AQA GCSE Chemistry

Revision Notes

9.3.2 Properties & Effects of Atmospheric Pollutants

Properties & Effects of Atmospheric Pollutants

Carbon Monoxide & Soot

  • Carbon monoxide is an extremely poisonous gas as it combines with haemoglobin in blood and prevents it from carrying oxygen
  • It is particularly malevolent as it is colourless and odourless, making it difficult to detect
  • A lack of oxygen supply to the brain can lead to fainting, coma or in worst case scenarios, even death
  • The carbon particles released from incomplete combustion clump together to form soot which gradually falls back to the ground
  • Soot causes respiratory problems and covers buildings and statues, making them look unclean and accelerating corrosion

Soot Statue, Edexcel GCSE Chemistry

Statues and monuments in very polluted areas become blackened over time from soot

Sulfur Dioxide

  • Sulfur dioxide is a colourless, pungent smelling gas that is a major air pollutant responsible for acid rain
  • The sulfur dioxide released mixes with clouds and readily dissolves in rainwater
  • SO2 is a non-metal oxide so it forms an acidic solution in water, hence forming acid rain
  • Acid rain causes corrosion to metal structures, buildings and statues made of carbonate rocks
  • It causes damage to aquatic organisms, pollutes crops and water supplies, and irritates lungs, throats and eyes

How acid rain is produced, downloadable IGCSE & GCSE Biology revision notes

Oxides of sulfur and nitrogen contribute to the formation of acid rain

Oxides of Nitrogen

  • Oxides of nitrogen come largely from vehicle exhausts and also contribute to acid rain
  • Aside from acid rain, oxides of nitrogen produce photochemical smog and breathing difficulties, in particular for people suffering from asthma

Exam Tip

Greenhouse gases and atmospheric pollutants are not the same thing. A greenhouse gas causes global warming whereas a pollutant is something which is not found in clean air and which causes problems close to the ground such as smog and breathing difficulties.

Author: Francesca

Fran has taught A level Chemistry in the UK for over 10 years. As head of science, she used her passion for education to drive improvement for staff and students, supporting them to achieve their full potential. Fran has also co-written science textbooks and worked as an examiner for UK exam boards.

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