Glossary of Indoor Air Quality Terms
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
ABSOLUTE HUMIDITY: the amount of water vapor in a given volume of air
ABSORPTION: the process of one substance entering into the inner structure of another
ACALCULIA: a dysfunction in calculation ability
ACCEPTABLE INDOOR AIR QUALITY: The physical and chemical nature of indoor air (as delivered to the breathing zone of the building occupants) which produces a complete state of mental, physical, and social well-being of the occupants, not merely the absence of disease and sickness.
ACGIH: The American Conference of Governmental Industrial Hygienistsis a community of professionals who work to advance worker health and safety through education and the development and dissemination of scientific and technical knowledge.
ACH: Air Changes per Hour is the number of changes of outdoor air per unit of time.
ACID AEROSOL: Acidic liquid or solid particles that are small enough to become airborne. High concentrations of acid aerosols can be irritating to the lungs and have been associated with some respiratory diseases, such as asthma.
ACTIVATED CHARCOAL: A highly absorbent form of carbon used to remove odors and toxic substances from liquids or gases.
ACUTE: Health effects which show up a short length of time after exposure. An acute exposure runs a relatively short course.
ACUTE EXPOSURE: a single exposure to a toxic substance that results in biological harm or death; usually characterized as lasting no longer than a day
ACUTE TOXICITY: the ability of a substance to cause poisonous effects resulting in severe biological harm or death soon after a single exposure or dose. Any severe poisonous effect resulting from a short-term exposure.
ADSORPTION: the adhesion of a thin film of liquid or gases to the surface of a solid substance
AEROSOL: a gaseous medium containing suspended particles
AGRAPHIA: a disorder marked by loss of the ability to write
AHAM: Association of Home Appliances Manufacturers
AIHA: American Industrial Hygiene Association
AIR CLEANING SYSTEM: A device or combination of devices applied to reduce the concentration of airborne contaminants such as microorganisms, dusts, fumes, respirable particles, other particulate matter, gases, and vapors in air.
AIR-CONDITIONING: the process of treating air to meet the requirements of a conditioned space by controlling its temperature, humidity, cleanliness, and distribution
ALA: American Lung Association is the oldest voluntary health organization in the United States. Founded in 1904 to fight tuberculosis, ALA today fights lung disease in all its forms, with special emphasis on asthma, tobacco control and environmental health.
ALDEHYDES: Reactive organic compounds that contain HC=O group such as formaldehyde and hexanal.
ALGAE: simple rootless plants that grow in sunlit waters at the level of how many nutrients are available
ALLERGEN: A substance capable of causing an allergic reaction because of an individual's sensitivity to that substance.
ALLERGIC RHINITIS: inflammation of the mucous membranes of the nose
ALLERGY (adj. allergic): an abnormal response of a hypersensitive person to chemical and physical stimuli; allergic manifestations of major importance occur in about 10 percent of the population (adjective form: ALLERGIC).
ALLERGY, CHEMICAL: adverse reaction to a chemical resulting from previous sensitization to that chemical or one structurally similar
AMBIENT AIR: the outdoor air surrounding an object
ANEMIA: Too few red blood cells in the bloodstream, resulting in not enough oxygen to tissues and organs.
ANIMAL DANDER: tiny scales of animal skin
ANTIBODY: A protein substance produced in the blood or tissues in response to a specific antigen, such as a bacterium or a toxin. Antibodies destroy or weaken bacteria and neutralize organic poisons, thus forming the basis of immunity.
ANTIGEN: A substance that when introduced into the body stimulates the production of an antibody. Antigens include toxins, bacteria, foreign blood cells, and the cells of transplanted organs.
APHA: The American Public Health Association consists of a group of public health professionals concerned with a broad set of issues affecting personal and environmental health, including federal and state funding for health programs, pollution control, programs and policies related to chronic and infectious diseases, a smoke-free society, and professional education in public health.
APHONIA: loss of the voice resulting from disease, injury to the vocal cords, or various psychological causes, such as hysteria
ASBESTOS: A naturally occurring mineral fiber that can cause cancer.
ASHRAE: American Society of Heating, Refrigerating and Air-conditioning Engineers is an international organization with the goal of conducting research, writing standards and publications, and providing continuing education to the public regarding heating, ventilation, air-conditioning and refrigeration systems.
