Nitrogen dioxide is the chemical compound with the formula NO2. It is one of several nitrogen oxides. NO2 is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year, used in the production of fertilizers. At higher temperatures it is a reddish-brown gas that has a characteristic sharp, biting odor and is a prominent air pollutant. Nitrogen dioxide is a bent molecule with C2v point group symmetry. Nitrogen dioxide is a reddish-brown gas above 21.2 °C with a pungent, acrid odor, becomes a yellowish-brown liquid below 21.2 °C, converts to the colorless dinitrogen tetroxide below −11.2 °C. The bond length between the nitrogen atom and the oxygen atom is 119.7 pm. This bond length is consistent with a bond order between two. Unlike ozone, O3, the ground electronic state of nitrogen dioxide is a doublet state, since nitrogen has one unpaired electron, which decreases the alpha effect compared with nitrite and creates a weak bonding interaction with the oxygen lone pairs.
The lone electron in NO2 means that this compound is a free radical, so the formula for nitrogen dioxide is written as •NO2. The reddish-brown color is a consequence of preferential absorption of light in the blue, although the absorption extends throughout the visible and into the infrared. Absorption of light at wavelengths shorter than about 400 nm results in photolysis. Nitrogen dioxide arises via the oxidation of nitric oxide by oxygen in air: 2 NO + O2 → 2 NO2Nitrogen dioxide is formed in most combustion processes using air as the oxidant. At elevated temperatures nitrogen combines with oxygen to form nitric oxide: O2 + N2 → 2 NOIn the laboratory, NO2 can be prepared in a two-step procedure where dehydration of nitric acid produces dinitrogen pentoxide, which subsequently undergoes thermal decomposition: 2 HNO3 → N2O5 + H2O 2 N2O5 → 4 NO2 + O2The thermal decomposition of some metal nitrates affords NO2: 2 Pb2 → 2 PbO + 4 NO2 + O2Alternatively, reduction of concentrated nitric acid by metal.
4 HNO3 + Cu → Cu2 + 2 NO2 + 2 H2OOr by adding concentrated nitric acid over tin. 4 HNO3 + Sn → H2O + H2SnO3 + 4 NO2 NO2 exists in equilibrium with the colourless gas dinitrogen tetroxide: 2 NO2 ⇌ N2O4The equilibrium is characterized by ΔH = −57.23 kJ/mol, exothermic. NO2 is favored at higher temperatures, while at lower temperatures, dinitrogen tetroxide predominates. Dinitrogen tetroxide can be obtained as a white solid with melting point −11.2 °C. NO2 is paramagnetic due to its unpaired electron; the chemistry of nitrogen dioxide has been investigated extensively. At 150 °C, NO2 decomposes with release of oxygen via an endothermic process: 2 NO2 → 2 NO + O2 As suggested by the weakness of the N–O bond, NO2 is a good oxidizer, it will combust, sometimes explosively, with many compounds, such as hydrocarbons. It hydrolyses to give nitric acid and nitrous acid: 2 NO2 + H2O → HNO2 + HNO3This reaction is one step in the Ostwald process for the industrial production of nitric acid from ammonia; this reaction is negligibly slow at low concentrations of NO2 characteristic of the ambient atmosphere, although it does proceed upon NO2 uptake to surfaces.
Such surface reaction is thought to produce gaseous HNO2 in indoor environments. Nitric acid decomposes to nitrogen dioxide by the overall reaction: 4 HNO3 → 4 NO2 + 2 H2O + O2The nitrogen dioxide so formed confers the characteristic yellow color exhibited by this acid. NO2 is used to generate anhydrous metal nitrates from the oxides: MO + 3 NO2 → M2 + NO Alkyl and metal iodides give the corresponding nitrites: 2 CH3I + 2 NO2 → 2 CH3NO2 + I2TiI4 + 4 NO2 → Ti4 + 2 I2 NO2 is introduced into the environment by natural causes, including entry from the stratosphere, bacterial respiration and lightning; these sources make NO2 a trace gas in the atmosphere of Earth, where it plays a role in absorbing sunlight and regulating the chemistry of the troposphere in determining ozone concentrations. NO2 is used as an intermediate in the manufacturing of nitric acid, as a nitrating agent in manufacturing of chemical explosives, as a polymerization inhibitor for acrylates, as a flour bleaching agent, and as a room temperature sterilization agent.
