Oxides of Nitrogen
- Nitrogen: 78%
- Oxygen: 21%
- Noble gases: 1%
- Carbon dioxide: 0.03%
- Water vapour: Variable
- Source: Incomplete combustion of carbon-containing fuels.
- Effect: A poisonous and odourless gas binds irreversibly with haemoglobin in blood, reducing ability of the blood to carry oxygen, thus causing death.
- Source: Bacterial decay of vegetable matter.
- Effect: A greenhouse gas which causes global warming.
Oxides of Nitrogen
- Source: During lightning activity & Reaction between oxygen & nitrogen in internal combustion engines at high temperatures.
- Effect: Nitrogen oxides reacts with oxygen and water vapor to form nitric acid which dissolves in water to form acid rain which causes corrosion of limestone buildings and metal structure.
- Source: During volcanic eruptions & Combustion of fossil fuels containing sulfur as an impurity
- Effect: Sulfur dioxide reacts with oxygen and water vapor to form sulfuric acid which dissolves in water to form acid rain which causes corrosion of limestone buildings and metal structure.
- Source: Action of UV light on oxides of nitrogen, carbon monoxide and unburnt hydrocarbons.
- Effect: Forms photochemical smog which causes breathing difficulties, especially for asthma sufferers.
- Source: Due to incomplete combustion of fuel from internal combustion engines of vehicles.
- Effect: Reacts with nitrogen oxides and carbon monoxide in the presence of UV light to produce ozone
- To remove carbon monoxide, unburnt hydrocarbons and oxides of nitrogen: Install catalytic converters in cars
- To remove sulfur dioxide: Flue gas desulfurisation
- To reduce effect of acid rain: Burn fuels which contain little or no sulfur. OR Use of catalytic converter in cars and removal of acidic gases in power stations.
- The ozone layer forms a thin shield in the upper atmosphere, protecting life on Earth from the sun's ultraviolet (UV) rays.
- Chlorofluorocarbons (CFCs) release chlorine atoms in the presence of sunlight, reacting with the ozone molecules, depleting the ozone layer.
- Excess UV rays reach the earth’s atmosphere, causing increased skin cancer & eye cataracts.
- Carbon dioxide is released into the atmosphere by combustion, decay and respiration.
- Carbon dioxide is removed from the atmosphere by plants during photosynthesis. The percentages of carbon dioxide and oxygen is kept constant.
- Carbon dioxide and methane are the main greenhouse gases that cause global warming.
- Consequences of global warming:
- Ice caps melt
- Sea level rises, causing floods to low-lying lands.
- Big changes in global climate, equatorial countries will experience more rain but others might experience drought.
- Disruption to food production