B.C. Air Quality


See also Acronyms.

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Acid Rain (Acid Deposition / Acid Precipitation)
The deposition of acidic compounds, produced in the atmosphere from pollutants such as sulphur oxides (SOx) and nitrogen oxides (NOx) to the earth — either dry particles, or with rain, snow or fog.

Acrolein is a clear or yellow liquid with a strong smell. Inhaling acrolein can irritate the eyes and respiratory tract. With severe exposure, death can occur from damage to the lungs and respiratory system.

A suspension in a gaseous medium of solid and/or liquid particles having a negligible falling velocity.

IPCC Definition "Adjustment in natural or human systems in response to actual or expected climatic stimuli or their effects, which moderate harm or exploits beneficial opportunities." The definition recognizes that humans can adjust to past ("actual") climate change and its impacts, or prepare for projected future ("expected") climate change and its impacts. Adaptation can include changes in behaviour, technology, institutions, policies, and other aspects of human systems.

Planting trees where none existed before. Afforestation can be used to increase the planet's carbon sinks.

Air Quality
The state of the air within a specific area. “Air quality” is a neutral term: it can be good or bad (in or between).

Air Quality Health Index (AQHI)
The Air Quality Health Index reports on the current state of the air and identifies the related health risk associated it.

Air Quality Index (AQI)
The Air Quality Index (AQI) reports current air quality based on a specific level of an individual air pollutant.

Air Mass
A large volume of air with with similar temperature and moisture characteristics. Air masses cover many hundreds or thousands of square miles, and slowly change in accordance with the surface below them

Air Pollution
Unwanted chemicals or other materials found in the air, at high enough concentrations to endanger the environment and people’s health. Many air pollutants occur as gases or vapours, but some are very tiny solid particles: dust, smoke or soot. Common pollutants are wood smoke, ground-level ozone and particulate matter.

Air Toxics
Air pollutants that are toxic to humans, fish, wildlife and marine animals. (See Hazardous Air Pollutants.)

An area where the movement of air tends to be limited to the bounds of that area, as a result of specific geographical or meteorological conditions.

Ambient Air
Outside air, surrounding air, air occurring at a particular time and place outside of structures.  All living beings are exposed to the ambient air.

Ambient Air Quality Objectives or Standards
Air quality levels for specific pollutants that are determined to be necessary to protect human health and/or the environment. They typically consist of a numeric pollutant concentration, averaging time, and rules or guidance on sampling methodology and how the objectives or standards are to be applied. They may also be referred to as "ambient air quality criteria" or "guidelines."

Made by humans. Human-caused.

Area Sources
Stationary sources which are not normally required to obtain an air discharge permit from the Ministry of Environment. They include prescribed burning, residential fuel wood use, light industrial, and other residential, commercial and institutional sources. Emissions from most of these area sources individually are small compared to emissions from point sources but can be significant when considered collectively.

When people have asthma, the airways in their lungs get inflamed (red and swollen). They become extremely sensitive to dust particles and other airborne substances like pet dander. When these substances come in contact with the already inflamed and sensitive airways, the airways tighten and narrow, making it hard to breathe.

The layer of gases surrounding Earth. It is about 480 kilometres thick, and mainly composed of nitrogen, oxygen, carbon dioxide, and a few other trace gases.


Base-Year Emissions
GHG emissions in a specified (usually historical) year, against which future emissions are measured. Emission targets are often defined relative to base year emissions, e.g. 10% below 1990 emission levels.

A colourless member of the VOCs (volatile organic compounds) family. It is used widely by the chemical industry, and is also found in tobacco smoke, vehicle emissions, and gasoline fumes. Exposure to benzene may increase the risk of developing cancer.

A form of renewable energy derived from biomass, which can be used for electricity, space heating and to power motor vehicles. Today, the three main types of bioenergy are bioethanol, biodiesel and biogas. (Burning wood to heat homes and cook food is a traditional kind of bioenergy.)

Material produced by living organisms such as wood and vegetation, as well as animals and microorganisms. British Columbia has an abundance of biomass resources, including sawmill residues, timber killed by mountain pine beetles logging debris, and agricultural and municipal wastes.

Inflammation of the mucous membrane of the main airways of the lung, or the bronchial tubes.


