Document Archives Glossary

A

Access, Accessibility

The opportunity to reach jobs, services, housing, recreation, shopping, and entertainment within a reasonable time frame, and without being impeded by physical, social, or economic barriers. Enhancing mobility is one way of providing improved access.

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Aerosol

Tiny particles dispersed in gases. Often used synonymously with particulate matter (PM).

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Air Pollution Control Division

A subset of the Colorado Department of Public Health and Environment.

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Air Quality Control Commission (AQCC)

Established in 1973 under section 25-7-109 of the Colorado Air Quality Control Act, the AQCC is an eight-member elected commission with authority to adopt, promulgate, modify. or repeal emission control regulations which require the use of effective practical air pollution controls.

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AirCare Colorado

The emissions testing program for the state of Colorado. See www.aircarecolorado.com for more details.

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Alternative Fuels

Any motor fuel other than ordinary gasoline, especially those that result in lower levels of air pollutants (e.g. reformulated gasoline, natural gas, and liquid propane).

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AQI

Acronym for Air Quality Index. The EPA (Environmental Protection Agency) developed the AQI to make reading ambient air data more understandable to the general public. When ambient air data is collected, the numbers are converted from their concentration levels into numbers on a scale. That scale is the pollutant’s AQI value.

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AQS

Acronym for EPA’s Air Quality System – the system records air quality data and makes it available for public review.

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Area Source

A collection of similar seemingly small sources of pollution from throughout the non-attainment area. Examples include lawn mowers, barbecue grills, and fireplaces.

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Attainment Area

An area with air quality that meets or exceeds the U.S. Environmental Protection Agency (EPA) health standards used in the Clean Air Act. An area may be an attainment area for one pollutant and a non-attainment area for others. Non-attainment areas are those that have not met the standards for designated pollutants.

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B

BACT

Acronym for Best Available Technology.

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Brown Cloud

The Brown Cloud — a pollutant-related visibility problem — is caused by tiny particles smaller than 10 microns in size, carbon-containing particles and the chemical reactions of certain gases, including NOx, NH3, and SO2. The collective pollutants block light, causing the distinctive Brown Cloud and impeding visibility.

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Build/No-Build

Conformity requirement that Metropolitan Planning Organizations must show that “building” or implementing a long-range plan or Transportation Improvement Program will provide more emissions reductions that “not building” or not implementing than same long-range plan and program.

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C

Carbon Monoxide (CO)

A colorless, odorless, tasteless gas that impedes the oxygenation of blood. CO is formed in large part by incomplete combustion of fuel.
Clean Air Act Amendments (CAAA)
The 1990 Clean Air Act is a piece of United States environmental policy relating to the reduction of smog and air pollution. It follows the Clean Air Act in 1963, the Clean Air Act Amendment in 1966, the Clean Air Act Extension in 1970, and the Clean Air Act Amendments in 1977. It was enacted by the 101st United States Congress (Pub.L. 101-549).

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Colorado Dept. of Public Health and Environment (CDPHE)

A state agency responsible for the implementation of air quality programs such as oxygenated fuels and the enhanced inspection and maintenance program, the monitoring of daily ambient pollutant levels, and the compliance of industrial and area sources with state and federal law.

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Colorado Dept. of Transportation (CDOT)

A state agency responsible for a 9,161 mile highway system, including 3,775 bridges. Each year, this system handles over 28.6 billion vehicle miles of travel. Although the Interstate system accounts for only about 10 percent (915 miles) of the total mileage on the state system, 40 percent of all travel takes place on our Interstate highways.  CDOT’s highway construction program attracts  private contractors and the low bidder is awarded the project and in turn is responsible for construction of that project. This partnership between government (CDOT) and business works well as we improve and expand our transportation system.

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Conformity

Process to assess the compliance of any transportation plan, program or project with air quality control plans. The conformity process is defined by the Clean Air Act. Federal Highway funds are tied to the region’s conformity determination.

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Congestion Management and Air Quality Improvement Program (CMAQ)

Federal funding for projects that contribute to meeting national air quality standards. CMAQ funds generally may not be used for projects that result in the construction of new capacity available to single-occupant vehicles. Part of the Intermodal Surface Transportation Efficiency Act of 1991.

