Causes and Effects of Air Pollution
Any undesirable change in quality of air that affects life on planet earth is called air pollution. Air pollution is one of the most dangerous and common kind of environmental pollution that is reported in most industrial towns and metropolitans.
Causes and Effects of Air Pollution
Air pollutants are either natural or anthropogenic. The natural air pollutants include volcanic eruptions, forest fires, and dust due to erosion by wind, hydrocarbons released by plants. These natural air pollutants are easily stabilized by eco-system.
Man made air pollutants are released mostly due to burning of fossil fuel in industries, vehicles, cement factories, thermal power stations and chemical manufacturing plants. The most important and major air pollutants are; Carbon Monoxide, Sulfur Dioxide, Nitrogen oxides, Carbon Dioxide, Gaseous Hydro Carbons, Aerosols, Dust, Smog, etc.
It is the most abundant air pollutant released into the atmosphere. Burning of fossil fuels in vehicles, burning of firewood in rural areas, cigarette smoking, thermal power plants were the major sources of carbon monoxide. Vehicular emission alone contributes to 80% of carbon monoxide pollution. The life span of carbon monoxide is three years.
Carbon Monoxide causes anemic hypoxia which is due to reduced oxygen carrying capacity of hemoglobin. This is further due to the formation of stable carboxy hemoglobin by carbon monoxide with hemoglobin. Effects due to carbon monoxide are dizziness, headache, nausea, heart palpitation, anxiety, blood clots in the vessels and increased rate of fat deposition in the arteries. If the carbon monoxide in the blood is more than 5% it results in coma and death.
The important sources of sulfur dioxide are thermal power plants, petroleum refineries, biological decomposition and volcanic eruptions. It is the second most abundant air pollutant but more toxic than carbon monoxide. Sulfur dioxide is less stable and its maximum life span is three days.
The direct effects of sulfur-dioxide are headache, high irritation and irritation of mucous membrane of respiratory tract, burning and bleeding in nose, bronchitis and emphysema. Sulfur dioxide damage leather, paper and accelerates corrosion of metals, alloys and marbles. It is a phytotoxic pollutant and enhances chlorosis (loss of chlorophyll), hence excessive sulfur dioxide pollution decreases crop yield. Sulfur dioxide also contributes to acid rains.
Carbon Dioxide has no direct effect on the living organisms. Increased carbon dioxide concentration in the atmosphere due to burning of fossil fuels increases the heat in atmosphere. This is due to the heat trapping ability of carbon dioxide.
The result of the above said heat trapping ability is global warming and subsequently the polar ice melts. Further, mean sea level rises and in consequence coastal regions and islands submerge under the water. Agricultural productivity and food security are also affected. Summer temperature increases, water availability is reduced and bio-diversity is affected ultimately.
These include nitric oxide, nitrous oxide and nitrogen dioxide. The sources are nitrogen fertilizers making industries, manufacturing of explosives and burning of organic waste. The nitrogen oxides released into the atmosphere reacts immediately with gaseous hydrocarbons in the presence of sunlight to produce secondary pollutants like aldehydes, ozone and peroxyacetyl nitrate which accumulate as smoke. This smoke when mixed with for produce smog. Maximum life span is three to four days on an average.
The effects of smog on man include nasal inflammation, reddening and bleeding of nasal mucosa and high irritation. The nitrogen oxides also contribute to acid rains.
Gaseous Hydro Carbons and Ozone
These are the compounds of Hydrogen and Carbons released from automobile petroleum refineries and manufacturing of explosives.
Example: Aniline damages the leaves of plant. 3,4- Benzepyrene causes lung cancer, ethylene and acetylene cause neurosis and chlorosis of leaves.
Ozone is released into the troposphere as a secondary pollutant. It damages leaves and accelerates the production of unstable nitrate which further leads to acid rains.
It is the dissolved solid or liquid matter in the atmosphere. Hence, also called as suspended particulate matter. It is of three types namely; Aerosols, Dust and Smog.
- Aerosols: These are dissolved solid or liquid particles released from jet planes, aerosol cans and sprays. They have a size of less than 1 micron.
- Dust: It is suspended solid matter like cotton dust, iron dust and cold dust with size of more than 1 micron.
- Smog: It is suspended liquid matter with size of more than 1 micron.
A particulate matter mainly effects respiratory system and cause sneezing, cough, irritation, asthma and bronchitis. Cotton dust causes byssinosis. Iron dust causes siderosis and coal mining dust causes black lung disease.
Measures to control Air Pollution
- The important measure is to control or prevent the vehicular pollution. This can be achieved by the decrease in dependence on fossil fuels like crude oil and increasing use of clean fuels like liquid natural gas, compressed natural gas, gasohol, bio-diesel and bio ethanol.
- Filters can be used to capture and recycling the escaping gases like hydrocarbons from the automobiles engines.
- Industrial air pollutants can be prevented from releasing into atmosphere by using electrostatic precipitators.
- Installation of tall chimneys prevents the pollution at the surface level.
- Hydro Precipitation: This involves the flour of toxic gases through water which are easily dissolved such water later can be purified. This measure prevents atmospheric pollution.
- Catalytic converters can be used both in industries as well as vehicles which breakdown the toxic gases into harmless products.
- Afforestation is industrial estates and urban areas are an important measure to prevent pollution by carbon dioxide and sulfur dioxide.
- The provisions of air prevention and control laws should be strictly are dealt with severe punishments and penalties.
What an individual can do to control Air Pollution?
- Use motor vehicles only when absolutely necessary.
- Walk or cycle as much as possible instead of using fossil fuel powered vehicles.
- Use public transport as far as possible, as more people can travel in single large vehicles rather then using multiple small vehicles which add to pollution.
- Do not use air fresheners, aerosols and other aerosol and sprays which contain CFC that deplete the ozone layer.
- Do not smoke in a public place. It is illegal and endangers not only your only health but also that of the others.
- Coughing and sneezing can spread bacteria and viruses. Use a hand kerchief to prevent droplet infection which is airborne as it endangers the health of other people.
- One should prevent and report to the authorities on any incidents of cutting down of trees.