Carbon (C) is the building block of life. It is the basic element in all living things, including 50% of the dry weight in the human body. In the form of carbon dioxide, carbon is a powerful greenhouse gas. However, the term "carbon" used in discussing climate change does not just to refer to carbon dioxide. It includes the other powerful greenhouse gases, such as methane and nitrous oxide. Scientists are able to lump these six gases together under the name "carbon" by figuring out their carbon dioxide equivalent. So when we talk about "carbon footprint" and "carbon neutral," for example, we are referring to all the major greenhouse gases, not just carbon dioxide.

Carbon Dioxide (CO2)
A colourless, odourless gas. It is formed during breathing, combustion, and decaying of organic materials (e.g., plants, animals). Carbon dioxide is a major greenhouse gas, mainly emitted by the combustion of fossil fuels.

Carbon Dioxide Equivalent (CO2e)
The unit of measurement that defines the global warming potential (GWP) of the six greenhouse gases. CO2e is expressed in terms of the global warming potential of one unit of carbon dioxide. Expressing all greenhouse gases in terms of tonnes of CO2e allows the different gases to be grouped together.

Carbon Footprint
The total amount of greenhouse gases produced by human activities. This is usually expressed in equivalent tons of carbon dioxide (CO2), which is the major greenhouse gas. For example, when we burn fossil fuels to run our vehicles or heat our homes, we are releasing carbon dioxide. The food we buy gets to the grocery store by motor vehicle, and possibly train or plane, which emit CO2. Our carbon footprint is the sum of the CO2 emissions caused by our activities, usually calculated over a year.

Carbon Monoxide (CO)
A colorless, odourless, poisonous gas produced when carbon-containing substances such as coal, oil, gasoline, wood, or natural gas do not burn completely. CO can cause angina in people with heart disease. It is lethal at high concentrations.

Carbon Neutral
Being carbon neutral refers to maintaining a balance between producing and using carbon. For example, we release carbon dioxide when we burn fossil fuels in vehicles. We can balance out those emissions by planting trees because vegetation absorbs carbon dioxide. There are many ways governments, industry and individuals can work towards being carbon neutral. An organization is carbon neutral if it has calculated its total emissions, taken measures to minimize those emissions, and used emissions offsets to net those emissions to zero. For more details, see: What You Can Do: Go Carbon Neutral (David Suzuki Foundation).

Carbon Sink
Processes that remove more carbon dioxide from the atmosphere than they release, as part of the carbon cycle. For example, forests and oceans act as carbon sinks. Forests can be planted specifically for this purpose, which is called carbon sequestration.

Carbon Sequestration
The process of increasing the carbon stored in a reservoir other than the atmosphere, in order to reduce carbon dioxide emitted by human activities. Carbon dioxide can be removed from the atmosphere through such actions as planting forests (trees absorb CO2). This removal is temporary, though, because CO2 returns to the atmosphere when plants die or are burned. Carbon dioxide can also be captured from flue gases or from processing fossil fuels and stored underground.

Carbon Tax
A surcharge on the carbon content of oil, coal, and gas that discourages the use of fossil fuels and aims to reduce carbon dioxide emissions. B.C. has introduced a carbon tax that will be revenue neutral, meaning all revenue generated by the tax will be returned to individuals and businesses through reductions in other taxes.

Carbon Tetrachloride
A colorless, nonflammable liquid that is an ozone-depleting substance. It was formerly used in fire extinguishers, as a cleaning agent, and to make refrigerants (CFCs), but its production has sharply declined since the '80s due to its environmental impacts.

A substance that causes cancer.

A mandated restraint in a scheduled timeframe that puts a "ceiling" on the total amount of anthropogenic greenhouse gas emissions that can be released into the atmosphere.  This can be measured as gross emissions or as net emissions (emissions minus gases that are sequestered).

Cap and Trade System
Cap and trade systems set a specific limit on GHG emissions. They promote the trading of emissions allowances between emitters who can meet the cap efficiently and those who face more of a challenge in reducing emissions. 

Relating to the heart.

Relating to the heart and blood vessels.

An outdoor wood-burning appliance that is usually ceramic, but also may be made of cast iron or aluminum. It usually has a short chimney to pull air into the fire and draw the smoke out of it.

Chlorofluorocarbons (CFCs)
Potent ozone-depleting substances made up of carbon, hydrogen and chlorine atoms.  These substances were used as coolants in refrigerators, freezers and air conditioners, foaming agents, solvents, aerosol sprays and propellants until 1987 when their production and import were prohibited under the Montreal Protocol on Substances that Deplete the Air. However, CFCs are still banked in many of these products.