ASTHMA: common disease of the lower respiratory system with episodic bronchial restrictions
ASTM: American Society for Testing Materials
ATAXIA: loss of the ability to coordinate muscular movement
ATS: The American Thoracic Society is an independently incorporated, international, educational and scientific society that helps to prevent and fight respiratory disease around the globe through research, education, patient care, and advocacy.
BACTERIUM (pl. BACTERIA): Microorganisms, mostly single-celled; their DNA is naked rather than being enclosed in a nucleus.
BAKE-OUT: A process to flush out volatile organic compounds by elevating the temperature in an unoccupied fully-furnished and ventilated building.
BAQ: Building Air Quality refers to the quality of air in a building.
BENZENE: A major organic intermediate and solvent derived from coal or petroleum.
BENZOPYRENE: a yellow, crystalline, aromatic hydrocarbon, that is a carcinogen found in coal tar and cigarette smoke
BIOAEROSOL: An airborne organic contaminant that is either generated by or is itself a living organism; examples of bioaerosols are fungi, bacteria, viruses, protozoa, pollen, animal dander, insect emanations, microbial endotoxins, and human skin scales.
BIOCIDE: any poison that kills a living organism
BIOHAZARD: a combination of the words biological and hazard; organisms or products of organisms that present a risk to humans
BREATHING ZONE: the area of a room in which occupants breathe as they stand, sit, or lie down
BRI:Building-Related Illness: This term is used when symptoms of a disease from several occupants of a building can be directly linked to specific airborne contaminants in that building. This differs from SBS because with SBS no specific illness or cause can be identified.
BUILDING ENVELOPE: outer walls, windows, doors, etc. of a building or the “building shell”
BYSSINOSIS: An occupational respiratory disease caused by the long-term inhalation of cotton, flax, or hemp dust and is characterized by shortness of breath, coughing, and wheezing. It is also called brown lung disease.
CADR: Clean Air Delivery Rate is the amount of clean air measured in cubic feet per minute (cfm) that an air cleaner delivers to a room.
CARBON BLACK: Any of various finely divided forms of carbon derived from the incomplete combustion of natural gas or petroleum oil and used to reinforce rubber and as an ingredient in inks, paints, crayons, and polishes.
CARBON DIOXIDE (CO2): an odorless, colorless gas that is a product of human respiration
CARBON MONOXIDE (CO): an odorless, colorless gas that is a product of incomplete combustion
CARBON MONOXIDE POISONING: a poisoned state in which carbon monoxide gas has been breathed and soaked up by the blood. Too much carbon monoxide limits the ability of the blood to transport oxygen. It is treated by removing the patient from the source right away and giving oxygen.
CARBOXYHEMOGLOBIN: A compound produced when carbon monoxide links with red blood cells. It is breathed into the lungs and enters the bloodstream. It blocks the sites on the cells that carry oxygen. Oxygen in the blood decreases and, when it decreases too much, suffocation and death result.
CARCINOGEN: a substance that can cause or contribute to cancer.
CDC: Centers for Disease Control and Prevention, located in Atlanta, Georgia, USA, is an agency whose purpose is to promote health and quality of life by preventing and controlling disease, injury, and disability.
CFC: Chlorofluorocarbon is any of various halocarbon compounds consisting of carbon, hydrogen, chlorine, and fluorine, once used widely as an aerosol propellant and a refrigerant. CFCs are believed to cause depletion of the atmospheric ozone layer.
CFM: Cubic Feet per Minute is the amount of air, in cubic feet, that flows through a given space in one minute.
CFU: Colony Forming Unit is enough spores, hyphae or bacteria to form a colony.
CHEMICAL SENSITIZATION: Evidence suggests that some people may develop health problems characterized by effects such as dizziness, eye and throat irritation, chest tightness, and nasal congestion that appear whenever they are exposed to certain chemicals. People may react to even trace amounts of chemicals to which they have become "sensitized."
CHEMISORB: to take up and hold, usually irreversibly, by chemical forces
CNS: Central Nervous System is the portion of the vertebrate nervous system consisting of the brain and spinal cord.
COLONY: a single point of growth of mold or bacteria
COMBUSTION: burning or rapid oxidation accompanied by a release of energy
COMPLIANCE TESTS: used to determine whether a product complies with a defined program specification such as State of Washington or EPA. A compliance or certification sheet is supplied with the test report.
