The quality of the air is dependent on the rate at which pollutants are emitted into the atmosphere and the ability of the atmosphere to disperse these pollutants. The movement and dispersion of air pollutants is controlled by wind, temperature, turbulence and the changes in these elements caused by local topography (mountains and valleys).
Air pollutants are substances such as carbon monoxide, oxides of nitrogen, ozone, sulphur dioxide, hydrogen sulphide, particulate matter (such as dust and smoke), total hydrocarbons and hydrogen sulphide.
Air pollutants come from many sources. Industrial sources such as energy and manufacturing facilities are considered point sources. Automobiles and residences are considered area sources.
Oxides of Nitrogen (NOx)
Oxides of nitrogen, mostly in the form of nitrogen oxide (NO) and nitrogen dioxide (NO2), are produced by the high temperature combustion of fossil fuels. Nitrogen oxide is the predominant species emitted by combustion sources but it is rapidly changed to nitrogen dioxide in the atmosphere.
Nitrogen dioxide is a reddish-brown gas with a pungent irritating odour. It has been linked to respiratory disease and contributes to acid rain. It plays a major role in atmospheric photochemical reactions and ground level ozone formation and destruction.
Exposure of vegetation to high concentrations of nitrogen oxides results in silvering of the lower leaf surface. A waxy appearance appears shortly after exposure followed by bronzing after two or three days.
Motor vehicles account for over 50% of the total NO2 genetared, however, any combustion source will emit nitrogen dioxide (e.g. power plants, furnaces, space heaters, etc.) Some natural sources include volcanoes, lightning, biological decay, oceans.
What Can We Do?
- Conserve Energy. By reducing your demand on the power generating stations you will help reduce the amount of NO2 emitted. Also, consider finding alternative forms of transportation (eg: walking, biking, public transit, car pooling) or plan your outings in order to minimize your overall travel distance. Do not allow your vehicle to idle for long periods (eg: car starters).
- Support alternative fuels. Utilizing ‘Greenpower’, like wind, and solar power will reduce the amount of NO2 being generated.
- Properly insulate your house and body.
PM10 & PM2.5
Particulate Matter (PM10 and PM2.5) Ambient particulate matter consists of a mixture of particles of varing size and chemical composition. Particles that are less than 10 micrometers in diameter (PM10) can be inhaled. The fraction of particles, which are less than 2.5 micrometers in diameter (PM2.5) can be trapped in the airways and lungs and is believed to cause adverse health effects. Fine particles (PM2.5) also reduce visibility and can contribute to acidification of soils.
PM10 size particles include windblown soil, road dust, and industrial activities. PM2.5 size particles are formed from gases released to the atmosphere by combustion processes such as from motor vehicles, power plants, gas processing plants, compressor stations, household heating, and forest fires. Pollen and bacteria also account for particulate matter.
What Can We Do?
- Stay indoors during periods of known high ambient PM concentrations
- Reduce vehicle use and the use of less-efficient vehicles
- Apply dust suppressants to aid in the control of fugitive dust
- Use proper dust collection at source
- Use of modern farming practices
Guidelines for ambient atmospheric concentrations of PM10 and PM2.5 size particles are under consideration by the Alberta and federal governments. A provisional Canada-Wide Standard has been adopted for PM2.5 of 30 µg/m3, 24-hour averaging time, by the year 2010.
Hydrocarbons (THC, CH4 and NMHC)
The term “total hydrocarbons” (THC) refers to a broad family of chemicals that contain carbon and hydrogen atoms. Methane (CH4), a non-reactive hydrocarbon, is the most common hydrocarbon in the earth’s atmosphere. Specific reactive hydrocarbons or non-methane hydrocarbons (NMHC) can react with oxides of nitrogen in the presence of sunlight to form ozone. Health effects may result at varying concentrations depending on the hydrocarbon. Alberta has ambient air quality objectives for specific hydrocarbons. For more information on Alberta’s Ambient Air Quality Objectives please go to http://environment.alberta.ca/03116.html.
Sources of hydrocarbons include vegetation, vehicle emissions, gasoline marketing and storage tanks, petroleum and chemical industries, dry cleaning, fireplaces, natural gas combustion and aircraft traffic. Hydrocarbons are also emitted by fugitive sources such as evaporation of solvents, or leaking valves, flanges, pumps and compressors at industrial facilities. Incinerator and flare stacks can also be sources of hydrocarbons.
Hydrocarbon concentrations are highest in the winter at monitoring stations located close to major traffic arteries. In downtown Edmonton and Calgary, maximum hydrocarbon values are observed during the morning and afternoon rush hours. Vehicles are the major source of hydrocarbons at urban locations.
Hydrocarbons are monitored continuously by a hydrogen flame ionization detector. When burned, carbon hydrogen bonds break creating ions that conduct an electric current. This current is then measured by an electrometer to give a signal proportional to the number of ions.
Alberta does not have ambient air quality Objectives for hydrocarbons. Many hydrocarbons, such as CH4, are emitted by natural sources. Normal background THC concentrations recorded in rural Alberta range from 1.5 to 2 ppm. Background hydrocarbons are primarily composed of CH4 with a small contribution from NMHC (about 0.2 ppm).
