Pollution is the introduction of contaminants into an environment that causes instability, disorder, harm or discomfort to the ecosystem i. e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat, or light. Pollutants, the elements of pollution, can be foreign substances or energies, or naturally occurring; when naturally occurring, they are considered contaminants when they exceed natural levels. Pollution became a popular issue after World War II, due to radioactive fallout from atomic warfare and testing.
Then a non-nuclear event, The Great Smog of 1952 in London, killed at least 4000 people. This prompted some of the first major modern environmental legislation, The Clean Air Act of 1956. Air pollution Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or damages the natural environment into the atmosphere. The atmosphere is a complex dynamic natural gaseous system that is essential to support life on planet Earth.
Stratospheric ozone depletion due to air pollution has long been recognized as a threat to human health as well as to the Earth’s ecosystems. Pollutants An air pollutant is known as a substance in the air that can cause harm to humans and the environment. Pollutants can be in the form of solid particles, liquid droplets, or gases. In addition, they may be natural or man-made. Pollutants can be classified as either primary or secondary. Usually, primary pollutants are substances directly emitted from a process, such as ash from a volcanic eruption, the carbon monoxide gas from a motor vehicle exhaust or sulfur dioxide released from factories.
Secondary pollutants are not emitted directly. Rather, they form in the air when primary pollutants react or interact. An important example of a secondary pollutant is ground level ozone — one of the many secondary pollutants that make up photochemical smog. Major primary pollutants produced by human activity include: Sulfur oxides (SOx) – especially sulfur dioxide, a chemical compound with the formula SO2. SO2 is produced by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide.
Further oxidation of SO2, usually in the presence of a catalyst such as NO2, forms H2SO4, and thus acid rain. [2] This is one of the causes for concern over the environmental impact of the use of these fuels as power sources. Nitrogen oxides (NOx) – especially nitrogen dioxide are emitted from high temperature combustion. Can be seen as the brown haze dome above or plume downwind of cities. Nitrogen dioxide is the chemical compound with the formula NO2. It is one of the several nitrogen oxides. This reddish-brown toxic gas has a characteristic sharp, biting odor. NO2 is one of the most prominent air pollutants.
Carbon monoxide – is a colourless, odourless, non-irritating but very poisonous gas. It is a product by incomplete combustion of fuel such as natural gas, coal or wood. Vehicular exhaust is a major source of carbon monoxide. Carbon dioxide (CO2) – a greenhouse gas emitted from combustion but is also a gas vital to living organisms. It is a natural gas in the atmosphere. Odors — such as from garbage, sewage, and industrial processes Radioactive pollutants – produced by nuclear explosions, war explosives, and natural processes such as the radioactive decay of radon.
Secondary pollutants include: Particulate matter formed from gaseous primary pollutants and compounds in photochemical smog. Smog is a kind of air pollution; the word “smog” is a portmanteau of smoke and fog. Classic smog results from large amounts of coal burning in an area caused by a mixture of smoke and sulfur dioxide. Modern smog does not usually come from coal but from vehicular and industrial emissions that are acted on in the atmosphere by sunlight to form secondary pollutants that also combine with the primary emissions to form photochemical smog. Ground level ozone (O3) formed from NOx and VOCs.
Ozone (O3) is a key constituent of the troposphere (it is also an important constituent of certain regions of the stratosphere commonly known as the Ozone layer). Photochemical and chemical reactions involving it drive many of the chemical processes that occur in the atmosphere by day and by night. At abnormally high concentrations brought about by human activities (largely the combustion of fossil fuel), it is a pollutant, and a constituent of smog. Peroxyacetyl nitrate (PAN) – similarly formed from NOx and VOCs. Minor air pollutants include: A large number of minor hazardous air pollutants.
Some of these are regulated in USA under the Clean Air Act and in Europe under the Air Framework Directive. A variety of persistent organic pollutants, which can attach to particulate matter. Persistent organic pollutants (POPs) are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. Because of this, they have been observed to persist in the environment, to be capable of long-range transport, bioaccumulate in human and animal tissue, biomagnify in food chains, and to have potential significant impacts on human health and the environment.
Health effects of Air Pollution: The World Health Organization states that 2. 4 million people die each year from causes directly attributable to air pollution, with 1. 5 million of these deaths attributable to indoor air pollution. Worldwide more deaths per year are linked to air pollution than to automobile accidents. Direct causes of air pollution related deaths include aggravated asthma, bronchitis, emphysema, lung and heart diseases, and respiratory allergies. The worst short term civilian pollution crisis in India was the 1984 Bhopal Disaster.
Leaked industrial vapors from the Union Carbide factory, belonging to Union Carbide, Inc. , U. S. A. , killed more than 2,000 people outright and injured anywhere from 150,000 to 600,000 others, some 6,000 of whom would later die from their injuries. The United Kingdom suffered its worst air pollution event when the December 4 Great Smog of 1952 formed over London. In six days more than 4,000 died, and 8,000 more died within the following months Water pollution Water pollution is the contamination of water bodies (e. g. lakes, rivers, oceans, groundwater).