It is used as an oxidizer in rocket fuel, for example in red fuming nitric acid. For the general public, the most prominent sources of NO2 are internal combustion engines burning fossil fuels. Outdoors, NO2 can be a result of traffic from motor vehicles. Indoors, exposure arises from cigarette smoke, butane and kerosene heaters and stoves. Workers in industries where NO2 is used are exposed and are at risk for occupational lung diseases, NIOSH has set exposure limits and safety standards. Astronauts in the Apollo–Soyuz Test Project were killed when NO2 was accidentally vented into the cabin. Agricultural workers can be exposed to NO2 arising from grain decomposing in silos. Nitrogen dioxide was produced by atmospheric nuclear tests, was responsible for the reddish colour of mushroom clouds. Gaseous NO2 diffuses into the epithelial lining fluid of the res
Water pollution is the contamination of water bodies as a result of human activities. Water bodies include for example lakes, oceans and groundwater. Water pollution results. For example, releasing inadequately treated wastewater into natural water bodies can lead to degradation of aquatic ecosystems. In turn, this can lead to public health problems for people living downstream, they may use the same polluted river water for bathing or irrigation. Water pollution is the leading worldwide cause of death and disease, e.g. due to water-borne diseases. Water pollution can be grouped into surface water pollution. Marine pollution and nutrient pollution are subsets of water pollution. Sources of water pollution are either non-point sources. Point sources have one identifiable cause of the pollution, such as a storm drain, wastewater treatment plant or stream. Non-point sources are more diffuse, such as agricultural runoff. Pollution is the result of the cumulative effect over time. All plants and organisms living in or being exposed to polluted water bodies can be impacted.
The effects can damage individual species and impact the natural biological communities they are part of. The causes of water pollution include a wide range of chemicals and pathogens as well as physical parameters. Contaminants may include inorganic substances. Elevated temperatures can lead to polluted water. A common cause of thermal pollution is the use of water as a coolant by power plants and industrial manufacturers. Elevated water temperatures decrease oxygen levels, which can kill fish and alter food chain composition, reduce species biodiversity, foster invasion by new thermophilic species. Water pollution is measured by analysing water samples. Physical and biological tests can be done. Control of water pollution requires appropriate management plans; the infrastructure may include wastewater treatment plants. Sewage treatment plants and industrial wastewater treatment plants are required to protect water bodies from untreated wastewater. Agricultural wastewater treatment for farms, erosion control from construction sites can help prevent water pollution.
Nature-based solutions are another approach to prevent water pollution. Effective control of urban runoff includes reducing quantity of flow. In the United States, best management practices for water pollution include approaches to reduce the quantity of water and improve water quality. Water is referred to as polluted when it is impaired by anthropogenic contaminants. Due to these contaminants it either does not support a human use, such as drinking water, or undergoes a marked shift in its ability to support its biotic communities, such as fish. Natural phenomena such as volcanoes, algae blooms and earthquakes cause major changes in water quality and the ecological status of water. Water pollution is a major global problem, it requires ongoing revision of water resource policy at all levels. It has been suggested. Water pollution accounted for the deaths of 1.8 million people in 2015. India and China are two countries with high levels of water pollution: An estimated 580 people in India die of water pollution related illness every day.
About 90 percent of the water in the cities of China is polluted. As of 2007, half a billion Chinese had no access to safe drinking water. In addition to the acute problems of water pollution in developing countries, developed countries continue to struggle with pollution problems. For example, in a report on water quality in the United States in 2009, 44 percent of assessed stream miles, 64 percent of assessed lake acres, 30 percent of assessed bays and estuarine square miles were classified as polluted. Surface water pollution includes pollution of rivers and oceans. A subset of surface water pollution is marine pollution. One common path of entry by contaminants to the sea are rivers. An example is directly discharging sewage and industrial waste into the ocean. Pollution such as this occurs in developing nations. In fact, the 10 largest emitters of oceanic plastic pollution worldwide are, from the most to the least, Indonesia, Vietnam, Sri Lanka, Egypt, Malaysia and Bangladesh through the rivers Yangtze, Yellow, Nile, Pearl, Amur and the Mekong, accounting for "90 percent of all the plastic that reaches the world's oceans."Large gyres in the oceans trap floating plastic debris.
