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Environmental Issues In Tehran
Tehran, the capital city of Iran, suffers from severe air pollution, and it is located near three major fault lines, while being the most populous region of the country. The officials have created financial incentives to encourage around 5 million citizens to leave the city. On December 16, 2019 Tehran had its highest air pollution index of 181. Air pollution Tehran is rated as one of the world’s most polluted cities. Parts of the city are often covered by smog, making breathing difficult and causing widespread pulmonary illnesses. It is estimated that about 27 people die each day from pollution-related diseases. According to local officials, 3,600 people died in a single month due to the hazardous air quality. 80% of the city's pollution is due to cars. The remaining 20% is due to industrial pollution. Other estimates suggest that motorcycles alone account for 30% of air and 50% of sound pollution in Tehran. In 2007, Iran imposed fuel rations but the plan has met little su ...
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Tehran
Tehran (; fa, تهران ) is the largest city in Tehran Province and the Capital city, capital of Iran. With a population of around 9 million in the city and around 16 million in the larger metropolitan area of Greater Tehran, Tehran is the List of largest cities of Iran, most populous city in Iran and Western Asia, and has the Largest metropolitan areas of the Middle East, second-largest metropolitan area in the Middle East, after Cairo. It is ranked 24th in the world by metropolitan area population. In the Classical antiquity, Classical era, part of the territory of present-day Tehran was occupied by Ray, Iran, Rhages, a prominent Medes, Median city destroyed in the medieval Muslim conquest of Persia, Arab, Oghuz Turks, Turkic, and Mongol conquest of Khwarezmia, Mongol invasions. Modern Ray is an urban area absorbed into the metropolitan area of Greater Tehran. Tehran was first chosen as the capital of Iran by Agha Mohammad Khan Qajar, Agha Mohammad Khan of the Qajar dyn ...
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Economic System
An economic system, or economic order, is a system of Production (economics), production, resource allocation and Distribution (economics), distribution of goods and services within a society or a given geographic area. It includes the combination of the various institutions, agencies, entities, decision-making processes, and patterns of Consumer, consumption that comprise the economic structure of a given community. An economic system is a type of social system. The mode of production is a related concept. All economic systems must confront and solve the four fundamental economic problems: * What kinds and quantities of goods shall be produced: This fundamental economic problem is anchored on the theory of pricing. The theory of pricing, in this context, has to do with the economic decision-making between the production of capital goods and consumer goods in the economy in the face of scarce resources. In this regard, the critical evaluation of the needs of the society based on ...
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Sulfur Dioxide
Sulfur dioxide ( IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a toxic gas responsible for the odor of burnt matches. It is released naturally by volcanic activity and is produced as a by-product of copper extraction and the burning of sulfur- bearing fossil fuels. Structure and bonding SO2 is a bent molecule with ''C''2v symmetry point group. A valence bond theory approach considering just ''s'' and ''p'' orbitals would describe the bonding in terms of resonance between two resonance structures. The sulfur–oxygen bond has a bond order of 1.5. There is support for this simple approach that does not invoke ''d'' orbital participation. In terms of electron-counting formalism, the sulfur atom has an oxidation state of +4 and a formal charge of +1. Occurrence Sulfur dioxide is found on Earth and exists in very small concentrations and in the atmosphere at about 1 ppm. On other p ...
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Nitrogen Dioxide
Nitrogen dioxide is a chemical compound with the formula . It is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year for use primarily in the production of fertilizers. At higher temperatures it is a reddish-brown gas. It can be fatal if inhaled in large quantities. Nitrogen dioxide is a paramagnetic, bent molecule with C2v molecular symmetry, point group symmetry. It is included in the NOx, NOx family of air pollution, atmospheric pollutants. Properties Nitrogen dioxide is a reddish-brown gas with a pungent, acrid odor above , becomes a yellowish-brown liquid below , and converts to the colorless dinitrogen tetroxide () below . The chemical bond, bond length between the nitrogen atom and the oxygen atom is 119.7 picometre, pm. This bond length is consistent with a bond order between one and two. Unlike ozone, O3, the ground state, ground electronic state of nitrogen dioxide is ...
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Atmospheric Particulate Matter
Particulates – also known as atmospheric aerosol particles, atmospheric particulate matter, particulate matter (PM) or suspended particulate matter (SPM) – are microscopic particles of solid or liquid matter suspended in the air. The term ''aerosol'' commonly refers to the particulate/air mixture, as opposed to the particulate matter alone. Sources of particulate matter can be natural or anthropogenic. They have impacts on climate and precipitation that adversely affect human health, in ways additional to direct inhalation. Types of atmospheric particles include suspended particulate matter; thoracic and respirable particles; inhalable coarse particles, designated PM, which are coarse particles with a diameter of 10 micrometers (μm) or less; fine particles, designated PM, with a diameter of 2.5 μm or less; ultrafine particles, with a diameter of 100 nm or less; and soot. The IARC and WHO designate airborne particulates as a Group 1 carcinogen. Parti ...