CONCENTRATION: the quantity of one part in a defined amount of another (ex. ppm, ppb)
CONIDIUM (pl. CONIDIA): an asexual spore that is released when mature
CONIDIOPHORE: a hypha with specialized cells that produce conidia
CONTAMINANT: any physical, chemical, biological, or radioactive substance that can adversely affect air, water or soil
COOLING COIL: an arrangement of pipe or tubing that transfers heat from air to a refrigerant or brine
CPSC: Consumer Product Safety Commission is an independent federal agency formed to protect the public against unreasonable risks of injuries and deaths associated with consumer products.
CREOSOTE: A yellowish to greenish-brown oily liquid containing phenols and creosols, obtained from coal tar and used as a wood preservative and disinfectant. It can cause severe neurological disturbances if inhaled in strong concentrations.
CYANOSIS: a bluish discoloration of the skin and mucous membranes; a sign that oxygen in the blood is dangerously diminished (as in carbon monoxide poisoning)
DEHUMIDIFICATION: the condensation of water vapor from air by cooling below the dewpoint or removal of water vapor from air by chemical or physical methods
DEHUMIDIFIER: (1) An air cooler or washer used for lowering the moisture content of the air passing through it; (2) An absorption or adsorption device for removing moisture from air.
DEMENTIA: an organic mental disorder characterized by a general loss of intellectual abilities involving impairment of memory, judgment and abstract thinking as well as changes in personality
DERMATITIS: inflammation of the skin
DILUTION: additional supply of outdoor air introduced to reduce concentration of indoor pollutants
DUCT: a passageway made of sheet metal or other suitable material, not necessarily leaktight, used for conveying air or other gas at low pressures
DUST: an air suspension (aerosol) of particles of any solid material, usually with particle size less than 100 micrometers
DUST MITE: a microscopic arachnid, commonly Dermatophagoides pteronyssinus or Dermatophagoides farinae
DUST MITE ALLERGEN: allergenic proteins (antigens) derived from dust mites
EMFs: Electromagnetic Fields
EMISSION: pollution discharge from a source
EMISSION FACTOR: a single point quantitative measurement of gaseous or particle emission from a material source as determined by an environmental chamber
EMISSION PROFILE (DECAY CURVE): used to measure how emissions decay or decrease over time. It can be used to predict exposure concentrations, such as those required by the State of Washington
EMISSION RATE: the actual rate of release of volatile vapors from a product over time
EMLAP: The Environmental Microbiology Laboratory Accreditation Program, which is associated with AIHA, is designed specifically for laboratories involved in analyzing microbiological samples to evaluate exposures in a variety of workplaces. Participation assists the laboratory in maintaining high quality standards.
EMPHYSEMA: chronic pulmonary disease characterized by loss of lung function after many alveolar walls have been destroyed, with resulting enlargement of the air space. Emphysema patients have reduced capacity for gas exchange in the lungs.
ENDOTOXIN: a toxin produced by certain bacteria and released upon destruction of the bacterial cell
ENVIRONMENTAL CHAMBER: a controlled, non-reactive testing device of known volume with dynamically maintained air change rate, temperature, and humidity
EPA: The United States Environmental Protection Agency is a federal agency established to coordinate programs aimed at reducing pollution and protecting the environment.
ERGONOMIC: design factors, as for the workplace, intended to maximize productivity by minimizing operator fatigue and discomfort
ETS: Environmental Tobacco Smoke is a mixture of smoke from the burning end of a cigarette, pipe, or cigar and smoke exhaled by the smoker (also secondhand smoke or passive smoking).
EVAPORATION: change of state from liquid to vapor
EXFILTRATION: air leakage outward through cracks and other openings such as ceilings, floors and walls of a space or building
EXHAUST AIR: air removed from a space and not reused therein
FASCICULATIONS: muscular twitching of adjoining groups of muscle fibers
FDA: The Food and Drug Administration is the U.S. Agency responsible for the regulation of biotechnology food products. The major laws under which the agency has regulatory powers include the Food, Drug and Cosmetic Act, and the Public Health Service Act.
FEVER: an abnormal temperature of the body above 98.6°F (37°C). Exercise, anxiety, and dehydration may increase the temperature of healthy people. Infection, nerve disease, cancer, anemia, and many drugs may cause fever. No single theory explains why the temperature is increased.
