Parameters

Sulphur dioxide is generated both naturally and anthropogenically (human-made), including the processing and combustion of fossil fuels containing sulphur. It is a colourless gas with a pungent odour (like a lit match) and can be detected by taste and odour at concentrations as low as 300 ppb. Sulphur dioxide (SO₂) reacts in the atmosphere to form sulphuric acid and acidic aerosols, which contribute to acid rain. SO₂combines 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. People with asthma may have increased symptoms such as chest tightness and difficulty breathing.

Ground-level ozone is formed by photochemical reactions in the atmosphere. It mainly comes from vehicle and industrial emissions in urban centres. It can be a major component of smog during the summer, especially during hot sunny weather, and is generally low in the winter. Ozone (O₃) can be transported long distances and can be responsible for large regional air pollution episodes.

People most at risk from exposure to higher levels of O₃ include those with asthma, children, older adults and those who are active outdoors, especially outdoor workers. Children are at greatest risk because their lungs are still developing. High levels of O₃ can cause the muscles in the airways to constrict, trapping air inside the tiny air sacs within the lungs (alveoli). This can lead to wheezing, shortness of breath and can be serious in people with lung diseases such as asthma.

Nitrogen oxides, mostly in the form of nitric oxide (NO) and nitrogen dioxide (NO₂), are produced by high temperature combustion of fossil fuels. Nitrogen oxide is the predominant pollutant emitted by combustion sources, but it is rapidly changed to nitrogen dioxide in the atmosphere. NOx contributes to acid rain and plays a major role in atmospheric photochemical reactions and ground level ozone formation and destruction. Oil and gas activities and transportation account for approximately 85% of the nitrogen emissions in Alberta; however, any combustion source will emit nitrogen dioxide (e.g. power plants, furnaces, space heaters). Some natural sources include volcanoes, lightning, biological decay, and oceans.

NO₂ has been linked to respiratory disease. Short-term exposure to NO₂ can cause airway inflammation. Individuals with pre-existing conditions such as asthma, chronic obstructive pulmonary disorder (COPD), and chronic bronchitis can be more sensitive to exposure.

Total reduced sulphur includes hydrogen sulphide (H₂S), mercaptans, dimethyl sulphide, dimethyl disulphide and other sulphur compounds. Sources include fugitive emissions from petroleum refineries, tank farms for unrefined petroleum products, natural gas plants, petrochemical plants, oil sands facilities, sewage treatment facilities, pulp and paper operations that use the kraft pulp process, and animal feed lots.

Health concerns related to exposure to TRS can include respiratory symptoms, decreased pulmonary function test results, and increases in pulmonary disease.

Carbon monoxide is a colourless, odourless gas emitted into the atmosphere primarily from incomplete combustion of carbon-based fuels such as gasoline, oil, and wood. Natural and human sources of carbon monoxide include burning of vegetation such as forest fires and wildfires, and emissions from vehicles.

Breathing carbon monoxide decreases the amount of oxygen carried by the blood stream and can have serious health effects.

Total Hydrocarbons are divided into two broad categories: “non-reactive” and “reactive” hydrocarbons. The major non-reactive hydrocarbon in the atmosphere is methane, which is a naturally occurring colourless, odourless gas recognized as a major contributor to the greenhouse effect. Reactive hydrocarbons consist of many volatile organic compounds, some of which react with oxides of nitrogen in the atmosphere to form ozone. They generally occur at much lower concentrations than methane. Trees and plants are major natural emitters of reactive hydrocarbons and large amounts of methane are produced naturally through the decay of vegetation. Other significant sources include motor vehicles, petroleum refineries, petrochemical plants, chemical solvents, and combustion from burning coal, gas, and wood.

Health effects from long-term or chronic exposure to petroleum hydrocarbons are known to cause decreased immune function, breathing problems, severe kidney, and liver damage.

Ambient particulate matter consists of a mixture of particles of varying size and chemical composition. Particles that are less than 10 micrometers in diameter (PM₁₀) can include windblown soil, road dust, and particles from industrial activities. Fine particles which are less than 2.5 micrometers in diameter (PM_2.5) can reduce visibility and contribute to acidification of soils. PM_2.5 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. Particulate matter can also be comprised of biological material such as mold, bacteria, and pollen fragments.

Fine particles are small enough to enter the lungs and can be a human health concern. PM_2.5has been linked to many health issues. Long-term exposure has been associated with increased lung and heart problems and even premature death.

Meteorological parameters measured are:

wind speed and direction
temperature
relative humidity

WCAS monitors 8 air quality parameters in our airshed region.

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