Plastic debris can absorb toxic chemicals from ocean pollution poisoning any creature that eats it. Many of these long-lasting pieces end up in the stomachs of marine animals; this results in obstruction of digestive pathways, which leads to reduced appetite or starvation. There are a variety of secondary effects stemming not from the original pollutant, but a derivative condition. An example is silt-bearing surface runoff, which can inhibit the penetration of sunlight through the water column, hampering photosynthesis in aquatic plants. Interactions between groundwater and surface water are complex. Groundwater pollution referred to as groundwater contamination, is not as classified as surface water pollution. By its nature, groundwater aquifers are susceptible to contamination from sources that may not directly affect surface water bodies; the distinction of point vs. non-point source may be irrelevant. Analysis of groundwater contamination may focus on soil characteristics and site
Government of Japan
The government of Japan is a constitutional monarchy in which the power of the Emperor is limited and is relegated to ceremonial duties. As in many other states, the Government is divided into three branches: the Legislative branch, the Executive branch, the Judicial branch; the Government runs under the framework established by the Constitution of Japan, adopted in 1947. It is a unitary state, containing forty-seven administrative divisions, with the Emperor as its head of state, his role is ceremonial and he has no powers related to Government. Instead, it is the Cabinet, comprising the Ministers of State and the Prime Minister, that directs and controls the Government; the Cabinet is the source of power of the Executive branch, is formed by the Prime Minister, the head of government. He or she is appointed to office by the Emperor; the National Diet is the organ of the Legislative branch. It is bicameral, consisting of two houses with the House of Councillors being the upper house, the House of Representatives being the lower house.
Its members are directly elected from the people. The Supreme Court and other inferior courts make up the Judicial branch, they are independent from the executive and the legislative branches. Prior to the Meiji Restoration, Japan was ruled by successive military shōguns. During this period, effective power of the government resided in the Shōgun, who ruled the country in the name of the Emperor; the Shoguns were the hereditary military governors, with their modern rank equivalent to a generalissimo. Although the Emperor was the sovereign who appointed the Shōgun, his roles were ceremonial and he took no part in governing the country; this is compared to the present role of the Emperor, whose official role is to appoint the Prime Minister. The Meiji Restoration in 1868 led to the resignation of Shōgun Tokugawa Yoshinobu, agreeing to "be the instrument for carrying out" the Emperor's orders; this event restored the country to the proclamation of the Empire of Japan. In 1889, the Meiji Constitution was adopted in a move to strengthen Japan to the level of western nations, resulting in the first parliamentary system in Asia.
It provided a form of mixed constitutional-absolute monarchy, with an independent judiciary, based on the Prussian model of the time. A new aristocracy known as the kazoku was established, it merged the ancient court nobility of the Heian period, the kuge, the former daimyōs, feudal lords subordinate to the shōgun. It established the Imperial Diet, consisting of the House of Representatives and the House of Peers. Members of the House of Peers were made up of the Imperial Family, the Kazoku, those nominated by the Emperor, while members of the House of Representatives were elected by direct male suffrage. Despite clear distinctions between powers of the executive branch and the Emperor in the Meiji Constitution and contradictions in the Constitution led to a political crisis, it devalued the notion of civilian control over the military, which meant that the military could develop and exercise a great influence on politics. Following the end of World War II, the Constitution of Japan was adopted as an intention to replace the previous Imperial rule with a form of Western-style liberal democracy.
The Emperor of Japan is the ceremonial head of state. He is defined by the Constitution to be "the symbol of the State and of the unity of the people". However, he is not the nominal Chief Executive and he possesses only certain ceremonially important powers, he has no real powers related to the Government as stated in article 4 of the Constitution. Article 6 of the Constitution of Japan delegates the Emperor the following ceremonial roles: Appointment of the Prime Minister as designated by the Diet. Appointment of the Chief Justice of the Supreme Court as designated by the Cabinet. While the Cabinet is the source of executive power and most of its power is exercised directly by the Prime Minister, several of its powers are exercised by the Emperor; the powers exercised via the Emperor, as stipulated by Article 7 of the Constitution, are: Promulgation of amendments of the constitution, cabinet orders and treaties. Convocation of the Diet. Dissolution of the House of Representatives. Proclamation of general election of members of the Diet.