Water pollution affects plants and organisms living in these bodies of water; and, in almost all cases the effect is damaging not only to individual species and populations, but also to the natural biological communities. Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds. 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. 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. Effects of Water Pollution Water pollution is a major problem in the global context An estimated 700 million Indians have no access to a proper toilet, and 1,000 Indian children die of diarrheal sickness every day. Some 90% of China’s cities suffer from some degree of water pollution, and nearly 500 million people lack access to safe drinking water. Chemical and other contaminants
Organic water pollutants include: Detergents Disinfection by-products found in chemically disinfected drinking water, such as chloroform Food processing waste, which can include oxygen-demanding substances, fats and grease Insecticides and herbicides, a huge range of organohalides and other chemical compounds Petroleum hydrocarbons, including fuels (gasoline, diesel fuel, jet fuels, and fuel oil) and lubricants (motor oil), and fuel combustion byproducts, from stormwater runoff[15] Tree and bush debris from logging operations
Volatile organic compounds (VOCs), such as industrial solvents, from improper storage. Chlorinated solvents, which are dense non-aqueous phase liquids (DNAPLs), may fall to the bottom of reservoirs, since they don’t mix well with water and are denser. Various chemical compounds found in personal hygiene and cosmetic products Inorganic water pollutants include: Acidity caused by industrial discharges (especially sulfur dioxide from power plants) Ammonia from food processing waste Chemical waste as industrial by-products
Fertilizers containing nutrients–nitrates and phosphates–which are found in stormwater runoff from agriculture, as well as commercial and residential use[15] Heavy metals from motor vehicles (via urban stormwater runoff)[15][16] and acid mine drainage Silt (sediment) in runoff from construction sites, logging, slash and burn practices or land clearing sites Land pollution Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.
Land pollution is the degradation of Earth’s land surfaces often caused by human activities and their misuse of land resources. It occurs when waste is not disposed properly. Health hazard disposal of urban and industrial wastes, exploitation of minerals, and improper use of soil by inadequate agricultural practices are a few factors. Urbanization and industrialization are major causes of land pollution. Increased mechanization The major increase in the concentration of population in cities, along with the internal combustion engine, led to the increased number of roads and all the infra structure that goes with them.
Roads cause visual, noise, light, air and water pollution, in addition to land pollution. The visual and noise areas are obvious, however light pollution is becoming more widely recognized as a problem. From outer space, large cities can be picked out at night by the glow of their lighting, so city dwellers seldom experience total darkness. As the demand for food has grown very high, there is an increase in field size and mechanization. The increase in field size makes t economically viable for the farmer but results in loss of person and shelter for wildlife, as hedgerows and copses disappear. When crops are harvested, the naked soil is left open to wind after the heavy machinery has compacted it. Another consequence of more intensive agriculture is the move to monoculture. This is unnatural, it depletes the soil of nutrients, allows diseases and pests to spread and, in short, brings into play the use of chemical substances foreign to the environment. A pesticide is a substance or mixture of substances used to kill a pest.
A pesticide may be a chemical substance, biological agent (such as a virus or bacteria), antimicrobial, disinfectant or device used against any pest. Pests include insects, plant pathogens, weeds, mollusks, birds, mammals, fish, nematodes (roundworms) and microbes that compete with humans for food, destroy property, spread or are a vector for disease or cause a nuisance. Although there are benefits to the use of pesticides, there are also drawbacks, such as potential toxicity to humans and other organisms. Pesticides are used to control organisms which are considered harmful.
For example, they are used to kill mosquitoes that can transmit many potentially deadly diseases like west Nile virus, yellow fever, and malaria disease. They can also kill bees, wasps or ants that can cause allergic reactions. Insecticides can protect animals from illnesses that can be caused by parasites such as fleas. Pesticides can prevent sickness in humans that could be caused by moldy food or diseased produce. Mining Modern mining projects leave behind disrupted communities, damages landscapes, and polluted water.
Mining also affects ground and surface waters, the aquatic life, vegetation, soils, animals, and the human health. Acid mine drainage can cause damage to streams which in return can kill aquatic life. The vast variety of toxic chemicals released by mining activities can harm animals and aquatic life as well as their habitat. The average mine disturbs over a thousand acres of land. Construction See the bodies of water. doing this, natural water filters are damaged. Natural water filters help break down many pollutants before they reach other water bodies.
Some that may run off with water and sediments from construction sites are oils, debris, and paint. This can cause damage to soil, aquatic life, and promote hazardous chemicals to get into drinking water. Effects A large percentage of material that is dumped into waters not only destroys habitats for animals but for humans as well. Below is a list of some impacts of land pollution. There are some habitats, where aquatic animals feed and live, so there is a risk of destruction of habitat of aquatic animals.
Reduced oxygen levels from decomposition of organic material dumped from drains. Reduced light penetration in the water column, from sediments and excessive algal growth, leading to oxygen depleted water. *Massively changed flow regimes, large fast flows can scour existing habitat and wash species downstream. Increased human health risks, from syringes, broken glass and cans washing onto creek banks and beaches. Reduced aesthetic appeal of areas from litter strewn on banks and beaches, thus reducing recreation and tourist appeal. Acid rain damages trees and other plants.