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E-FAST Glossary

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Air Flow
Absorbed Dose
Acute Dose Rate (ADR)
Averaging Time
Bounding Estimates
Concentration of Concern (CoC or CC)
Exposure Factors
Exposure Scenario
Higher Tier Tools
Inhalation Rate
Lifetime Average Daily Dose (LADD)
PDM Model
Potential Dose
Screening Level Tools
Standard Industrial Classification (SIC)
Surface Area to Body Weight Ratio
Surface Water
Time-varying Emission Rate
Wastewater Treatment Facility
Zone Volume

Air Flow: The volume of air that moves between the zones of a house, or into and out of a residence.

Absorbed Dose: The amount of a chemical penetrating across an absorption barrier or exchange boundary via either physical or biological processes.

Acute: Exposed to a chemical substance for a short duration, in the case of E-FAST, 1 day.

Acute Dose Rate (ADR): The estimated dose on a given day; used in assessments of the risk of acute toxic effects.

Averaging Time: The time dimension in the exposure assessment equation.  In E-FAST, the acute exposures averaging time is 1 day, while the chronic non-cancer exposure averaging time is 57 years.

Bounding Estimate: An estimate of exposure, dose or risk that is higher than that incurred by the person in the population with the highest exposure, dose or risk.  Bounding estimates are useful in developing statements that exposures, doses, or risks are "not greater than" the estimated value.

Carcinogen: A cancer causing substance.

Characterization: The description of the nature and often the magnitude of exposure or risk to humans and the environment, including attendant uncertainty.

Chronic: Exposed to a chemical substance for a long duration, in the case of E-FAST, 57 years.

Concentration: The concentration of a chemical in its transport or carrier medium at the point of contact.

CoC:  Concentration of Concern (sometimes called CoC):  The concentration of concern (sometimes reported in parts per million, parts per billion, or parts per trillion) provides the concentration of a given chemical in a stream.  This measure is determined by dividing the lowest chronic toxicity value by a factor of 10.  Harm to the aquatic environment is more likely to occur if the CoC is exceeded.

Effluent:  The stream flowing out of a facility or water body.  The concentrations in its flow are used to estimate potential health effects of the discharge.

Exposure: Contact of chemical with outer boundary of a person, (e.g. skin, nose, mouth).

Exposure Factors: Data on human behaviors and characteristics which affect exposure to environmental contaminants.

Exposure Scenario: A set of facts assumptions, and inferences about how exposure takes place that aids the exposure assessor in evaluating, estimating, or quantifying exposures.

Film Thickness: A layer of the consumer product on a defined skin surface area.

High-end: A plausible estimate of an individual exposure, dose or risk for those persons at the upper end of an exposure, dose or risk distributions, above the 90th percentile, but no higher than the individual in the population who has the highest exposure.

Higher Tier Tools: Tools developed to be tailored to the specific exposures and the specific environment in which exposures occur.  When used appropriately, these models can provide comprehensive exposure estimates with a greater level of accuracy.

Inhalation: The act of breathing.

Inhalation Rate: The volume of air being breathed in during a time period such as an hour or a day.

Lifetime Average Daily Dose (LADD): The estimated dose to an individual averaged over a lifetime of 70 years; used in assessments of carcinogenic risk.

Mass-Balance: The model requires the conservation of pollutant mass as well as the conservation of air mass.

PDM Model:  The Probabilistic Dilution Exposure Model.  It is a screening-level model which estimates potential health effects of the discharge.

Potential Dose: Amount of chemical contained in material ingested, air breathed, or bulk material applied to skin.

Risk:  The probability of deleterious health or environmental effects.  Usually thought of as a function of the intrinsic hazard of a chemical and the amount of exposure to it.

Screening-level Tools: Tools developed to be easy to use, fast and conservative.  These tools can often be used in the absence of appropriate monitoring data or to complement exposure-related data.

Sink: An object in the indoor environment (could be a couch, carpet, the walls) that reduce the concentration of a chemical either temporarily (reversible) or permanently (irreversible).

Standard Industrial Classification: A system developed by the Office of Management and Budget that characterizes industries by numeric code.  For example, a petroleum refining facility might have the SIC code 2911.  The classification system currently used by E-FAST is based on the 1987 SIC system.  In 1999, the Office of Management and Budget initiated efforts to replace the SIC system with the North American Industry Classification System (NAICS).

Surface Area to Body Weight Ratio: The ratio between the surface area of an individual and their body weight.  This approach is preferred for E-FAST since combining surface area distributions with unrelated body weight data may lead to biases in estimating exposures.

Surface Water:  Water Bodies on the earth's surface, such as streams, rivers, lakes, bays, estuaries and oceans.

Time-varying Emission Rate: E-FAST uses a set of differential equations whereby the time-varying emission and subsequent concentration of the chemical in each zone is a function of the rate of the pollutant loss and gain for the zone.

Wastewater:  Water exiting a potential source of contamination (e.g., industrial facility or residence).  Wastewater could either enter into a wastewater treatment facility, or be discharged directly into a water body.

Wastewater Treatment Facility:  Utilities that treat waste water and usually discharge treated water to nearby surface water bodies.

Weight Fraction: The ratio of the weight of the chemical being analyzed found in the product to the weight of the product.

Zone Volume: The volume of a defined area of an indoor environment (i.e. a room, or the entire house).

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