Attestation of the appointment and dismissal of Ministers of State and other officials as provided for by law, of full powers and credentials of Ambassadors and Ministers. Attestation of general and special amnesty, commutation of punishment and restoration of rights. Awarding of honors. Attestation of instruments of ratification and other diplomatic documents as provided for by law. Receiving foreign ambassadors and ministers. Performance of ceremonial functions; the Emperor is known to hold the nominal ceremonial authority. For example, the Emperor is the only person that has the authority to appoint the Prime Minister though the Diet has the power to designate the person fitted for the position. One such example can be prominently seen in the 2009 Dissolution of the House of Representatives; the House was expected to be dissolved on the advice of the Prime Minister, but was temporarily unable to do so for the next general election, as both the Emperor and Empress were visiting Canada. In this manner, the Emperor's modern role is compared to those of the Shogunate period and much of Japan's history, whereby the Emperor held great symbolic authority but had little political power.
Today, a legacy has somewhat continued for a retired Prime Minister who still wields considerabl
Cadmium is a chemical element with symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of its compounds, like mercury, it has a lower melting point than the transition metals in groups 3 through 11. Cadmium and its congeners in group 12 are not considered transition metals, in that they do not have filled d or f electron shells in the elemental or common oxidation states; the average concentration of cadmium in Earth's crust is between 0.5 parts per million. It was discovered in 1817 by Stromeyer and Hermann, both in Germany, as an impurity in zinc carbonate. Cadmium is a byproduct of zinc production. Cadmium was used for a long time as a corrosion-resistant plating on steel, cadmium compounds are used as red and yellow pigments, to color glass, to stabilize plastic. Cadmium use is decreasing because it is toxic and nickel-cadmium batteries have been replaced with nickel-metal hydride and lithium-ion batteries.
One of its few new uses is cadmium telluride solar panels. Although cadmium has no known biological function in higher organisms, a cadmium-dependent carbonic anhydrase has been found in marine diatoms. Cadmium is a soft, ductile, bluish-white divalent metal, it forms complex compounds. Unlike most other metals, cadmium is resistant to corrosion and is used as a protective plate on other metals; as a bulk metal, cadmium is not flammable. Although cadmium has an oxidation state of +2, it exists in the +1 state. Cadmium and its congeners are not always considered transition metals, in that they do not have filled d or f electron shells in the elemental or common oxidation states. Cadmium burns in air to form brown amorphous cadmium oxide. Hydrochloric acid, sulfuric acid, nitric acid dissolve cadmium by forming cadmium chloride, cadmium sulfate, or cadmium nitrate; the oxidation state +1 can be produced by dissolving cadmium in a mixture of cadmium chloride and aluminium chloride, forming the Cd22+ cation, similar to the Hg22+ cation in mercury chloride.
Cd + CdCl2 + 2 AlCl3 → Cd22The structures of many cadmium complexes with nucleobases, amino acids, vitamins have been determined. Occurring cadmium is composed of 8 isotopes. Two of them are radioactive, three are expected to decay but have not done so under laboratory conditions; the two natural radioactive isotopes are 116Cd. The other three are 106Cd, 108Cd, 114Cd. At least three isotopes – 110Cd, 111Cd, 112Cd – are stable. Among the isotopes that do not occur the most long-lived are 109Cd with a half-life of 462.6 days, 115Cd with a half-life of 53.46 hours. All of the remaining radioactive isotopes have half-lives of less than 2.5 hours, the majority have half-lives of less than 5 minutes. Cadmium has 8 known meta states, with the most stable being 113mCd, 115mCd, 117mCd; the known isotopes of cadmium range in atomic mass from 94.950 u to 131.946 u. For isotopes lighter than 112 u, the primary decay mode is electron capture and the dominant decay product is element 47. Heavier isotopes decay through beta emission producing element 49.
One isotope of cadmium, 113Cd, absorbs neutrons with high selectivity: With high probability, neutrons with energy below the cadmium cut-off will be absorbed. The cadmium cut-off is about 0.5 eV, neutrons below that level are deemed slow neutrons, distinct from intermediate and fast neutrons. Cadmium is created via the s-process in low- to medium-mass stars with masses of 0.6 to 10 solar masses, over thousands of years. In that process, a silver atom captures a neutron and undergoes beta decay. Cadmium was discovered in 1817 by Friedrich Stromeyer and Karl Samuel Leberecht Hermann, both in Germany, as an impurity in zinc carbonate. Stromeyer found the new element as an impurity in zinc carbonate, for 100 years, Germany remained the only important producer of the metal; the metal was named after the Latin word for calamine. Stromeyer noted that some impure samples of calamine changed color when heated but pure calamine did not, he was persistent in studying these results and isolated cadmium metal by roasting and reducing the sulfide.
