CONTENTS:-

Atmosphere Gases AIR FOR LIFE Air quality Pollutants Major primary pollutants produced by human activity include: global warming Particulates Ozone layer CFC Secondary pollutants include US Airways Acid rain ACID RAIN HISOTRY

ATMOSPHERE.

The Earth's atmosphere, or air, is made of gases like nitrogen, carbon dioxide and oxygen.  Every time we take a breath, we use the oxygen part of air.  When we breathe out, carbon dioxide goes into the air.  Sometimes particles of water, dust and bits of smoke can be in the air too.

GASES oxygen :-(O2), (20.95% of volume) almost entirely of biological

origin, produced by auto-Trophic organisms (plants), thanks to the function of the chlorophyll in the photosynthesis;

carbon dioxide :-(CO2) (in varying proportions) of natural and anthropogenic origin (i.e. generated by man’s activities: for instance combustion processes);

water :-(H2O), (in varying proportions) that may be present in the atmosphere as steam or in a liquid or solid state;

nitrogen :-(N2), equal to 78% of the volume and argon (A) equal to 0.93% of the volume, both inert gases;

other gases :-such as neon, krypton, xenon, hydrogen and others that taken together make up just 0.01% of the volume of the atmosphere.  Solid and liquid particles (dust, spores, pollen, etc.) are present in limited amounts and their size, physical characteristics and chemical properties are extremely variable.

AIR FOR LIFEThe atmosphere is an essential component for life on

Earth, since it contains the oxygen that living organisms need to breathe. In addition, it filters out the harmful solar radiations, reflecting them and preventing them from reaching the soil, and allows the Earth’s surface to maintain the right temperature for plants and animals to live. The atmosphere is also the place where the main weather phenomena (wind, rain, snow, etc.), that compose the climate, occur.

AIR QUALITY "Bad air quality" and "Air quality" redirect here. For the obsolete

medical theory, see Bad air. For the measure of how polluted the air is , see Air quality index.

Not to be confused with Qualities of air. Air pollution from a World War II wartime production plant Air pollution is the introduction of chemicals, particulates,

biological materials, or other harmful materials into the Earth's atmosphere, possibly causing disease, death to humans, damage to other living organisms such as food crops, or the natural or built environment.

The atmosphere is a complex 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.

Indoor air pollution (see Airlog) and urban air quality are listed as two of the world’s worst toxic pollution problems in the 2008 Blacksmith Institute World's Worst Polluted Places report.

POLLUTANTS Main articles: Pollutant and Greenhouse gas Before flue-gas desulfurization was installed, the emissions from

this power plant in New Mexico contained excessive amounts of sulfur dioxide.

Schematic drawing, causes and effects of air pollution: (1) greenhouse effect, (2) particulate contamination, (3) increased UV radiation, (4) acid rain, (5) increased ground level ozone concentration, (6) increased levels of nitrogen oxides.

An air pollutant is a substance in the air that can have adverse effects on humans and the ecosystem. The substance can be solid particles, liquid droplets, or gases. A pollutant can be of natural origin or man-made. Pollutants are classified as primary or secondary. Primary pollutants are usually produced from a process, such as ash from a volcanic eruption. Other examples include carbon monoxide gas from motor vehicle exhaust, or the sulfur dioxide released from factories. Secondary pollutants are not emitted directly. Rather, they form in the air when primary pollutants react or interact. Ground level ozone is a prominent example of a secondary pollutant. Some pollutants may be both primary and secondary: they are both emitted directly and formed from other primary pollutants.

MAJOR PRIMARY POLLUTANTS PRODUCED BY HUMAN ACTIVITY INCLUDE: SOx) - particularly sulfur dioxide, a chemical compound with the

formula SO2. SO2 is produced by volcanoes and in various industrial processes. Coal and petroleum often contain sulfur compounds, and 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) - Nitrogen oxides, particularly nitrogen dioxide, are expelled from high temperature combustion, and are also produced during thunderstorms by electric discharge. They can be seen as a brown haze dome above or a plume downwind of cities. Nitrogen dioxide is a chemical compound with the formula NO2. It is one of several nitrogen oxides. One of the most prominent air pollutants, this reddish-brown toxic gas has a characteristic sharp, biting odor.

Carbon monoxide:- (CO)- CO is a colorless, odorless, toxic yet non-irritating 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.

