not containing carbon.

A naturally occurring metal found deep within the ground. Used in creation of old pipes, ceramics and paint. Also the stable final element of uranium's radioactive decay series.

"Darkness hormone" whose levels in the body is regulated by the circadian rhythm and the presence of light and in humans acts a driver for sleep.

Bacteria and microscopic algae and fungi, especially those living in a particular site or habitat.

A product of combustion mainly found near burning sources (for instance, wood smoke and traffic combustion).

Broadly refers to chemical compounds that possess carbon-based atoms, generally found in biological systems.

Triatomic form of oxygen. Hazardous to the respiratory system at ground level, but a layer in the upper atmosphere blocks much of the ultraviolet radiation from the sun.

A complex mixture of elemental and organic carbon, salts, mineral and metal dust, ammonia and water that coagulate together into tiny solids and globules.

A chemical that is made from petroleum or natural gas.

Polyunsaturated fats are among the "good" fats that can help reduce cholesterol levels and risk of heart disease and stroke. Polyunsaturated fats are found in sunflower, corn, soybean and flaxseed oils, walnuts and many fish.

An inexpensive plastic that is widely used for many objects. Exposure to its chemical precursors, additives and products of combustion can be harmful.

Typically solid at room temperature, saturated fats are found in high concentrations in salmon, butter, bacon, beef and cheese.

Widely used in agriculture as an herbicide to control weeds; high levels of simazine exposure over a short period can cause weight loss and blood damage.

Sulfates occur naturally and can erode into water supplies; the health effects of sulfates are uncertain, but ingesting large amounts has been linked to negative health effects.

Any toxic substance, generally created by human activity.

Chlorine in water can combine with organic matter to form compounds called disinfectant byproducts (DBPs), such as trihalomethanes.

A low-cost thermosetting resin that is used in the wood product industry.

Typical applications include solvents for the printing, rubber and leather industries as well as ingredients in paper and fabric coatings.

A measure of how many times the volume of air within a defined space is replaced, used in the context of building ventilation and air tightness.

Acoustic decibel modified using "A-weighting" to adjust the frequency-dependent response of human hearing.

Clothing insulation is the resistance to heat transfer provided by clothing measured in clo (1 clo = 0.155 m²K/W = 0.88°F ft²h/BTU).

Spectral distribution of electromagnetic radiation of a blackbody at a given temperature. For example, the color temperature during the daytime is approximately 15,000 K, while during sunset is approximately 1,850 K.

A unit of measurement for sound. The decibel is a logarithmic unit so an increase in 10 decibels equals an increase by a factor of 10.

The time averaged sound pressure level on the A-weighted scale, converted to decibels.

Unit of illuminance, equivalent to one lumen per square foot.

Amount of light passing through a given area in space. Measured in lux or foot-candles.

Rating from 0 (black) to 100 (white) describing the amount of visible and usable light that reflects from (or absorbs into) a painted surface.

Measurement of how bright a surface or light source will appear to the eye. Measured in candela/m² or foot-lamberts.

Radiant power weighted to human vision, describing light emitted by a source in a particular direction. Measured by the candela.

Concentration of a substance in drinking water believed to result in no adverse effects. Derived from on Population Adjusted Dose and estimated daily water consumption, fraction of exposure from water and body weight.

The uniform surface temperature of an imaginary black enclosure in which an occupant would gain or lose the same amount of radiant heat as in the actual non-uniform space; MRT is a primary driver of human thermal comfort, roughly equal in influence to air temperature.

Rate that chemical energy in the body is converted to heat and mechanical energy.

Unit of measurement for electromagnetic radiation, equal to 1/1000 watt. Not weighted to biological responses such as vision.

Measure the turbidity of water.

Field test for determining the sound transmitting abilities of a wall. Higher NIC values indicate better sound insulation i.e. more effective sound cancellation between spaces. NIC specifications are defined in ASTM Standard E366.

Measurement of the mass of a chemical or contaminate per unit volume of water.

A non-SI unit of radioactivity.

Time it takes for sound to decay. The most commonly used reverberation time is RT60, the time it takes for the sound level to decrease 60 decibels. Additional reverberation time measurements are RT20 and RT30, for decreases of 20 and 30 decibels, respectively.

A laboratory method for determining the sound transmission through a wall. Higher STC values indicate more effective noise isolation than lower ones. STC specifications are found in ASTM Standards E90-09 and E1425.

Amount of light in the visible portion of the spectrum that passes through a glazing material.

The distance between two points on a wave in which the wave repeats itself. Often used to describe light waves.