The potential for cadmium yellow as pigment was recognized in the 1840s, but the lack of cadmium limited this application. Though cadmium and its compounds are toxic in certain forms and concentrations, the British Pharmaceutical Codex from 1907 states that cadmium iodide was used as a medication to treat "enlarged joints, scrofulous glands, chilblains". In 1907, the International Astronomical Union defined the international ångström in terms of a red cadmium spectral line. This
Acid rain is a rain or any other form of precipitation, unusually acidic, meaning that it has elevated levels of hydrogen ions. It can have harmful effects on aquatic animals and infrastructure. Acid rain is caused by emissions of sulfur dioxide and nitrogen oxide, which react with the water molecules in the atmosphere to produce acids; some governments have made efforts since the 1970s to reduce the release of sulfur dioxide and nitrogen oxide into the atmosphere with positive results. Nitrogen oxides can be produced by lightning strikes, sulfur dioxide is produced by volcanic eruptions. Acid rain has been shown to have adverse impacts on forests and soils, killing insect and aquatic life-forms, causing paint to peel, corrosion of steel structures such as bridges, weathering of stone buildings and statues as well as having impacts on human health. "Acid rain" is a popular term referring to the deposition of a mixture from wet and dry acidic components. Distilled water, once carbon dioxide is removed, has a neutral pH of 7.
Liquids with a pH less than 7 are acidic, those with a pH greater than 7 are alkaline. "Clean" or unpolluted rain has an acidic pH, but no lower than 5.7, because carbon dioxide and water in the air react together to form carbonic acid, a weak acid according to the following reaction: H2O + CO2 ⇌ H2CO3 Carbonic acid can ionize in water forming low concentrations of carbonate and hydronium ions: H2O + H2CO3 ⇌ HCO3− + H3O+ Unpolluted rain can contain other chemicals which affect its pH. A common example is nitric acid produced by electric discharge in the atmosphere such as lightning. Acid deposition as an environmental issue would include additional acids other than H2CO3; 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.
In the late 1960s scientists began observing and studying the phenomenon. The term "acid rain" was coined in 1872 by Robert Angus Smith. Canadian Harold Harvey was among the first to research a "dead" lake. At first the main focus in research lay on local affects of acid rain. Waldemar Christofer Brøgger was the first to acknowledge long-distance transportation of pollutants crossing borders from the United Kingdom to Norway. Public awareness of acid rain in the US increased in the 1970s after The New York Times published reports from the Hubbard Brook Experimental Forest in New Hampshire of the harmful environmental effects that 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 areas downwind from them; these areas all burn sulfur-containing coal to generate 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.
Deposition occurs a considerable distance downwind of the emissions, with mountainous regions tending to receive the greatest deposition. An example of this effect is the low pH of rain; the earliest report about acid rain in the United States was from the chemical evidence from Hubbard Brook Valley. In 1972, a group of scientists including Gene Likens discovered the rain, deposited at White Mountains of New Hampshire was acidic; the pH of the sample was measured to be 4.03 at Hubbard Brook. The Hubbard Brook Ecosystem Study followed up with a series of research that analyzed the environmental effects of acid rain. Acid rain that mixed with stream water at Hubbard Brook was neutralized by the alumina from soils; the result of this research indicates the chemical reaction between acid rain and aluminum leads to increasing rate of soil weathering. Experimental research was done to examine the effects of increased acidity in stream on ecological species. In 1980, a group of scientists modified the acidity of Norris Brook, New Hampshire, observed the change in species' behaviors.