FIBROMYALGIA: a chronic disorder characterized by widespread musculoskeletal pain, fatigue, and multiple tender points. "Tender points" refers to tenderness that occurs in precise, localized areas, particularly in the neck, spine, shoulders, and hips. People with this syndrome may also experience sleep disturbances, morning stiffness, irritable bowel syndrome, anxiety, and other symptoms.
FLUSH OUT: period in which a building's HVAC system is operated at maximum outdoor air in order to remove contaminants from the space
FORMALDEHYDE: a volatile organic compound that is a natural product of human metabolism, a byproduct of the combustion process, and an important industrial chemical used to produce synthetic urea- and phenol-formaldehyde
FRUITING STRUCTURE (OF MOLDS): conidiophores or other structures that produce spores
FTC: Federal Trade Commission
FUMES: airborne solid particles usually less than 1 micrometer in size formed by condensation of vapors, sublimation, distillation, calcination, or chemical reaction
FUNGAL PROPAGULES: spores or hyphal fragments capable of producing colonies
FUNGUS (pl. FUNGI): non-photosynthesizing parasitic lower plants that secrete enzymes and absorb food, producing and living inside branched tubes called hyphae (includes molds, mildew, yeasts, and mushrooms)
FUNGICIDE: biocides used to control, prevent, or kill fungi
GAO: The General Accounting Office is an investigative arm of Congress that examines the use of public funds, evaluates federal programs and activities, and provides analyses, options, recommendations, and other assistance to help the Congress make effective oversight, policy, and funding decisions.
GAS: a state of matter in which substances exist in the form of nonaggregated molecules, and which, within acceptable limits of accuracy, satisfies the ideal gas laws; usually a highly superheated vapor
GERMICIDE: an agent capable of killing germs
GRAM-NEGATIVE BACTERIA: in gram-staining, gram-negative bacteria incorporate the counterstain (pink) rather than the primary stain (purple), because of a lack in peptidoclycan in the cell wall. The pathogenic nature of gram-negative bacteria is usually associated with certain components of their cell walls, particularly the lipopolysaccharide (endotoxin) layer.
GRAM-POSITIVE BACTERIA: characterized by their blue-violet color reaction in the gram-staining procedure. The blue-violet color reaction is caused by crystal violet, the primary gram-stain dye. A distinguishing factor among gram-positive bacteria is that roughly 90% of their cell wall is comprised of peptidoglycan.
HARDBOARD: like particleboard, it is made from particles and shavings of wood glued together with synthetic resin. Its density, however, is higher than particleboard or MDF. Hardboard has multiple uses in the building/construction and furniture industries.
HEPA: High Efficiency Particulate Air (filter) is a disposable, extended medium, dry type filter with a particle removal efficiency of no less than 99.97 percent for 0.3 micrometer particles.
HEPATITIS: inflammation of the liver, caused by infectious or toxic agents and characterized by jaundice, fever, liver enlargement, and abdominal pain
HISTOPLASMOSIS: a disease caused by the inhalation of spores of the fungus Histoplasma capsulatum, most often asymptomatic but occasionally producing acute pneumonia or an influenzalike illness and spreading to other organs and systems in the body
HUD: Department of Housing and Urban Development is the federal department that administers federal programs dealing with better housing and urban renewal; created in 1965.
HUMIDIFIER: a device to add moisture to the air
HUMIDIFIER FEVER: ("Ventilation Fever") a respiratory illness caused by exposure to toxins from microorganisms found in wet or moist areas in humidifiers and air-conditioners.
HUMIDITY: water vapor in the air
HVAC: Heating, Ventilation, and Air-Conditioning system is a system concerned with the temperature, humidity, cleanliness, and distribution of air.
HYALINE (OF MOLDS): colorless
HYDROCARBONS: common organic compounds that contain carbon and hydrogen
HYPERREFLEXIA: exaggeration of reflexes
HYPERSENSITIVITY: the immune system's exaggerated response to an allergen
HYPERSENSITIVITY PNEUMONITIS: a group of respiratory diseases, including humidifier fever that involves inflammation of the lungs. Most forms of hypersensitivity pneumonitis are caused by the inhalation of organic dusts, including molds.
