Common atmospheric pollutants and their sources

9.3.1 Atmospheric pollutants from fuels

9.3.2 Properties and effects of atmospheric pollutants

Pollutant How it’s produced Effects Solution
Carbon dioxide CO2 & water vapour H2O(g) Complete combustion of hydrocarbon fuels

Eg CH4 + 2O2 → CO2 + 2H2O

Greenhouse gases – enhance greenhouse effect → cause global warming → climate change             –
Carbon monoxide CO Incomplete combustion of hydrocarbon fuels due to lack of O2

Eg 2CH4 + 3O2 → 2CO + 4H2O

A toxic gas

Colourless & odourless so not easily detected

Binds to haemoglobin in RBC in place of O2, leads to health problems

Ensure good supply of O2 when burning
Sulfur dioxide SO2 Sulfur impurities with O2 during combustion to produce sulfur dioxide

S + O2 → SO2

Respiratory problems

Acid rain – erosion/kills fish

Remove SO2 from waste gas

Remove S from fuels before burning in fuels

Nitrogen oxides
NO / NO2 / N2O
High temp of internal combustion engines of cars causes N2 + O2 → 2NO Respiratory problems

Acid rain – erosion/kills fish

Catalytic converter in cars
Particulates / soot If diesel doesn’t burn completely, then tiny solid particles of C and unburnt hydrocarbons are produced to form particulates

2C14H20 + 15O2 → 28C + 30H2O

Global dimming

(Particulates in upper atm reflect sunlight back into space → less reaches Earth)

Respiratory problems – lung cancer

Ensure good supply of O2 when burning

Describe how CO2 is released into the atmosphere from carbonate rocks by geological activity (1)

  • Rock is heated then decomposed

Hydrocarbons and calcium carbonate contain locked up carbon dioxide. What is locked up carbon dioxide? (2)

  • CO2 from air formed rocks / fossil fuels


Limestone contains calcium carbonate. Name the type of reaction that takes place when calcium carbonate is heated strongly and the products formed. (3)

  • Thermal decomposition
  • To produce CaO and CO2

2CaCO3 + 2SO2 + O2 → 2CaSO4 + 2CO2

How does limestone used in power station release CO2 and SO2? (1)

  • CO2 – thermal decomposition
  • SO2 reacts with CaCO3

In this question you will be assessed on using good English, organizing information clearly and using specialist terms where appropriate.

Limestone is heated in a lime kiln to produce calcium oxide. Figure 4 shows the reactants used and the products made in a lime kiln.

Use information from Figure 4 to explain the potential environmental impacts of quarrying, drilling and the thermal decomposition of limestone used in the production of calcium oxide. (6)

Examples of chemistry points made in the response could include:

Processes Types of pollution and problematic effects
  • Quarrying
  • Drilling
  • Thermal decomposition
  • Combustion of fossil fuel
  • Use of explosives
  • Visual pollution
  • Noise pollution
  • Dust pollution
  • Destruction of land
  • Air / atmospheric pollution (CH4, CO2, SO2, NOx, particulates)
  • Water (rivers / lakes / seas) pollution
  • Earth tremors

Environmental impacts:

  • Destruction of areas of natural beauty
  • Disturbance of people and animals
  • Breathing problems or asthmatic attacks
  • Destruction of habitats or biodiversity or kills wildlife and plants
  • CH4 and CO2 – greenhouse gases → global warming → consequences
  • Particulates – global dimming → consequences including breathing problems
  • SO2 and NOx – acidic gas / rain → consequences including breathing problems
  • Damage to buildings / infrastructure