Chemistry of the Atmosphere

• 78% nitrogen • 21% oxygen • 1% all other gases incl. water vapour and CO2 (0.03%)

• massive amounts of volcanic activity helped the earth cool down more quickly by releasing heat energy • large amounts of CO2 released, as a consequence, along with water vapour - but the earth’s surface was still too hot for the water vapour to condense onto - at this time the atmosphere was ~90% CO2

• the earth’s surface became cool enough for water to condense onto it, allowing lakes, rivers and oceans to develop • CO2 dissolved into the developing oceans, enabling the amount of CO2 in the atmosphere to decrease

• plants and algae photosynthesised, decreasing CO2 and increasing O2 levels • O2 reacted in the atmosphere to produce ozone (O3) providing a protective layer of gas around the outer limits of the atmosphere, protecting life on earth from UV radiation

• oxygen rich, CO2 poor • Nitrogen levels in the atmosphere begin to increase as denitrifying bacteria in soil break down compounds containing nitrogen

• Higher oxygen levels • higher nitrogen levels • lower co2 levels • less water vapour • less hydrogen

• earth’s surface cooled enough for water vapour to condense on it • CO2 dissolved in newly formed oceans and rivers • plants and algae that photosynthesise began to evolve, increasing O2 and decreasing CO2 levels • denitrifying bacteria began to break down nitrogen-containing compounds

• formation of the oceans • photosynthetic organisms evolved • evolution of marine animals

• by unlocking carbon dioxide that has been locked up in fossil fuels and sedimentary rocks • deforestation • cattle farming

• burning fossil fuels releases locked-up CO2 and energy - CH4 + O2 ⇒ CO2 +H2O • thermal decomposition of limestone to produce cement and concrete released locked-up CO2 - CaCO3 ⇒ CaO + CO2

• UV radiation with a short wavelength comes from the sun and hits the earth’s surface • it reflects as longer wavelength infra-red radiation but can’t get through the greenhouse gases, so the heat gets trapped

stop infra-red radiation passing out of the atmosphere and trapping heat which maintains a suitable temperature for life to thrive.

Increased flooding and loss of coastal habitats/coastal erosion

Rising sea levels, extreme weather events, loss of biodiversity, crop failure and famine, drought

• Carbon monoxide • sulfur dioxide • nitrogen oxides (NOx gases) • carbon particulates • carbon dioxide

oxygen and nitrogen in the atmosphere reacting in very hot engines

they cause acid rain

use a catalytic converter to convert NOx gases back into nitrogen and oxygen

Burning of fossil fuels containing sulfur, which reacts with oxygen

it causes acid rain

remove sulfur from fuel and use FGD (flue-gas desulfurization)

Incomplete combustion of fuels, creating smoke

create smog and poor air quality in turn, causing respiratory problems

Using filters in industrial processes to capture carbon particulates or do complete combustion by providing more oxygen