Environment terminology · MLC-0121

Environment terms: H (1,010)

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• H-1 Receptor BlockerDrugs that selectively bind to but do not activate histamine H1 receptors, thereby blocking the actions of...
• H-2 BlockerAny agent that competitively binds to and blocks the histamine H2 receptors found in the stomach, heart...
• Habitat1. The place where an organism lives and its surrounding environment, including its biotic and abiotic...
• Habitat ConservationThe preservation, maintenance, protection, restoration and enhancement of habitats for wild species.
• Habitat EncroachmentTerm used to describe the way natural habitats are destroyed as human development of new areas continues to...
• Habitat Equivalency AnalysisAn analysis designed to determine the compensation the public is due to reconcile injuries to the ecosystem...
• Habitat Fragmentation1. A process during which larger areas of habitat are broken into a number of smaller patches of smaller...
• Habitat IndicatorA physical attribute of the environment measured to characterize conditions necessary to support an organism...
• Habitat NicheParticular area within a habitat that an organism lives and functions in.
• Habitat PatchAreas distinguished from their surroundings by environmental discontinuities. Patches are organism-defined...
• Habitat SharingA situation in which species occupy the same habitat without competition,
• HabituationIn animal behavior, the temporary waning or disappearance of an innate response when it is elicited many...
• Hadley Cell1. A major Earth atmospheric circulation pattern that consists of rising air at or near the Equator and...
• HailPrecipitation in the form of small balls or other pieces of ice falling separately or frozen together in...
• HairA filament-like structure consisting of a shaft which projects to the surface of the skin from a root which...
• Hair DyeDyes used as cosmetics to change hair color either permanently or temporarily.
• Hair MousseHairstyling foam designed to facilitate styling of a coiffure and provide limited holding power.
• Hair PreparationHair grooming, cleansing and modifying products meant for topical application to hair, usually human. They...
• Hair PulpRemoval of hair by chemical dissolution.
• Hair SavePhysical or mechanical removal of hair which has not been chemically dissolved, and either selling the hair...
• Hair Styling GelHigh-viscosity, often gelatinous product that contains a resin and is designed for the application to hair to...
• HairsprayConsumer product designed primarily for the purpose of dispensing droplets of a resin on and into a hair...
• Half-life1. The length of time required for the mass, concentration, or activity of a chemical or physical agent to be...
• Half-Saturation ConstantNutrient concentration at which the growth rate of a population of a species or group of species is half the...
• Halite1. A soft, soluble evaporate mineral commonly known as salt or rock salt. Can be critical in forming...
• Hall-Heroult Process1. Electrolytic reduction of alumina using cryolite in the melt
• Halo EffectThe halo effect refers to the tendency to rate a person's skills and talents in many areas based upon an...
• Haloacetic AcidsFive haloacetic acid constituents are monochloroacetic acid, dichloroacetic acid, trichloroacetic acid...
• Haloacetic Acids (Sum of Five)Sum of the concentrations in milligrams per liter of the haloacetic acid compounds (monochloroacetic acid...
• Halocarbons1. Compounds containing either chlorine, bromine or fluorine and carbon. Such compounds can act as powerful...
• Halocline1. In the oceans, a well-defined vertical gradient of salinity.
• Halogen1. One of the chemical elements chlorine, bromine, or iodine.
• Halogen Acid FurnaceHalogen acid furnaces (HAFs) for the production of acid from halogenated hazardous waste generated by...
• Halogen Atom1. Atoms of chlorine or fluorine.
• Halogenated Aggregate Batch Vent Stream1. Aggregate batch vent stream determined to have a total mass emission rate of halogen atoms contained in...
• Halogenated Batch Front-End Process VentBatch front-end process vent determined to have a mass emission rate of halogen atoms contained in organic...
• Halogenated Batch Process VentBatch process vent determined to have a mass emission rate of halogen atoms contained in organic compounds of...
• Halogenated Compounds1. Organic HAP compounds that contain halogen atoms.
• Halogenated Continuous Front-End Process VentContinuous front-end process vent determined to have a mass emission rate of halogen atoms contained in...
• Halogenated Continuous Process VentContinuous process vent determined to have a mass emission rate of halogen atoms contained in organic...
• Halogenated Hydrocarbon DetectorPortable device capable of detecting vapor concentrations of PCE of 25 parts per million by volume and...
• Halogenated HydrocarbonsA group of chemicals that are very resistant to decay. The banned pesticide DDT and PCBs fall into this...
• Halogenated Organic CompoundA halogenated organic compound is a compound containing molecules of chlorine, bromine iodine, and fluorine...
• Halogenated Organic CompoundsThose compounds having a carbon-halogen bond which are listed under appendix III to this part.
• Halogenated Vent Stream1. Any vent stream determined to have a total concentration (by volume) of compounds containing halogens of...
• Halogens and HalidesOne of the chemical elements chlorine, bromine or iodine.
• Halogens and Hydrogen Halides1. Hydrogen chloride (HCl), chlorine (Cl2), hydrogen bromide (HBr), bromine (Br2), and hydrogen fluoride...
• Halon1. Bromine-containing compounds with long atmospheric lifetimes whose breakdown in the stratosphere causes...
• Halon BankFacility run by a national government or privately run and authorized by a national government that collects...
• Halon BlendAny mixture or combination of substances that contains two or more halons.
• Halon DisposalProcess leading to and including discarding of halon from halon-containing equipment.
• Halon ProductAny mixture or combination of substances that contains only one halon (e.g., Halon 1301 plus dinitrogen gas...
• Halon-Containing EquipmentEquipment used to store, transfer, and/or disperse halon.
• Halon-Disposal Equipment DisposalProcess leading to and including: (1) The discharge, deposit, dumping or placing of any discarded...
• HalonsCompounds, also known as bromofluorocarbons, that contain bromine, fluorine, and carbon. They are generally...
• Ham ProcessorOperation producing hams, alone or in combination with other finished products, at rates greater than 6000...
• Hammer MillA high-speed machine that uses hammers and cutters to crush, grind, chip, or shred solid waste.
• Hammer ProvisionsRequirements written directly into RCRA by Congress, as in the case of the Hazardous and Solid Waste...
• HandThe distal portion of the upper extremity. It consists of the carpus, metacarpus, and digits.
• Hand Blending Detergent FacilityAny facility (including, but not limited to, a truck or individual storage tank) at which detergent is...
• Hand Glass Melting FurnaceGlass melting furnace where the molten glass is removed from the furnace by a glassworker using a blowpipe or...
• Hand HygienePractices involved in preventing the transmission of diseases by hand.
• Hand MatingAn individual female that is ready to be bred is exposed to an individual boar in a small pen for a few...
• Hand MilkingThe manual milking of an animal as opposed to the use of mechanical milking devices.
• Handheld Equipment1. Relating to equipment that meets any of the following criteria:(1) It is carried by the operator...