Chronic Obstructive Pulmonary Disease (COPD)
COPD is a term that includes a number of lung diseases. The most common are chronic bronchitis and emphysema. Many people with COPD have both of these lung diseases. COPD makes breathing hard. It slowly damages the airways of the lungs, making them swollen and blocked and causing them to lose their elasticity or stretchiness.

The climate of an area is its local weather conditions — such as temperature, precipitation (rainfall, snow, etc.), humidity, sunshine, cloudiness, wind, and air pressure. It is the weather averaged over a long period of time. Some people say climate is what you expect, and weather is what you get.

(Global) Climate Change
Changes in the climate of the earth as a whole, caused by human activities that release greenhouse gases.

Climate System
Involves the natural reactions between the gases in the atmosphere, the planet’s water, ice, the land and living things, and solar energy. Together, they determine the earth's climate.

The combustion of wood waste to generate both electricity and heat (steam) in industries such as pulp mills. Burning wood waste can also fire power plants, such as the Williams Lake Power Plant, which provide electricity for B.C.'s power grid.

Conformity with guidelines and regulatory requirements established by government to protect the environment, human health and safety.

The amount of a pollutant in the air at a given location.

Conserve Energy
See “Energy Conservation.”

Burning or the production of heat and light energy through a chemical process.

Common Air Contaminants (CACs) (Also called "Criteria Air Contaminants")
Air pollutants commonly found in the atmosphere, namely carbon monoxide (CO), particulate matter (PM), sulphur oxides (SOx), nitrogen oxides (NOx), volatile organic compounds (VOCs) and ammonia (NH3). Ground-level ozone (O3) is often referred to with CACs because it is  a byproduct of CAC interactions.

Also referred to as “level." The amount of.

Criteria (Emission)
Emission criteria refer to discharge targets and associated conditions prescribed for specific source types. They help define the requirements laid out in regulations, codes of practice and other air-quality-management instruments.


The direct human-induced conversion of forested land to nonforested land.

Dioxins and Furans
A group of chemicals that are among the most toxic chemicals currently known to science, causing cancer, among other things.

Separate / break up and go in different directions.

Dosage (Dose)
The amount of a pollutant a person inhales or absorbs over a certain period of time. The amount determines the health outcomes.


Interacting system of a biological community and its nonliving environmental surroundings.

The release of substances (pollutants) into the atmosphere from natural or human sources.

Emissions Inventory
See Inventory.

Emissions Offsets
See Offsets.

Emissions Trading
A market mechanism that allows emitters (countries, companies or facilities) to buy emissions from or sell emissions to other emitters.  Emissions trading is expected to bring down the costs of meeting emission targets by allowing those who can achieve reductions less expensively to sell excess reductions (e.g. reductions in excess of those required under some regulation) to those for whom achieving reductions is more costly.

The fundamental substance of everything in the universe. When we are talking about the environment, energy is the power we get from burning fossil fuels; electricity; and nuclear power — along with the more green options: solar and wind power.

Energy Conservation
Cutting down on energy use to reduce emissions caused by such energy-generating processes as the combustion of fossil fuels and wood, and power plants.

The combination of all external conditions and influences relating to the life, development, and survival of all living things.

Generally a multi-day period of poor air quality.

The process by which a liquid is turned into a gas.

A combination of the amount of a pollutant in the air and the amount of time a person stays in the presence of a pollutant. Exposure determines the level of risk associated with different levels of pollutants.


A colorless and strong-smelling gas that is harmful when inhaled. Its mainly used as a disinfectant and preservative, and in making other compounds (e.g., resins).

Fossil Fuels
Fossil fuels, also known as mineral fuels, are natural resources such as coal, oil and natural gas. They are called “fossil” fuels because they are formed from the remains of ancient plant and animal life.

Fugitive Dust
Dust (airborne particulate matter) that does not come from a specific source, such as a smokestack. Rather, fugitive dust comes from such sources as roads and parking lots, soil cultivation, quarries and storage piles.

See Dioxins and Furans.


Geothermal Energy
The generation of energy generated from heat stored in the earth.

Global Climate Change
See (Global) Climate Change

Global Warming
The progressive rise of the earth’s surface temperature thought to be caused by the enhanced greenhouse effect. Global warming may be responsible for changes in global climate patterns.