HYPHAE: single threads of a fungal body, also used for certain bacteria (actinomycetes)
HYPOKINESIA: decreased muscular activity
HYPOXIA: deficiency in the amount of oxygen reaching body tissues
IAQ:Indoor Air Quality refers to the quality of the air in the indoor environment. This may also be referred to as Indoor Environmental Quality (IEQ). Typical symptoms of poor IAQ include headaches, unusual fatigue, itching or burning eyes, skin irritation, nasal congestion, dry and/or irritated nose or throat, and nausea.
IARC: International Agency for Research on Cancer
IEQ:Indoor Environmental Quality refers to all the factors that influence the working environment including such things as lighting and air temperature.
IMMUNE SYSTEM: all internal structures and processes providing defense against disease-causing organisms such as viruses, bacteria, fungi, and parasites
INCUBATION PERIOD: the development of an infection from the time the pathogen enters the body until signs or symptoms first appear
INDOOR AIR: the air within an indoor structure such as residence, office building, any public or private building, and transportation vehicle
INFILTRATION: air leakage inward through cracks and other openings such as ceilings, floors and walls of a space or building
INH: a trademark used for the drug isoniazid; an orally administered drug used to treat tuberculosis infection in people without active disease. INH is also administered in combination with other drugs to treat active tuberculosis.
INSECTICIDE: any material or agent capable of killing insects
ION: an electrically charged atom. An atom that has lost one or more of its electrons is left with a positive electrical charge; those that have gained one or more extra electrons are left with a negative charge.
IRRITANT: physical, biologic, or chemical stressors that induce acute symptoms and inflammation of the tissue
ISO: An organization, the International Organization for Standardization, which sets standards in many businesses and technologies, to improve quality
JAUNDICE: yellowish discoloration of the whites of the eyes, skin, and mucous membranes caused by deposition of bile salts in these tissues. It occurs as a symptom of various diseases, such as hepatitis, that affect the processing of bile.
LASSITUDE: a state or feeling of weariness, diminished energy, or listlessness
LEGIONNAIRES' DISEASE (or Legionnaire's): illness produced by Legionella pneumophila bacteria that can affect lungs and other body systems
LETHARGY: a condition of abnormal drowsiness or inactivity; a great lack of energy; lack of interest
MAKEUP AIR: outdoor air supplied to replace exhaust air and exfiltration
MALAISE: a vague feeling of discomfort or uneasiness
MAN-MADE MINERAL FIBERS: generic term denoting fibrous inorganic substances made primarily from rock, clay, slag, or glass
MCS: Multiple Chemical Sensitivity is an unexplained condition where a person reports sensitivities and adverse reactions to low levels of chemicals.
MDF: Medium Density Fiberboard is a type of particleboard—it is made of wood particles glued together by synthetic resin, with a medium density, as opposed to hardboard. They are typically found in 4' x 8' sheets, with 3/4" thickness, and are commonly used in furniture and cabinetry.
MENINGITIS: inflammation of the meninges of the brain and the spinal cord, most often caused by a bacterial or viral infection and characterized by fever, vomiting, intense headache, and stiff neck
METHANE: a colorless, flammable gas created by anaerobic decomposition of organic compounds
METHEMOGLOBINAEMIA: an inability of the blood to carry oxygen and can cause headaches, fatigue, dizziness, and a blue color to the skin and lips
METHYLENE CHLORIDE: a chlorinated hydrocarbon that has been used as an inhalation anaesthetic and acts as a narcotic in high concentrations. Its primary use is as a solvent in manufacturing and food technology.
MICROGRAM (µg): one microgram is equal to one thousandth (1/1,000) of a milligram or one millionth (1/1,000,000) of a gram
MICROMETER (µm): one micrometer is equal to one thousandth (1/1,000) of a millimeter or one millionth (1/1,000,000) of a meter
MICROORGANISM: a microscopic organism, especially a bacterium, fungus, or a protist
MITE: See Dust mite
MOLD: a common term for microscopic forms of fungi; a growth of fungi forming a furry patch, as on stale bread or cheese. See also spore
MPI: Mass Psychogenic Illness is where persons experience similar symptoms traceable to psychological factors. Symptoms typically include fainting, nausea, headaches and dizziness.
