Air Quality Glossary

The following is a listing of Air Quality-terms developed by CCMPO. Acronyms are listed by letter, but are not in alphabetical order.

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Term	Acronym	Definition
Attainment Area		Air quality designation where measures of selected pollutants do not exceed established (NAAQS) standards.
Carbon Monoxide	CO	A colorless, tasteless gas produced primarily by inefficient combustion of organic fuels in transportation and industrial activities. Overly high levels of CO reduces oxygen in the bloodstream, preventing normal respiration. CO emissions are regulated by the Agency of Natural Resources.
Clean Air Act Amendments of 1990	CAAA	Federal legislation that sets allowable levels, known as NAAQS, for various pollutants. Where these standards are not attained, officials must take specified actions within a mandatory time frame or face sanctions such as loss of federal highway funds.
Cold Start		The starting of an engine which is significantly below normal operating temperature, of significance in understanding vehicle emissions since the rate and composition of emissions vary with engine temperature. Often the most polluting time of car operation.
Compressed Natural Gas	CNG	Fuel for natural gas powered vehicles (primarily buses). Natural gas is comprised mostly of methane that is compressed (about 2,400 lbs. per square inch) and stored in high-pressure design containers.
Conformity		The requirement that the state or metropolitan transportation plan, programs, and projects are consistent with the purpose of the State Implementation Plan (SIP). The CAAA does not permit federal approvals of funding of any project that does not meet this test.
Congestion Mitigation and Air Quality	CMAQ	A program authorized by the 1991 ISTEA provided billions of dollars in funding for surface transportation and other projects that contribute to air quality improvements and reduce traffic congestion. The CMAQ program has been improved and reauthorized in all subsequent federal transportation re-authorization bills.
Corporate Average Fuel Economy	CAFE	Automobile manufacturer vehicle fleet fuel economy standards. More specifically, CAFE is the sales weighted average fuel economy, expressed in miles per gallon (mpg), of a manufacturer’s fleet of passenger cars or light trucks with a gross vehicle weight rating (GVWR) of 8,500 lbs. or less, manufactured for sale in the United States, for any given model year. Fuel economy is defined as the average mileage traveled by an automobile per gallon of gasoline (or equivalent amount of other fuel) consumed as measured in accordance with the testing and evaluation protocol set forth by the Environmental Protection Agency (EPA). The “Energy Policy Conservation Act,” enacted into law by Congress in 1975, added Title V, “Improving Automotive Efficiency,” to the Motor Vehicle Information and Cost Savings Act and established CAFE standards for passenger cars and light trucks. The Act was passed in response to the 1973-74 Arab oil embargo. The near-term goal was to double new car fuel economy by model year 1985.
Emissions Budget		An aspect of the State Implementation Plan (SIP) that identifies allowable emissions levels, mandated by the National Ambient Air Quality Standards (NAAQS) for certain pollutants emitted from mobile, stationary, and area sources. The emissions levels are used for meeting emission reduction milestones, attainment, or maintenance demonstrations.
Emissions Inventory		An emissions inventory is a database that lists (by source of emission) the amount of air pollutants discharged into the atmosphere of a community or region during a given period of time.
Global Climate Change	GCC	Global Climate Change
Greenhouse Gases	GHG	Identified by the Intergovernmental Panel on Climate Change (IPCC), anthropogenic greenhouse gases are recognized by the international scientific community as having the potential to bring about climate change. Such gases include; Carbon Dioxide (CO2), Methane (CH4), Nitrous Oxide (NOX), Carbon Tetrafluoride, Hexafluoromethanem, Sulfur Hexafluoride, and others.
Hot Spot		A location with higher-than-ambient levels of pollution. Hot spots may be attributed to such things as weather patterns, topography, and traffic intensity.
Hydrocarbons	HC	Hydrocarbons are a Volatile Organic Compound (VOC) that is released into the atmosphere because of incomplete combustion of petroleum fuels or by their evaporation. The strong odor of diesel fuel is associated with HC. The EPA states that 47% of Hydrocarbon emissions in our atmosphere can be attributed to vehicles. Hydrocarbons combined with Nitrogen Oxides, and sunlight form Ozone (O3).
Liquefied Natural Gas	LNG	A natural gas fuel comprised mainly of methane, cooled to below its boiling point of -260 degrees Fahrenheit, where it becomes a liquid. LNG is stored at very low temperatures within a special low-pressurized vacuum container. LNG does not burn in liquid form.
Low Emission Vehicle	LEV	A vehicle certified to meet low emission standards set by the California Air Resources Board. These regulations are stricter than the US national "Tier" regulations.
Maintenance Area		Any U.S. region previously designated "Nonattainment" pursuant to the Clean Air Act Ammendments of 1990 (CAAA) and subsequently redesignated to "Attainment". Such regions are subject to develop a maintenance plan under section 175A of the Clean Air Act as ammended.
