Words: 2001
Blacksmith Institute World’s Worst Polluted Places report. [l] 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. [2] Pollutants can be classified as primary or secondary. Usually, primary pollutants are 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. Some pollutants may be both primary and secondary: that is, they are both emitted directly and formed from other primary pollutants. About 4 percent of deaths in the United States can be attributed to air pollution, according to the Environmental Science Engineering Program at the Harvard School of Public Health.
Major primary pollutants produced by human activity include: Sulfur oxides (SOX) – specially sulfur dioxide, a chemical compound with the formula SIS. SIS 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 SIS, usually in the presence of a catalyst such as NON, forms HOSES, 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 (Knox) – 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 NON. It is one of the several nitrogen oxides. This reddish-brown toxic gas has a characteristic sharp, biting odor. NON is one of the most prominent air pollutants. C] Carbon monoxide – is a colorless, odorless, 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. D Carbon dioxide (CO) – a colorless, odorless, non-toxic greenhouse gas associated with ocean acidification, emitted from sources such as combustion, cement production, and aspiration C Volatile organic compounds – Voss are an important outdoor air pollutant. In this field they are often divided into the separate categories of methane (CHI) and non-methane (Moves). Methane is an extremely efficient green house gas which contributes to enhanced global warming.
Other hydrocarbon Voss are also significant greenhouse gases via their role in creating ozone and in prolonging the life of methane in the atmosphere, although the effect varies depending on local air quality. Within the Moves, the aromatic compounds benzene, toluene and Selene are suspected organogenesis and may lead to leukemia through prolonged exposure. 1,3- butadiene is another dangerous compound which is often associated with industrial uses. [1 Particulate matter – Particulates, alternatively referred to as particulate matter (PM) or fine particles, are tiny particles of solid or liquid suspended in a gas.
In contrast, aerosol refers to particles and the gas together. Sources of particulate matter can be man made or natural. Some particulates occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living vegetation, and sea spray. Human activities, such as the burning of fossil fuels in vehicles, power plants and various industrial processes also generate significant amounts of aerosols. Averaged over the globe, anthropogenic aerosols-??those made by human activities-??currently account for about 10 percent of the total amount of aerosols in our atmosphere.
Increased levels of fine particles in the air are linked to health hazards such as heart altered lung function and lung cancer. N Persistent free radicals connected to airborne fine particles could cause cardiopulmonary ; Toxic metals, such as lead, cadmium and copper. Chlorofluorocarbons (CIFS) – harmful to the ozone layer emitted from products currently banned from use. CLC Ammonia (NH) – emitted from agricultural processes. Ammonia is a compound with the formula NH. It is normally encountered as a gas with a characteristic pungent odor.
Ammonia contributes significantly to the nutritional needs Of terrestrial organisms by serving as a precursor to foodstuffs and fertilizers. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceuticals. Although in wide use, ammonia is both caustic and hazardous. C Odors such as from garbage, sewage, and industrial recesses CLC 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 ultraviolet light room the sun to form secondary pollutants that also combine with the primary emissions to form photochemical smog.
Ground level ozone (03) formed from Knox and Voss. Ozone (03) 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.
D Approximately nitrate (PAN) – similarly formed from Knox and Voss. Minor air pollutants include: CIA 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. CLC 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 rainspout, fasciculate in human and animal tissue, abominating in food chains, and to have potential significant impacts on human health and the environment. Sources Dust storm approaching Stratford, Texas Controlled burning of a field outside absorbents, Georgia in preparation for spring planting Sources of air pollution refer to the various locations, activities or factors which are responsible for the releasing of pollutants in the atmosphere.
These sources can be classified into two major categories which are: Anthropogenic sources (human activity) mostly related to burning efferent kinds of fuel D "Stationary Sources” include smoke stacks of power plants, manufacturing facilities (factories) and waste incinerators, as well as furnaces and other types of fuel-burning heating devices a "Mobile Sources” include motor vehicles, marine vessels, aircraft and the effect of sound etc. L] Chemicals, dust and controlled burn practices in agriculture and forestry management.
