Science and Technology Corner – Environmental Health

March 5, 2003

Environmental health is an issue of considerable concern to everyone these days. The nightly news is filled with stories of environmental disasters and warnings from scientists about the risks of pollution to our air, land and water. In political elections, the environment has become a significant topic on which each candidate is expected to comment. Nevertheless, many people still don’t know as much about the issue as they need to, and many of the terms used in environmental discussions may not be clearly understood. Below is an exploration of many of these terms, and some of the effects that environmental pollution can have on human health.


Our atmosphere is made up of 78% nitrogen, 20% oxygen and a mixture of gases which includes carbon-dioxide, methane, nitrous oxide and ozone. These gases are present in the atmosphere naturally and produce what is called the greenhouse effect, which helps to keep the earth’s temperature optimal for the existence of life. Due to recent increases human activity, however, levels of these gases have increased considerably, causing more of the sun’s energy to reflect back to earth and hence resulting in Global Warming.

There is difference between global warming and climate change. Climate is the average weather of a particular location whereas global warming is a change in the overall climate of the earth. Global warming can raise global temperatures but effects may vary from region to region and in different parts of world. It can cause lower water levels in lakes creating drought conditions, but it can also cause extreme flooding for the 50% of the world’s population who live along ocean coastlines, in areas like Bangladesh [Environment Canada].


“¢ Toxic contaminants;
“¢ Green house gases;
“¢ Persistent organic pollutants;
“¢ Mercury;
“¢ Ozone.


We need clean air to live healthy lives. When air becomes polluted, people become sick and health care costs rise. In fact, the Ontario Medical Association says that toxic pollutants in the air cost Ontario $1 billion alone each year for “hospital admissions, emergency room visits and absenteeism.”

According to the Toronto Public Health department “Air pollution causes hundreds of premature deaths a year and numerous health related problems.”


Smog: Smog is a combination of air pollutants. It is mainly composed of ground level ozone and fine air-borne particles. It looks like a haze in the air and can make people susceptible to heart and lung diseases.

Acid Rain: Acid rain forms when carbon-dioxide and chlorine gas react with the moisture in the atmosphere. It is called acid rain due to its pH level of below 5. During the burning process of fossil fuels, sulphur dioxide and nitrogen oxides release as air pollutants. These pollutants also contribute to the formation of acid rain. Acid rain effects soil, water, plants, forests, and human beings. “The more acidic a lake becomes, the fewer species it can support” [Environment Canada]. Sulphate particles in acid rain are also bad for human lungs.

Ground-level Ozone: This is a colourless, irritating gas which forms when nitrogen oxides and volatile organic compounds react together. About 95% of nitrogen oxides are produced by the following human activities [Environment Canada: Clean Air]:
“¢ Burning of coal
“¢ Gas and oil use in motor vehicles
“¢ Gasoline combustion
“¢ Evaporation of solvents

Ozone not only affects human health, it can damage vegetation and decrease the productivity of some crops.


We are surrounded by water in oceans, lakes, seas and other forms, which covers 75% of the earth’s surface. We use water in our daily life activities ranging from drinking and irrigating crops to filling pools and washing our cars. Today our water reserves (drinking water, ground and surface water and wetlands) face several threats in the form of ocean dumping, marine discharge, and vessel discharges.

Drinking Water – How Do We Measure Water Quality?

Drinking Water Quality is defined by taste, clarity, odour and other properties such as the absence of harmful and hazardous materials. To identify the substances in water there are different instruments used such as a plasma emission spectrometer (to detect metals) and gas chromatograph-mass spectrometer (to analyze the presence of pesticides and other organic compounds).

Surface And Groundwater Quality

“The eventual quality of the ground water depends on temperature and pressure conditions [and] on the kinds of rock and soil formations through which the water flows” (Environment Canada: Groundwater). Hardness, salinity and pH (a measure of acidity or alkalinity) are the factors that determine the possible future uses of water. Ground water is naturally filtered. This filtering happens when it flows through an aquifer, and it ensures that this water is free from disease causing micro-organisms. Ground water usually contains less suspended and undissolved solids compared to surface water.


Oil spills: Oil spills kill not only marine life but can also destroy water desalination plants. There are laws which require that any discharge of a pollutant from a municipal or industrial facility must be covered by a permit of pollutant discharge elimination systems. Vessel discharges from recreational, military and commercial fleets destroy coastal and ocean ecosystems.

Poor management of existing water resources: Overuse of water resources can shrink the water supply as is already happening in the Aral and North seas. We can stop this shrinkage by protecting and enhancing the quality of the water resources and promoting the wise and efficient management and use of water

Toxic substances in the food chain: Toxic substances from industries, agriculture and domestic use are the major contributors of water pollutants. Major pollutants are PCBs, mercury, petroleum and pesticides. Excess nutrients such as nitrogen and phosphorous come from sewage and farm run-offs , and sedimentation of some of these elements can also cause a breakdown in the food chain by killing fish.

Sedimentation: Human activities like forestry, farming and construction lead to the excess depositing of solid particles in water, which kills aquatic life forms.


Prevention: It took years to contaminate our world, now it will take time and effort to clean up the mess. Prevention will not occur in a day but we surely can contribute something every day to accelerate this process. We can start working toward prevention by looking at factors causing pollution and then find ways to minimize the use of those factors by substituting less toxic items or by completely eliminating them.


Kyoto Protocol: According to David Suzuki, “The Kyoto Protocol is the only international agreement that sets targets to reduce the greenhouse gas emissions causing climate change.”

In December 2002, the Government of Canada ratified the Kyoto Protocol on Global Warming, which is another step toward a cleaner and safer environment. There are other laws which enforce environmental controls, such as:

The Canadian Environmental Protection Act Part 10 Enforcement (Sections 216-312), which “authorises enforcement officers to issue environmental protection compliance orders on the spot to stop illegal activity and to correct violations.”

And there are also initiatives which encourage voluntary pollution reduction, such as Environment Canada’s Pollution Prevention (P2) program. Below are some examples of how the Material and Feedstock Substitution program can be put into effect to reduce environmental harm:

Benefits of Pollution Prevention: Pollution prevention is not only a government responsibility. We should all work together toward our safe and healthy futures. Here are the some benefits we can achieve collectively – not only for us but for our future generations:

“¢ By avoiding or minimizing the use of pollutants will contribute toward a safe and healthy environment.

“¢ Our collective efforts directed towards the elimination of pollutants will stop transferring them from one place to another.

“¢ Promotion of pollution prevention technologies at every stage of life ensures the acceleration of not only clean-ups but also minimizing their use also.

“¢ Energy, raw materials and natural resources must be used with high efficiency, which means that future costly clean-ups of oil spills and hazardous gases leakage will be less.

Information on environmental health adapted from:

Environment Canada: Great Art for Great Lakes

Environment Canada: Clean Air

Environment Canada: Water quality

Toronto Public Health Department:

David Suzuki Organization: Climate Change

The Canadian Environmental Protection Act Part 10 Enforcement (Sections 216-312)

P2 Material and feedstock substitution: