air quality

What is produced during complete combustion?

CO2 + H2O

What is produced during incomplete combustion?

C or CO
+ H2O

Percentage of gases in air

78% nitrogen

21% oxygen

0.97% noble gases, mostly argon

0.03% carbon dioxide

Carbon Monoxide sources

incomplete combustion of carbon-containing fuels or petrols

Carbon Monoxide effects

Reacts with haemoglobin in blood to form carboxyhaemoglobin, which reduces its ability to transport oxygen around the body — causes headaches, fatigue, breathing difficulties and even death

Sulfur Dioxide causes

combustion of sulfur-containing fuels or fossil fuels, emissions from volcanic eruption

Sulfur Dioxide effects

• irritates eyes and lungs and cause breathing difficulties

• high levels lead to inflammation of lungs (bronchitis)

• reacts with rain water to form acid rain, corroding metal structures, limestone buildings and harming aquatic life and plants

formation of acid rain from sulfur dioxide

1) Sulfur dioxide dissolves in water to form sulfurous acid

SO2(g) + H2O(l) → H2SO3(aq)

2) Sulfurous acid oxidises in air to form sulfuric acid

2H2SO3(aq)+O2(g)→2H2SO4(aq)

sources of oxides of nitrogen

nitrogen reacting with oxygen at very high temperatures

• during lightning strikes

• in a car engine

formation of oxides of nitrogen

N2(g)+O2(g)→2NO(g)

2NO(g)+O2(g)→2NO2(g)

effects of oxides of nitrogen

• irritates eyes and lungs and causes breathing difficulties

• high levels lead to inflammation of lungs (bronchitis)

• (applies to NO2 only) reacts with rain water to form acid rain, corroding metal structures, limestone buildings and harming aquatic life and plants

all pollutants

• unburnt hydrocarbons

• methane

• ozone

• oxides of nitrogen

• sulfur dioxide

• carbon monoxide

flue gas desulfurisation — reaction with sulfur dioxide

SO2(g) + CaCO3(s) → CaSO3(s) + CO2 (g)

SO2(g) + CaO(s) → CaSO3(s)

O2(g) + 2CaSO3(g) → 2CaSO4(s)

reactions in catalytic convertors

2CO(g)+O2(g)→2CO2(g)

2NO(g)+2CO(g)→N2(g)+2CO2(g)

2C8H18(l)+25O2(g)→16CO(g)+18H2O(g)

photosynthesis

6CO2(g)+6H2O(l)→C6H12O6(aq)+6O2(g)

combustion of fuels

CH4(g)+2O2(g)→CO2(g)+2H2O(g)

respiration

C6H12O6(aq)+6O2(g)→CO2(g)+H2O(g)

effects of global warming

• unusual weather condition such as hurricanes, tsunamis and droughts

• melting of polar ice caps, causing floods to low-lying lands

how do greenhouse gases cause global warming

CO2 and water vapour are capable of retaining heat in the atmosphere — they play an important role in maintaining the temperature on Earth’s surface

An increase in the amount of CO2 and greenhouse gases such as methane and nitrous oxide leads to global warming and causes Earth’s average temperature to increase

effects of ozone depletion

• skin cancer

• genetic mutations

• damage to the eye