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Wednesday, March 18, 2015

Cancer research


From Wikipedia, the free encyclopedia


University of Florida Cancer Hospital

Cancer research is basic research into cancer in order to identify causes and develop strategies for prevention, diagnosis, treatments and cure.

Cancer research ranges from epidemiology, molecular bioscience to the performance of clinical trials to evaluate and compare applications of the various cancer treatment. These applications include surgery, radiation therapy, chemotherapy, hormone therapy, Immunotherapy and combined treatment modalities such as chemo-radiotherapy. Starting in the mid-1990s, the emphasis in clinical cancer research shifted towards therapies derived from biotechnology research, such as cancer immunotherapy and gene therapy.

Areas of research

Cause

Early research on the cause of cancer was summarized by Haddow in 1958.[1] The first chemical carcinogen was identified in 1928-29 as 1:2-5:6-dibenzanthracene, and the carcinogeneic substance in pitch was identified as 3:4-benzopyrene in 1933. Haddow concluded that “there can be little doubt of the importance of their [chemical] combination with the genetical material” as the source of the chemical mechanism of action of carcinogens. Brookes and Lawley, in 1964, summarized ongoing research into the causes of cancer.[2] They referred to the competing hypotheses that carcinogens reacted mainly with proteins versus mainly with DNA. The direct research of Brookes and Lawley, testing carcinogenic hydrocarbons, indicated that they react with DNA. McCann et al.[3] in 1975 and McCann and Ames, in 1976,[4] tested 175 known carcinogens for interaction with DNA sufficient to cause mutations in their new Salmonella/microsome test. This test uses bacteria as sensitive indicators of DNA damage.
They found that 90% of known carcinogens caused mutations in their test. They indicated that the carcinogens that did not cause mutations in their assay were likely due to the need for the carcinogens to be activated by enzymes not available in their system.

By 1981, Doll and Peto conducted an epidemiological study in which they compared cancer rates for 37 specific cancers in the United States to rates for these cancers in populations in which the incidence of these cancers is low.[5] The populations compared with US populations included Norwegians, Nigerians, Japanese, British, and Israeli Jews. Their conclusion was that 75 - 80% of the cases of cancer in the United States were likely avoidable. The avoidable sources of cancer included tobacco, alcohol, diet (especially meat and fat), food additives, occupational exposures (including aromatic amines, benzene, heavy metals, vinyl chloride), pollution, industrial products, medicines and medical procedures, UV light from the sun, exposure to medical x-rays, and infection. Many of these sources of cancer are DNA damaging agents.

More recent research, indicating both the role of DNA damage in causing cancer and other factors including reduced expression of DNA repair genes by epigenetic alterations (allowing DNA damages to accumulate) are summarized in Carcinogenesis and in an article by Bernstein et al. in 2013.[6]

Research into the cause of cancer involves many different disciplines including genetics, diet, environmental factors (i.e. chemical carcinogens). In regard to investigation of causes and potential targets for therapy, the route used starts with data obtained from clinical observations, enters basic research, and, once convincing and independently confirmed results are obtained, proceeds with clinical research, involving appropriately designed trials on consenting human subjects, with the aim to test safety and efficiency of the therapeutic intervention method. An important part of basic research is characterization of the potential mechanisms of carcinogenesis, in regard to the types of genetic and epigenetic changes that are associated with cancer development. The mouse is often used as a mammalian model for manipulation of the function of genes that play a role in tumor formation, while basic aspects of tumor initiation, such as mutagenesis, are assayed on cultures of bacteria and mammalian cells.