MSDS: Material Safety Data Sheets provide necessary, helpful, and useful information on the properties of a chemical or chemical product.
MTBE: Methyl Tertiary Butyl Ether is a fuel oxygenate which enhances the octane in gasoline and decreases carbon monoxide emission by increasing burning efficiencies.
MUCOUS MEMBRANES: lining of the hollow organs of the body, notably the nose, mouth, stomach, intestines, bronchial tubes, and urinary tract
MUTAGEN: any substance that can cause a change in genetic material
MVOCs: Microbial Volatile Organic Compounds are volatile chemicals produced by the metabolism of fungi and bacteria.
MYALGIA: pain in one or more muscles
MYCOTOXIN: toxins produced by certain molds; natural exposures to these toxins are poisonous to man and animals
NNATURAL VENTILATION: the movement of air into and out of a space through intentionally provided openings, such as windows and doors, or through nonpowered ventilators or by infiltration
NEGATIVE PRESSURE: condition that exists when less air is supplied to a space than is exhausted from the space, so the air pressure within that space is less than that in surrounding areas
NEUROTOXIC: chemicals that causecentral nervous system (CNS) problems such as dizziness, headaches and ability to think clearly
NIH: The National Institutes of Health is a nonregulatory U.S. Federal agency that has oversight of research activities that the agency funds.
NIOSH: National Institute for Occupational Safety and Health is the agency in the Centers for Disease Control (CDC) of the U.S. Department of Health and Human Services that researches safety and health hazards in the workplace and makes recommendations to improve conditions. Unlike OSHA, they have no enforcement powers.
NOEL: The No Observable Effect Level is the highest dose level that has not been associated with an observable harm in humans or test animals.
NOSOCOMIAL INFECTIONS: the type of infections that are acquired in hospitals
NTP: The National Toxicology Program is a Federal agency that coordinates toxicology research and testing activities within the Department; provides information about potentially toxic chemicals to regulatory and research agencies and the public; and strengthens the science base in toxicology.
OOCCUPIED ZONE: the area within six feet of the floor and not within one foot of the walls or fixed air-conditioning equipment. As this is the area of occupancy, it is desirable to avoid excessive draft velocities and temperature differences within this space.
ODOR: a quality of gases, liquids or particles that stimulates the olfactory organ
OFF-GASSING: the production of gases from the chemical deterioration of a substance over time
OSHA:Occupational Safety and Health Administration is the agency in the U.S. Department of Labor that enforces safety and health regulations in private workplaces to ensure safe and healthy working conditions.
OUTDOOR AIR: air taken from the external atmosphere and, therefore, not previously circulated through any system
OXIDATION: a reaction in which oxygen combines with another substance
OZONE (O3): a reactive form of oxygen that is a strong mucous membrane and pulmonary irritant
PAHs: Polycyclic Aromatic Hydrocarbons are natural products of the incomplete combustion of carbon compounds.
PARESTHESIA: a skin sensation, such as burning, prickling, itching, or tingling, with no apparent physical cause
PARTICULATE: a state of matter in which solid or liquid substances exist in the form of aggregated molecules or particles. Airborne particulate matter is typically in the size range of 0.01 to 100 micrometers.
PARTICULATE MATTER: a suspension of fine solid or liquid particles in air, such as dust, fog, fume, mist, smoke, or sprays. Particulate matter suspended in air is commonly known as an aerosol.
PATHOGEN: any microorganism capable of causing disease
PCBs: Polychlorinated Biphenyls are any of a family of industrial compounds produced by chlorination of biphenyl, noted primarily as an environmental pollutant that accumulates in animal tissue with resultant pathogenic and teratogenic effects.
PCM: Per Cubic Meter, for example, is the number of CFUs in a one-meter cube of air.
PEL:Permissible Exposure Level is an exposure limit that is published and enforced by OSHA as a legal standard.
