The Importance Of Air Other planets have sunlight, but the Earth is the only planet we know that has air and water. Without air and water, the Earth would be unable to sustain life. A diverse community of plant and animal life has thrived on this planet for millions of years, sustained by the sun and supported by the soil, water and air. Definition of air pollution Air pollution occurs when the air contains gases, dust, fumes or odour in harmful amounts. That is, amounts which could be harmful to the health or comfort of humans and animals or which could cause damage to plants and materials.
The substances that cause air pollution are called pollutants. Pollutants that are pumped into our atmosphere and directly pollute the air are called primary pollutants. Primary pollutant examples include carbon monoxide from car exhausts and sulphur dioxide from the combustion of coal. Further pollution can arise if primary pollutants in the atmosphere undergo chemical reactions. The resulting compounds are called secondary pollutants. Photochemical smog is an example of this. Historical explanation
In the days before the proliferation of large cities and industry, nature’s own systems kept the air fairly clean. Wind mixed and dispersed the gases, rain washed the dust and other easily dissolved substances to the ground and plants absorbed carbon dioxide and replaced it with oxygen. With increasing urbanisation and industrialisation, humans started to release more wastes into the atmosphere than nature could cope with. Since then, more pollution has been added to the air by industrial, commercial and domestic sources.
As these sources are usually found in major cities, the gases that are produced are usually concentrated in the air around them. The adverse effects of air pollution were graphically illustrated in London in 1952 when, in just a few days, an estimated 4000 people died from effects of fine particle pollution. It is when these concentrated gases exceed safe limits that we have a pollution problem. Nature can no longer manage air pollution without our help. More about pollutants Air pollutants mainly occur as a result of gaseous discharges from industry and motor vehicles.
There are also natural sources such as wind-blown dust and smoke from fires. Some forms of air pollution create global problems, such as upper atmosphere ozone depletion and global warming. These problems are very complex, and require international cooperative efforts to find solutions. PollutantSourceHuman Health Effects Particles (API) – Air Particle Index•Internal combustion engines (eg, cars and trucks); •Industry (eg, factories); •Burning wood; •Cigarette smoke; and •Bushfires. Long term exposure is linked to: Lung Cancer; •Heart Disease; •Lung Disease; •Asthma Attacks; and •Other health problems. Nitrogen Dioxide (NO2)•Motor Vehicles are the biggest contributors; •Other combustion processes; Exposure to high levels of NO2 may lead to: •Lung damage; or •Respiratory Disease. It has also been linked to: •Increased hospital admissions for asthma and respiratory problems; •Increased mortality. Ozone (O3)Formed by various complex chemical reactions involving the exposure of the oxides of nitrogen and some hydro-carbons.
Ozone is the main ingredient of photochemical smog in summer and early autumn. Ozone effects the •lining of the lungs; •lining of the respiratory tract; and •causes eye irritation. Ozone also damages plants, buildings and other materials. Carbon Monoxide (CO)Motor vehicle exhaust and burning of materials such as coal, oil and wood. It is also released from industrial processes and waste incinerationWhen inhaled Carbon Monoxide enters the bloodstream and disrupts the supply of oxygen to the body’s tissues. A range of health ffects may result depending on the extent of exposure. Lead (Pb)Is largely derived from the combustion of lead additives in motor fuels as well as lead smelting. Lead pollution from vehicle emissions is declining due to the introduction of unleaded fuels and reductions in lead levels in leaded fuel. Other atmospheric sources of lead include waste incineration and renovation of old houses (from leaded paint). Lead retards learning in children and the development of their nervous system; Lead effects almost every organ in the body, whether it is inhaled or ingested.
Young children are particularly susceptible; Hydro-carbons (HC) – chemical compounds composed of Hydrogen and Carbon atomsMost fuel combustion processes result in the release of hydro carbons to the environment. The largest fuel sources are natural gas and petrol. Note that hydrocarbons can enter the environment both as evaporative emissions from vehicle fuel systems, or in exhaust emissions. They are also a component of the smoke from wood fires. Exposure can cause headaches or nausea, while some compounds may cause cancer. Some may also damage plants.
