Supervised by : Prof. Madi jaghbir Atmospheric Air Supervised by : Prof. Madi jaghbir

Layers of the atmosphere The atmosphere can be divided into layers based on its temperature. These layers are the troposphere, the stratosphere, the mesosphere and the thermosphere. A further region, beginning about 400 km above the Earth's surface, is called the exosphere. (1)

Layers of the atmosphere (2) Characteristics Range (Km) Layer Temperature decrease with height contains about 80% of all of the air in the atmosphere and almost all of the water vapor . Turbulent and changeable weather . Earth's Surface - 10 troposphere Temperature increase with height . Very low pressure . Ozone layer is here protect earth from UV radiation. Tropopause - 30 stratosphere very cold . Meteors burn up in this layer . Stratopause – 50 mesosphere Very low pressure , low density of molecules . International space station orbits here. Northern light due to ionization of atmosphere by solar radiation . Mesopause - 400 thermosphere contains mainly oxygen and hydrogen atoms. > thermopause exosphere

Earth's atmospheric air The Earth's atmospheric air is a colorless, odorless and tasteless mixture of gases consisting mostly of nitrogen (N2) and oxygen (O2). It is the part of Earth's atmosphere that humans and all other animals breathe in order to obtain the oxygen needed to sustain life. The Earth's atmosphere not only contains the air we breathe, but also it holds clouds of moisture (water vapor) that become the water we drink. Furthermore, it protects life from meteors and harmful solar radiation and warms the Earth's surface by heat retention. As a result , the atmosphere is an envelope that protects all life on Earth. (3)

Composition of the atmospheric air There are fourteen gases present in filtered dry air. Two of the gases, nitrogen and oxygen make up 99.03 percent of the clean, dry air. The other listed gases total to 0.97 percent. greenhouse gases that are present in very minute amounts include: water vapor, carbon dioxide, methane, nitrous oxide, and ozone. The atmospheric air is rarely, if ever, dry. Water vapor is nearly always present up to about 4% of the total volume. In the desert regions, when dry winds are blowing, the water vapor content will be near zero.

Cont…. Unfiltered air contains minute amounts of various types of particulate matter derived from sources such as dust, pollen and spores, sea spray, volcanoes, meteoroids and industrial activities. (3)

Air pollution Air pollution : is contamination of the indoor or outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere. Household combustion devices, motor vehicles, industrial facilities and forest fires are common sources of air pollution. Pollutants of major public health concern include particulate matter, carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide. Outdoor and indoor air pollution cause respiratory and other diseases, which can be fatal. (4)

Air pollution occurs when the air contains gases, dust, fumes or odors in harmful amounts. That is, amounts which could be harmful to the health or comfort of humans and animals or which could cause damage to plants and materials. The substances that cause air pollution are called pollutants. Pollutants that are pumped into our atmosphere and directly pollute the air are called primary pollutants. Primary pollutant examples include carbon monoxide from car exhausts and sulfur dioxide from the combustion of coal. Further pollution can arise if primary pollutants in the atmosphere undergo chemical reactions. The resulting compounds are called secondary pollutants. Photochemical smog is an example of this. (5)

Sources of air pollution Most air toxics originate from human-made sources, including: mobile sources (e.g., cars, trucks, buses) . stationary sources (e.g., factories, refineries, power plants). indoor sources (e.g., building materials and activities such as cleaning). (6) naturally occurring sources such as windblown dust, and volcanic eruptions . (7)

stationary sources There are two types of stationary sources that generate routine emissions of air toxics: "Major" sources : are defined as sources that emit 10 tons per year of any of the listed toxic air pollutants, or 25 tons per year of a mixture of air toxics. These sources may release air toxics from equipment leaks, when materials are transferred from one location to another, or during discharge through emission stacks or vents "Area" sources : are defined as sources that emit less than 10 tons per year of a single air toxic, or less than 25 tons per year of a combination of air toxics. these sources consist of smaller-size facilities that release lesser quantities of toxic pollutants into the air. Though emissions from individual area sources are often relatively small, collectively their emissions can be of concern - particularly where large numbers of sources are located in heavily populated areas. (6)

