A form of pollution produced when acid compounds formed in the atmosphere are incorporated into rain, snow, fog, or mist. The acid compounds come from sulphur oxides and nitrogen oxides, products of burning coal and other fuels and from certain industrial processes. Acid rain can affect the environment and human health and damages property.

Choosing active modes of transportation, like walking, cycling, or in-line skating.

Air pollution is the presence in the air of any substance that can affect our health or the health of plants and animals or causes damages to property and to our environment. These substances are in large part emitted by human activities but can also have natural origins.

Allergy is the human body’s immune system response to a substance that it has mistakenly identified as harmful, even though others may not experience the substance as harmful. There are different kinds, food allergies, respiratory allergies, and skin allergies. When someone has an extreme allergic response to a substance, it’s called anaphylaxis.

A tiny, thin-walled, capillary-rich sac in the lungs where the exchange of oxygen and carbon dioxide takes place.

Air Quality Health Index developed by Environment Canada is a scale designed to help Canadians understand what the air quality around them means to their health The AQHI communicates a number from 1 and 10+ indicating the quality of the air. The higher the number, the greater the health risk associated with the air quality.

A chronic respiratory disease, often arising from allergies, that is characterized by sudden recurring attacks of laboured breathing, chest constriction, and coughing.

A thin layer of gases surrounding the Earth, composed of 78 percent nitrogen, 21 percent oxygen, 0.9 percent argon, 0.03 percent carbon dioxide, and trace amounts of other gases. There is no exact place where the atmosphere ends; it just gets thinner and thinner, until it merges with outer space.

A colourless, odourless, incombustible gas produced by the incomplete burning of solid, liquid, and gaseous fuels. Appliances fueled with natural gas, liquefied petroleum (LP gas), oil, kerosene, coal, or wood may produce CO2. Burning charcoal produces CO2 and car exhaust contains CO2.

A colourless, odourless, tasteless and highly toxic gas.

Stable, low toxic, and inexpensive chemicals that were most commonly used as refrigerants, solvents, and aerosol propellants. CFCs and their relatives, when released into the air, rise into the stratosphere and take part in chemical reactions that result in reduction or depletion of the stratospheric ozone layer.

The average weather (usually taken over a 30 year period) for a particular region and time period. Elements include precipitation, temperature, humidity, sunshine, wind velocity, and fog, frost and hail storms.

Greenhouse gases such as carbon dioxide, methane, nitrous oxide and chlorofluorocarbons help trap the Earth’s radiant heat, keeping our lower atmosphere warm. The majority of scientists believe that the increased production of these gases contributes to climate change.

There are seven air pollutants that are considered Criteria Air Contaminants (CAC) that are emitted predominantly to the air. The seven contaminants are Total Particulate Matter, Particulate Matter with a diameter less than 10 microns, Particulate Matter with a diameter less than 2.5 microns, Carbon Monoxide, Nitrogen Oxide, Sulphur Dioxide, and Volatile Organic Compounds. A brief description of each CAC is provided in this glossary.

When many trees are cleared from a large area.

Gases, particles, and materials released or emitted into the environment often due to combustion or burning of a fuel. http://www.nesea.org/education/gscleanenergy/glossary.htm

Endangered species are those listed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as "facing imminent extinction or extirpation."

The ability to do work. Energy is never created or lost but only changed from one form to another.

The living things, soil, air, climate and other factors that surround us.

Fossil fuels are the non-renewable remains of plant and animal life that are used to provide energy by combustion; coal, oil, natural gas.

A large body of ice moving slowly down a slope or valley or spreading outward on a land surface.

An increase in the average temperature of the Earth’s surface because of an increase in air emissions and greenhouse gases that trap heat in the Earth’s atmosphere.

A natural phenomenon whereby clouds and greenhouse gases, such as water vapour and carbon dioxide, trap some of the Sun’s heat in the atmosphere. The greenhouse effect helps regulate the temperature of the Earth. Human activities are adding greenhouse gases to the natural mix.

Greenhouse gases are gases that absorb and trap heat in the atmosphere and cause a warming effect on earth. Some occur naturally in the atmosphere, while others result from human activities. Greenhouse gases include carbon dioxide, water vapor, methane, nitrous oxide, ozone, chlorofluorocarbons, hydrofluorocarbons and perfluorocarbons. http://www.ec.gc.ca/default.asp?Lang=En&n=7EBE5C5A-1

Created on hot sunny days when there are lots of Nitrogen oxides and Volatile organic compounds mixing with sunlight. Ground Level Ozone is also a main component of smog.

A cyclone formed in the tropics by winds of 117 kilometres per hour or greater usually accompanied by rain, thunder and lightning.

Power obtained from the natural movement of masses of water.

The most fatal form of skin cancer. Malignant melanomas may appear suddenly without warning as a dark mole or other dark spot on the skin and can spread quickly.

