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.

A condition that results from insufficient nutrient intake, excess nutrient intake or nutrient intake in the wrong proportions.

A cluster of medical conditions or risk factors that increase the chances of developing cardiovascular disease, diabetes fatty liver disease and several cancers.

Particles between 1 and 100 nanometers in size.

ANSI/ASHRAE Standards 62.1 is the recognized standard for ventilation system design and acceptable procedure with regards to establishing an effective ventilation system.

Products or materials applied or installed within one year prior to the WELL Performance Verification are considered to be newly installed.

Outlines current indoor air quality guidelines for the workplace.

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

Unenforced regulations developed by California Office of Environmental Health Hazard Assessment. Similar in concept to the EPA's Maximum Contaminant Level Goal (MCLG).

An area that has daily, continuous use, at minimum an hour per day, by one or more individuals.

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.

A set of symptoms, such as headache, fatigue, eye irritation and breathing difficulties, that typically affect workers in modern airtight office buildings, and that are believed to be caused by indoor pollutants and poor environmental control.

A teleconference room is a space within the office that is primarily used for audio or video conferencing.

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.

Act of spatial problem solving.

An area where an individual performs daily work-related tasks. In an office setting this would comprise a desk, writing area, computer and possibly filing cabinets.

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 cancer.

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.