There are many different chemical substances that contribute to air pollution. These chemicals come from a variety of sources. Among the many types of air pollutants are nitrogen oxides, carbon monoxides, and organic compounds that can evaporate and enter the atmosphere. Air pollutants have sources that are both natural and human. Now, humans contribute substantially more to the air pollution problem. Forest fires, volcanic eruptions, wind erosion, pollen dispersal, evaporation of organic compounds, and natural radioactivity are all among the natural causes of air pollution. Usually, natural air pollution does not occur in abundance in particular locations.
The pollution is spread around throughout the world, and as a result, poses little threat to the health of people and ecosystems. Though some pollution comes from these natural sources, most pollution is the result of human activity. The biggest causes are the operation of fossil fuel-burning power plants and automobiles that combust fuel. Combined, these two sources are responsible for about 90% of all air pollution in the United States. Some cities suffer severely because of heavy industrial use of chemicals that cause air pollution. Places like Mexico City and Sao Paulo have some of the most deadly pollution levels in the world.
Causes of water pollution
The specific contaminants leading to pollution in water include a wide spectrum of chemicals, pathogens, and physical or sensory changes such as elevated temperature and discoloration. While many of the chemicals and substances that are regulated may be naturally occurring (calcium, sodium, iron, manganese, etc.) the concentration is often the key in determining what is a natural component of water, and what is a contaminant. High concentrations of naturally occurring substances can have negative impacts on aquatic flora and fauna. Oxygen-depleting substances may be natural materials, such as plant matter (e.g. leaves and grass) as well as man-made chemicals.
Other natural and anthropogenic substances may cause turbidity (cloudiness) which blocks light and disrupts plant growth, and clogs the gills of some fish species. Many of the chemical substances are toxic. Pathogens can produce waterborne diseases in either human or animal hosts. Alteration of water’s physical chemistry includes acidity (change in pH), electrical conductivity, temperature, and eutrophication. Eutrophication is an increase in the concentration of chemical nutrients in an ecosystem to an extent that increases in the primary productivity of the ecosystem. Depending on the degree of eutrophication, subsequent negative environmental effects such as anoxia (oxygen depletion) and severe reductions in water quality may occur, affecting fish and other animal populations.
Causes of soil pollution
Soil pollution is a result of many activities and experiments done by mankind which end up contaminating the soil. Here are some of the leading soil pollution causes:
* Industrial wastes such as harmful gases and chemicals, agricultural pesticides, fertilizers and insecticides are the most common causes of soil pollution.
* Ignorance towards soil management and related systems.
* Unfavorable and harmful irrigation practices.
* Improper septic system and management and maintenance of the same.
* Leakages from sanitary sewage.
* Acid rains, when fumes released from industries get mixed with rains.
* Fuel leakages from automobiles, that get washed away due to rain and seep into the nearby soil.
* Unhealthy waste management techniques, which are characterized by release of sewage into the large dumping grounds and nearby streams or rivers.
* Causes of Noise Pollution
The sources/causes of noise pollution increased in number with the invention of machines. Here are the different causes of noise pollution.
* It is the biggest source of noise pollution in today’s times, especially in urban areas. In the past few years, the rate of automobile manufacturing has increased manifold. Traffic problems created by these vehicles is an important source of noise pollution. Sound produced by the exhaust systems of trucks, autos, buses, motorcycles, etc. cause a lot of noise. The noise created by a bus or truck is 10-15 times that of a car. Use of diesel which results into high airborne vibration emission is one of the reasons why trucks and buses cause greater amount of noise. Also, the noise created by road traffic gets amplified in narrow streets.
* Railway Stations
* Locomotive engines of trains are an important source of noise pollution. Besides, the shunting and switching operations in rail yards too causes noise pollution to a great extent. The whistles and horns used by railway employees add to the effect and thereby, increase noise pollution.
* The national parks and wastelands were earlier considered to be pollution free zones and people traveled to such places for relaxation. Nowadays, the sound created by low-flying military aircraft cause noise pollution in these areas too. Aerodynamic noise, the noise emanating from aircraft systems and mechanical noise are the different kinds of noise produced by an aircraft.
* Industrial Noise
* The machines used in industries are a major cause of noise pollution. The different machines responsible for creating noise include compressors, motors and other machinery. It is therefore recommended to grow trees in the premises of industries, which act as absorbents of noise. Trees grown in the premises of ‘Tata Motors’, an automobile company based in Pune (India) is the perfect example of how to reduce noise pollution in industrial belts.
* Construction Equipment
* The different types of machines and equipment used in the construction of roads and buildings is also an important cause of noise pollution. The machinery used for the purpose of construction includes pneumatic hammers, bulldozers, air compressors, dump trucks, loaders, sidewalk breakers, etc. is also responsible for noise pollution to a great extent.
* Quick Fact!
The sound above the level of 45 dB holds the potential to create disturbances in sleep patterns. Ear pain can result from sound that is above 120 dB.
* Household Equipment
* The household equipment are amongst the minor contributors to noise pollution. Such machines include the mixers, vacuum cleaners and other noise creating equipment. The effects of noise created by these machines cannot be neglected; this is because one has to work in close contact with the equipment. Moreover, the magnitude of sound one has to bear is quite high.
* Other Causes
* The boilers, plumbing equipment, air conditioners, generators and fans contribute to noise pollution to a small extent. Noise created by people in public places too is a major contributor. The loudspeakers used in public places are amongst the sources of noise of a high degree/amplitude. In countries like India, the use of loudspeakers during festivals creates a lot of noise. Bursting firecrackers during festivals is also one of the major causes of noise pollution.