LEARNING OBJECTIVES
By the end of this lesson you should be able to:
Air pollution is the presence or the release of harmful substances in the atmosphere. These substances can be harmful to human health, other living things, or cause damage to materials or climate. Air pollutants are the materials that cause pollution of the air. They can be of different types such as gases (for example, carbon monoxide, ammonia, nitrous oxides, methane, sulfur dioxide, and chlorofluorocarbons), biological molecules, and particulates (organic and inorganic).
Air pollution can cause allergies, diseases or even death to humans, other living organisms such as crops and animals can also be harmed. Natural and built environments are also affected negatively by air pollution. Air pollution can be generated by natural processes or human activity. Gases are present in the atmosphere in a certain percentage. A decrease or increase in this composition of gases is harmful to the survival of living things. This imbalance in the composition of gases has led to increased earth’s temperature, which is referred to as global warming.
TYPES OF AIR POLLUTANTS
Air pollutants can be grouped into two:
Primary Pollutants
These refer to those pollutants that cause air pollution directly. Sulfur dioxide released from factories is an example of a primary pollutant. Other examples of primary pollutants are particulates, carbon monoxide, nitrogen oxide.
Primary pollutants can be emitted from many sources including cars, coal-fired power plants, natural forest fires, volcanoes, and so on.
Secondary pollutants
This refers to the pollutants that are formed as a result of intermingling and reaction of other primary pollutants. For example, smog is formed by the intermingling of fog and smoke. Therefore, smog is an example of a secondary pollutant. Other examples are ozone and secondary organic aerosol (haze).
These pollutants are harder to control because they have different ways of synthesizing and the formation is not well understood.
CAUSES OF AIR POLLUTION
The following are the major causes of air pollution:
Burning of fossil fuels
Large amounts of Sulphur dioxide are emitted during the combustion of fossil fuels. The incomplete combustion of fossil fuels results in the release of carbon monoxide which also contributes to the pollution of air.
Automobiles
Most automobiles use petrol or diesel. The gases emitted from automobiles like vehicles and motorcycles pollute the environment. These account for the major part of greenhouse gases and contribute to respiratory diseases in humans.
Agricultural activities
One of the most hazardous gases that is emitted during agricultural activities is ammonia. The fertilizers, insecticides, and pesticides used in agriculture emit harmful chemicals and contaminate the atmosphere.
Factories and industries
Factories and industries make up the major sources of carbon monoxide, hydrocarbons, organic compounds, and chemicals. These wastes are released into the air and cause contamination.
Mining activities
In the process of mining, minerals found below the earth are extracted using large equipment. The chemicals and dust released in the process pollute the air and may have a negative health effect on the workers and the people living near the area.
Domestic sources
Paints and household cleaning products are examples of domestic sources of air pollution. They release toxic chemicals into the air and contaminate it.
EFFECTS OF AIR POLLUTION
Some of the major effects of air pollution include;
Diseases
Air pollution can cause several respiratory diseases and heart disorders in humans. Lung cancer and heart attack are examples of these diseases. Children that live near polluted areas are more prone to asthma and pneumonia. Many people lose their lives every year as a result of the direct or indirect effects of air pollution.
Global warming
The emission of greenhouse gases has led to an imbalance in the composition of gases. This has led to an increase in the earth’s temperatures (global warming). This has resulted in the melting of glaciers and sea-level increase. Many areas have been submerged underwater.
Acid rain
The burning of fossil fuels emits harmful gases like Sulphur oxides and nitrogen oxides in the air. Water droplets combine with these pollutants and fall as acid rain. This damages human, plant, and animal life.
Ozone layer depletion
The release of halons and chlorofluorocarbons in the atmosphere is a major cause of ozone layer depletion. This allows harmful ultraviolet rays from the sun and causes skin diseases and eye problems.
Effect on animals
Air pollution has many negative effects on animals. Pollution compels animals to leave their natural habitats. This has led to the extinction of several animal species. Air pollutants that suspend on water bodies also affect aquatic life.
CONTROL OF AIR POLLUTION
The following are some of the measures that we should adopt to control pollution of air:
Use of clean energy sources
The use of wind, geothermal and solar energies greatly reduce air pollution. Some countries like India have implemented the use of these resources with the aim of a cleaner environment.
Energy conservation
Fossil fuels are mainly burnt to produce electricity. Therefore by conserving energy, for example, the use of power-saving devices can reduce the amount of fossil fuels being burnt and thus reduce air pollution.
Other measures of controlling air pollution include:
