Q: What is Ambient Air Monitoring?

  • A: According to the US Environmental Protection Agency, ambient air is the portion of the atmosphere, external to buildings, to which the general public has access. Ambient Air Quality affects everyone everywhere. Whether it is agricultural dust, pollution from vehicles, or smog from major industry, ambient air can have major effects on the health of individuals.

Over the past several years, EnviroMed has worked closely with various clients in developing their Ambient Air Monitoring Programs to ensure compliance with regulatory bodies.

Monitoring programs at various industrial sites may continuously monitor air pollution levels associated with day-to-day operations to ensure compliance with Government's air pollution regulations. Daily dial-in to sites for equipment monitoring, data acquisition, analytical instruments status, and computer-based resources are all modern techniques employed for ambient air monitoring.

As well as client-operated sites, government-operated ambient monitoring stations are also commonly deployed at various sites around the country. For example, the National Air Pollution Surveillance (NAPS) Network was established in 1969 as a joint program of the federal and provincial governments to monitor and assess the quality of the ambient air in Canadian urban centres.

Air quality data for sulfur dioxide (SO2), carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3) and total suspended particulates (TSP) are measured at over 152 stations in 55 cities in the ten provinces and two territories. Various statistics derived from the measurements and comparisons with the National Air Quality Objectives prescribed under the Canadian Environmental Protection Act are published in annual data reports.

Some ambient air pollutants that are commonly monitored include SO2, NO2, Particulate, Ozone, H2S, others:

  • Sulfur dioxide, or SO2, belongs to the family of sulfur oxide gases (SOx). These gases dissolve easily in water. Sulfur is prevalent in all raw materials, including crude oil, coal, and ore that contains common metals like aluminum, copper, zinc, lead, and iron. SOx gases are formed when fuel containing sulfur, such as coal and oil, is burned, and when gasoline is extracted from oil, or metals are extracted from ore. SO2 dissolves in water vapor to form acid, and interacts with other gases and particles in the air to form sulfates and other products that can be harmful to people and their environment. SO2 causes a wide variety of health and environmental impacts because of the way it reacts with other substances in the air. Particularly sensitive groups include people with asthma who are active outdoors and children, the elderly, and people with heart or lung disease.

  • SO2 in the air can cause
    • Respiratory illness and aggravate existing heart disease
    • Smog
    • Acid Rain, which damages forests crops, soil, and fish habitat in lakes and streams
    • Accelerated decay of building materials and paints

  • Ozone (O3) is a gas composed of three oxygen atoms. It is not usually emitted directly into the air, but at ground-level is created by a chemical reaction between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of sunlight. Ozone has the same chemical structure whether it occurs miles above the earth or at ground-level and can be "good" or "bad," depending on its location in the atmosphere. In the earth's lower atmosphere, ground-level ozone is considered "bad." Motor vehicle exhaust and industrial emissions, gasoline vapors, and chemical solvents as well as natural sources emit NOx and VOC that help form ozone. Ground-level ozone is the primary constituent of smog. Sunlight and hot weather cause ground-level ozone to form in harmful concentrations in the air. As a result, it is known as a summertime air pollutant. Many urban areas tend to have high levels of "bad" ozone, but even rural areas are also subject to increased ozone levels because wind carries ozone and pollutants that form it hundreds of miles away from their original sources.

  • Particulate Matter, also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets. Particle pollution is made up of a number of components, including acids (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles.

The size of particles is directly linked to their potential for causing health problems. Fine particles, are unhealthy to breathe and have been associated with premature mortality and other serious health effects. Fine particles such as those found in smoke and haze, are 2.5 micrometers in diameter and smaller, and are also referred to as PM2.5. These particles can be directly emitted from sources such as forest fires, or they can form when gases emitted from power plants, industries and automobiles react in the air.

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