Mobile Source Pollutants		Vehicle-generated pollutants as regulated by the U.S. Environmental Protection Agency (EPA) for air quality. These include; Carbon Monoxide (CO), Hydrocarbons (HC) or Volatile Organic Compounds (VOCs), Nitrogen Oxides (NOx), Small Particulate Matter (PM-10), and Large Particulate Matter (PM 2.5).
Mobile6		A vehicle emission modelling software, which develops factors for predicting gram per mile emissions of Hydrocarbons (HC), Carbon Monoxide (CO), Nitrogen Oxides (NOx), Carbon Dioxide (CO2), Particulate Matter (PM), and toxics from mobile sources under various conditions. This model has been upgraded/replaced by a model called MOVES.
Motor Vehicle Emission Simulator	MOVES	EPA's Office of Transportation and Air Quality (OTAQ) is developing the "MOtor Vehicle Emission Simulator" (MOVES). The successor to MOBILE6, this more recent emission modeling system estimates emissions for on-road and nonroad mobile sources, covers a broader range of pollutants, and allows multiple scale analysis from fine-scale analysis to national inventory estimation. MOVES is planned to serve as the replacement for MOBILE6 and NONROAD for all official analyses associated with regulatory development, compliance with statutory requirements, and national/regional inventory projections.
National Ambient Air Quality Standards	NAAQS	Clean Air Act standards for widespread pollutants from numerous and diverse sources considered harmful to public health and the environment.
Natural Gas Vehicle	NGV	NGV's use Compressed Natural Gas (CNG)- composed of Methane, or a less common Liquefied Natural Gas (LNG) as a cleaner alternative to petroleum-based fossil fuels.
Nitrogren Oxides	NOX	Precursor emission that forms from high-temperature combustion processes. React with VOCs in the presence of heat and sunlight to form ozone.
Nonattainment Area		A geographic area that in the US EPA has designated as not meeting the NAAQS. The Chittenden County area has not been designated as a nonattainment area for ozone or CO at this time.
Ozone	O3	A colorless gas with a sweet odor that is not a direct emission from transportation sources, but is formed when VOCs and NOx from car exhausts and some industrial emissions combine in the presence of sunlight. Ground-level ozone is associated with smog conditions and initiates damage to lungs, trees, crops and materials. Requlated by the Clean Air Act Amendments of 1990 (CAAA).
Partial Zero Emission Vehicle	PZEV	A vehicle that has zero evaporative emissions from its fuel system, has a 15 year (or at least 150,000 mile) warranty, and meets SULEV tailpipe emission standards.
Particulate Matter	PM	An indicator used in the description of Air Quality assessment. PM is a term describing a mixture of solid particles and liquid droplets monitored in the air. PM originates from fuel combustion from automobiles, power plants, industrial facilities, and residential fireplaces and wood stoves. Fine particles (PM 2.5 = 2.5 microns or smaller) are closely associated with health effects, such as; increased hospital admissions and emergency room visits for heart and lung disease, increased respiratory symptoms and disease, decreased lung function, and premature death. Larger particles (PM10 = 2.5 - 10 microns) generally occur as smoke, dust, pollen, etc., which settle relatively quickly when compared to fine particles.
Parts per Million	PPM	A measure of air pollutant concentrations.
Sulfur Dioxide	SO2	Petroleum fuels contain traces of sulphur compounds and produce Sulfur Dioxide (SO2) during combustion. The majority of the SO2 pollution comes from power generation, which is a significant cause of "Acid Rain". Except for the shipping mode, transportion is not a major contributing source of SO2.
Super Ultra Low Emission Vehicle	SULEV	A vehicle producing 90 percent less pollutants than an average gasoline-powered vehicle for the year of manufacture.
Transportation Control Measures	TCM	Actions, which are usually found in a State Implementation Plan (SIP), that improves traffic flow, reduce vehicle use, or decrease congestion with the objective of lessening air pollutant emissions.
Transportation Demand Management	TDM	Low-cost programs that focus on decreasing travel and the use of SOVs, and increasing the use of other modes.
Ultra Low Emission Vehicle	ULEV	A vehicle producing 50 percent less pollutants than an average gasoline-powered vehicle for the year of manufacture.
Volatile Organic Compounds	VOC	A group of chemicals that reacts in the atmosphere with NOx in the presence of heat and sunlight to form ozone. Examples include gasoline fumes and oil-based paints.
Way To Go Week	W2GW	Vermont annual TDM program that encourages the population to commute non-SOV for one week in the month of May.
Zero Emission Vehicle	ZEV	Vehicles which do not produce tailpipe and evaporative emissions, where emission-control systems cannot fail, and do not cause emissions from gasoline purchase or its refinement. Of the vehicles which fall in this classification are; Bicycles, Electric vehicles, Compressed-air vehicles, Fuel-cell vehicles, Solar & Hydrogen-powered vehicles, and other human or animal-powered vehicles.

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