GLOBAL WARMING VOCs are a well known outdoor air pollutant. They

are categorized as either methane (CH4) or non-methane (NMVOCs). Methane is an extremely efficient greenhouse gas which contributes to enhanced global warming. Other hydrocarbon VOCs are also significant greenhouse gases because of their role in creating ozone and prolonging the life of methane in the atmosphere. This effect varies depending on local air quality. The aromatic NMVOCs benzene, toluene and xylem are suspected carcinogens and may lead to leukemia with prolonged exposure. 1,3-butadiene is another dangerous compound often associated with industrial use.

PARTICULATES

Particulates, alternatively referred to as particulate matter (PM), atmospheric particulate matter, or fine particles, are tiny particles of solid or liquid suspended in a gas. In contrast, aerosol refers to combined particles and gas. 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 worldwide, anthropogenic aerosols—those made by human activities—currently account for approximately 10 percent of our atmosphere. Increased levels of fine particles in the air are linked to health hazards such as heart disease, altered lung function and lung cancer.

OZONE LAYER connected to airborne fine particles are linked to cardiopulmonary

disease. Toxic metals, such as lead and mercury, especially their compounds. Chlorofluorocarbons (CFCs) - harmful to the ozone layer; emitted from

products currently banned from use <-- These are gases which are released from air conditioners,

refrigerators, aerosol sprays, etc. CFC's on being released into the air rises to stratosphere. Here they come in contact with other gases and damage the ozone layer. This allows harmful ultraviolet rays to reach the earth's surface. This can lead to skin cancer, disease to eye and can even cause damage to plants.

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 — such as from garbage, sewage, and industrial processes Radioactive pollutants - produced by nuclear explosions, nuclear

events, war explosives, and natural processes such as the radioactive decay of radon.

CFC connected to airborne fine particles are linked to cardiopulmonary

disease. Toxic metals, such as lead and mercury, especially their compounds. Chlorofluorocarbons (CFCs) - harmful to the ozone layer; emitted from

products currently banned from use <-- These are gases which are released from air conditioners, refrigerators,

aerosol sprays, etc. CFC's on being released into the air rises to stratosphere. Here they come in contact with other gases and damage the ozone layer. This allows harmful ultraviolet rays to reach the earth's surface. This can lead to skin cancer, disease to eye and can even cause damage to plants.

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 — such as from garbage, sewage, and industrial processes Radioactive pollutants - produced by nuclear explosions, nuclear events,

war explosives, and natural processes such as the radioactive decay of radon.

Particulates created from gaseous primary pollutants and compounds in photochemical smog. Smog is a kind of air pollution. 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 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 DirectiveA variety of persistent organic pollutants, which can attach to particulates

Secondary pollutants include

US AIRWAYS US Airways is a major U.S. airlzzine owned by the American Airlines

Group. It operates an extensive international and domestic network, with 193 destinations in 24 countries in North America, South America, Europe, and the Middle East.

The airline is a member of the Star Alliance and utilizes a fleet of 343mainline jet aircraft, as well as 278 regional jet and turbo-prop aircraft operated by contract and subsidiary airline as US Airways Express. The carrier operates the US Airways Shuttle, a US Airways brand which provides hourly service between Boston, New York City, and Washington, D.C. As of October 2013, US Airways employed 32,312 people worldwide and operated 3,028 daily flights (1,241 US Airways Mainline, 1,790 US Airways Express).

In February 2013, American Airlines and US Airways announced plans to merge, creating the largest airline in the world. The holding companies of American and US Airways merged effective December 9, 2013. In preparation for their eventual integration, the airlines began offering reciprocal frequent flyer benefits on January 7, 2014,and US Airways has announced plans to leave Star Alliance to join Oneworld as an affiliate member of American Airlines on March 31, 2014. The combined airline will carry the American Airlines name and branding, and will maintain the existing US Airways hubs in Charlotte, Philadelphia, and Phoenix for a period of at least five years under the terms of a settlement with the Department of Justice and several state attorneys-general. US Airways management will run the combined airline from the American headquarters in Fort Worth, Texas.