• Handheld Equipment EngineNonroad engine that meets the requirements specified in § 90.103(a)(2)(I) through (v).
• Handicapped Person1. Person who has a physical or mental impairment which substantially limits one or more major life...
• HandlersProcessors or dealers of milk who commonly purchase raw milk and sell pasteurized milk and milk products.
• Hand-to-Mouth ContactForm of incidental ingestion of a harmful substance, which is acquired in the mouth, nose or eye via the hand...
• Hand-Wipe Cleaning OperationRemoval of contaminants such as dirt, grease, oil, and coatings from an aerospace vehicle or component by...
• Handwritten signatureAs defined in § 3.3 of CROMERR, the scripted name or legal mark of an individual, handwritten by that...
• Hang-tagPromotional print item with a cut-out portion that permits it to be hung on a doorknob or other hanger.
• Hantavirus Pulmonary SyndromeAcute respiratory illness in humans caused by the Muerto Canyon virus whose primary rodent reservoir is the...
• Haplotype1. A mitochondrial DNA genotype. One of several forms of the circular mitochondrial DNA molecule that differs...
• HaptophytaA group (or phylum) of unicellular Eukaryota (or algae) possessing chloroplasts and flagella.
• Harbor Management PlanProvides a comprehensive evaluation of municipal harbor management activities; a detailed assessment of...
• Hard Bottom HabitatShallow and deep-water habitats with substrates consisting of bedrock, rocks, boulders, gravel, or pebbles...
• Hard Chromium ElectroplatingProcess by which a thick layer of chromium (typically 1.3 to 760 microns) is electrodeposited on a base...
• HARD COPY1. Recorded information copied from a computer onto paper or some other durable surface, such as microfilm...
• Hard Water1. Alkaline water containing dissolved salts that interfere with some industrial processes and prevent soap...
• Hardboard1. Composite panel composed of inter-felted cellulosic fibers made by dry or wet forming and pressing of a...
• Hardboard OvenOven used to heat treat or temper hardboard after hot pressing. Humidification chambers are not considered as...
• HardenerCoating component specifically designed to promote a faster cure of an enamel finish.
• Hardness, WaterA characteristic of water caused mainly by the salts of calcium and magnesium, such as bicarbonate...
• Hard-Piping1. Pipe or tubing that is manufactured and properly installed using good engineering judgment and standards...
• hardrockLocatable minerals that are neither leasable minerals (oil, gas, coal, oil shale, phosphate, sodium...
• Hardrock MineralLocatable minerals that are neither leasable minerals (oil, gas, coal, oil shale, phosphate, sodium...
• Hard-Rock Mining1. Traditional hardrock mining usually involves digging tunnels and adits (horizontal entrances into...
• Hardware1. A computer system's physical equipment, including the central processing unit (CPU), control unit, memory...
• HardwoodWood of a broad-leafed tree, either deciduous or evergreen. Examples of hardwoods include, but are not...
• Hardwood PlywoodHardwood or decorative panel that is intended for interior use and composed of (as determined under ANSI/HPVA...
• Hardwood Veneer DryerDryer that removes excess moisture from veneer by conveying the veneer through a heated medium on rollers...
• Hardy-Weinberg DistributionThe ratio of genotype frequencies that evolve when mating is random and neither selection nor drift are...
• Harmful algae bloomAn algae bloom that produces chemicals toxic to humans and aquatic life.
• Harmful Algal Bloom1. A harmful algal bloom (HAB)can occur when certain types of microscopic algae grow quickly in water...
• Harmful algal bloomsOvergrowths of algae in water. Some produce dangerous toxins in fresh or marine water, but even nontoxic...
• Harmonic MeanKind of average. To find the harmonic mean of a set of n numbers, add the reciprocals of the numbers in the...
• harmonic meansA kind of average. To find the harmonic mean of a set of n numbers, add the reciprocals of the numbers in the...
• Harmonization1. A process whereby national or regional standards and requirements are aligned, including product and...
• Harmonized standards1. Standards on the same subject approved by different standardizing bodies that establish interchangeability...
• Harpin alpha beta proteinA combination of four harpin protein fragments derived from naturally occurring bacteria; used as a...
• Harpin EaA protein secreted by the gram negative bacterium Erwinia amylovora. It is used as a preventative treatment...
• Harrowing (disking)A mechanical means to scarify the soil to reduce competing vegetation and to prepare a site to be seeded.
• Hartig NetA hyphal network between root cortex cells.
• Harvesting1. An automated process to extract information (i.e., resource metadata) from another registry, catalog or...
• Harvestore SiloA brand of oxygen limiting (air tight) upright silos with bottom unloading.
• Hash ValuesOne-way mathematical algorithms that take an arbitrary length input and produce a fixed-length output string...
• HatchbackPassenger automobile where the conventional luggage compartment, i.e., trunk, is replaced by a cargo area...
• Hauler1. Refers to a waste collection company that provides complete refuse removal services. Many will also...
• Hauling EquipmentTruck trailers, utility bodies, camper shells)
• Hauling Solid WasteHauling of solid waste (not generated from wastewater treatment).
• HawaiiThe drainage on the island of Hawaii; and associated waters. Hawaii. Area = 4030 sq.mi.
• Hawaii RegionThe drainage within the state of Hawaii. Includes all of Hawaii.
• Hawaii-Aleutian Standard TimeTen hours behind Coordinated Universal Time
• Hawaiian Native Home Lands1. Census Bureau-defined areas depicting the 75 Hawaiian homelands in the U.S. state of Hawaii in pursuant...
• Hawthorne EffectWhen people know that they are being observed and someone is interested in them, their production increases...
• HayDried feed consisting of the entire plant that can be used a feed for ruminant animals. Alfalfa, clover...
• HaylandSubcategory of Cropland managed for the production of forage crops that are machine harvested. The crop may...
• Hazard1. The likelihood that a substance will cause an injury or adverse effect under specified conditions.
• hazard analysis critical control point system1. A systematic methodology to control hazards in a process by applying a two-part technique: first, an...
• Hazard Assessment1. This term has been used to mean either (1) evaluating the intrinsic effects of a stressor (U.S. EPA, 1979)...
• Hazard CategoryAny of the following:(1) Immediate (acute) health hazard, including highly toxic, toxic, irritant...
• Hazard Characterization1. A description of the potential adverse health effects attributable to a specific environmental agent, the...
• Hazard Communication Standard1. An OSHA regulation that requires chemical manufacturers, suppliers, and importers to assess the hazards of...
• Hazard Evaluation1. A component of risk assessment that involves gathering and evaluating data on the types of health injury...
• Hazard Identification1. The process of determining whether exposure to a stressor can cause an increase in the incidence or...
• Hazard Index1. The sum of more than one hazard quotient for multiple substances and/or multiple exposure pathways. The HI...