PERCHLOROETHYLENE: a colorless, nonflammable organic solvent, used in dry-cleaning solutions and as an industrial solvent
PESTICIDE: a chemical used to kill pests (as rodents or insects)
pH: means used to express the degree of acidity or alkalinity of a solution with neutrality indicated as seven
PICOCURIE (pCi): a unit for measuring radioactivity often expressed as picocuries per liter (pCi/L) of air
PLENUM: a condition, as in an occupied room, in which the pressure of the air is greater than that of the outside atmosphere; as, a plenum may exist in a hall ventilated by a fan blower
PLUG FLOW: a flow regime where the flow is predominately in one direction and contaminants are swept along with the flow
PNAs: Polynuclear Aromatics, synonymous to PAHs
PNEUMONIA: a swelling of the lungs, commonly caused by breathed-in bacteria (Diplococcus pneumoniae). Parts of the lungs become plugged with a fiber-like fluid. Pneumonia may also be caused by Rickettsiae, viruses, and fungi. Symptoms of pneumonia are severe chills, a high fever (which may reach 105°F), headache, cough, and chronic pain. Breathing often becomes painful, shallow, and rapid.
POLLUTANT: an airborne contaminant associated with illness
PONTIAC FEVER: a milder illness of Legionnaires' disease. Persons with Pontiac fever experience fever and muscle aches and do not have pneumonia. They generally recover in 2 to 5 days without treatment.
POSITIVE PRESSURE: condition that exists when more air is supplied to a space than is exhausted, so the air pressure within that space is greater than that in surrounding areas
POTABLE WATER: water that is safe for human consumption
PPB: Parts Per Billion is 1 part in 1,000,000,000. The difference between 1 ppm and 1 ppb is important—it is like the difference between $1 and $1000.
PPM: Parts Per Million is a unit of concentration often used when measuring levels of pollutants in air, water, body fluids, etc. One ppm is 1 part in 1,000,000. The common unit, µg/liter, is equal to ppm.
PRESSED WOOD PRODUCTS: a group of materials used in building and furniture construction that are made from wood veneers, particles, or fibers bonded together with an adhesive under heat and pressure
PSI: Pollution Standards Index, or Pounds per Square Inch
PULMONARY FIBROSIS: chronic inflammation and progressive fibrosis of the pulmonary alveolar walls, with steadily progressive difficulty in breathing, resulting finally in death from lack of oxygen or heart failure
PVC: Polyvinyl Chloride is a common thermoplastic resin, used in a wide variety of manufactured products, including rainwear, garden hoses, phonograph records, and floor tiles.
RRADON: a known human carcinogen; is a naturally occurring, radioactive gas that is colorless, odorless, and tasteless. It comes from the natural decay of uranium, a radioactive metal found in soil and rock in the earth's crust. Radon is found in low amounts in soils all over the world at varying low levels.
RADON DECAY PRODUCTS (radon daughters or progeny): the result of the decaying of radon; they can be breathed into the lung where they continue to release radiation as they further decay
RAST: Radioallergosorbent test is an allergy test done on a sample of blood. The aim with RAST, as with skin tests, is to check for allergic sensitivity to specific substances.
RECIRCULATED AIR: air removed from the conditioned space and intended for reuse as supply air
REPRODUCTIVE TOXICANT: an agent that causes birth defects or other reproductive harm.
RESPIRABLE PARTICLES: particles that penetrate into and are deposited in the non-ciliated portion of the lung. Particles greater than 10 micrometers aerodynamic diameter are not respirable. Peak deposition of respirable particles occurs within the size range of 0.2 to 5 micrometers.
RETURN AIR: air removed from a space to be then recirculated or exhausted
RH: Relative Humidity is the ratio of the amount of water in the air at a given temperature to the maximum amount it could hold at that temperature; expressed as a percentage.
RHINITIS: inflammation of nasal mucous membranes; "runny nose"
SAPROTROPHIC FUNGI: fungi that obtain nutrition from dead organisms
SBS: Sick Building Syndrome refers to when many occupants in a building or in the same part of a building experience immediate health problems that seem to be due to the building, but no specific illness or cause can be identified. (Contrast with BRI)
SENSITIZATION: an allergic condition that usually affects the skin or lungs. Once exposure to a substance has caused a reaction, the individual may be sensitized to it, and further exposure may elicit an adverse reaction even at low levels.
SICK BUILDING: a building whose occupants complain of health and comfort problems that can be related to working or being in a building
SILICOSIS: a lung disease caused by inhaling particles of silica or quartz or slate
SINGLE POINT TEST: used to compare emission levels across products, compare to a baseline, evaluate source of odor, or see what VOCs and levels are associated with a product. A single point cannot accurately predict exposure concentrations.