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D

Demand Management Activities

Activities designed to reduce the need for transportation systems. An example of demand management strategy is telecommuting. By contrast, supply-side activities address meeting the needs of the traveling population rather than diminishing the need to travel.

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Denver Regional Council of Governments (DRCOG)

Since 1955, DRCOG has provided local governments with technical and planning assistance for regional issues of transportation and air quality. In 1991, with passage of ISTEA and CMAQ, DRCOG was given the authority to match federal transportation funds to regional air quality objectives. For more information, see http://www.drcog.org.

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DERA

Diesel Emissions Reduction Act (DERA).

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DIA

Denver International Airport (DIA) is an airport in Denver, Colorado, United States.

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DMA/NFR

Acronym for Denver Metro Area/North Front Range.

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DOE

Department of Energy (DOE) is a Cabinet-level department of the United States Government concerned with the United States’ policies regarding energy and safety in handling nuclear material.

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DSM

Demand Side Management (DSM) is the modification of consumer demand for energy through various methods such as financial incentives and behavioral change through education.

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DV

Design Value (DV) is a statistic that describes the air quality status of a given location relative to the level of the National Ambient Air Quality Standards (NAAQS).

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DVB

Base Design Value (DVB).

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DVF

Future Design Value (DVF).

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E

EAC

Early Action Compact (EAC) is an agreement with the U.S. Environmental Protection Agency in December 2002 that lays out a process for achieving attainment with EPA’s new 8-hour ozone standard in an expeditious manner.  The agreement sets forth a schedule for the development of technical information and the adoption and implementation of the necessary control measures into the state implementation plan (SIP) in order to comply with the 8-hour standard.

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EGU

Electric Generating Units (EGU)  is used to mean a solid fuel-fired steam generating unit that serves a generator that produces electricity for sale to the electric grid.

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Emission Budget

The part of the State Implementation Plan (the state air quality plan or SIP) that identifies allowable emissions levels for specific pollutants emitted from mobile sources. The emissions levels in the budget are used for meeting emission reduction milestones, attainment or maintenance demonstrations.

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Enhanced Inspection and Maintenance Program (I/M)

Program passed by the Colorado State Legislature that requires 1982 and newer vehicles to be inspected with a new high-tech treadmill test called I/M 240. Because the new test simulates actual driving conditions, it is more efficient than previous stagnant inspection and maintenance programs at identifying tailpipe emissions.

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EnviroFlash

EnviroFlash is an e-mail and pager notification system that provides subscribers with instant air quality information that can be customized for individual needs. Denver-metropolitan area residents can sign up for this free service at: https://enviroflash.epa.gov/airnow/subscriber/Subscriber.do?method=start

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Environmental Protection Agency (EPA)

EPA leads the nation’s environmental science, research, education and assessment efforts. The mission of the Environmental Protection Agency is to protect human health and the environment. Since 1970, EPA has been working for a cleaner, healthier environment for the American people.

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Envirotest

Envirotest Systems Corp., a subsidiary of Environmental Systems Products, Inc.     (ESP), operates the Air Care Colorado emissions testing centers under contract to     the State of Colorado.

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EV

An Electric Vehicles (EV) also called an electric drive vehicle, uses one or more electric motors or traction motors for propulsion.

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F

FHWA

Acronym for Federal Highway Administration.  This federal agency carries out the Federal highway programs in partnership with the State and local agencies to meet the Nation’s transportation needs. FHWA adds value to the delivery of the Federal highway programs by administering and overseeing these programs to ensure that Federal funds are used efficiently. In administering these Federal funds, we apply flexible and innovative financing techniques permissible under the law, and use efficient administrative processes, such as electronic signatures, online processing, Web information dissemination, and videoconferencing.

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FIP

A Federal Implementation Plan (FIP) is an air quality plan developed by EPA under certain circumstances to help states or tribes attain and/or maintain the National Ambient Air Quality Standards (NAAQS) for common air pollutants.