• Hazard Quotient1. The ratio of an exposure level to a substance to a toxicity value selected for the risk assessment for...
• Hazard Ranking System1. The NCP defines the HRS as "the method used by EPA to evaluate the relative potential of hazardous...
• Hazard Ranking System FactorPrimary rating elements internal to the HRS.
• Hazard Ranking System Factor CategorySet of HRS factors (that is, likelihood of release [or exposure], waste characteristics, targets).
• Hazard Ranking System Migration PathwayHRS ground water, surface water, and air migration pathways. .
• Hazard Ranking System Package1. A numeric estimate of the relative severity of a hazardous substance release or potential release based on...
• Hazard Ranking System PathwaySet of HRS factor categories combined to produce a score to measure relative risks posed by a site in one of...
• Hazard Ranking System ScoreThe Hazard Ranking System (HRS) is the principal screening tool used by EPA to evaluate relative risks to...
• Hazard Ranking System Site Score1. Composite of the four HRS pathway scores.
• Hazard Ratio1. A term used to compare an animal's daily dietary intake of a pesticide to its LD 50 value. A ratio greater...
• Hazard TypeA grouping representing hazards of various origins and/or manifestations that have similar severities of...
• Hazard Vulnerability AnalysisA systematic approach to identifying all hazards that may affect an organization, assessing the risk...
• hazard/agent/stressorHazard, agent, and stressor can sometimes be used synonymously. However, there are cases where the terms need...
• Hazard-basedRSEI produces three main types of results: pounds-based, hazard-based, and risk-related. Hazard-based results...
• Hazardous Air Pollutant1. Air pollutants that are not covered by ambient air quality standards but which, as defined in the Clean...
• Hazardous Air Pollutant Applied1. Organic HAP content of all inks, coatings, varnishes, adhesives, primers, solvent, and other materials...
• Hazardous Air Pollutant Auxiliary Blowing AgentMethylene chloride, or any other HAP compound used as an auxiliary blowing agent.
• Hazardous Air Pollutant Based AdhesiveAdhesive containing 1.0 percent by weight or more of any individual or combination HAP listed in Table 8 to...
• Hazardous Air Pollutant Exposure ModelA computer model designed to estimate inhalation exposure for specified population groups and air toxics. The...
• Hazardous Air Pollutant Metal1. Metal portion of antimony compounds, arsenic compounds, beryllium compounds, cadmium compounds, chromium...
• Hazardous Air Pollutant Transfer VehicleRailcar, tank truck, or other vehicle used to transport HAP ABA to the flexible polyurethane foam facility.
• Hazardous Air Pollutant UsedOrganic HAP applied by a publication rotogravure printing affected source, including all organic HAP used for...
• Hazardous Air Pollutant-BasedTo contain 5 percent (by weight) or more of HAP. This applies to equipment cleaners (and mixhead flushes) and...
• Hazardous Air Pollutants1. Air pollutants which are not covered by ambient air quality standards but which, as defined in the Clean...
• Hazardous and Solid Waste Amendments1. HSWA are 1984 amendments to RCRA which required phasing out land disposal of hazardous waste and added...
• Hazardous and Solid Waste Amendments of 1984The Hazardous and Solid Waste Amendments of 1984 established the statutory authority for Corrective Action.
• Hazardous Chemical1. EPA's designation for any hazardous material that requires a Material Safety Data Sheet. Such substances...
• Hazardous Constituent1. Those constituents listed in appendix VIII to part 261 of this chapter.
• Hazardous Constituent QuantityThe mass (in pounds) of CERCLA hazardous substances allocated to a source (with certain exceptions for RCRA...
• Hazardous Constituents1. EPA interprets "hazardous wastes" to include all wastes that are hazardous within the statutory definition...
• Hazardous DebrisDebris that contains a hazardous waste listed in subpart D of part 261 of this chapter, or that exhibits a...
• Hazardous InputAny element of the ecosystem that can affect a community resource (e.g., sediment, nutrients, heat).
• Hazardous Material1. The definition of hazardous materials includes those materials designated by the Secretary of the...
• Hazardous Materials Removal WorkerIdentify, remove, package, transport, and dispose of asbestos, radioactive and nuclear waste, arsenic, lead...
• Hazardous Materials Transportation ActTo regulate commerce by improving the protection afforded the public against risks connected with the...
• Hazardous Ranking SystemThe principal screening tool used by EPA to evaluate risks to public health and the environment associated...
• Hazardous Secondary MaterialSecondary material (e.g., spent material, by-product, or sludge) that, when discarded, would be identified as...
• Hazardous Secondary Material GeneratorAny person whose act or process produces hazardous secondary materials at the generating facility. For...
• Hazardous Substance1. CERCLA defines a hazardous substance as "(A) any substance designated pursuant to section 1321(b0(2)(A) of...
• Hazardous Substance Facility1. Defined by section 101(9) of CERCLA, means any building, structure, installation, equipment, pipe or...
• Hazardous Substance Migration ManagementActions that are taken to minimize and mitigate the migration of hazardous substances or pollutants or...
• Hazardous Substance Migration PathThe path that hazardous substances travel (or would travel) overland from a source to surface water (overland...
• Hazardous Substance Removal1. Removal of the oil from the water and shorelines or the taking of such other actions as may be necessary...
• Hazardous Substance Research CentersSee http://www.hsrc.org/. Hazardous Substance Research Centers (HSRC) are a set of national organizations...
• Hazardous Substance SourceAny area where a hazardous substance has been deposited, stored, disposed, or placed, plus those soils that...
• Hazardous Substance Storage1. The holding of hazardous substances for a temporary period, at the end of which the hazardous substance is...
• Hazardous Substance Underground Storage Tank SystemUnderground storage tank system that contains a hazardous substance defined in section 101(14) of the...
• Hazardous SubstancesHazardous substances consist of CERCLA hazardous substances, pollutants, and contaminants as defined in...
• Hazardous Waste1. A subset of solid wastes that pose substantial or potential threats to public health or the environment...
• Hazardous Waste Burning Cement KilnRotary kiln and any associated preheater or precalciner devices that produce clinker by heating limestone and...
• Hazardous Waste CombustorHazardous waste incinerator, hazardous waste burning cement kiln, hazardous waste burning lightweight...
• Hazardous Waste ConsigneeThe ultimate treatment, storage or disposal facility in a receiving country to which the hazardous waste will...
• Hazardous Waste ConstituentConstituent that caused the Administrator to list the hazardous waste in part 261, subpart D, of this...
• Hazardous Waste DischargeAccidental or intentional spilling, leaking, pumping, pouring, emitting, emptying, or dumping of hazardous...
• Hazardous Waste Facility1. Any resource recovery system or component thereof, any system, program or facility for resource...
• Hazardous Waste Facility in OperationFacility which is treating, storing, or disposing of hazardous waste.