Cont… EPA published the initial list of "source categories" in 1992 and since that time has issued several revisions and updates to the list and promulgation schedule. For each listed source category, EPA indicates whether the sources are considered to be "major" sources or "area" sources. The 1990 Clean Air Act Amendments direct EPA to set standards for all major sources of air toxics (and some area sources that are of particular concern). (6) EPA : United States Environmental Protection Agency 

Types of air pollutant in the U.S., substances in the air that are harmful are classified in two ways, as criteria pollutants or as hazardous air pollutants (HAPs). (8)

Criteria pollutants U.S. EPA uses six Criteria pollutants as indicators of air quality, and has established for each of them a maximum concentration above which adverse effects on human health may occur. These threshold concentrations are called National Ambient Air Quality Standards (NAAQS). The six criteria pollutants are: Particulate matter Ground-level ozone Nitrogen dioxide Carbon monoxide Sulfur dioxide Lead .

When an area does not meet the air quality standard for one of the criteria pollutants, it may be subject to the formal rule-making process which designates it as non- attainment. The Clean Air Act further classifies ozone, carbon monoxide, and some particulate matter non-attainment areas based on the magnitude of an area's problem. Non-attainment classifications may be used to specify what air pollution reduction measures an area must adopt, and when the area must reach attainment. A major issue related to two of the criteria pollutants is acid rain because sulfur dioxide (SO2) and nitrogen oxides (NOx) are the primary causes of acid rain.

hazardous air pollutants Toxic air pollutants, also known as hazardous air pollutants (HAPs), are those pollutants that are known or suspected to cause cancer or other serious health effects, such as reproductive effects or birth defects, or adverse environmental effects. The U.S. EPA is working with state, local, and tribal governments to reduce air toxics releases of 188 pollutants to the environment. Examples of toxic air pollutants include benzene, which is found in gasoline; perchlorethlyene, which is emitted from some dry cleaning facilities; and methylene chloride, which is used as a solvent and paint stripper by a number of industries. Examples of other listed air toxics include dioxins, asbestos, toluene, and metals such as cadmium, mercury, chromium, and lead compounds.

worldwide statistics Air pollution is a worldwide problem , it is much worse in some countries than in others . In 2009, the 27 members of the European Union reported a cumulative drop in sulfur oxides by roughly 80% since 1990. Despite major gains in lowering pollution throughout the European Union, some major metropolitan cities like London are currently suffering from some of the worst air quality they've ever seen. A study by the World Health Organization reported in national geographic news states that air pollution in China is related to around 656,000 deaths every year throughout the country. (9)

Cont … The same report by the World Health Organization states that an average of 2 million people are killed worldwide every year due to air pollution. In India, almost half of all monitored cities have above-average or critical levels of particulate matter pollution below 10 micrometers.

Cont …. (10) صصصصصصص

References (1) https://www.niwa.co.nz/education-and-training/schools/students/layers (2) https://www.google.com/search?q=layers+of+the+atmosphere&biw=1280&bih=640&tbm=isch&tbo=u&s ource=univ&sa=X&ved=0ahUKEwj2sOOItL_JAhVL1xQKHZwtC_0Q7AkIKg#imgrc=fwkSau0cOZy44M %3A . (3) http://www.eoearth.org/view/article/170977/ . (4) http://www.who.int/topics/air_pollution/en/ . (5) http://www.epa.vic.gov.au/air/aq4kids/pollution.asp . (6) http://www3.epa.gov/airtoxics/pollsour.html . (7) http://www3.epa.gov/airquality/cleanair.html (8) http://www3.epa.gov/airquality/aqmportal/pollutant_types.htm . (9) http://greenliving.lovetoknow.com/Air_Pollution_Statistics . (10) https://www.google.jo/search?q=air+pollution+statistics+world&sa=X&biw=1280&bih=640&tbm=isch&t bo=u&source=univ&ved=0ahUKEwj59837nrjJAhVBtQ8KHQjCBhwQsAQIGg#imgrc=39tRN_on2iqv4M %3A . (11) http://alraicenter.com/alraicenter.com/User_Site/Site/images/stories/pdf/air.pdf .