Important cell types involved in cancer growth

There are several different cell types that are critical to tumor growth. In particular Endothelial Progenitor Cells are a very important cell population in tumor blood vessel growth. This finding was demonstrated in the high impact factor journals of Science (2008) and Genes and Development (2007)which also showed that Endothelial Progenitor Cells are critical for metastasis and the angiogenesis.[7][8] This importance of endothelial progenitor cells in tumour growth and angiogenesis has been confirmed by a recent publication in Cancer Research (August 2010). This seminal paper has demonstrated that endothelial progenitor cells can be marked using the Inhibitor of DNA Binding 1 (ID1). This novel finding meant that investigators were able to track endothelial progenitor cells from the bone marrow to the blood to the tumour-stroma and even incorporated in tumour vasculature. This finding of endothelial progenitor cells incorporated in tumour vasculature proves the importance of this cell type in blood vessel development in a tumour setting. Furthermore, ablation of the endothelial progenitor cells in the bone marrow lead to a significant decrease in tumour growth and vasculature development. Therefore endothelial progenitor cells are very important in tumour biology and present novel therapeutic targets.[9]

In vitro research using cell lines


Electroporation is used extensively in cancer research for gene and drug delivery. Gemini X2 system manufactured by BTX Harvard Apparatus

In vitro assays allow scientists to conduct studies under reasonable conditions in the lab. In order to study the communication between a tumor cell and a host cell in vitro assays have been created. The use of fragmented chicken heart cells as a host case for nutrients[10] Thus allowing the HeLa cells to, in a sense win, and over take the PHF. In the case of the L tumor cells, they were not able to invade the PHF. Though HeLa cells were able to accomplish invasion after several hours the L cells are structurally different rendering them inadequate. The L cells have much more intercellular free space and do not surround the host cell as tightly as Hela cells. It was concluded that with a tight gap junction nutrients cannot enter the cell allowing the cancer cells to invade. With this information about the gap junction process between host cell and the tumor cell, further studies were conducted in cancer gene therapy with the use of Hela cells and the herpes virus.[11]

Oncogenomics/Genes involved in cancer

The goal of oncogenomics is to identify new oncogenes or tumor suppressor genes that may provide new insights into cancer diagnosis, predicting clinical outcome of cancers, and new targets for cancer therapies. As the Cancer Genome Project stated in a 2004 review article, "a central aim of cancer research has been to identify the mutated genes that are causally implicated in oncogenesis (cancer genes)."[12] The Cancer Genome Atlas project is a related effort investigating the genomic changes associated with cancer, while the COSMIC cancer database documents acquired genetic mutations from hundreds of thousands of human cancer samples.[13]
These large scale projects, involving about 350 different types of tumour, have identified ~130,000 mutations in ~3000 genes that have been mutated in the tumours. The majority occurred in 319 genes of which 286 were tumour suppressor genes and 33 oncogenes.

Several hereditary factors can increase the chance of cancer-causing mutations, including the activation of oncogenes or the inhibition of tumor suppressor genes. The functions of various onco- and tumor suppressor genes can be disrupted at different stages of tumor progression. Mutations in such genes can be used to classify the malignancy of a tumor.

In later stages, tumors can develop a resistance to cancer treatment. The identification of oncogenes and tumor suppressor genes is important to understand tumor progression and treatment success. The role of a given gene in cancer progression may vary tremendously, depending on the stage and type of cancer involved.[14]

Genes and protein products that have been identified by at least two independent publications as being involved in cancer are:[12]

ABI1, ABL2, ACSL6, AF1Q, AF5Q31 (also known as MCEF), AKT1, ARNT, ASPSCR1, ATF1, ATIC, BCL10, BFHD, BIRC3, BMPR1A, BTG1, CBFA2T1, CBFA2T3, CBFB, CCND1, CDC2, CDK4, CHIC2, CHN1, COPEB, COX6C, CTNNB1, CYLD, DDB2, DDIT3, DEK, Eif4a, EIF4A2, EPS15, ERCC2, ERCC3, ERCC5, ERG, ETV4, ETV6, EWSR1, EXT1, EXT2, FANCC, FANCG, FGFR1OP, FGFR3, FH, FIP1L1, FUS, GAS7, GATA1, GMPS, GOLGA5, GPC (gene), GPHN, HIST1H4I, HRAS, HSPCA, IL21R, IIRF4, KRAS2, LASP1, LCP1, LHFP, LMO2, LYL1, MADH4, MEIS1, MLF1, MLH1, MLLT3, MLLT6, MNAT1, MSF, MSH2, MSN, MUTYH, MYC, NCOA4, NF2, NPM1, NRAS, PAX8, PCBD, PDGFB, PHOX2B, PIM1, PLK2, PNUTL1, POU2F1, PPARG, PRCC, PRKACB, PRKAR1A, PTEN, PTPN11, RABEP1, RAD51L1, RAP1GDS1, RARA, RB1, RET, RHOH, RPL22, SBDS, SDHB, SEPTIN6, SET, SH3GL1, SS18L1, SSX1, SSX2, SSX4, STAT3, TAF15, TCF12, TCL1A, TFE3, TFEB, TFG, TFPT, TFRC, TNFRSF6, TP53, TPM3, TPM4, TRIP11, VHL, WAS, WT1, ZNF198, ZNF278, ZNF384, ZNFN1A1