• Hazardous Waste Facility PersonnelAll persons who work at, or oversee the operations of, a hazardous waste facility, and whose actions or...
• Hazardous Waste Generator1. Any person, by site, whose act or process produces hazardous waste identified or listed in part 261 of...
• Hazardous Waste Hydrochloric Acid Production FurnaceHalogen acid furnace defined under § 260.10 of this chapter that produces aqueous hydrochloric acid (HCl)...
• Hazardous Waste IncineratorDevice defined as an incinerator in § 260.10 of this chapter and that burns hazardous waste at any time. For...
• Hazardous Waste Landfill1. A specially permitted, excavated or engineered area in which hazardous waste is deposited and covered...
• Hazardous Waste Lightweight Aggregate KilnRotary kiln that produces clinker by heating materials such as slate, shale and clay for subsequent...
• Hazardous Waste Liquid Fuel BoilerBoiler defined under § 260.10 of this chapter that does not burn solid fuels and that burns hazardous waste...
• Hazardous Waste ManagementSystematic control of the collection, source separation, storage, transportation, processing, treatment...
• Hazardous Waste Management Facility1. All contiguous land, and structures, other appurtenances, and improvements on the land, used for treating...
• Hazardous Waste Management InfrastructureEquipment and devices used to collect, reduce, treat, transport, and store hazardous waste.
• Hazardous Waste Management Unit1. Contiguous area of land on or in which hazardous waste is placed, or the largest area in which there is...
• Hazardous Waste MinimizationReducing the amount of toxicity or waste produced by a facility via source reduction or environmentally sound...
• Hazardous Waste MovementHazardous waste transported to a facility in an individual vehicle.
• Hazardous Waste Operations and Emergency Response Worker Protection StandardThe OSHA standard that protects the health and safety of workers engaged in operations at hazardous waste...
• Hazardous Waste PileAny non-containerized accumulation of solid, nonflowing hazardous waste that is used for treatment or storage...
• Hazardous Waste Proximity1. The environmental burden indicator for hazardous waste proximity measures how close people might live to a...
• Hazardous Waste Quantity Factor ValueAn assigned value for the pathway that is based on the sum of all source hazardous waste quantity values, and...
• Hazardous Waste Solid Fuel BoilerBoiler defined under § 260.10 of this chapter that burns a solid fuel and that burns hazardous waste at any...
• Hazardous Waste Transfer Facility1. Any transportation-related facility, including loading docks, parking areas, storage areas and other...
• Hazardous Waste TransportationMovement of hazardous waste by air, rail, highway, or water.
• Hazardous Waste TransporterPerson engaged in the offsite transportation of hazardous waste by air, rail, highway, or water.
• Hazardous Waste Treatment1. Any method, technique, or process, including neutralization, designed to change the physical, chemical, or...
• Hazardous Waste Treatment and DisposalThis U.S. industry comprises establishments primarily engaged in (1) operating treatment and/or disposal...
• Hazardous Waste (TSDF and LQGs)Hazardous waste information contained in the Resource Conservation and Recovery Act Information (RCRAInfo)...
• Hazardous Waste (Under Response)Waste with properties that make it dangerous or capable of having a harmful effect on human health or the...
• Hazardous Waste Unit Final Closure1. The closure of all hazardous waste management units at the facility in accordance with all applicable...
• Hazardous Wastes1. EPA interprets "hazardous wastes" to include all wastes that are hazardous within the statutory definition...
• Hazardous WastestreamMaterial containing CERCLA hazardous substances (as defined in CERCLA section 101[14]) that was deposited...
• Hazards Analysis1. Procedures used to: (1) identify potential sources of release of hazardous materials from fixed facilities...
• Hazards IdentificationProviding information on which facilities have extremely hazardous substances, what those chemicals are, how...
• Haze1. Haze consists of sufficient smoke, dust, moisture, and vapor suspended in air to impair visibility. The...
• Hazmat RouteState-assigned hazardous material routes from the National Transportation Atlas Database (NTAD).
• HCFC-141b Exemption AllowancePrivileges granted to a HCFC-141b formulator; an agency, department, or instrumentality of the U.S.; or a...
• HCl1. Emissions of hydrogen chloride that serve as a surrogate measure of the total emissions of the HAPs...
• HDFAny of the dibenzofurans totally chlorinated or totally brominated at the following positions on the...
• Head1. The vertical distance (in feet) equal to the pressure (in psi) at a specific point. The pressure head is...
• Head FrameA structure erected over a shaft to support the sheave wheel for hoisting purposes.
• Head LossThe head, pressure or energy (they are the same) lost by water flowing in a pipe or channel as a result of...
• Head of a RipThat part of a rip current circulation typically located beyond the breakers, marked by a spreading out or...
• HeadbandComponent of hearing protective device which applies force to, and holds in place on the head, the component...
• HeadendThe electronic control center of a cable system. This is the site of the receiving antenna and the signal...
• HeaderA large pipe to which a series of smaller pipes are connected.
• Header CellsTitle cells for data in tables.
• HeadingThe stage in which the head pushes its way through the flag leaf collar.
• HeadlandHeadlands are projections of land that stick out into a sea or lake.
• HeadlocksSelf-locking stanchions along a feed alley in which cows voluntarily enter the head slot when going to eat...
• Head-of-Hollow FillA fill structure consisting of any materials, other than a coal processing waste or organic material, placed...
• HeadspaceThe vapor mixture trapped above a solid or liquid in a sealed vessel.
• HeadwaterWater level above the powerhouse or at the upstream face of a dam.
• Headwaters1. The upper watershed area where streams generally begin; typically consists of 1st- and 2nd-order streams.
• Health Advisory1. A USEPA document that provides guidance and information on contaminants that can affect human health and...
• Health Advisory LevelA non-regulatory health-based reference level of chemical traces (usually in ppm) in drinking water at which...
• Health and Environmental Impacts DivisionHealth and Environmental Impacts Division (of EPA's Office of Air, OAQPS, located in RTP, NC). Responsible...
• Health and Safety DataInformation described in paragraphs (a)(3)(i) (A), (B), and (C) of this section with respect to any chemical...
• Health and Safety PlanPlan that specifies the procedures that are sufficient to protect on-site personnel and surrounding...
• Health and Safety Study1. Any study of any effect of a substitute or its components on health and safety, or the environment or...
• Health Assessment1. Estimate of the nature and probability of adverse health effects in humans who may be exposed to chemicals...
• Health Based StandardsStandards based on contaminant concentrations in environmental media or exposure doses that are likely to be...
• Health Care and Social AssistanceThe Health Care and Social Assistance sector comprises establishments providing health care and social...
• Health Care AvailabilityAvailability and affordability of health care
• Health Care RationingPlanning for the equitable allocation, apportionment, or distribution of available health resources.
• health consultationIn a public health assessment, a review of available information or collection of new data to respond to a...
