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The Environment and Human Health

The Environment and Human Health. Air Pollution. What is smog? Smog is a mixture of pollutants with ground-level ozone as the main component. Ground-level ozone is formed when nitrogen oxides and volatile organic compounds interact in the presence of sunlight.

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The Environment and Human Health

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  1. The Environment and Human Health

  2. Air Pollution What is smog? • Smog is a mixture of pollutants with ground-level ozone as the main component. • Ground-level ozone is formed when nitrogen oxides and volatile organic compounds interact in the presence of sunlight. • High up in the stratosphere, ozone protects the earth from harmful ultraviolet rays, but at ground level, it can be a harmful air pollutant.

  3. Smog • About 95 per cent of nitrogen oxides that lead to the formation of smog, are produced when we burn fuels in our cars and trucks, or generate energy using combustion engines, combustion turbines, industrial boilers and power plants.

  4. Smog in Hangzhou, China

  5. Smog and Human Health • Smog can irritate the eyes, nose and throat. It can also worsen existing heart and lung problems. In exceptional cases it may result in an early death. • The people most at risk are those who suffer from heart and lung problems. Many of these problems are more common in seniors, making them more likely to experience the negative effects of air pollution.

  6. Smog and Human Health • Children can be more sensitive to the effects of air pollution because their respiratory systems are still developing and they tend to have an active lifestyle. Even healthy young adults breathe less well on days when the air is heavily polluted. • 21,000 Canadians die each year as a result of poor air quality.

  7. Automobiles and Pollution • In one year, a new 2001 model small car, traveling the average 12,513.2 miles per year, getting 28.7 miles to the gallon, using 436 gallons/year, spews into the air we breathe: • 8,725 lbs of carbon dioxide (CO2) • 193 lbs of carbon monoxide (CO) • 5.7 lbs of hydrocarbons • 18 lbs of nitrogen oxide (NOx) • Smaller amounts of benzene, formaldehyde, volatile organic compounds, and other toxic materials. • Larger vehicles, like popular sport utility vehicles (SUVs), can produce more than twice as much pollution as a small car.

  8. Ozone Depletion

  9. The Ozone Layer • The ozone layer is one of the keys to the survival of life on the planet. A natural layer of ozone molecules absorbs 93-99% of the Ultraviolet (UV) radiation emitted by the sun that would be harmful to us.

  10. Ozone Depletion • Chlorofluorocarbons • CFCs are released into the atmosphere by spray cans, discarded or leaking refrigeration and air conditioning equipment, and the burning plastic foam products. • Recently, there has been much greater attention to their affects, and they have been banned in some countries under the Montreal Protocol in 1978.

  11. Ozone Depletion • CFCs react with sunlight when they reach the stratosphere, where the are broken down and release chlorine molecules. • These chlorine molecules bond and break apart ozone (O3) and oxygen (O2) molecules. This leaves the layer depleted, allowing increased UV radiation to reach the surface.

  12. The “Ozone Hole”

  13. Consequences of Ozone Depletion • UV Radiation can be a major cause for skin cancer and cataracts for humans. • It is speculated that increased radiation would lead to greater incidences of malaria and other diseases. • Certain crop types, including rice would be negatively affected by increased UV radiation.

  14. Pesticides and Human Health

  15. Pesticides • Pesticides are chemicals used to protect plants from pests (insects and weeds) and help them grow. • These chemicals often leave residues that can impact plants and animals upwards through the food chain. • Certain pesticides have been made illegal in many countries (ie. DDT) but other chemicals are still widely used.

  16. Pesticide Issues • The main concerns stemming from pesticides come from biomagnification and groundwater contamination. • Many plants we consume are regularly sprayed. • Apples commonly are sprayed with 36 chemicals over 16 sprayings. • A study showed that 37% of apples had chemical residues as a result of pesticides.

  17. Bhopal, India • The negative affects of pesticide manufacturing became clearly visible to the world in 1984 following the events that occurred in Bhopal India. • Due to a chemical leak at the Union Carbide Pesticide Plant, the city was engulfed with a cloud of toxic chemicals, killing nearly 20,000 overnight. • These chemicals continue to leak into the groundwater and affect the city today. • http://www.youtube.com/watch?v=Xz-BfXLjQ9c

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