Methane (CH4) is a greenhouse gas that remains in the atmosphere for approximately 9-15 years. It is an odourless, flammable gas that consists of carbon and hydrogen and is over 20 times more effective in trapping heat in the atmosphere than carbon dioxide (CO2) over a 100-year period and is emitted from a variety of natural and human-influenced sources. Human-influenced sources include landfills, natural gas and petroleum systems, agricultural activities, coal mining, stationary and mobile combustion, wastewater treatment, and certain industrial process. http://www.epa.gov/methane/

An organism of microscopic or submicroscopic size, especially a bacterium or protozoan.

A brownish to yellowish poisonous gas that is used especially in making nitric acid and is an air pollutant formed from automobile exhausts.

A criteria air contaminant. Nitrogen oxides are produced from burning fuels, including gasoline and coal, and react with volatile organic compounds to form smog. Nitrogen oxides are also major components of acid rain.

A long-lived greenhouse gas with emissions created by agricultural practices, and industrial productions such as in the making of nylon.

Nuclear energy regarded as a source of electricity for the power grid.

An ozone molecule consists of three oxygen atoms. Stratospheric ozone shields the Earth against harmful rays from the sun, particularly ultraviolet B. Ground-level ozone contributes to smog.

The ozone layer is damaged when substances such as chlorofluorocarbons accelerate the natural process of destruction and regeneration of stratospheric ozone. As the ozone layer breaks down, it absorbs smaller amounts of UV radiation, allowing more of it to reach the Earth.

A layer of gas (three atoms of oxygen) in the upper atmosphere that acts as a natural filter blocking harmful UV rays from the sun.

A criteria air contaminant. Particulate matter includes dust, soot, and other tiny bits of solid materials that are released into and move around in the air.

All leisure and non-leisure body movement produced by the skeletal muscles and resulting in an increase in energy expenditure.

A disease affecting the respiratory system (breathing).

A mixture of pollutants, principally ground-level ozone, produced by chemical reactions in the air involving smog-forming chemicals. A major portion of smog-formers come from burning of petroleum- based fuels such as gasoline. Major smog occurrences are often linked to heavy motor vehicle traffic, sunshine, high temperatures, and calm winds or temperature inversion (weather condition in which warm air is trapped close to the ground instead of rising).

A renewable energy source that arises from the conversion of solar radiation into heat or electricity.

The stratosphere starts just above the troposphere and extends to 50 kilometres high. The temperature in this region increases gradually to -3 degrees Celsius, due to the absorption of ultraviolet radiation. The ozone layer, which absorbs and scatters the solar ultraviolet radiation, is in this layer. Ninety-nine percent of air is located in the troposphere and stratosphere.

A bluish gas composed of three oxygen atoms. Natural processes destroy and regenerate ozone in the atmosphere. When ozone-depleting substances such as chlorofluorocarbons accelerate the destruction of ozone, there is less ozone to block UV radiation from the sun, allowing more UV radiation to reach the Earth.

A criteria air contaminant. Sulphur dioxide is a gas produced by burning coal, most notably in power plants. Sulphur dioxide plays an important role in the production of acid rain.

A substance, usually a lotion that you can apply to protect your skin from UV radiation. It works by reflecting UV radiation away from your skin in addition to absorbing UV radiation before it can penetrate your skin.

Involves the combustion of primarily fossil fuels, but also biomass, to vapourize water as it passes through a boiler. The vapour passes through a turbine, where it expands to a lower pressure causing the shaft to rotate. The turbine shaft is connected to an electrical generator.

A violent destructive whirling wind accompanied by a funnel-shaped cloud that moves in a narrow path over the land.

The roads and equipment necessary for the movement of passengers or goods.

The troposphere is the lowest region in the Earth’s (or any planet’s) atmosphere, starting at ground (or water) level up and reaching to about 17 kilometres high. The weather and clouds occur in the troposphere.

A type of sunlight. Ultraviolet B exposure has been associated with skin cancer, eye cataracts, and damage to the environment. The ozone in the stratosphere, high above the Earth, filters out ultraviolet B rays and keeps them from reaching the Earth. Thinning of the ozone layer in the stratosphere results in increased amounts of ultraviolet B reaching the Earth.

Heat islands develop in cities as naturally vegetated surfaces are replaced with asphalt, concrete, rooftops and other manufactured materials. The artificial materials store much of the sun's energy and remain hot long after sunset. This produces a dome of elevated temperatures over a city that is significantly higher than air temperatures over adjacent rural or suburban areas.

A tool that predicts the next day’s UV intensity on a scale from 0 to 10+, helping people determine appropriate sun-protective behaviours.

A portion of the electromagnetic spectrum with wavelengths shorter than visible light. UV radiation produced by the sun is responsible for sunburn and other adverse health effects. Scientists classify UV radiation into three types: UVA, UVB, and UVC.

Chemicals that produce vapours readily at room temperature and normal atmospheric pressure, so that vapours escape easily from volatile liquid chemicals. Organic chemicals all contain the element carbon and are the basic chemicals found both in living things and in products derived from living things, such as coal, petroleum and refined petroleum products. Many volatile organic chemicals are also hazardous air pollutants.