• Health DisparityParticular type of health difference that adversely affects one group more than others. Typically, such...
• Health EffectsThe result(s) of exposure to substances (such as radiation) that cause any harm to a person's health. It...
• health endpointAn observable or measurable biological event used as an index to determine when a deviation in the normal...
• Health endpointsAn effect of exposure to a toxic chemical, such as carcinogenicity or reproductive toxicity. RSEI considers...
• Health Hazard1. Source, situation, or act with a potential for harm in terms of human injury or ill health, or a...
• Health HazardsAny factor or exposure that may adversely effect health.
• Health Impact1. The impact on human health. Note: These terms are separate from the specific disease or syndrome.
• Health Impact Assessment1. Health Impact Assessment (HIA) (https://www.who.int/health-topics/health-impact-assessment) is most often...
• Health Information SystemCombination of health statistics from various sources, used to derive information about health status, health...
• Health of ChildrenThe effect of environmental exposure during early life: from conception, infancy, early childhood and through...
• health outcome data1. In a public health assessment, community-specific health information such as morbidity and mortality data...
• health outcomes studyIn a public health assessment, an investigation of exposed persons designed to assist in identifying exposure...
• Health Physics1. A scientific field that focuses on the radiation protection of humans and the environment. A health...
• Health Related Quality of Life ImpactEffect on those aspects of overall quality of life that can be clearly shown to affect health - either...
• Health Risk AssessmentScientific evaluation of the probability of harm resulting from exposure to hazardous materials.
• Health RisksRisk: The probability that something will cause injury or harm.
• Health-Based ViolationA type of violation of the Safe Drinking Water Act incurred by a public water system. These violations fall...
• Health-Based Water ConcentrationLevel below which there are no known or anticipated adverse health effects over a lifetime of exposure...
• Healthcare WorkerMedical doctors, nurses, pharmacists, etc.
• Healthy ChildConcept that promotes the provision of living environments for children that are safe and free of health risk...
• Healthy High Performance SchoolFacilities that integrate all aspects of the design process starting with selection of the design team and...
• Healthy high performance schoolsFacilities that integrate all aspects of the design process starting with selection of the design team and...
• Healthy HomeConcept that promotes safe, decent, and sanitary housing as a means for preventing human disease and injury.
• healthy-years equivalentsThe number of years of perfect health that are considered equivalent to (i.e., have the same utility as) the...
• Heap Leach PilePile of uranium ore placed on an engineered structure and stacked so as to allow uranium to be dissolved and...
• Heap Leach Pile Operational LifeTime period from the first time that lixiviant is placed on the heap leach pile until the time the final...
• Heap Leaching1. A process for recovery of minerals from heaps of crushed ore by percolation of a solvent (such as cyanide...
• Hearing1. Public hearing which is conducted pursuant to the provisions of chapter 5, subchapter II of title 5 of the...
• Hearing Clerk1. EPA employee designated by the Administrator to establish a repository for all books, records, documents...
• Hearing Impaired PersonPersons with any degree of loss of hearing that has an impact on their activities of daily living or that...
• Hearing Protective DeviceAny device or material, capable of being worn on the head or in the ear canal, that is sold wholly or in part...
• Hearing Protective Device Carrying CaseContainer used to store reusable hearing protectors.
• Hearing Protective Device CategoryGroup of hearing protectors which are identical in all aspects to the parameters listed in § 211.210-2(c).
• Hearing Protector DispenserPermanent (intended to be refilled) or disposable (discarded when empty) container designed to hold more than...
• HeartA hollow organ located slightly to the left of the middle portion of the chest. It is composed of muscle and...
• Heart Conduction SystemAn impulse-conducting system composed of modified cardiac muscle, having the power of spontaneous rhythmicity...
• Heart DiseaseHeart disease prevalence among adults aged 18 years or older. The term "heart disease" refers to several...
• Heart DiseasesAny deviation from the normal structure or function of the cardiac system that is manifested by a...
• Heart RotDecay, typically caused by fungi, that is characteristically confined to the heartwood.
• Heart SeptumThe tissue in the heart that separates the two atria (atrial septum) and the two ventricles (ventricular...
• HeartwoodCentral mass of tissue in tree trunks, with no living cells and no longer functioning in water conduction...
• Heat1. Refers to the estrous period for a female of breeding age. In swine, the first estrous normally occurs 3...
• Heat BalanceEquilibrium existing between the radiation received and emitted by a planetary system.
• heat capacityThe quantity of energy that must be supplied to raise the temperature of a substance. For contaminated soils...
• Heat contentThe amount of heat per unit mass released upon complete combustion.
• Heat Exchange System1. Any cooling tower system or once-through cooling water system (e.g., river or pond water). A heat exchange...
• Heat ExchangerDevice such as a coil or radiator that is used to transfer heat between two physically separate fluids.
• Heat Exchanger Exit LineCooling water line from the exit of one or more heat exchangers (where cooling water leaves the heat...
• Heat ExhaustionHeat exhaustion is a phenomenon caused by fluid loss, which in turn causes decreased blood flow to vital...
• Heat IndexIndex that combines air temperature and relative humidity to determine an apparent temperature-how hot it...
• Heat Input1. Total gross calorific value (where gross calorific value is measured by ASTM Method D2015-66, D240-64, or...
• Heat Input Rate1. Product (expressed in mmBtu/hr) of the gross calorific value of the fuel (expressed in mmBtu/mass of fuel)...
• Heat IslandAn urban area characterized by temperatures higher than those of the surrounding non-urban area. As urban...
• Heat Island Effect1. This phenomenon describes urban and suburban temperatures that are 2° to 10°F (1° to 6°C) warmer than...
• Heat PipeA device that can quickly transfer heat from one point to another. Heat pipes are often referred to as the...
• Heat Pump1. An electric device with both heating and cooling capabilities. It extracts heat from one medium at a lower...
• Heat Pump/Air Conditioning Return Flow WellsClass V wells that reinject ground water that has been passed through a heat exchanger to heat or cool...
• Heat Rate1. For a unit, the unit's maximum design heat input (in Btu/hr), divided by the product of 1,000,000...
• Heat Reactive CoatingHigh performance phenolic-based coating requiring a minimum temperature of 191 °C (375 °F) to 204 °C (400 °F)...
• Heat Recovery Steam Generating UnitEGU in which hot exhaust gases from the combustion turbine engine are routed in order to extract heat from...
• Heat Recovery SystemProcess by which the exhaust air preheats the supply air when the outdoor air is cooler than the inside air...
• Heat Release RateSteam generating unit design heat input capacity (in MW or Btu/hr) divided by the furnace volume (in cubic...
• Heat Resistant Specialty CoatingAny coating that during normal use must withstand a temperature of at least 204 °C (400 °F).
• Heat SensorA device that opens and closes a switch in response to changes in the temperature. This device might be a...