Ground Level Ozone (O3)
Ozone is both a natural component of the atmosphere and a major constituent of photochemical smog. At normal atmospheric concentrations it is an odourless, colorless gas. However, at concentrations higher than one ppm, such as found near photocopier machines and near electrical discharges, it has a sharp odour.
Ozone is considered a secondary pollutant as it is created through reactions with other airborne substances, and can react with other pollutants to form photochemical smog. The largest source is vehicle exhaust; other man-made sources are from industry and chemical solvents. Natural sources include lightning and some vegetation species.
Ozone is a strong oxidizer and can irritate eyes, nose and throat and decrease athletic performance. High concentrations can increase susceptibility to respiratory disease and reduce crop yields.
What Can We Do?
- Reduce the amount of vehicle use.
- Use alternative transportation (car pool, walk, bike, use public transportation)
- Use Alternative fuels (wind & solar).
- Conserve energy. Use ‘muscle power’ rather than fuel powered machines (eg: use rake rather than lawn blower).
Alberta Environment guidelines for ozone are:
- a 1-hour average of 82 ppb
Provincial and federal guidelines are currently under review.
Sulphur Dioxide (SO2)
Sulphur dioxide is generated both naturally and anthropeogenically (man-made), including the processing and combustion of fossil fuels containing sulphur. It is a colourless gas with a pungent odour (similar to a lit match), and can be detected by taste and odour at concentrations as low as 300 ppb.
Sulphur dioxide reacts in the atmosphere to form sulphuric acid and acidic aerosols, which contribute to acid rain (accounts for about 70% of the total acid rain generate). Sulphur dioxide combines with other atmospheric gases to produce fine particles, which may reduce visibility.
Brief exposure to high concentrations of sulphur dioxide and its products can produce human health effects, irritating the upper respiratory tract and aggravating existing cardiac and respiratory disease. Long-term exposure may increase the risk of developing chronic respiratory disease.
What Can We Do?
- Conserve Energy. The best way to reduce the amount of Sulphur Dioxide is to reduce the amount of energy you need, thereby reducing the demand for burning the fuel source. Insulating your home properly, wearing sweaters in the winter, using low energy lighting.
- Support alternative fuels. Natural gas burns cleaner and is more efficient in some processes. Solar, wind and hydrogen power are all great examples of alternative fuel that would result in a reduction of SO2 production.
- Support ‘Emission Scrubbing’ technology. Scrubbers introduce a ‘basic’ compound, usually Calcium Carbonate (Limestone), or Calcium Oxide (Lime) into an effluent stream. The ‘basic’ materials react with the acidic effluent being produced by the process to neutralize the emission and reduce the potential for formation of acid rain.
- Recycle Paper. A source of SO2 is pulp and paper mills, by recycling your paper, you can help save the environment as recycling processes are far less detrimental to the environment. However, reducing and reusing your paper is even more environmentally friendly.
Alberta Environment has adopted the Environment Canada’s most rigorous objectives for sulphur dioxide. The Alberta guidelines for ambient air are:
- 1-hour average of 170 ppb;
- 24-hour average of 60 ppb;
- an annual average of 10 ppb
Table of Human Symptoms and Other Effects
Carbon Monoxide (CO)
Carbon monoxide is a colourless, odourless gas fromed from incomplete fossil fuel combustion. CO is toxic to all humans and animals, and is the most commonly inhaled poisonous substance.
The major source of carbon monoxide is idling automobiles in lcosed areas. Other sources include gas applicances, blocked fireplaces, charcoal grills and smoking.
What Can We Do?
- Reduce the amount of idling of vehicles (warming up time, and use of car starters)
- Use alternative transportation (walk, bike, car pool or use public transportation)
- Use oxygenated gasolines (Ethanol blended gasolines)
- Set your home furnace to a lower temperature, wear sweaters during the winter
- Reduce any drafts in home, or building, during winter months
- Utilize “Green Power” (eg: wind generated and solar)
- Promote use of hydrogen fuel cell technology, solar powered vehicles, and electrical powered vehicles.
- The 1-hour Average Alberta Ambient Air Quality Guideline is 13.0 ppm averaged over a one-hour period
- Currently, there are no 24-hour, or Annual Average Alberta Ambient Air Quality Guidelines
Table of Human Symptoms and Other Effects
Influence of Meteorology
Air quality depends on the rate that pollutants are emitted to the atmosphere and the rate at which these pollutants are dispersed away from the sources. Air pollution transport and dispersion are influenced by wind speed and direction, the temperature structure of the atmosphere, the solar cycle, turbulence, precipitation and changes in these elements induced by local topography.
Precipitation may remove pollutants from the atmosphere, depositing them on soils and vegetation. Rates of deposition of pollutant gases are highest when vegetation and soils are wet. Vegetation is more susceptible to damage during periods of highest growth.
Meteorlogical parameters measured in support of the Calgary Region Airshed Zone air quality monitoring program are:
- wind speed and direction
- difference in temperature a two heights
- solar radiation
- photosynthetically active radiation
- amount of precipitation
- relative humidity
- surface wetness
Precipitation samples are also collected and chemically analyzed for acidity and major constituents.