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FR

Federal Register (FR) is the official journal of the federal government of the United States that contains government agency rules, proposed rules, and public notices.

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FTA

Acronym for Federal Transit Authority. As authorized by the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users of 2005 (SAFETEA-LU), the FTA supports locally planned and operated public mass transit systems throughout the United States.

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FTP

Federal Test Procedure (FTP) are a series of tests defined by the US Environmental Protection Agency (EPA) to measure tailpipe emissions and fuel economy of passenger cars (excluding light trucks and heavy-duty vehicles).

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G

GIS

Geographical Information System (GIS) is a computer system for capturing, storing, checking, and displaying data related to positions on Earth’s surface.

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Greenhouse Gases (GHG)

Greenhouse gases are gases in an atmosphere that absorb and emit radiation within the thermal infrared range. Greenhouse gases greatly affect the temperature of the Earth; without them, Earth’s surface would be on average about 15°C (59°F) colder than at present.

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H

HAP

Hazardous Air Pollutants (HAP) are those known to cause cancer and other serious health impacts.

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HEV

Hybrid Electric Vehicle (HEV) is a type of hybrid vehicle and electric vehicle that combines a conventional internal combustion engine (ICE) system with an electric propulsion system (hybrid vehicle drivetrain).

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Hot-Spot Analysis

Analysis of particulate matter and/or carbon monoxide emissions at particularly polluted or high-emission areas or intersections.

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HOV

High Occupancy Vehicle (HOV) a motor vehicle with seating for several passengers, especially one that is carrying carpoolers.

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I

ICG

Inter-agency Consultation Group (ICG) is a subcommittee that focuses on coordination of the transportation conformity process. This group works to promote coordination among the transportation and air quality agencies for the region.

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IM

Vehicle Inspection And Maintenance (IM) programs help improve air quality by identifying cars and truck with high emissions and that may need repairs. Owners or operators of vehicles with high emissions are notified to make any repairs so that emissions are within legal limits.

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Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA)

Congressional initiative that restructured funding for transportation programs. ISTEA authorized increased levels of highway and transportation funding and an enlarged role for regional planning commissions (DRCOG in the Denver region) in funding decisions. The Act also requires comprehensive regional long-range transportation plans extending to the year 2015 and places an increased emphasis on public participation and alternatives to the automobile.

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ISR

Indirect Source Rule is a measure that helps developers take into account how the design, location and other decisions they make as they conceive projects affect air pollution, and then allows them to make changes onsite or offsite that will reduce that pollution.

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L

Land Use

Refers to the manner in which portions of land or the structures on them are used, e.g., commercial, residential, retail, industrial, etc.

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LDAR

Leak Detection And Repair Program (LDAR): A Best Practices Guide – is intended for use by regulated entities, such as petroleum refineries and chemical manufacturing facilities, as well as compliance inspectors. The guide details some of the problems identified with leak detection and repair (LDAR) programs.

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LED

Light Emitting Diode (LED) is a semiconductor device that emits visible light when an electric current passes through it.

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M

MDA8

Maximum Daily Average Ozone Over An 8-Hour Period (MDA8).

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MEGAN

Model of Emissions of Gasses and Aerosols (MEGAN) is a modeling system for estimating the emission of gases and aerosols from terrestrial ecosystems into the atmosphere.

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Metropolitan Planning Organization (MPO)

A metropolitan planning organization is a transportation policy-making organization made up of representatives from local government and transportation authorities. In 1962, the United States Congress passed legislation that required the formation of an MPO for any Urbanized Area (UZA) with a population greater than 50,000. Congress created MPOs in order to ensure that existing and future expenditures for transportation projects and programs are based on a continuing, cooperative, and comprehensive (“3-C”) planning process. Federal funding for transportation projects and programs are channeled through this planning process. Statewide and metropolitan transportation planning processes are governed by Federal law (23 USC 134 and 135). As of 2005, there are 385 MPOs in the U.S.

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Mobile Source

A source of pollution that is mobile such as automobile, plane, and train.

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Mode, Intermodal, Multimodal

Form of transportation, such as automobile, transit, bicycling, and walking. Intermodal refers to the connections between modes and multimodal refers to the availability of transportation options within a system or corridor.

