The occur of Air Pollution is when pollutants (eg. Dust & Smoke) are released into the enviroment. When such particles are suspended in the air, sometimes it could result in haze. Dust and Smoke can also combine with water vapour and toxic gases from factories to form smog, a more serious form of Air Pollution.
The Natural Causes of Air Pollution
- Volcanic Eruptions
Large amounts of volcanic ash, smoke and gases are released during eruptions. For example, the 1991 eruption of Mount Pinatubo in the Philippines released hot volcanic ash and gases into the air, which blocked out the sunlight and caused grey skies in the surrounding region for days.
- Forest Fires
Another cause of air pollution, they can occur naturally in times of prolonged hot and dry weather. High temperatures and low rainfall create very dry conditions in forests, resulting in the risk of vegetation catching fire. The dust and smoke particles produced by a forest fire are suspened in the air and maybe carried by winds to areas surrounding the forest or even other nearby countries.
The Human Causes of Air Pollution
- Industries
Power stations and manufacturing industries release large amounts of dust and smoke into the air. When fossil fuels are burnt in power stations, besides dust, waste is also released into the air. This waste includes fine, black, carbon-based smoke particles called soot, as well as poisonous gases like sulphur dioxide.
- Motor Vehicles
The greatest source of air pollution in urban areas is vechicals. In many cities, it is estimated that as much as 90percent of dust and smoke particles present in the air are emitted by vehicals. These emissions also contain harmful gases, such as carbon monoxide and nitrogen oxides.
- Construction Work
The clearing of land, construction of buildings and transportation of construction materials pollute the air with dust and smoke particles. These particles may be transported by wind to nearby residental areas.
Extend of Air Pollution
Air Pollutions, such as dust, smoke and harmful gases can be carried by winds from their source to other parts of the country, or across international boundaries to other countries.
For example, in recent times, hazy skies haven been occurring almost every year but were especially bad in 1997. Smoke particles from the burning forests in Indonesia were carriied by winds to nearby countries like Singapore, Malaysia and Brunei, causing hazy skies in the Southeast Asian region. Let us take a look at some of the problems caused by air pollution.
- Health Problems
Dust and smoke can cause difficulty in breathing as well as irritations to people's throats and eyes. When we are exposed to dust and smoke for a long time, we can develop respiratory problems such as bronchitis and asthma.
When a city experiences a smog, toxic gases such as carbon monoxide can cause serious health problems and even death. Sulphur dioxidde and nitrogen oxides which are also found in smoke can attack a person's respiratory system, increasing the risk of developing lung and heart diseases, and even cancer! Some studies have shown that the lifespan of people in cittes is shortened by an average of one to two years due to air pollution.
- Traffic Hazards
High amounts of dust and smoke in the air makes it difficult for us to see distant objects. Thus, when countries experience a haze, airports may have to stop all flights until visibility improves. It also poses an inconvenience and may be dangerous for those driving vehicals.
- Enviromental Problems
In some cities, acid rain cause air pollution, destroys forests, kills fish in rivers and lakes, as well as corrodes buildings. Acid rain is a common problem in places which have a large number of heavy industries present. For example, in chemical industries, large amounts of sulphur dioxide and nitrogen oxides are released into the air as the chemicals are being processed. These chemicals will mix the water vapour in the air, forming acid rain.
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