• Heat Shock ProteinsA group of proteins that are present in the cells of all living organisms. They are induced when a cell is...
• Heat Stroke1. Heat stroke occurs when the body's heat regulating mechanisms-including convection, sweating, and...
• Heat Transfer CoilTube-and-fin assembly used in large appliance products to remove heat from a circulating fluid.
• Heat Transfer MediumAny material that is used to transfer heat from one point to another point.[40 CFR 60.41b (CFR 2013)]
• Heat Transfer SystemSystems designed to provide indirect heat to processes using a fluid, such as water, glycol, water-glycol...
• Heat TreatingModifying the physical properties of a part by applying controlled heating and cooling cycles. This operation...
• Heat Treatment1. Application of heat of specified temperature and duration to change the physical properties of the metal...
• Heat waveA long period of abnormally hot weather, typically lasting for several days.
• Heat WavesA prolonged period of excessive heat, often combined with excessive humidity.
• Heat-Health Watch Warning SystemsHeat-health watch warning systems correlate weather conditions with human comfort and health risks. When...
• Heating CoilDevice used to heat the air stream circulated from the dry cleaning machine drum, after perchloroethylene has...
• Heating Degree DayHeating degree days are used to estimate how cold the climate is and how much energy may be needed to keep...
• Heating Degree DaysThe number of degrees per day that the average daily temperature is below 65° Fahrenheit. The daily average...
• Heating EquipmentAny equipment designed and/or specifically used for heating ambient air in an enclosed space. Common types of...
• Heating Oil1. Meaning given in § 80.2(ccc).
• Heating PenaltyCool roofs reflect solar energy year-round. In the winter, cool roofs reflect solar energy that could have...
• Heating seasonal performance factorThe measure of seasonal or annual efficiency of a heat pump operating in the heating mode. It takes into...
• Heating StoveAny free-standing box or controlled-draft stove; or a stove installed in a fireplace opening, using the...
• Heating, Ventilation, and Air ConditioningControls the ambient environment (temperature, humidity, air flow, and air filtering) of a building and must...
• Heating, Ventilation, and Air Conditioning ProductBonded wool fiberglass insulation manufactured for use in HVAC systems for the distribution of air or for...
• Heating, Ventilation, and Air Conditioning systemControls a homes internal environment (temperature, humidity, air flow, and air filtering).
• Heat-Shock ResponseA constellation of responses that occur when an organism is exposed to excessive heat and other environmental...
• Heavy Duty Truck EngineAny engine to be used in a heavy-duty truck or heavy-duty vehicle for the purpose of propelling the truck or...
• Heavy Duty Vehicle EngineAny engine to be used in a heavy-duty truck or heavy-duty vehicle for the purpose of propelling the truck or...
• Heavy Gas OilPetroleum distillates with an approximate boiling range from 651 °F to 1,000 °F.
• Heavy Heavy-Duty VehicleThose vehicles with GVWR above 33,000 pounds. Vehicles in this class include tractors, urban buses, and other...
• Heavy Light-Duty TruckAny light-duty truck rated greater than 6000 lbs. GVWR. [40 CFR 88.102-94 (CFR 2013)]
• Heavy Metal1. A common hazardous waste; can damage organisms at low concentrations and tends to accumulate in the food...
• Heavy Metal RemediationCleaning up heavy metals in water and soils. In soils, the commonly encountered cationic metals are mercury...
• Heavy Metals1. Metallic elements with high atomic weights; (e.g., mercury, chromium, cadmium, arsenic, and lead); can...
• Heavy Precipitation EventAn episode of abnormally high rain or snow. The definition of "extreme" is a statistical concept that varies...
• Heavy RailAn electric railway with the capacity to transport a heavy volume of passenger traffic and characterized by...
• Heavy-Density ProductBonded wool fiberglass insulation manufactured on a flame attenuation manufacturing line and having a loss on...
• Heavy-duty Diesel EngineA heavy-duty engine that runs on diesel fuel.
• Heavy-duty Engine1. Any engine to be used in a heavy-duty truck or heavy-duty vehicle for the purpose of propelling the truck...
• Heavy-duty Gasoline EngineA heavy-duty engine that runs on gasoline.
• Heavy-duty TruckAny motor vehicle (including buses) having a GVWR of greater than 8,500 pounds, or curb weight of more than...
• Heavy-duty Truck or Vehicle EngineAny engine to be used in a heavy-duty truck or heavy-duty vehicle for the purpose of propelling the truck or...
• Heavy-duty Vehicle1. Any motor vehicle (including buses) having a GVWR of greater than 8,500 pounds, or curb weight of more...
• Heavy-Haul TractorTractor with GCWR greater than or equal to 120,000 pounds. A heavy-haul tractor is not a vocational tractor...
• Heavy-Passenger CarFor the 1984 model year only, a passenger car or passenger car derivative capable of seating 12 passengers or...
• Heck ReactionA reaction which produces a carbon-carbon bond between aryl halides and activated alkenes in the presence of...
• Hectare(HECK-tar) A measure of area in the metric system similar to an acre. One hectare is equal to 10,000 square...
• Hedera helixEnglish ivy is an evergreen climbing vine that attaches to the bark of trees, brickwork, and other surfaces...
• Hedonic Analysis1. An economic valuation method that uses statistical methods to decompose the price of an asset by (1)...
• Hedonic priceHedonic price, recreational demand or locational choice models may be regarded as “reduced form”...
• Hedonic Pricing MethodA revealed preference technique that relies on the analysis of price data, often used with home sales, which...
• Hedonic ToneThe degree to which an odor is perceived as pleasant or unpleasant. Expressed in terms of preference by...
• hedonic wage studiesStatistical analyses that estimate the effect of intrinsic job characteristics, such as health risks, fringe...
• HeelThe residual amount of a substance that remains in a container after it is discharged or offloaded. By law, a...
• Heel (Residuals)1. Any material remaining in a tank following unloading, delivery, or discharge of the transported cargo...
• Heifer1. A bovine female less than three years of age who has not borne a calf. Young cows with their first calves...
• Height of burstThe height above the Earth’s surface at which a bomb is detonated.
• Helical VirusThe virus has a helical capsid
• Helicobacter pyloriA spiral bacterium active as a human gastric pathogen. It is a gram-negative, urease-positive, curved or...
• HelminthosporiumA mitosporic fungal genus including both saprophytes and plant parasites.
• Help Desk ServicesHelp Desk Services involves the management of a service center to respond to government and contract...
• Hematocrit MeasurementA measure of the volume of red blood cells expressed as a percentage of the total blood volume.
• Hematologic and Lymphocytic DisordersA neoplastic or non-neoplastic disorder that affects the production and proliferation of the hematopoietic...
• HematomaLocalized collection of blood, usually clotted, in an organ, space, or tissue, due to a break in the wall of...
• HematophagyThe blood meals of hematophagous organisms.