ACID RAIN Acid rain:- is a rain or any other form

of precipitation that is unusuallyacidic, meaning that it possesses elevated levels of hydrogen ions (low pH). It can have harmful effects on plants, aquatic animals and infrastructure. Acid rain is caused by emissions of sulfur dioxide andnitrogen oxide, which react with the water molecules in the atmosphere to produce acids. Governments have made efforts since the 1970s to reduce the release of sulfur dioxide into the atmospherewith positive results. Nitrogen oxides can also be produced naturally by lightning strikes and sulfur dioxide is produced by volcaniceruptions. The chemicals in acid rain can cause paint to peel,corrosion of steel structures such as bridges, and erosion of stone statues.

ACID RAIN HISOTRY The corrosive effect of polluted, acidic city air on limestone and marble was

noted in the 17th century by John Evelyn, who remarked upon the poor condition of the Arundel marbles. Since the Industrial Revolution, emissions of sulfur dioxide and nitrogen oxides into the atmosphere have increased.[In 1852, Robert Angus Smith was the first to show the relationship between acid rain and atmospheric pollution in Manchester, England.

Though acidic rain was discovered in 1853, it was not until the late 1960s that scientists began widely observing and studying the phenomenon. [he term "acid rain" was coined in 1872 by Robert Angus Smith. Canadian Harold Harvey was among the first to research a "dead" lake. Public awareness of acid rain in the U.S increased in the 1970s after The New York Times published reports from the Hubbard Brook Experimental Forest in New Hampshire of the myriad deleterious environmental effects shown to result from it.

Occasional pH readings in rain and fog water of well below 2.4 have been reported in industrialized areas. Industrial acid rain is a substantial problem in China and Russia and areas downwind from them. These areas all burn sulfur-containing coal to generate heat and electricity.[

The problem of acid rain has not only increased with population and industrial growth, but has become more widespread. The use of tall smokestacks to reduce local pollution has contributed to the spread of acid rain by releasing gases into regional atmospheric circulation.[Often deposition occurs a considerable distance downwind of the emissions, with mountainous regions tending to receive the greatest deposition (simply because of their higher rainfall). An example of this effect is the low pH of rain which falls in Scandinavia.

ACID RAIN HISOTRY n 1980, the U.S. Congress passed an Acid Deposition Act.[This Act established an 18-year assessment

and research program under the direction of the National Acidic Precipitation Assessment Program (NAPAP). NAPAP looked at the entire problem from a scientific perspective. It enlarged a network of monitoring sites to determine how acidic the precipitation actually was, and to determine long term trends, and established a network for dry deposition. It looked at the effects of acid rain and funded research on the effects of acid precipitation on freshwater and terrestrial ecosystems, historical buildings, monuments, and building materials. It also funded extensive studies on atmospheric processes and potential control programs.

From the start, policy advocates from all sides attempted to influence NAPAP activities to support their particular policy advocacy efforts, or to disparage those of their opponents.the U.S. Government's scientific enterprise, a significant impact of NAPAP were lessons learned in the assessment process and in environmental research management to a relatively large group of scientists, program managers and the public.[ In 1991, DENR provided its first assessment of acid rain in the United States. It reported that 5% of New England Lakes were acidic, with sulfates being the most common problem. They noted that 2% of the lakes could no longer support Brook Trout, and 6% of the lakes were unsuitable for the survival of many species of minnow. Subsequent Reports to Congress have documented chemical changes in soil and freshwater ecosystems, nitrogen saturation, decreases in amounts of nutrients in soil, episodic acidification, regional haze, and damage to historical monuments.

Meanwhile, in 1989, the U.S. Congress passed a series of amendments to the Clean Air Act. Title IV of these amendments established the Acid Rain Program, a cap and trade system designed to control emissions of sulfur dioxide and nitrogen oxides. Title IV called for a total reduction of about 10 million tons of SO2 emissions from power plants. It was implemented in two phases. Phase I began in 1995, and limited sulfur dioxide emissions from 110 of the largest power plants to a combined total of 8.7 million tons of sulfur dioxide. One power plant in New England (Merrimack) was in Phase I. Four other plants (Newington, Mount Tom, Brayton Point, and Salem Harbor) were added under other provisions of the program. Phase II began in 2000, and affects most of the power plants in the country.

During the 1990s, research continued. On March 10, 2005, EPA issued the Clean Air Interstate Rule (CAIR). This rule provides states with a solution to the problem of power plant pollution that drifts from one state to another. CAIR will permanently cap emissions of SO2and NOx in the eastern United States. When fully implemented, CAIR will reduce SO2 emissions in 28 eastern states and the District of Columbia by over 70% and NOx emissions by over 60% from 2003 levels.[