Global Warming Potential (GWP)
An estimate of how much a greenhouse gas can contribute to global warming. Each greenhouse gas has a different ability to trap heat, or global warming potential. To determine how powerful a greenhouse gas is, the gas in question is compared to the global warming potential of carbon dioxide (which, by definition, is 1). On a unit mass basis, the GWP of methane and nitrous oxide trap 23 and 296 times more heat respectively than carbon dioxide. The heat-trapping ability of several ozone-depleting substances is thousands of times more than that of carbon dioxide.

A popular term, describing an action, process or product that causes less harm to the environment (environmentally friendly).

Greenhouse Effect
The heating that occurs when greenhouse gases such as carbon dioxide trap heat escaping from the earth and radiate it back to the surface. The gases are transparent to sunlight but not to heat and thus act somewhat like the glass in a greenhouse.

Greenhouse Effect: Enhanced
The enhancement of the greenhouse effect. The enhanced greenhouse effect is probably being caused by human activities — especially the burning of fossil fuels — that are increasing greenhouse gas concentrations in the atmosphere. This is making the atmosphere warm beyond its natural level.

Greenhouse Gases (GHGs)
Several important gases in the earth’s atmosphere: carbon dioxide, methane, nitrous oxide, ozone, other trace gases and water vapour. Surrounding the earth like a giant greenhouse, they maintain the earth’s climate. However, in excessive concentrations they contribute to accelerated global climate change which may adversely affect various aspects of ecosystem.  The six greenhouse gases included under the Kyoto Protocol are: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), sulphur hexafluroide (SF6), hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs).

Ground-Level Ozone (O3)
A colourless and highly irritating gas, and a primary component of smog and is formed by the reaction of volatile organic compounds (VOCs) and nitrogen oxides (NOx) in the presence of sunlight and warm temperatures. Ground-level ozone is harmful to human health and the environment.


An area where animals grow, live and reproduce.

Chemicals that are both ozone-depleting substances and greenhouse gases. Their most common use is in refrigeration and air conditioning technologies. They include chlorofluorocarbons (CFCs) , hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), halons, methyl chloride and methyl bromide.

A group of "brominated organic compounds" used as fire retardants, which have a high ozone-depletion potential.

Hazardous Air Pollutants (HAPs)
Pollutants released into the atmosphere as particles and volatile organic compounds (VOCs) — including the known carcinogens of benzene and toluene — from a variety of sources such as vehicle emissions, petrochemical products, and tobacco smoke. Of particular concern are persistent organic pollutants (POPs) that are not easily broken down, and can therefore travel great distances, as well as accumulate in living organisms.

Airborne particles of extremely small size. These particles are individually not visible to the naked eye. However,  in large enough numbers they can result in opalescence in the atmosphere and reduced visibility.

Heavy Metals
Metallic elements with high atomic weights, such as mercury, chromium, cadmium, arsenic, and lead. They are harmful at low concentrations.

Organic compounds containing primarily carbon and hydrogen, but may also contain nitrogen, sulphur, halogens and other substances. They are mainly produced from coal, petroleum and natural-gas use, solvent evaporation, and incomplete combustion of fuels, wastes and biomass. Vegetation is a natural source of hydrocarbons.

Hydrofluorocarbons (HFCs)
One of the six main greenhouse gases. Synthetic industrial gases, mainly used in refrigeration and other applications as substitutes for chlorofluorocarbons (CFCs), which deplete the stratospheric ozone layer. This group of chemicals is being developed to replace CFCs and HCFCs, for uses such as vehicle air conditioning (HFC-134a). HFCs do not deplete ozone, but they are strong greenhouse gases

Hydrochlorofluorocarbons (HCFCs)
HCFCs have become major, “transitional” substitutes for CFCs. They are much less harmful to stratospheric ozone than CFCs are. But HCFCs they still cause some ozone destruction and are potent greenhouse gases. (See HFCs, above.)


Running the vehicle engine, instead of turning it off, when it’s sitting still or parked longer than 10 seconds (e.g., when you’re waiting for someone). Idling is a health risk, wastes fuel and money, contributes unnecessarily to engine wear, and generates needless greenhouse gas (GHG) emissions.

Measuring sticks that track the results achieved by governments, industries and individuals to protect and improve the environment.

