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Human beings need water and air to survive—both supplied by ecosystems. Ecosystems are made up of living organisms (animals, insects, plants, and human beings) that share a physical environment – including water and air – and interact with each other.

Because human beings are part of ecosystems, changes to our water and air systems—often caused by our own activity—can have direct repercussions on our health.

As we become more aware of the impact of human activity on the environment, we can begin to make changes that stop or reduce the deterioration of our water and our air.

Water—the source of life

Freshwater represents only 2.5% of all of the earth's water. According to Environment Canada, 68.9% of the earth's fresh water exists in the form of glaciers and permanent snow cover. Of the total world's freshwatersupply, 30.8% is groundwater, including soil moisture, swamp water and permafrost. Only 0.3% of total global fresh water is stored in lakes and rivers.

Human beings depend on aquatic ecosystems to support our fresh drinking water. We can survive a month without food, but only 5-7 days without water.

Human activity can damage water systems and supply:

• Emissions caused by industrial activity, motor vehicles and airplanes contribute to climate change. One result of climate change is a rise in the temperature of our oceans, lakes, rivers and streams, which makes them more vulnerable to develop Blue-Green Algae (Cyanobacteria) and other microbes.
  
  
• Intensive pesticide use and the discharge of water pollutants, including household wastewater, manure, and toxic chemical products directly into our rivers and streams modify the chemical composition of water.
  
  
• Deforestation and urban growth can reduce the size of wetlands and forest zones that protect us by filtering the number of microbes, chemical substances, and other potentially toxic elements such as heavy metals in our environment.
  
  
• Excessive use of water by industry, agriculture and individuals can lead to water shortages.

Supply and safety of freshwater key to human health

When water quality is compromised by these human activities, it becomes more difficult to disinfect and purify it, thereby raising the risk of diseases such as gastroenteritis and, in warmer climates, cholera. Even in small proportions, many of the chemicals that penetrate water are toxic for human beings.

Air—the breath of life

The air that we breathe makes life on earth possible. Air is a common term for the atmosphere, a complex natural system.

Various human activities affect air quality

Air pollution affects living things in a variety of negative ways:

• Energy production and consumption are the main human activities associated with the emission of pollutants that are harmful to humans (ozone, particles, sulphur dioxide, etc.). They are also the main source of carbon dioxide (CO₂) because of the combustion of fossil fuel (coal, natural gas, or oil).
  
  
• Smog is caused by a variety of sources, including motor vehicles, farming equipment and even wood burning stoves.
  
  
• Indoor air pollution – including mold, volatile organic compounds (VOCs), and carbon monoxide – is caused by microscopic fungi, building materials and certain household changes such as some oven cleaners, hairsprays and second-hand smoke.

Air pollution has a considerable impact on our health

Many human health problems such as asthma, lung cancer, cardiovascular disease, and allergies are associated with air pollution.

Smog contributes to thousands of premature deaths across the country each year. It also results in frequent hospitalisations and many lost work and school days.

How can you make a difference?

Reversing the deterioration of our ecosystems is a major challenge that requires significant changes by individuals and our broader society. The first step is to recognize the collective impact that we have on our environment.

We can protect our water supply

• Reduce water use for non-essential activities such as

  • washing cars or driveways
  • watering the lawn
  • filling pools.

• Let the rain clean your car and water your lawn.
  
  
• Support the construction and use of more community pools for many families.
  
  
• Reduce your use of products that become hazardous waste (e.g. antifreeze, car batteries, propane tanks, fluorescent lights, used oil, oil filters, medication, household batteries, aerosols, solvents, etc.). Avoid pouring toxic products into drains, toilets and sewers.
  
  
• Encourage governments to protect wetlands.

We can improve air quality

• Plant a tree, or two or more and help reduce the amount of CO₂ in the atmosphere… naturally!
  
  
• Use energy efficiently:

  • Use a manual lawnmower.
  • Turn off the TV, the computer or any other appliance not in use.
  • Start the dishwasher only when it is full.
  • Lower the thermostat at night or when you are out of the house.

• Limit the use of your vehicle and avoid idling your engine.
  
  
• Ride your bicycle, walk, or use public transportation.
  
  
• Reduce residential wood burning.

Small actions can make a big difference

Our health depends on the health of the ecosystems around us. We need to recognize the damage that our human activities can cause, and make choices that protect our precious water and air systems. All actions—big and little—count and can make a difference.