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Model

A mathematical and geometric projection of activity and the interactions in the transportation system in an area. This projection must be able to be evaluated according to a given set of criteria which might include land use, economics, social values, and travel patterns.

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MOVES2

Mobile Vehicle Emissions Simulator (MOVES2) is a state-of-the-science emission modeling system that estimates emissions for mobile sources at the national, county, and project level for criteria air pollutants, greenhouse gases, and air toxins.

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MPE

Model Performance Evaluation (MPE) is a software has been developed that includes a database of relevant air quality data as well as software for the calculation of a large array of model performance statistics.

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MSRP

Manufacturer’s Suggested Retail Price (MSRP) is the amount of money the producer of a product recommends the product be sold for in retail stores.

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MVEB

The allocation of emissions reductions and control strategies results in an emission reduction target for all sources. For on-road mobile sources, this target can be translated into an area’s motor vehicle emissions budget (MVEB), which identifies the allowable on-road emissions levels to attain the air quality standards.

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MW

Megawatt (MW) a unit of power equal to one million watts, especially as a measure of the output of a power station.

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MY

The Model Year (MY) of a product is a number used worldwide, but with a high level of prominence in North America, to describe approximately when a product was produced, and it usually indicates the coinciding base specification (design revision number) of that product.

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N

NAA

Non-attainment Area (NAA) is an area considered to have air quality worse than the National Ambient Air Quality Standards as defined in the Clean Air Act Amendments of 1970.

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National Ambient Air Quality Standards (NAAQS)

Federal standards that set allowable concentrations and exposure limits for various pollutants.

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NEI

National Emissions Inventory (NEI) is a comprehensive and detailed estimate of air emissions of criteria pollutants, criteria precursors, and hazardous air pollutants from air emissions sources.

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NESHAP

National Emission Standards for Hazardous (NESHAP) are stationary source standards for hazardous air pollutants.

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NFRMPO

North Front Range Metropolitan Planning Organization (NFRMPO) is an association of 15 local governments working together to improve regional transportation and air quality. The NFRMPO does long-range and short-range planning, and prioritizes which projects in those plans will receive state and federal funding. The goal of the NFRMPO is to enhance air quality and mobility among northern Colorado communities, and between the North Front Range and the Denver Metro area.

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NH3

Ammonia Gas.

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NOAA

National Oceanic and Atmospheric Administration (NOAA) is an American scientific agency within the United States Department of Commerce that focuses on the conditions of the oceans and the atmosphere.

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NODA

Notice of Data Availability.

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Northern Front Range Air Quality Study (NFRAQS)

A major measurement effort aimed at enhancing our understanding of the sources and processes which influence the Brown Cloud.

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NOx

The sum of nitric oxide, and nitrogen dioxide. The primary nitrogen pollutant emitted for the combustion process.

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NPS

The National Park Service (NPS) is an agency of the United States federal government that manages all national parks, many national monuments, and other conservation and historical properties with various title designations.

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NREL

The National Renewable Energy Laboratory (NREL), located in Golden, Colorado, is the United States’ primary laboratory for renewable energy and energy efficiency research and development.

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NSPS

The New Source Performance Standards (NSPS) are pollution control standards issued by the United States Environmental Protection Agency (EPA).

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NSR

The New Source Review  (NSR) is a permitting process created by the US Congress in 1977 as part of a series of amendments to the Clean Air Act.

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O

OBD

On-Board Diagnostics (OBD) is an automotive term referring to a vehicle’s self-diagnostic and reporting capability. OBD systems give the vehicle owner or repair technician access to the status of the various vehicle subsystems.

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OEM

Original Equipment Manufacture (OEM) is a company that produces parts and equipment that may be marketed by another manufacturer.

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OTC

The Ozone Transport Commission (OTC) is a multi-state organization founded in 1991 and created under the Clean Air Act. They are responsible for advising EPA on air pollution transport issues and for developing and implementing regional solutions to the ground-level ozone problem in the Northeast and Mid-Atlantic regions.