Intergovernmental Panel on Climate Change (IPCC)
A panel of over 2,000 climate experts set up by the United Nations and the World Meteorological Organization to review scientific information on climate change. The IPCC provides the Conference of the Parties to the United Nations Framework Convention on Climate Change (UNFCCC) with established scientific information on climate change.

Inventory (Emissions)
A database that lists, by source, the amount of air pollutants — such as greenhouse gases — discharged into the atmosphere over a given time period, such as a year.

Inversion (Temperature Inversion)
A weather condition in which air doesn't rise because it is trapped near the ground by a layer of warmer air above it. The cooler air is heavier and will not move up to mix with the warmer air above. Any pollutants released near the surface will get trapped and build up in the cooler layer of air near the surface. Inversions are very common in British Columbia.


Kyoto Protocol
An international agreement adopted in December 1997 in Kyoto, Japan. The Kyoto Protocol sets binding emission targets for developed countries that would reduce their emissions on average 5.2 percent below 1990 levels.


Written laws, often referred to as acts or statutes, which are enacted by the B.C. Legislative Assembly, the legislative arm of government.


The study of the atmosphere and its weather and climatic conditions.

Mercury is a heavy silvery metal that is liquid at room temperature. Mercury can be highly poisonous when it is inhaled, and ingested or absorbed through the skin.

Methane (CH4)
A colorless, odourless gas. Methane is a powerful greenhouse gas (one of the six major GHGs), mainly released by landfills, cattle farming, rice farming, and oil-and-gas production.

Methyl Chloroform
A nonflammable liquid that is an ozone-depleting substance. It is mainly used as a solvent, paint remover and refrigerant.

Micron (µm)
A millionth of a metre. Also referred to as "micrometre."

Actions that reduce the sources of greenhouse gases, or enhance carbon sinks. Examples include using fossil fuels more efficiently for industrial processes or electricity generation, switching from oil to natural gas as a heating fuel, improving the insulation of buildings, and expanding forests and other sinks to remove greater amounts of carbon dioxide from the atmosphere. (UNFCCC)

Mixing Height
The height to which the lower atmosphere will undergo mechanical or turbulent mixing, producing a nearly homogeneous (uniform) air mass.

Mobile Sources
Mobile sources include on-road motor vehicles primarily involved in the transportation of people and goods, including passenger cars, trucks and motorcycles, and off-road sources including aircraft, marine vessels and railways, off-road vehicles and small off-road engines such as agricultural, lawn and garden, construction, or recreational equipment.

Montreal Protocol on Substances that Deplete the Ozone Layer
An international agreement to end the production of CFCs, halons and other ozone-depleting substances. The protocol has been amended several times, to speed up ODS phaseout dates and to include more types of ozone-depleting substances.

The number of sick persons or cases of disease within a particular population group.

The death rate, the ratio of the number of deaths to a particular population group.


Natural Sources
Sources of emissions that occur in nature without the influence of human beings. They include categories such as wildfires, plants, wildlife and marine aerosols.

A substance naturally formed or produced from nitric acid and a base element. In the context of air pollution, ammonium nitrate is a secondary particle formed in the atmosphere from nitrogen oxides, water vapour and ammonia.

Nitrogen Oxide (NO)
A gas that produces a brownish colour when emitted into the atmosphere before it is oxidized relatively quickly to nitrogen dioxide. It is one of the components of nitrogen oxides and takes part in forming ground-level ozone.

Nitrogen Dioxide (NO2)
A common pollutant along with particles in the air can often be seen as a reddish-brown layer over many urban areas. It causes lung irritation and damage, and environmental impacts.

Nitrogen Oxides (NOx)
A generic term for a group of highly reactive gases containing nitrogen and oxygen. The primary sources are motor vehicles, electric utilities, and other industrial, commercial and residential sources that burn fuels. NOx cause a wide variety of health and environmental impacts, including bronchial congestion and scarring of the lungs. They also react with volatile organic compounds when it’s sunny and warm, producing ground-level ozone.

Nitrous Oxide (N2O)
A colourless gas with a slightly sweet odour (also called "laughing gas"). One of the six major greenhouse gases, nitrous oxide is emitted by chemical fertilizers and burning fossil fuels.

Failure by a regulated party to meet regulatory requirements.

Nonpoint Source
Pollution that comes from many sources, such as motor vehicles, rather than one source, such as an industrial facility.


Air quality objectives (standards) are designed to facilitate air quality management on regional scales. See "Standard."

