Lesson 1: Changes to the air
AIMS:
- Identify some of the major causes of air quality change
- Look at managing air quality around the world.
- Make predictions for future air quality with use of reasoning
Degrading the atmosphere
The layer of gases that surrounds the Earth – known as the atmosphere – is being degraded in many ways. Pollutants such as carbon, nitrogen and sulphur released into the atmosphere from factories and transport are disturbing the natural balance of gases that form the atmosphere. This change in the composition of the atmosphere, together with a reduction in forest cover, is responsible for an increase in global temperatures and changes in our climate.
Facts about air quality
Air pollution is considered to be one of the world's greatest environmental health risks to date. Global it has been said to lead to:
increased rates of asthma, increased lung and heart disease. It is estimated that more than 3.5 million people around the world die each year from outdoor air pollution (see Source 1). This is largely the result of breathing air with high concentrations of fine particles from traffic exhaust, factory and power plant emissions, and fires. Another 4.3 million deaths each year are the result of indoor air pollution. These are largely due to fuels such as coal and dried animal waste that are burned indoors for heating and cooking (mainly in developing countries).
Reasoning for decline in air quality
In many countries across the developing world, air quality is actually getting worse. This is particularly true of countries in Asia and Africa. In these countries, the number of deaths each year from air pollution is increasing. This is due mainly to the rapid growth and expansion of cities. As these cities grow, the demand for cheap energy increases. Currently, the cheapest and most reliable source of energy in these countries comes from burning fossil fuels such as coal and oil. Measurements of air quality show that 98 per cent of cities in the developing world have rates of air pollution that exceed safe guidelines.
Air pollution is considered to be one of the world's greatest environmental health risks to date. Global it has been said to lead to:
increased rates of asthma, increased lung and heart disease. It is estimated that more than 3.5 million people around the world die each year from outdoor air pollution (see Source 1). This is largely the result of breathing air with high concentrations of fine particles from traffic exhaust, factory and power plant emissions, and fires. Another 4.3 million deaths each year are the result of indoor air pollution. These are largely due to fuels such as coal and dried animal waste that are burned indoors for heating and cooking (mainly in developing countries).
Reasoning for decline in air quality
In many countries across the developing world, air quality is actually getting worse. This is particularly true of countries in Asia and Africa. In these countries, the number of deaths each year from air pollution is increasing. This is due mainly to the rapid growth and expansion of cities. As these cities grow, the demand for cheap energy increases. Currently, the cheapest and most reliable source of energy in these countries comes from burning fossil fuels such as coal and oil. Measurements of air quality show that 98 per cent of cities in the developing world have rates of air pollution that exceed safe guidelines.
Recovering the air quality - Good news about the Ozone
Around 10 kilometres above the surface of the Earth
sits a concentration of ozone – molecules that contain three atoms of oxygen. This region of the atmosphere is known as the ozone layer. The ozone layer shields the Earth and its inhabitants from much of the Sun’s ultraviolet radiation. Exposure to this radiation is linked to increased rates of cancer, especially skin cancer, as well as lower productivity of plants. The number of ozone molecules in the ozone layer is constantly changing, but in the 1970s scientists recorded a steady decline of ozone (particularly in an area above Antarctica). Known as the ozone hole, this reduction of molecules was linked to the release of chemicals into the atmosphere from aerosol cans and refrigerators. In 1987, an international agreement banned the use of these chemicals in an attempt to stop the ozone hole from increasing in size. In recent years, there are signs that the ozone layer is beginning to recover. It is now expected that it will return to 1980 levels by 2070. The Secretary-General of the United Nations referred to this agreement as ‘perhaps the single most successful international agreement to date’. Questions
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