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Oxidation Catalyst

A catalytic converter designed to reduce particulate emissions from diesel vehicles.

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Oxygenated Fuels

 Gasoline blended with alcohol or ether containing oxygen. Use of such fuels reduces carbon monoxide production and other emissions.

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Ozone

Ozone is a colorless gas with a sweet odor. Ozone is not a direct emission from transportation sources. It is a secondary pollutant formed when hydrocarbons (HC) and nitrogen oxides (NOx) combine in the presence of sunlight. Ozone is associated with smog or haze conditions.

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Ozone Action Plan

A State plan proposed to the AQCC reduce ozone levels in the Denver/North Front Range area by 2010.

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P

Particulate Matter (PM), (PM10) (PM2.5)

Any material that exists as solid or liquid in the atmosphere. Particulate matter may be in the form of fly ash, soot, dust, fog, fumes, etc. Small particulate matter, or PM10, is less than 10 microns in size (about one-eighth the diameter of a human hair) and is too small to be filtered by the nose and lungs. PM2.5 is small particulate matter that is less than 2.5 microns in size).

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PHEV

Plug-In Hybrid Electric Vehicle (PHEV) is a hybrid electric vehicle that uses rechargeable batteries, or another energy storage device, that can be recharged by plugging it in to an external source of electric power.

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ppb

Abbreviation for parts per billion.  A unit of concentration used to measure     pollutant levels.

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ppm

Abbreviation for parts per million.  A unit of concentration used to measure pollutant levels.

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Primary Pollutant

Pollutant gases or particle directly emitted from a pollutant source.

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Q

Quality Assurance Process

A process for determining the accuracy of emissions information. Examples of activities include checking with specific industrial firms concerning the information reported on the Air Pollution Emission Notifications, and reviewing the body of literature regarding the best methods for estimating emissions.

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R

RACM

Reasonably Available Control Measures (RACM) is a control measure developed by the EPA which apply to residential wood combustion, fugitive dust, and prescribed and silvicultural burning in and around “moderate” PM-10 non-attainment areas. RACM is designed to bring an area back into attainment and uses a smoke management program which relies on weather forecasts for burn/no-burn days.

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RACT

Acronym for Reasonably Available Control Technology.

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RAQC

Acronym for the Regional Air Quality Council, metro Denver’s lead air quality planning agency.

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RCRA

The Resource Conservation and Recovery Act (RCRA) gives EPA the authority to control hazardous waste from the “cradle-to-grave.” This includes the generation, transportation, treatment, storage, and disposal of hazardous waste.

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Re-entrained Road Dust

Particulate emissions that are kicked-up from movement of vehicles on paved roadway surfaces.

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Reformulated Gasoline

Gasoline that is reformulated (refined and blended) to burn more efficiently and cleanly in motor vehicles.

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Reid Vapor Pressure (RVP)

A measure which indicates how volatile a fuel is (how easily it evaporates).

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RES

Renewable Energy Sources (RES) are biomass, hydro-power, geothermal, wind, and solar which provide 8% of the energy used in the United States.

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RFG

Reformulated Gasoline (RFG) is gasoline blended to burn more cleanly than conventional gasoline and to reduce smog-forming and toxic pollutants in the air we breathe.

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RFP

The Reasonable Further Progress (RFP) Annual incremental reductions in air pollutant emissions as reflected in a State Implementation Plan that EPA deems sufficient to provide for the attainment of the applicable national ambient air quality standards by the statutory deadline.

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RICE

Acronym for Reciprocating Internal Combustion Engines.

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ROP

The Rate of Progress (ROP) documents the control strategies a State is implementing to reduce emissions of ozone precursors.

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RRF

Relative Response Factor (RRF) is an analytical parameter used in chromatographic procedures to control impurities/degradants in drug substance and drug product. RRF is used to correct the difference in detector response of impurities with analyte peak.

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RTD

Regional Transportation District (RTD) is a bus and rail transit system  in the Denver, Colorado, metropolitan area.

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RTP

The Regional Transportation Plans (RTP) is a long-term blueprint of a region’s transportation system.

