Problem Solution free essay sample

Air pollution  is the introduction of  chemicals,  particulate matter, or  biological materials  that cause harm or discomfort to humans or other living organisms, or cause damage to the  natural environment  or  built 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 Earths  ecosystems. A substance in the air that can cause harm to humans and the environment is known as an air pollutant. 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. We will write a custom essay sample on Problem Solution or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page 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  Ã¢â‚¬â€ 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. [citation needed] MAJOR PRIMARY POLLUTANTS PRODUCED BY HUMAN ACTIVITY INCLUDE: * Sulfur oxides  (SOx) especially sulphur dioxide, a chemical compound with the formula SO2. SO2  is produced by volcanoes and in various industrial processes. Since coal and petroleum often contain sulphur 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, 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. * Carbon dioxide  (CO2) a colourless, odorless, non-toxic  greenhouse gas  associated with  ocean acidification, emitted from sources such as combustion, cement production, and  respiration * Volatile organic compounds   VOCs are an important outdoor air pollutant. In this field they are often divided into the separate categories of methane (CH4) and non-methane (NMVOCs). Methane is an extremely efficient greenhouse gas which contributes to enhanced global warming. Other hydrocarbon VOCs 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 NMVOCs, the aromatic compounds benzene, toluene and xylene are suspected carcinogens and may lead to leukemia through prolonged exposure. 1,3-butadiene is another dangerous compound which is often associated with industrial uses. * 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 disease,[3]altered lung function and lung cancer. * Persistent free radicals  connected to airborne fine particles could cause cardiopulmonary disease. [4][5] * Toxic  metals, such as  lead,  cadmium  and  copper. * Chlorofluorocarbons  (CFCs) harmful to the  ozone layer  emitted from products currently banned from use. * Ammonia  (NH3) emitted from agricultural processes. Ammonia is a compound with the formula NH3. 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. * Odors  Ã¢â‚¬â€ 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  ultrav iolet  light from the sun 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.