Evolution of atmosphere and pollutants

atmosphere gas composition

78% nitrogen

21% oxygen

1%Other gases

In the first billion years of the earth

Earth was covered in volcanoes that released CO2, water vapour and nitrogen

as water vapour condensed

Formed the oceans which dissolved the carbon dioxide forming carbon precipitates and then sediments

after oceans formed

Algae began to appear slowly

Green plants evolved rapidly over following billion years

Due to photosynthesis

Gases after plants began to evolve

Carbon dioxide started to decline

Oxygen began to build up

Allowed more complex life to evolve

How did algae and plants lead to sedimentary rock, oil and gas

-Algae and plants could only hold a small amount of carbon in their bodies

-when they died, they fell to the seabed

-then became buried in layers of sediment

-over millions of years thus sediment became compressed

-this formed sedimentary rock, oil and gas which trapped the carbon

-this stopped carbon from getting back into the atmosphere

How was crude oil and natural gas formed?

1. Plankton were deposited in muds on the sea floor

2. They were covered and compressed over millions of years to form crude oil and natural gas

How was coal formed?

Plants in swamps decay under high temperatures and pressures over billions of years.

How was limestone formed?

Mostly made from calcium carbonate that marine organisms incorporated into their shells and skeletons

Atmosphere now

nitrogen and oxygen

source of carbon monoxide

incomplete combustion

Source of sulfur dioxide

Combustion of sulfur impurities in hydrocarbon fuels

effects of acid rain

damage buildings

reacts with limestone and weakens buildings

Source of oxides of nitrogen

Oxidation of nitrogen at high temps in car engines and further oxidation in the air

how to reduce air pollution from cars

walking, cycling and cycling

what is fitted into cars to reduce harmful pollutants in exhaust

catalytic converter