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Compressed Natural Gas
Compressed natural gas (CNG) is a fuel gas mainly composed of methane (CH4), compressed to less than 1% of the volume it occupies at standard atmospheric pressure. It is stored and distributed in hard containers at a pressure of , usually in cylindrical or spherical shapes. CNG is used in traditional petrol/ internal combustion engine vehicles that have been modified, or in vehicles specifically manufactured for CNG use: either alone (dedicated), with a segregated liquid fuel system to extend range (dual fuel), or in conjunction with another fuel (bi-fuel). It can be used in place of petrol (gasoline), diesel fuel, and liquefied petroleum gas (LPG). CNG combustion produces fewer undesirable gases than the aforementioned fuels. In comparison to other fuels, natural gas poses less of a threat in the event of a spill, because it is lighter than air and disperses quickly when released. Biomethane – refined biogas from anaerobic digestion or landfills – can be ...
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Petrol Engine
A petrol engine (gasoline engine in American English) is an internal combustion engine designed to run on petrol (gasoline). Petrol engines can often be adapted to also run on fuels such as liquefied petroleum gas and ethanol blends (such as ''E10'' and ''E85''). Most petrol engines use spark ignition, unlike diesel engines which typically use compression ignition. Another key difference to diesel engines is that petrol engines typically have a lower compression ratio. Design Thermodynamic cycle Most petrol engines use either the four-stroke Otto cycle or the two-stroke cycle. Petrol engines have also been produced using the Miller cycle and Atkinson cycle. Layout Most petrol-powered piston engines are straight engines or V engines. However, flat engines, W engines and other layouts are sometimes used. Wankel engines are classified by the number of rotors used. Compression ratio Cooling Petrol engines are either air-cooled or water-cooled. Ignitio ...
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The Economist
''The Economist'' is a British weekly newspaper printed in demitab format and published digitally. It focuses on current affairs, international business, politics, technology, and culture. Based in London, the newspaper is owned by The Economist Group, with its core editorial offices in the United States, as well as across major cities in continental Europe, Asia, and the Middle East. In 2019, its average global print circulation was over 909,476; this, combined with its digital presence, runs to over 1.6 million. Across its social media platforms, it reaches an audience of 35 million, as of 2016. The newspaper has a prominent focus on data journalism and interpretive analysis over original reporting, to both criticism and acclaim. Founded in 1843, ''The Economist'' was first circulated by Scottish economist James Wilson to muster support for abolishing the British Corn Laws (1815–1846), a system of import tariffs. Over time, the newspaper's coverage expanded furthe ...
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The Huffington Post
''HuffPost'' (formerly ''The Huffington Post'' until 2017 and sometimes abbreviated ''HuffPo'') is an American progressive news website, with localized and international editions. The site offers news, satire, blogs, and original content, and covers politics, business, entertainment, environment, technology, popular media, lifestyle, culture, comedy, healthy living, women's interests, and local news featuring columnists. It was created to provide a progressive alternative to the conservative news websites such as the Drudge Report. The site offers content posted directly on the site as well as user-generated content via video blogging, audio, and photo. In 2012, the website became the first commercially run United States digital media enterprise to win a Pulitzer Prize. Founded by Andrew Breitbart, Arianna Huffington, Kenneth Lerer, and Jonah Peretti, the site was launched on May 9, 2005 as a counterpart to the Drudge Report. In March 2011, it was acquired by AOL for U ...
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Ozone
Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the lower atmosphere to ( dioxygen). Ozone is formed from dioxygen by the action of ultraviolet (UV) light and electrical discharges within the Earth's atmosphere. It is present in very low concentrations throughout the latter, with its highest concentration high in the ozone layer of the stratosphere, which absorbs most of the Sun's ultraviolet (UV) radiation. Ozone's odour is reminiscent of chlorine, and detectable by many people at concentrations of as little as in air. Ozone's O3 structure was determined in 1865. The molecule was later proven to have a bent structure and to be weakly diamagnetic. In standard conditions, ozone is a pale blue gas that condenses at cryogenic temperatures to a dark blue liquid and finally a violet-black ...
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Thermal Inversion
In meteorology, an inversion is a deviation from the normal change of an atmospheric property with altitude. It almost always refers to an inversion of the air temperature lapse rate, in which case it is called a temperature inversion. Normally, air temperature decreases with an increase in altitude, but during an inversion warmer air is held above cooler air. An inversion traps air pollution, such as smog, close to the ground. An inversion can also suppress convection by acting as a "cap". If this cap is broken for any of several reasons, convection of any moisture present can then erupt into violent thunderstorms. Temperature inversion can notoriously result in freezing rain in cold climates. Normal atmospheric conditions Usually, within the lower atmosphere (the troposphere) the air near the surface of the Earth is warmer than the air above it, largely because the atmosphere is heated from below as solar radiation warms the Earth's surface, which in turn then warms the ...
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Caspian Sea
The Caspian Sea is the world's largest inland body of water, often described as the List of lakes by area, world's largest lake or a full-fledged sea. An endorheic basin, it lies between Europe and Asia; east of the Caucasus, west of the broad steppe of Central Asia, south of the fertile plains of Southern Russia in Eastern Europe, and north of the mountainous Iranian Plateau of Western Asia. It covers a surface area of (excluding the highly saline lagoon of Garabogazköl to its east) and a volume of . It has a salinity of approximately 1.2% (12 g/L), about a third of the salinity of average seawater. It is bounded by Kazakhstan to the northeast, Russia to the northwest, Azerbaijan to the southwest, Iran to the south, and Turkmenistan to the southeast. The sea stretches nearly from north to south, with an average width of . Its gross coverage is and the surface is about below sea level. Its main freshwater Inflow (hydrology), inflow, Europe's longest river, the Volga, enters ...
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