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S

Secondary Pollutant

A pollutant formed in the atmosphere through the chemical or physical interaction between primary pollutants.

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SEP

Supplemental Environmental Project (SEPs) are a means by which penalties for environmental violations may be mitigated by directing funds toward environmentally beneficial projects.

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Single-Occupant Vehicles (SOVs)

A single-occupant vehicle refers to an automobile that is used to get just one person to a destination.

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SMOKE

Sparse Matrix Operator Kernel Emissions (SMOKE) is primarily an emissions processing system designed to create gridded, speciated, hourly emissions for input into a variety of air quality models.

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SO2

Sulfur Dioxide.

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Stage II Controls

Mechanisms on gasoline pumps designed to control and capture vapors during vehicle fueling.

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State Implementation Plan (SIP)

Required air quality planning documents prepared by states and submitted to EPA for approval. SIPs identify actions and programs to show how the various non-attainment areas of the state will attain and maintain air quality standards.

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STEM

The Storage tank emissions management (STEM) require emission reduction from storage tanks at exploration and production operations, well production facilities, compressor stations, and processing plants.

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T

TAZ

Transportation Analysis Zone (TAZ) is the unit of geography most commonly used in conventional transportation planning models.

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Telecommuting

Telecommuting is a work arrangement in which employees enjoy flexibility in working location and hours. In other words, the daily commute to a central place of work is replaced by telecommunication links.

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TMA

Transportation Management Associations (TMA) is a formal organization of businesses and local governments dedicated to solving local transportation concerns.

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TPD

Tons Per Day (TPD) is used as a measurement of the solid waste disposal rate at a landfill, incinerator or materials recovery facility.

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TPR

Transportation Planning Region.

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Transportation Control Measures (TCMs)

Local actions to adjust traffic patterns or reduce vehicle use in order to reduce air pollutant emissions. These may include High-Occupancy Vehicle lanes, provision of bicycle facilities, ridesharing, telecommuting, etc.

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Transportation Demand Management (TDM)

TDM is the application of strategies and policies to reduce automobile travel demand, or to redistribute this demand in space or in time.

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Transportation Improvement Program (TIP)

Document prepared by states and regional planning commissions (i.e., DRCOG) identifying projects to be funded under federal transportation programs for a full-year period. If it is not included in a conforming TIP, a project is ineligible for federal funding.

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Transportation Management Organization (TMO)

A voluntary association of public and private agencies and firms joined to cooperatively develop transportation-enhancing programs in a given area. TMOs typically manage transportation demand in congested urban and suburban communities. The first Denver region TMO formed Downtown in early 1995.

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TSSIP

Traffic Signal System Improvement Program (TSSIP), a combination of management and operations strategies designed to time and coordinate traffic signals in the Denver region.

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V

Vehicle Miles of Travel (VMT)

A standard areawide measure of travel activity. Most conventional VMT calculation is to multiply the average length of trips by the total number of trips.

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Visibility Standard

Established by the Colorado State Legislature, the visibility standard requires that not more than 7.6 percent of the light in a kilometer of air be blocked, averaged over four daylight hours. The standard is equivalent to a visual range of 32 miles and was established by the Colorado Department of Public Health and Environment after assessing public perception and values on visual aesthetics.

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Volatile Organic Compound (VOC)

Natural (Organic) Emissions from plant material or related solvents from industrial processes. Combine in the atmosphere with NOx to form ozone.

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W

WAQS

Western Air Quality Study (WAQS) is intended to facilitate air resource analyses for federal and state agencies in the inter-mountain western U.S. toward improved information for the public and stakeholders as a part of air quality planning including those undertaken under the National Environmental Policy Act (NEPA) as well as other studies.

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WOE

Weight of Evidence (WOE) is a measure of evidence on one side of an issue as compared with the evidence on the other side of the issue, or to measure the evidence on multiple issues.

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WRF

Weather Research and Forecasting (WRF) is a next-generation mesoscale numerical weather prediction system designed for both atmospheric research and operational forecasting needs.

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Z

ZEV

Zero Emission Vehicles (ZEV) is a vehicle that emits no tailpipe pollutants from the on-board source of power.

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