• Hematopoiesis1. The production of blood and blood cells; hemopoiesis.
• Hematopoietic and Lymphoid Cell Neoplasm1. A neoplasm arising from hematopoietic cells found in the bone marrow, peripheral blood, lymph nodes and...
• Hematopoietic SystemThe bodily system of organs and tissues, primarily the bone marrow, spleen, tonsils, and lymph nodes...
• Hematopoietic System MeasurementMeasurements of the functioning of blood-making organs and tissues, principally the bone marrow and lymph...
• HematuriaBlood in the urine
• Heme CoenzymesMolecule that contains iron in the ferrous state and serves as a coenzyme in multiple biochemical processes.
• Heme DegradationThe chemical reactions and pathways resulting in the breakdown of heme, any compound of iron complexed in a...
• Heme ProteinProteins that have a metal-containing cofactor that consists of an iron atom in the center of a large...
• Heme SynthesisThe chemical reactions and pathways resulting in the formation of heme, any compound of iron complexed in a...
• Hemicellulose1. Constituent of plant materials that is a polysaccharide, easily hydrated, and easily decomposed by...
• Hemocoelthe extensive spaces of an arthropod's body through which the hemolymph (blood) circulates.
• HemocyteAny blood or formed element especially in invertebrates.
• HemodynamicsThe movement and the forces involved in the movement of the blood through the cardiovascular system.
• HemoglobinThe oxygen-carrying proteins of erythrocytes. They are found in all vertebrates and some invertebrates. The...
• HemoglobinuriaPresence of free red blood cells and its appearance in the plasma
• HemolymphBloodlike fluid of the hemocoel in open circulatory systems of arthropods and most molluscs.
• HemolysisSeparation of hemoglobin from red blood cells and its appearance in the plasma
• HemolyticPertaining to or characterized by hemolysis
• Hemolytic ProcessAny cytolytic process occurring in erythrocytes, resulting in the release of hemoglobin.
• HemosiderosisAccumulation of iron in internal organs.
• HemostatisThe process which spontaneously arrests the flow of blood from vessels carrying blood under pressure. It is...
• Hendra VirusA species of HENIPAVIRUS first identified in Australia in 1994 in HORSES and transmitted to humans. The...
• Hendra Virus DiseaseA member of the family Paramyxoviridae and one of two virus species in the genus Henipavirus. HeV was first...
• Henry's Law1. The relationship between the partial pressure of a compound and the equilibrium concentration in the...
• Henry's Law Constant1. The ratio of the concentration of a compound in air (or vapor) to the concentration of the compound in...
• Henry's law constant (Kн)Ratio of vapor pressure to water solubility; provides an index of partitioning for a compound between...
• HEPA Filter1. High-efficiency particulate air filters that are rated to achieve a minimum initial particle-removal...
• HEPA VacuumVacuum cleaner which has been designed with a high-efficiency particulate air (HEPA) filter as the last...
• Heparan Sulfate BiosynthesisHeparan Sulfate Biosynthesis consists of cellular enzymatic reactions that produce heparan sulfate, a...
• Heparin BindingHeparin Binding involves a biophysical interaction between a biological molecule, such as a protein, and...
• HepaticPertaining to the liver.
• Hepatic ToxicityToxicity which damages the liver or its functions
• Hepatitis(HEP-uh-TIE-this) Hepatitis is an inflammation of the liver usually caused by an acute viral infection...
• Hepatitis A Infection1. Acute inflammation of the liver caused by the hepatitis A virus. It is highly contagious and usually...
• Hepatitis A VirusHepatitis A1 virus (HAV) is classified with the enterovirus group of the Picornaviridae family. HAV has a...
• Hepatobiliary DisordersA non-neoplastic or neoplastic disorder that affects the liver, bile ducts, and gallbladder. Representative...
• HepatomaA malignant tumor occurring in the liver.
• HepatopancreasA primitive form of digestive gland found in marine arthropods that contains cells similar to those found in...
• HeptachlorAn insecticide that was banned on some food products in 1975 and in all of them 1978. It was allowed for use...
• HerbPlant with little or no wood above ground; above-gound parts are of less than one year or growing season...
• HerbaceousPlants without woody stems.
• Herbaceous plant1. Any plant that is not woody.
• Herbicide1. A pesticide designed to control or kill plants, weeds, or grasses. Almost 70% of all pesticide used by...
• HerbicidesA chemical pesticide designed to control or destroy plants, weeds, or grasses.
• Herbicide-Tolerant CropCrops that have been developed to survive application(s) of particular herbicides by the incorporation of...
• Herbivore1. An animal that eats plants.
• HerdA group of animals (especially cattle), collectively considered as a unit.
• herd immunity1. An estimate of exposure, or dose level received anyone in a defined population that is greater than the...
• Herding AgentSubstances that form a film on the water surface to control the spreading of the oil to allow for oil removal.
• Hereditary Cancer1. Cancer that occurs due to the inheritance of an altered gene within a family.
• HermaphroditeA plant or animal that has both male and female reproductive organs and secondary sexual characteristics.
• HermaphroditicA plant or animal that has both male and female reproductive organs and secondary sexual characteristics.
• HerpetilesReptiles and amphibians.
• herptileA general term for amphibians and reptiles.
• Herringbone ParlorA milking parlor in which cows stand side-by-side, angled towards the pit. This allows milking from the side...
• HertzThe number of complete electromagnetic cycles or waves in one second of an electrical or electronic circuit.
• HeteroaggregationConglomeratrion of unlike substances
• Heterocyclic Compounds 1-RingA class of organic compounds containing a ring structure made up of more than one kind of atom, usually...
• Heterocyclic Compounds 2-RingsA class of organic compounds containing two ring structures, one of which is made up of more than one kind of...
• Heterocyclic Compounds 3-RingsA class of organic compounds containing three ring structures, one of which is made up of more than one kind...
• Heterocyclic Compounds by Ring NumberHeterocyclic compounds categorized by the number of rings
• HeterodimerizationHeterodimerization involves a biophysical interaction between two dissimilar biological molecules or...
• Heteroecious Rust FungusFungi with a life cycle that requires two hosts for completion of the cycle.
• heterogeneityCharacteristic of a medium in which material properties vary from point to point.
• heterogeneousVarying in structure or composition at different locations in space.
• Heterogeneous MixtureMixture in which the proportions of its components vary throughout the mixture. Also refers to a mixture...
• Heterogeneous NucleationAccumulation of material from the vapor phase onto an existing particle.
• Heterogeneous ReactionHeterogeneous reactions occur between reactants in two or more phases (e.g., solid and gas, solid and liquid)...
• heterogeneous reactionsHeterogeneous reactions occur between reactants in two or more phases (e.g., solid and gas, solid and liquid)...
• Heterogeneous WasteA waste for which a sample size suitable for analysis is not representative of the property of concern. Thus...