Odour Index
The Odour Index describes pollutants that present an odour problem, but not a direct health problem at usual concentrations.

Offsets are project-based emission reductions or removals that are used to meet voluntary or regulatory emission reduction obligations. Offset programs usually establish a number of specific eligibility criteria, and often require that offsets be real, quantifiable, verifiable or verified, surplus or additional, permanent and unique.

Open (Outdoor) Burning
The combustion of material with or without control of the combustion air and without a stack or chimney to vent the emitted products of combustion to the atmosphere.

Ozone (O3)
A colorless gas that is formed when pollutants react with sunlight. Ozone is a major part of smog (called "ground-level ozone"), which can make people sick. Ozone is also found in the stratosphere, where it forms a protective band of gases around the earth.

Ozone-Depleting Substances (ODS)
Substances responsible for depletion of the ozone layer in the stratosphere. They primarily contain chlorine, fluorine and/or bromine atoms. ODS include carbon tetrachloride, chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), brominated fluorocarbons (Halons), methyl bromide and methyl chloroform.

These substances are widely used in refrigeration units, insulating foams, as well as cleaning agents, solvents and fire extinguishing agents. The production and use of CFCs have been banned under the Montreal Protocol on Substances that Deplete the Ozone Layer, 1987. Some other substances are being used as transitional substances before their use is phased out because of high global warming potentials.

Ozone Depletion
Thinning (depletion) of the protective “ozone layer,” a fragile band of gases floating in the stratosphere, about 25 kilometres above the earth. This thinning is caused by ozone-depleting chemicals such as chlorofluorocarbons (CFCs), which are released by human activities and products. The ozone layer acts like a giant sunscreen enveloping the earth. It filters out most of the sun's harmful ultraviolet (UV) radiation. Depletion of the ozone layer is allowing more UV rays to reach the earth.


A very small piece or part of something bigger.

Particulate Matter (PM)
(Also referred to as fine particulates and inhalable particulate matter.) Tiny solid or liquid particles that are suspended in air. Particulate matter is produced from a wide variety of sources — natural and human-caused, large and small. They are comprised of directly emitted particles, and secondary particles formed in the atmosphere through interactions of directly emitted pollutants such as sulphur oxides, nitrogen oxides, ammonia, and volatile organic compounds. 

Wood and fossil-fuel burning are the two main human-caused sources. Particulate matter that is 10 microns (micrometres) in diameter or less is called PM10. Of major concern are particles that are 2.5 micrometres or smaller in diameter (PM2.5) because they can lodge deep in the lungs, and cause respiratory and cardiac problems.

Perfluorocarbons (PFCs)
Synthetic industrial gases whose global warming potential is thousands of times that of CO2. PFCs are one of the six major greenhouse gases.

Point Sources
Single, stationary sources of pollution, such as a stack or vent. Point sources are industrial facilities that operate under Ministry of Environment authorization (a permit, approval or regulation), or an air-discharge permit issued by Metro Vancouver.

A plan or course of action to guide decision making and achieve certain outcomes.

Pollution Prevention
A policy concept based on the fact that, “Prevention is often less expensive than after-the-fact measures.”  It is a proactive measure of preventing pollution generation at the outset, instead of cleaning-up after producing air pollutants. 

Polycyclic Aromatic Hydrocarbons (PAHs)
A family of chemicals that come from the burning of wood, fossil fuels, garbage and other materials. PAHs can make breathing more difficult and cause cancer.

Primary Pollutants
Air pollutants generated during various processes and emitted directly from the sources as such.


The receiving medium of an air pollutant, or a location where an air pollutant is measured.

Planting of forests on lands that have recently previously contained forests but that have been converted to some other use. Reforestation can be used to increase the planet's carbon sinks. The Kyoto Protocol limits reforestation to planting forests on lands that have not been forested since 1990.

“Electronic databases that track and record emissions and emission allowance holdings, retirements, cancellations and transfers.” (California Air Resources Board)

A form of law, sometimes referred to as subordinate legislation, which defines the application and enforcement of legislation. Regulations are made under the authority of an act, called an enabling act (e.g., the Environmental Management Act).

Renewable Energy
Energy produced without depleting resources. Renewable energy sources include sun, wind, water, earth and biomass power, and energy from waste.

