Air Pollution Flashcards

Clean Air and Air Pollution

Clean air is essential for healthy living, but unfortunately, much of the air we breathe is polluted and contains harmful pollutants.

Definition of Air Pollution

Air pollution is the condition in which air contains a high concentration of chemicals that may harm living things or damage the environment.

Sources of Common Air Pollutants

Air pollution is caused by solid particles (particulates) and harmful gases. These substances are called air pollutants.

Carbon Dioxide (CO_2)

• Produced when carbon-containing fuels like coal, crude oil, and natural gas are burned in excess oxygen.
• This process is called complete combustion.
• Complete combustion forms carbon dioxide and water.
• Methane, the main component of natural gas, also produces carbon dioxide and water when undergoing complete combustion.
• Equation for methane combustion:
  CH4(g) + 2O2(g) \rightarrow CO2(g) + 2H2O(g)

Effect: Global warming

Carbon Monoxide (CO) and Particulates

• Produced when carbon-containing fuels are burned in a limited supply of oxygen.
• This process is called incomplete combustion.
• Incomplete combustion forms carbon monoxide, water, and particulates (carbon soot).
• Particulates are very small particles (such as dust or soot) suspended in the atmosphere.
• Example of incomplete combustion of methane:
  4CH4(g) + 5O2(g) \rightarrow 2CO(g) + 8H_2O(g) + 2C(s)

Effect: poisonous; particulates cover surface with carbon

Methane (CH_4)

• A colorless and odorless gas.
• Produced when plant and animal matter decomposes.
• Livestock like sheep and cows emit methane due to digestion.

Oxides of Nitrogen (NO and NO_2)

• Nitrogen combines with oxygen in car engines at high temperatures to form nitrogen monoxide (NO).
• Equation for nitrogen monoxide formation:
  N2(g) + O2(g) \rightarrow 2NO(g)
• Nitrogen monoxide reacts with oxygen to form nitrogen dioxide (NO_2), a brown gas.
• Equation for nitrogen dioxide formation:
  2NO(g) + O2(g) \rightarrow 2NO2(g)

Effect: cause photochemical smog

Sulfur Dioxide (SO_2)

• Fossil fuels contain sulfur compounds.
• When burned in vehicles, power stations, and factories, sulfur is converted to sulfur dioxide.
• Equation for sulfur dioxide formation:
  S(s) + O2(g) \rightarrow SO2(g)

Adverse Effects of Air Pollutants

Air pollutants can negatively impact our health and the environment.

Carbon Dioxide (CO_2) Effects

• Higher levels of carbon dioxide lead to global warming and climate change.

Carbon Monoxide (CO) Effects

• A toxic gas that reduces the ability of hemoglobin to transport oxygen in the blood.
• Causes breathing difficulties and can lead to death.

Particulates Effects

• Very small particles like dust, ash, carbon (soot), toxic metals (like lead), or smoke.
• High levels increase the risk of respiratory problems and cancer.

Methane (CH_4) Effects

• Higher levels of methane lead to global warming and climate change.

Oxides of Nitrogen (NO and NO_2) Effects

• React with rainwater to form acid rain, which corrodes buildings and harms aquatic life and plants.
• Equation for nitric acid formation:
  4NO2(g) + 2H2O(l) + O2(g) \rightarrow 4HNO3(aq)
• React with hydrocarbons in the presence of light to form photochemical smog.
• Both photochemical smog and oxides of nitrogen can cause respiratory problems.

Sulfur Dioxide (SO_2) Effects

• Reacts with rainwater to form acid rain.
• Equation for sulfuric acid formation:
  2SO2(g) + 2H2O(l) + O2(g) \rightarrow 2H2SO_4(aq)

Nitrates and phosphates

• Eutrophication
• Source: Fertilisers

Lead Compounds Effects

• Source: Paints, petrol, car batteries.
• Cause brain damage, developmental delays, abdominal pain in adults, and affect the nervous system.

Chlorofluorocarbons (CFCs) Effects

• Source: Aerosol sprays, refrigerators, air conditioners.
• Destroy the ozone layer, increasing the amount of harmful UV rays reaching the Earth's surface, which can cause skin cancer.