• Heterothallic FungusA fungus which must have two compatible partners to reproduce sexually.
• HeterotrophAn organism that uses organic carbon for the formation of its cell tissue, e.g., is unable to synthesize...
• heterotrophicDesignating or typical of organisms that derive carbon for the manufacture of cell mass from organic matter.
• Heterotrophic Microorganism1. Microorganism whose main source of nutrition is complex organic matter.
• Heterotrophic MicroorganismsBacteria and other microorganisms that use organic matter synthesized by other organisms for energy and...
• Heterotrophic OrganismsSpecies that are dependent on organic matter for food.
• Heterotrophic Plate CountThe number of colonies of heterotrophic bacteria grown on selected solid media at a given temperature and...
• Heterotrophic ProcessA process by which organisms utilize organic substances as their nutrient sources. Contrasts with autotrophic...
• HeterozygosityThe proportion of individuals in a population that are heterozygous (possess more than one allele) at a locus.
• Heterozygote1. For diploid organisms, an individual whose cells contain two forms (alleles) of a gene, one derived from...
• Heuristic methodIn EMAP, a process for exploring and organizing information to conceptually discover and describe or...
• Heuristic ProcessProblem analysis based on informal judgment or experience versus data manipulation; a guideline or rule of...
• HexachlorobenzeneA stable, white, crystalline chlorinated hydrocarbon that emits very toxic fumes of carbon monoxide, carbon...
• Hexafluoropropylene OxideThe chemical substance hexafluoropropylene oxide, CAS Number 428-59-1. [Listed in TSCA Inventory as oxirane...
• Hexavalent Chromium1. Oxidation state of chromium with an oxidation number of +6; a coordination number of 4 and tetrahedral...
• Hexavalent Chromium-Based Chemicals ContainerAny bag, barrel, bottle, box, can, cylinder, drum, or the like that holds hexavalent chromium-based water...
• Hexavalent Chromium-Based Water Treatment ChemicalAny chemical containing hexavalent chromium which can be used to treat water, either alone or in combination...
• HFET-Based Fuel EconomyHighway fuel economy determined in § 600.113 of this part, on the basis of HFET testing.
• Hidden CostRefer to the results of assigning environmental costs to overhead pools or overlooking future and contingent...
• Hidden Markov ModelA statistical model in which the system being modeled has unknown parameters, but the hidden parameters can...
• HideSkins from cattle.
• Hierarchical BayesianRefers to statistical models which are formulated in a hierarchical format, i.e. with subunits, where...
• Hierarchical Cluster AnalysisMethod of data analysis in which clusters (of very similar objects) are arranged in hierarchical 'trees'...
• Hierarchical geometric decompositionThe mathematical process of breaking down a geometric structure into component parts. In the EMAP grid, the...
• Hierarchical model1. A construct in which component variables and systems of ecological entities are defined to have the...
• HIERARCHICAL SYSTEMAny classification system in which records are arranged under primary (first-level) categories and then, as...
• HierarchyIn animal behavior, any social rank-order established through physical or ritualistic combat, threat, passive...
• HighEmission release height from 25m to 100m [Orignal source: Humbert et al., 2011].
• High Altitude ConditionsTest altitude of 1,620 meters (5,315 feet), plus or minus 100 meters (328 feet), or equivalent observed...
• High Contact Residential/Commercial SurfaceA surface in a residential/commercial area which is repeatedly touched, often for relatively long periods of...
• High Conversion LatexLatex where all monomers are reacted to at least 95 percent conversion.
• High Definition TelevisionAn improved television system which provides approximately twice the vertical and horizontal resolution of...
• High Density Polyethylene1. Refers to a plastic product in which the ethylene molecules are linked in long chains with few side...
• High efficiency particulate airRefers to a filtering system capable of trapping and retaining at least 99.97 percent of all monodispersed...
• High Efficiency Particulate Air Filter1. A filtering system capable of trapping and retaining at least 99.97 percent of all monodispersed particles...
• High Efficiency Portable Air CleanerPortable air cleaners with high-efficiency filters that can reduce indoor particle concentrations by as much...
• High End Exposure (dose) EstimateAn estimate of exposure, or dose level received anyone in a defined population that is greater than the 90th...
• High Energy ScrubberA high energy scrubber expends the most energy and has a pressure drop of 25 to over 100 inches of water...
• High Flue Gas Desulfurization FlowMaximum daily volume of FGD wastewater that could be discharged by a facility is above 4 million gallons per...
• High Gradient StreamTypically appear as steep cascading streams, step/pool streams, or streams that exhibit riffle/pool sequences.
• High Heat Release RateHeat release rate greater than 730,000 J/sec-m3 (70,000 Btu/hr-ft3).
• High Intensity DischargeA generic term for mercury vapor, metal halide, and high pressure sodium lamps and fixtures.
• high marsh1. The part of a marsh that lies between the low marsh and the marsh's upland border; this area can be...
• High Mileage HouseholdHouseholds with estimated aggregate annual vehicle mileage that exceeds 12,500 miles.
• High Occupancy AreaAny area where PCB remediation waste has been disposed of on-site and where occupancy for any individual not...
• High Performance Liquid Chromatography1. Frequently referred to simply as HPLC, this form of column chromatography is used frequently in...
• High Performance Sterndrive/Inboard EngineRelating to a sterndrive/inboard engine with maximum engine power above 373 kW that has design features to...
• High Precipitation StormA supercell thunderstorm in which heavy precipitation (often including hail) falls on the trailing side of...
• High Pressure ProcessConventional production process for the manufacture of low density polyethylene in which a reaction pressure...
• High Priority ViolationThere are three ways in which a particular violation can be identified as an HPV. First, the violation may...
• High Production Volume ChemicalThe U.S. high production volume (HPV) chemicals are those which are manufactured in or imported into the...
• High Public Exposure LandLand that the public uses frequently. This includes, but is not limited to, a public contact site and a...
• High Purity AluminumAluminum produced with an average purity level of at least 99.9 percent.
• High Quality WatersHigh quality waters are water bodies in which, on a parameter by parameter basis, the quality of the waters...
• High Risk Community1. A community located within the vicinity of numerous sites of facilities or other potential sources of...
• High solids paints and coatingsPaints and coatings with more solids and less solvents than conventional coatings.
• High Spectral Resolution LidarVariation of lidar (light radar) which employs very high resolution optical detection to distinguish the...
• High Temperature Coating1. High performance coating formulated and recommended for application to substrates exposed continuously or...
• High Temperature Gas Chromatography/Mass SpectrometryAnalysis method in which gas chromatography at high temperatures (several hundred degrees Celsius) is coupled...
• High Temperature Metals RecoveryMetals recovery process in which solid forms of metal-containing materials are processed with a heat-based...

1,010 of 30,736 terms in Environment terminology (MLC-0121). Request the full dataset.