“A component of the climate system, other than the atmosphere, which has the capacity to store, accumulate, or release” carbon or a greenhouse gas. “Oceans, soils, and forests are examples of reservoirs of carbon.”  (IPCC)

Refers to the lungs and the act of breathing.

The installation of pollution-reduction technology on existing (not new) motor vehicles.

Run of the River
The generation of hydroelectricity using the natural flow and elevation drop of a river.


Secondary Pollutants
Pollutants generated in the atmosphere as a result of chemical reactions involving primary pollutants.

See Carbon Sink.

Smart Growth
An initiative or plan that intends to improve ways in which human settlement occurs for the purpose of reducing impact on the environment, as well as improve quality of life.  Smart-growth initiatives address urban sprawl, motor-vehicle use, environmental integrity, food-system security and affordable housing, among many other topics.

The word “smog” originated in the UK in the mid-20th century to refer to the unique atmospheric condition resulting from a combination of smoke and fog. Smog now refers to the yellow-brown haze that is a mixture of pollutants, mainly ground-level ozone and particulate matter (PM2.5).

A byproduct of combustion. The primary sources of smoke in British Columbia are wood burning, in wood-burning appliances, and such activities as land clearing (open burning) in forestry, agriculture and construction.

Sources of air pollution are identified by the activities that cause emissions. They can be natural or created through human activities. Natural sources include dust and forest fires. Human sources include fossil fuel burning and wood burning.

Solar Energy 
Energy derived from the Sun or sunlight for use as a source of electricity.

A process, activity or operation that releases pollutants, such as greenhouse gases.

(Air quality) levels for specific pollutants that are determined to be necessary to protect human health and/or the environment. It may also be referred to as "air quality criteria" or "guidelines." It usually includes a numeric pollutant concentration, averaging time, rules or guidance on sampling methodology, and how the objectives or standards are to be applied.

The portion of the atmosphere 10-to-40 km above the earth's surface, and the layer above the troposphere.

Stratospheric Ozone Depletion
See "Ozone Depletion."

Sulphur Dioxide (SO2)
A gas released into the atmosphere as a result of the combustion of fossil fuels containing sulphur, as well as production processes using sulphur-containing raw materials, e.g., cement manufacturing and sulphuric-acid production.

Sulphur Oxides (SOx) All forms of oxides of sulphur, such as sulphur dioxide and sulphur trioxide. Sources are the same as those for sulphur dioxide.  These pollutants contribute significantly to particulate matter pollution, visibility degradation, acid rain and global climate change.      

Sulphur Hexafluoride (SF6)
A synthetic industrial gas that is one of the six main greenhouse gases. Its global warming potential is estimated to be 22,200 times that of CO2.


Something that can be poisonous or deadly if it is eaten, touched, or inhaled in large enough amounts.

Part of the atmosphere that extends from the surface up to about 10 km in altitude. Almost all weather takes place in the troposphere as a result of changes of temperature and the movement of air. This process results in efficient mixing of the troposphere.   

An instability in the atmosphere that disrupts the wind flow, causing gusty, unpredictable air currents.


Ultraviolet (UV) Radiation
The portion of the electromagnetic spectrum with wavelengths shorter than visible light. The sun produces UV, which is commonly split into three bands: UV-A, UV-B, and UV-C. UV-A is not absorbed by the ozone layer. UV-B is mostly absorbed by ozone, although some reaches the earth. UV-C is completely absorbed by ozone and normal oxygen. Processes of ozone depletion allow for increased amounts of UV radiation to reach the earth’s surface. Increased UV radiation causes adverse effects on human health, plants, marine ecosystem and materials.

United Nations Framework Convention on Climate Change (UNFCCC)
The UNFCCC was signed in 1992 by over 150 countries and the European Community. Its goal is to stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous human-caused interference with the climate system.


The distance at which an object can be seen. Visibility is reduced by air pollution, so that mountains and other views are blotted out.

Volatile Organic Compounds (VOCs)
Pollutants that can irritate the respiratory tract irritation and cause illness. Some VOCs (e.g. benzene) can cause cancer. VOCs also help form ground-level ozone (O3) by reacting with NOx when it's sunny and warm. The most significant human-caused source of VOC emissions is motor vehicles. Evaporation of gasoline, solvents, oil-based paints, and hydrocarbons from the petrochemical industry are also significant sources.


Wildland Urban Interface
An area where wildland and urbanized areas join or mix.

Wind Power
The generation of electricity through wind turbines and wind mills.