Chemistry of the atmosphere

• The Proportion of Gases in the Earth's Atmosphere

  A) Argon 1%

  B) CO2 0.04%

  C) O2 21%

  D) Nitrogen 78%

  
• 2 largest proportions in the earth's atmosphere:

  Oxygen

  nitrogen
• For the 1st billion years the earths surface was covered with highly active volcanoes. These eruptions released a lot of CO2 and small amounts of water vapour, ammonia, nitrogen and methane.
• CO2 dominated the early atmosphere
• The water vapour in the early atmosphere condensed to form the oceans.
• • The atmospheric concentration of carbon dioxide decreases as it begins dissolving in the oceans
• Photosynthesis increased the atmospheric concentration of oxygen.
• Algae were the first photosynthetic organisms to evolve on Earth.
• At least 3 factors caused atmospheric carbon dioxide to decrease:

  Oceans

  Photosynthesis

  Marine Animals
• Greenhouse gases cause the greenhouse effect. This helps keep the Earth warm enough for life. But, the greenhouse effect can cause global warming if it's too strong.
• Greenhouse gases:

  CO2

  methane

  Water vapour
• Certain human activities cause the atmospheric concentrations of greenhouse gases to increase:

  Burning Fossil fuels

  Agriculture

  Deforestation

  Landfill sites
• Farm animals release methane during digestion.
• Mounds of waste in land fills sites decompose which releases methane.
• Deforestation causes less trees to absorb CO2 from the air so there are more greenhouse gases in the atmosphere.
• Burning fossil fuels releases carbon dioxide which has been stored away for millions of years.
• Greenhouse gases can't absorb the short-wavelength radiation emitted by the Sun, but they can absorb the reflected radiation. The gases re-radiate this as heat energy, some of which leads back to Earth.
• There is some evidence that increased greenhouse gas emissions caused by human activity will lead to global climate change.
• There is misinformation about whether or not greenhouse gases are related to climate change. This is because the global climate system makes it difficult to create accurate models.
• Consequences of climate change:

  Ice caps melting

  More frequent weather conditions- heatwaves, droughts

  Changes in water availability

  food shortages

  Changes in precipitation
• A carbon footprint is a measure of the total amount of greenhouse gases emitted as a result of a particular service, product or event.
• Carbon-neutral products don't change the amount of carbon dioxide in the atmosphere
• We can reduce our carbon footprint by planting more trees, using renewable energy sources and minimising waste
• Economic barriers to reducing carbon footprints are particularly prevalent in developing countries.
• Developing countries often have lower levels of education so people might not understand how important it is to take action against climate change.
• Incomplete combustion of fossil fuels produces carbon monoxide (a toxic gas) and particulates (small solid particles made up of carbon and unburnt fuel)
• Sulfur is an impurity that is present in all fossil fuels. When burnt it oxidises creating the toxic gas sulfur dioxide.
• The internal combustion in cars cause nitrogen oxides to be released into the atmosphere
• Common atmospheric pollutants from fossil fuels

  Nitrogen oxides

  Sulfur dioxide

  Carbon monoxide

  Carbon dioxide

  Particulates
• Acid rain occurs when sulfur dioxide reacts with water vapour in the air, forming sulfurous acid which falls as acid rain. Acid rain can damage buildings and crops. Nitric acid can also cause acid rain.
• Particulates ,sulfur dioxide and nitrogen oxides cause respiratory problems