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A Problem That Hasn’t Gone Away

Here Comes the Rain Again

BY Paul Provost, MSc, National Coordinator, Environmental Protection Programs

As if we didn’t have enough to worry about with the environmental effects of carbon dioxide (CO₂) and methane (CH₄) emissions, which cause the greenhouse effect and climate change; chlorofluorocarbons (CFCs), which cause thinning of the stratospheric ozone layer; and volatile organic compounds (VOCs), which contribute to urban smog. Nitrogen oxides (NO_x) and sulphur oxides (SO_x) are still causing problems of acidification of soil and water bodies. To reduce its contribution to this still unresolved ecological problem, the Correctional Service of Canada (CSC) recently took further steps aimed at reducing the gases responsible for acid precipitation.

Acid Precipitation

Acid precipitation results primarily from the transformation of sulphur dioxide (SO₂) and nitrogen oxides (NO_x) into dry or moist secondary pollutants, such as sulphuric acid and nitric acid. The transformation of SO₂ (a by-product of industrial processes and the burning of fossil fuels) and NO_x (gases generated by fuels used for heating equipment, vehicles, engines and industrial/ institutional boilers) into acidic particles and vapours occurs as these pollutants are transported in the atmosphere over long distances.

According to Environment Canada (EC), the provinces most affected by acid precipitation are Ontario, Quebec, New Brunswick and Nova Scotia because their aquatic and geological characteristics are unable to counter the adverse effects of acid precipitation. In the absence of additional control measures, an area of approximately 800,000 km² in southeastern Canada receives harmful quantities of acid precipitation. Studies have shown that the most serious negative effects include acidified lakes that are no longer able to support the same diversity of life forms as healthy lakes, while prolonged exposure to acid precipitation robs the soil of vital nutrients. Consequently, trees grow more slowly and are less resistant to other sources of stress, such as drought, diseases, insect pests and cold.

Attacking the Problem at the Source

In keeping with target 1.1.2 of its Sustainable Development Strategy, in 2005–06, CSC commissioned Natural Resources Canada’s Energy Technology Applications Group to analyze NO_x emissions, develop technical adjustments for the selected institutional boilers and propose corrective actions based on the data collected. In addition to previous projects with similar aims, the ultimate objective was to improve the efficiency of CSC’s heating plants in the short and medium terms while reducing their NO_x emissions. Visits were made to boilers at the 11 institutions selected, all located in the Quebec City–Windsor corridor and the Fraser Valley in British Columbia, namely Kent, Mission and Matsqui institutions in the Pacific Region; Leclerc, Ste-Anne-des-Plaines, Drummond and Donnacona institutions in Quebec; and Kingston, Bath, Collins Bay and Joyceville institutions in Ontario.

Future Actions

Since the transportation sector is a major source of NO_x emissions, initiatives promoting energy-efficient vehicles will continue to be a priority for the future, as will various energy efficiency measures in institutions. Studies conducted last year confirmed the positive benefits of regularly making the required adjustments to optimize the performance of institutional boilers. However, given the obsolete condition of some of these boilers, especially those located in the Quebec City–Windsor corridor, a number of heating plant renovation projects (including replacing old control systems with new ones and replacing inefficient burners with low-NO_x burners) will have to be carried out if we are to significantly reduce NO_x emissions from boiler rooms at certain CSC institutions.

What Goes Up Must Come Down

In the past, one way of minimizing the problem of air pollution was to build taller industrial stacks. But this “not in M. backyard” approach, which is largely to blame for the emergence of acid rain, is no longer acceptable given the borderless and macro-level environmental effects of the transport and transformation of air pollutants generated by human activities. In fact, the events of the past few decades have demonstrated in many ways that the equilibrium of our thin and precious tropospheric layer is much more fragile than previously thought. It is therefore in everyone’s interest to reduce our atmospheric emissions, since despite the invisible nature of this threat, the effects are, and will continue to be, very real.
For more details: http://www.ec.gc.ca/acidrain/acidfact.html♦