Evolution of the Atmosphere and Air Pollution

Question 1

percentage of gases in the atmosphere

Answer 1

80% nitrogen
20% oxygen
1% and less of other gases

Question 1

Describe the change in levels of CO2 in the early atmosphere, and the formation of oceans.

Answer 1

In the first billion years, the earth was really dry and there was intense volcanic activity - this produced lots of Carbon Dioxide, Water and Nitrogen.

As the atmosphere cooled down, the water vapour condensed and formed the oceans.

This allowed the Co2 to dissolve into the oceans and stay locked up - formed carbon precipitates and sediments.

Slowly algae and plants formed, and CO2 was taken in in photosynthesis and O2 was released, increasing the levels in the atmosphere.

Over around 3 billion years, levels declined.

Question 2

Incomplete combustion either produces: carbon monoxide

Answer 2

1. carbon monoxide - odourless colourless gas - if inhaled, binds to haemoglobin as oxygen does, preventing oxygen from being transported around the body.

Question 3

Incomplete combustion: particulates

Answer 3

soot - respiratory problems if inhaled + smog and global warming

Question 4

Sometimes fuels have impurities like…

Answer 4

sulfur