Chemistry of the atmosphere

• Evolution of the atmosphere phase 1 - earth formed 4.6 billion years ago, surface covered in volcanoes releasing lots of carbon dioxide, nitrogen, methane, ammonia and small amounts of water vapour (virtually no oxygen)
• • Evolution of the atmosphere phase 2 (locking up carbon) - water vapour condensed with natural temperature decrease forming oceans, carbon dioxide dissolved in oceans and went through a series of reactions to form carbon precipitates that formed sediments on the sea bed, some early marine animals evolved and formed shells and skeletons from the carbonates in the ocean, green and algae taking up carbon dioxide for photosynthesis
• • Locking up carbon in the early atmosphere, fossil fuels - plants, plankton and marine animals die, fall to sea bed and get buried by layers of sediment, over millions of years they become compressed under lots of pressure ad form sedimentary rock(coal), oil and gas e.g. crude oil + gas - deposits of plankton, coal - thick deposits of plants and limestone - calcium carbonate deposits from shells and skeletons of marine animals
• • Evolution of the atmosphere phase 3 (producing oxygen) - green plants and algae produce oxygen via photosynthesis,  6CO2 + 6H2O → C6H12O6 + 6O2, oxygen levels building meant more complex life forms could evolve, around 200 million years ago the atmosphere made a composition similar to today’s (80% nitrogen, 20% oxygen, small amounts of carbon dioxide, noble gases, water vapour)
• • Greenhouse effect: 1) short wavelength radiation radiated by the sun pass through the atmosphere (2) the earth absorbs radiation and warms up (3) the earth radiates long wavelength radiation (infrared) (4) some of the long wavelength radiations goes back into space, some is re-radiated by greenhouse gases causing the lower atmosphere to heat up
• • Greenhouse gases - carbon dioxide, methane, water vapour
• • Greenhouse gas levels are increase by: deforestation (less trees to absorb carbon dioxide), burning fossil fuels (carbon previously locked up in sedimentary rock or as crude oil or natural gas is released), agriculture (more farm animals means more methane being produced via their digestion), waste (more landfills, more carbon dioxide and methane via the decomposition of waste)
• • Climate change - the long term alterations of weather patterns
• • Effects of global warming - polar ice caps melting - rise in sea levels - increased flooding and coastal erosion
• • Effects of global warming - changes in rainfall patterns - too much or too little water in some regions - affect the ability for some regions to produce food
• • Effects of global warming - frequency and severity of storms increasing
• • Effects of global warming - habitats changing - changes in organism distribution
• • Carbon footprint - a measure of ow much carbon and other greenhouse gases is used through the activities of a person, company or country 
• • Reducing carbon footprints - renewable energy sources, taxing companies and individuals based on their greenhouse gas emissions, cycling or walking
• Reducing carbon footprints - reducing air travel, turning down heating, turn off lights and idol appliances
• Complete combustion - occurs when a good supply of oxygen is available, releases maximum amount of energy, methane + oxygen —> carbon dioxide + water, CH4 + 2O2 —> CO2+2H2O
• Incomplete combustion - occurs when there is a limited supply of oxygen, releases less energy than complete combustion, releases particulates and or carbon monoxide instead of carbon dioxide, ethane + oxygen —> carbon monoxide + water, 6C2H6 + 5O2 —> 4CO +6H2O3
• Problems with incomplete combustion - particulates irritate the lining of the lungs causing respiratory problems
• Problems with incomplete combustion - particulates cause global dimming as they reflect sunlight back to space
• Problems with incomplete combustion - carbon monoxide is poisonous and binds to the haemoglobin in red blood cells, preventing them from carrying oxygen to the cells in your body causing fainting, comas or death, carbon monoxide is colourless and has no smell so can only be detected by electronic detectors
• Sulphur dioxide - SO2
• Sulphur dioxide is release by the combustion of fossil fuels that contain sulphur impurities
• Sulphur dioxide - S + O2 → SO2
• Sulphur dioxide can further oxides to form sulphur trioxide, 2SO2 + O2 → 2SO3
• Sulphur trioxide can dissolve in clouds to produce sulfuric acid and therefore acid rain which damages aquatic environments, statues and buildings
• Sulphuric acid - SO3 + H2O → H2SO4
• Oxides of Nitrogen are created by high pressures in a car engine which cause nitrogen and oxygen to react together
• Oxides of nitrogen can dissolve in clouds it form nitric acid causing acid rain, cause photochemical smog ( air pollution that appears as a visible smoky fog) which has major health effects e.g. asthma attacks or even death