SINK: a material that can adsorb volatile chemicals or biocontaminants with subsequent re-emission
SINUSITIS: a swelling of one or more nasal sinuses. It may be a complication of an upper respiratory infection, dental infection, allergy, a change in atmosphere, as in air travel or underwater swimming, or a defect of the nose.
SOIL GASES: gases that enter a building from the surrounding ground
SOLVENT: substances that can dissolve other substances. Though water is sometimes called the “universal solvent,” most people mean organic solvents when they refer to these chemicals.
SOURCE CONTROL: strategy for reducing airborne contaminants by removing or reducing emitting materials or activities
SUPPLY AIR: that air delivered to the conditioned space and used for ventilation, heating, cooling, humidification or dehumidification
SURFACTANT: a substance capable of reducing the surface tension of a liquid in which it is dissolved [syn: wetting agent, surface-active agent]
SYNERGISM: the working together of two or more things (i.e. chemicals) to produce an effect greater than the sum of their individual effects
TERATOGEN: any medication, chemical, infectious disease, or environmental agent that might interfere with the normal development of a fetus and result in the loss of a pregnancy, a birth defect, or a pregnancy complication.
THERMOTOLERANT: able to grow at high temperatures (e.g. 37°C)
TLV:Threshold Limit Value is the air concentration of chemical substances to which healthy workers can be exposed for 8-hour work days during a 40-hour work week without suffering an adverse effect. A table of these values and accompanying precautions is published annually by the ACGIH.
TOLUENE: a colorless flammable liquid obtained from petroleum or coal tar; used as a solvent for gums and lacquers and in high-octane fuels
TOTAL SUSPENDED PARTICULATE: the mass of particulates suspended in a unit of volume of air when collected by a high volume sampler
TOXICITY: inherent ability of a chemical to adversely affect living organisms
TOXICOLOGY: study of harmful effects of chemicals on living organisms
TOXIN: a substance produced by a living organism that injures tissues or alters the functions of another organism
TUBERCULOSIS: an infectious disease of human beings and animals caused by the tubercle bacillus and characterized by the formation of nodules on the lungs and other tissues of the body, often developing long after the initial infection. In the lungs, it is characterized by the coughing up of mucous and sputum, fever, weight loss, and chest pain.
TVOC: Total Volatile Organic Compounds are the sum of all volatile organics collected and analyzed by a defined analytical method.
UEL: Upper Explosive Limit is the highest concentration (expressed in percent vapor or gas in the air by volume) of a substance that will burn or explode when an ignition source is present.
UPPER RESPIRATORY TRACT: structures that conduct air into the lungs, including the nasal cavity, mouth, pharynx, and larynx
VAPOR: any gas below its critical temperature; barely visible or cloudy diffused matter, such as mist, fumes, or smoke, suspended in the air
VENTILATION: the process of supplying and removing air by natural or mechanical means to and from any space; such air may or may not be conditioned
VENTILATION AIR: the portion of supply air that is outdoor air plus any recirculated air that has been treated for the purpose of maintaining acceptable indoor air quality
VENTILATION RATE: the rate at which indoor air enters and leaves a building. It is expressed in one of two ways: the number of changes of outdoor air per unit of time (air changes per hour, or "ach") or the rate at which a volume of outdoor air enters per unit of time (cubic feet per minute, or "cfm").
VERMICULITE: any of a group of micaceous hydrated silicate minerals related to the chlorites and used in heat-expanded form as insulation and as a planting medium
VIRUS (adj. VIRAL): an infectious agent that contains either RNA or DNA in its core surrounded by a protein shell, is able to alternate between intracellular and extracellular states, and replicates only when present in living cells.
VOCs: Volatile Organic Compounds: Chemicals containing carbon are called organic. Volatile means that they evaporate or get into the air easily which make them easier to breathe in. Examples of common VOCs include benzene and trichlorethylene.
WATER ACTIVITY (aW): a measure of the amount of water held within materials
WHO: The World Health Organization is a United Nations agency that coordinates international health activities and helps governments improve health services.
XEROTOLERANT: able to grow under relatively dry conditions (damp rather than wet)
XYLENE (also XYLOL): any of three flammable isomeric hydrocarbons, obtained from wood and coal tar; a mixture of xylene isomers used as a solvent in making lacquers and rubber cement and as an aviation fuel.