Controlled or prescribed burning is a technique sometimes used in forest management, farming, prairie restoration or greenhouse gas abatement. Fire is a natural part of both forest and grassland ecology and enthroned fire can be a tool for foresters. Controlled burning stimulates the germination of some desirable forest trees, thus renewing the forest. Fumes from paint, hair spray, varnish, aerosol sprays and other solvents CLC Waste deposition in landfills, which generate methane. Methane is not toxic; however, it is highly flammable and may form explosive mixtures with air.
Methane is also an asphyxia’s and may displace oxygen in an enclosed space. Asphyxia or suffocation may result if the oxygen concentration is reduced to below 19. 5% by displacement C] Military, such as nuclear weapons, toxic asses, germ warfare and rocketry Natural sources C] Dust from natural sources, usually large areas of land with little or no vegetation. C Methane, emitted by the digestion of food by animals, for example cattle. Radon gas from radioactive decay within the Earth’s crust Radon is a colorless, odorless, naturally occurring, radioactive noble gas that is formed from the decay of radium.
It is considered to be a health hazard. Radon gas from natural sources can accumulate in buildings, especially in confined areas such as the basement and it is the second most frequent cause of lung cancer, after cigarette smoking. њ Smoke and carbon monoxide from wildfires. C] Vegetation, in some regions, emits environmentally significant amounts of Voss on warmer days. These Voss react with primary anthropogenic pollutants-??specifically, Knox, SIS, and anthropogenic organic carbon compounds-??to produce a seasonal haze of secondary pollutants. 6] C Volcanic activity, which produce sulfur, chlorine, and ash particulates. Emission factors Air pollutant emission factors are representative values that people attempt to relate the quantity of a pollutant released to the ambient air with an activity associated with the release of that pollutant. These factors are usually expressed as the weight of pollutant divided by a unit weight, volume, distance, or duration of the activity emitting the pollutant (e. G. , kilograms of particulate emitted per anagram of coal burned). Such factors facilitate estimation of emissions from various sources of air pollution.
In most cases, these factors are simply averages of all available data of acceptable quality, and are generally assumed to be representative of long-term averages. The United States Environmental Protection Agency has published a compilation Of air pollutant emission factors for a multitude of industrial sources. 7] The united Kingdom, Australia,Canada and many other countries have published similar compilations, as well as the European Environment Indoor air quality (IAC) A lack of ventilation indoors concentrates air pollution where people often spend the majority of their time.
Radon (Urn) gas, a carcinogen, is exuded from the Earth in certain locations and trapped inside houses. Building materials including carpeting and plywood emit formaldehyde (HOC) gas. Paint and solvents give off volatile organic compounds (Voss) as they dry. Lead paint can degenerate into dust and be inhaled. Intentional air pollution is introduced with the use Of air fresheners, incense, and other scented items. Controlled wood fires in stoves and fireplaces can add significant amounts of smoke particulates into the air, inside and out. 13] Indoor pollution fatalities may be caused by using pesticides and other chemical sprays indoors without proper ventilation. Carbon monoxide (CO) poisoning and fatalities are often caused by faulty vents and chimneys, or by the burning of charcoal indoors. Chronic carbon monoxide poisoning can result even from poorly adjusted pilot lights. Traps are built into all domestic plumbing to keep sewer gas, hydrogen sulfide, out of interiors. Clothing emits transcontinental, or other dry cleaning fluids, for days after dry cleaning.
Though its use has now been banned in many countries, the extensive use of asbestos in industrial and domestic environments in the past has left a potentially very dangerous material in many localities. Asbestosis is a chronic inflammatory medical condition affecting the tissue of the lungs. It occurs after long-term, heavy exposure to asbestos from asbestos-containing materials in structures. Sufferers have severe dyspepsia (shortness of breath) and are at an increased sis regarding several different types of lung cancer.
As clear explanations are not always stressed in non-technical literature, care should be taken to distinguish between several forms of relevant diseases. According to the World Health Organization (WHO)Ceded link], these may defined as; asbestosis, lung cancer, and Mesopotamia (generally a very rare form of cancer, when more widespread it is almost always associated with prolonged exposure to asbestos). Biological sources of air pollution are also found indoors, as gases and airborne particulates.