What is Air Pollution?
Air pollution is the act of environmental contamination with man-made waste into the air. The air we breathe is composed of a mixture of gases: 78% nitrogen, 21% oxygen, and a small percentage of other gases like argon, carbon dioxide, and water vapour. (Kaufman and Franz). Other air pollution may be so apparent that it surrounds us like smog, which is a cloud or haze of air pollution. How often have you seen smog hanging over the tall skyscrapers in urban areas? Why do you think cities are more likely to have smog than suburban or rural areas? Cities have a tendency to have a greater portion of industrialized areas. Industry is the main contributor to air pollution. Many times factories release greenhouse gases like carbon dioxide, chlorofluorocarbons (CFCs), methane, and nitrous oxide into the atmosphere (Kaufman and Franz).
Greenhouse gases contribute to a phenomenon called the greenhouse effect or more simply put, global warming. These greenhouse gases trap heat within the atmosphere, thus raising the temperature of Earth. Air pollution is defined as the contamination of the atmosphere by the discharge of harmful airborne substances. While the sources of some air pollutants are natural, such as volcanic eruptions, much of air pollution is a result of human activities. The burning of fossil fuels for energy to run machinery, vehicles and generate electricity is the major source of air pollutants resulting from human activities. In urban areas, fossil fuel emissions of most concern include sulphur dioxide, nitrogen oxide, carbon monoxide and volatile organic organics compounds. Also, an estimated 500,000 tonnes of lead are released into the atmosphere through human activities each year, over half of which comes from vehicle exhausts.
Air pollution can seriously affect human health and also damage the environment and property. It can cause health problems such as burning eyes and nose, itchiness, throat irritations and breathing problems. Some chemicals found in polluted air can cause cancer, birth defects, brain and nerve damage, and long-term injury to the lungs and breathing passages in certain circumstances.Air pollution has also led to the thinning of the protective ozone layer above the Earth, causing more harmful ultra-violet radiations to reach the Earth. Increased human exposure to these harmful radiations has resulted in an alarming increase in incidents of skin cancer throughout the world. Falling as “acid rain”, air pollution is killing lakes and forests. In developed countries, air pollution has destroyed thousands of lakes and millions of hectares of forests. In Sweden for example, fish have died out in 4,000 of the lakes in the country and another 18,000 face the same predicament. Acid rain also has a corrosive effect which can cause much damage to buildings and other physical structures.
Most serious of all, a great majority of scientists now agree that air pollution is changing the climate by causing world temperatures to increase – the greenhouse effect or global warming. This has severe consequences for world climate and far reaching implications for food production in the new millennium. In Malaysia, air pollution is a serious environmental problem. This is sometimes compounded by smoke from forest fires in Indonesia, which causes a severe haze that may envelope the entire country. A good example was the haze in 1997 which affected major parts of the country, when almost the entire population in the country had to take emergency measures to avoid developing respiratory problems. Thousands of people were admitted to hospitals with health problems related to the haze during the period. In Sarawak, schools had to be closed, and many businesses had to shut down on government order, in order to minimize the local sources of pollution. Visibility was also poor that many flights at the KL International Airport were affected. In recent years, the country has also experienced some of the effects of global warming; the El Nino phenomenon, extreme changes in weather patterns, severe rains and floods, and sometimes, long periods of droughts with high daily temperatures.
a) Types of Air Pollution
Air pollution can be divided into two types; indoor and outdoor pollution.
Indoor air pollution - This is caused by tobacco smoke, emissions from cooking and heating appliances and vapours from building materials, paints and furniture inside buildings. The problem is exacerbated when the buildings are poorly ventilated – causing some buildings to be called “sick” buildings. Such buildings are unfit for human occupation.
Outdoor air pollution - This is caused by pollutants derived from many sources, primarily automobile exhausts and industrial emissions.
b) Sources of Air Pollution
i) Sulphur dioxide (SO2).
ii) Carbon Monoxide (CO).
iii) Nitrogen oxides (NOx).
iv) Volatile Organic Compounds (VOCs).
v) Lead and Heavy Metals.
vi) Halocarbons - Halocarbons such as chlorofluorocarbons (CFCs)
c) Effects of Air Pollution
i) Effects on Human Health
Every day, the average person inhales about 20,000 litres of air. Every time we breathe, we risk inhaling dangerous chemicals that have found their way into the air. Air pollution is responsible for major health effects. Older people are highly vulnerable to diseases induced by air pollution. Children, infants and those with heart or lung disorders are highly susceptible and more at risk of being exposed to air pollution.
Some pollutants such as lead, mercury, particulate matter, carbon dioxide and ozone-forming nitrogen dioxides cause cancer, birth defects, brain and nerve damage and long-term injury to the lungs and breathing passages. Sulphur dioxide in ambient air affect particularly those suffering from asthma and chronic lung diseases. Low level ozone have serious effects on human health, including a number of morbidity and mortality risks associated with lung inflammation, as well as asthma and emphysema.
ii) Effects on the Environment
Acid rain causes acidification of lakes and streams, contributes to damage of forests and trees and corrodes physical infrastructures. Global warming as a result of rising global temperatures caused by increased emissions of carbon dioxide and other greenhouse gases is expected to raise sea levels and cause extremes in climate patterns.
iii) Effects on the Economy
Air pollution will have serious costs for the economy due to increased health problems among people and damages to property and the natural environment.
iv) Acid Rain
Acid rain is produced when gaseous acidic pollutants such as sulphur dioxide, carbon monoxide and NOx dissolve in water droplets in the air to produce acidic solutions which fall back to the earth during rainfall. Acid rain has harmful impacts on the environment. It affects freshwater lakes and the wildlife that depend upon them. It also affects trees and forests by harming leaves and soil, and it damages buildings made of limestone and marble.