There was a decrease in species diversity, an increase in community dominants, a decrease in the food web complexity. In 1980, the US 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 looked at the entire problem from a scientific perspective, it enlarged a network of monitoring sites to determine how acidic the precipitation was, to determine long-term trends, 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 and building materials, it 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. For the US Government's scientific enterprise, a significant impact of NAPAP were lessons learned in the assessment process and in environmental research management to a relatively
Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form such as noise, heat or light. Pollutants, the components of pollution, can be either foreign substances/energies or occurring contaminants. Pollution is classed as point source or nonpoint source pollution. In 2015, pollution killed 9 million people in the world. Major forms of pollution include: Air pollution, light pollution, noise pollution, plastic pollution, soil contamination, radioactive contamination, thermal pollution, visual pollution, water pollution. Air pollution has always accompanied civilizations. Pollution started from prehistoric times. According to a 1983 article in the journal Science, "soot" found on ceilings of prehistoric caves provides ample evidence of the high levels of pollution, associated with inadequate ventilation of open fires." Metal forging appears to be a key turning point in the creation of significant air pollution levels outside the home.
Core samples of glaciers in Greenland indicate increases in pollution associated with Greek and Chinese metal production. The burning of coal and wood, the presence of many horses in concentrated areas made the cities the primary sources of pollution; the Industrial Revolution brought an infusion of untreated chemicals and wastes into local streams that served as the water supply. King Edward I of England banned the burning of sea-coal by proclamation in London in 1272, after its smoke became a problem, it was the industrial revolution. London recorded one of the earlier extreme cases of water quality problems with the Great Stink on the Thames of 1858, which led to construction of the London sewerage system soon afterward. Pollution issues escalated as population growth far exceeded viability of neighborhoods to handle their waste problem. Reformers began to clean water. In 1870, the sanitary conditions in Berlin were among the worst in Europe. August Bebel recalled conditions before a modern sewer system was built in the late 1870s: "Waste-water from the houses collected in the gutters running alongside the curbs and emitted a fearsome smell.
There were no public toilets in the squares. Visitors women became desperate when nature called. In the public buildings the sanitary facilities were unbelievably primitive.... As a metropolis, Berlin did not emerge from a state of barbarism into civilization until after 1870."The primitive conditions were intolerable for a world national capital, the Imperial German government brought in its scientists and urban planners to not only solve the deficiencies, but to forge Berlin as the world's model city. A British expert in 1906 concluded that Berlin represented "the most complete application of science and method of public life," adding "it is a marvel of civic administration, the most modern and most organized city that there is."The emergence of great factories and consumption of immense quantities of coal gave rise to unprecedented air pollution and the large volume of industrial chemical discharges added to the growing load of untreated human waste. Chicago and Cincinnati were the first two American cities to enact laws ensuring cleaner air in 1881.
Pollution became a major issue in the United States in the early twentieth century, as progressive reformers took issue with air pollution caused by coal burning, water pollution caused by bad sanitation, street pollution caused by the 3 million horses who worked in American cities in 1900, generating large quantities of urine and manure. As historian Martin Melosi notes, The generation that first saw automobiles replacing the horses saw cars as "miracles of cleanliness.". By the 1940s, automobile-caused smog was a major issue in Los Angeles. Other cities followed around the country until early in the 20th century, when the short lived Office of Air Pollution was created under the Department of the Interior. Extreme smog events were experienced by the cities of Los Angeles and Donora, Pennsylvania in the late 1940s, serving as another public reminder. Air pollution would continue to be a problem in England later during the industrial revolution, extending into the recent past with the Great Smog of 1952.
Awareness of atmospheric pollution spread after World War II, with fears triggered by reports of radioactive fallout from atomic warfare and testing. A non-nuclear event – the Great Smog of 1952 in London – killed at least 4000 people; this prompted some of the first major modern environmental legislation: the Clean Air Act of 1956. Pollution began to draw major public attention in the United States between the mid-1950s and early 1970s, when Congress passed the Noise Control Act, the Clean Air Act, the Clean Water Act, the National Environmental Policy Act. Severe incidents of pollution helped increase consciousness. PCB dumping in the Hudson River resulted in a ban by the EPA on consumption of its fish in 1974. National news stories in the late 1970s – the long-term dioxin contamination at Love Canal starting in 1947 and uncontrolled dumping in Valley of the Drums – led to the Superfund legislation of 1980; the pollution of industrial land gave rise to the name brownfield, a term now common in city planning.
The development of nuclear science introduced radioactive contamination, which can remain lethally radioactive for hundreds of thousands of years. Lake Karachay – named by the Worldwatch Institute as the "most polluted