Treatment

Current topics of cancer treatment research include:

Vaccines

Flaws and vulnerabilities

Newsweek magazine published an article criticising the use of lab rats on cancer research because even though researchers frequently manage to cure lab mice transplanted with human tumors, few of those achievements are relevant to humanity.[19] Oncologist Paul Bunn, from the International Association for the Study of Lung Cancer[20] said: "We put a human tumor under the mouse's skin, and that microenvironment doesn't reflect a person's—the blood vessels, inflammatory cells or cells of the immune system".[19] Fran Visco founder of the National Breast Cancer Coalition completed: "We cure cancer in animals all the time, but not in people."[19]

Most funding for cancer research comes from taxpayers and charities, rather than from profit-making businesses. In the US, less than 30% of all cancer research is funded by commercial researchers such as pharmaceutical companies.[21] Per capita, public spending on cancer research by taxpayers and charities in the US was five times as much in 2002-03 as public spending by taxpayers and charities in the 15 countries then full members of the European Union.[21] As a percentage of GDP, the non-commercial funding of cancer research in the US was four times the amount dedicated to cancer research in Europe.[21] Half of Europe's non-commercial cancer research is funded by charitable organizations.[21]

Cancer research processes have been criticised in many respects. These include, especially in the US, hypercompetition for the financial resources and positions required to conduct science, which seems to suppress the creativity, cooperation, risk-taking, and original thinking required to make fundamental discoveries, unduly favoring low-risk research into small incremental advancements over innovative research that might discover radically new and dramatically improved therapy. Other consequences of today's highly pressured competition for research resources appear to be a substantial number of research publications whose results cannot be replicated, and perverse incentives in research funding that encourage grantee institutions to grow without making sufficient investments in their own faculty and facilities.[22][23][24][25]

Distributed computing

One can share computer time for distributed cancer research projects like Help Conquer Cancer.[26] World Community Grid also had a project called Help Defeat Cancer. Other related projects include the Folding@home and Rosetta@home projects, which focus on groundbreaking protein folding and protein structure prediction research.

Organizations

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Smog


From Wikipedia, the free encyclopedia


Smog in New York City as viewed from the World Trade Center in 1988

German road sign until 2008, Verkehrsverbot bei Smog (No traffic allowed in smog conditions)

Smog is a type of air pollutant. The word "smog" was made in the early 20th century as a portmanteau of the words smoke and fog to refer to smoky fog.[1] The word was then intended to refer to what was sometimes known as pea soup fog, a familiar and serious problem in London from the 19th century to the mid 20th century. This kind of smog is caused by the burning of large amounts of coal within a city; this smog contains soot particulates from smoke, sulfur dioxide and other components.

Modern smog, as found for example in Los Angeles, is a type of air pollution derived from vehicular emission from internal combustion engines and industrial fumes that react in the atmosphere with sunlight to form secondary pollutants that also combine with the primary emissions to form photochemical smog. In certain other cities, such as Delhi, smog severity is often aggravated by stubble burning in neighboring agricultural areas. The atmospheric pollution levels of Los Angeles, Beijing, Delhi, Mexico City and other cities are increased by inversion that traps pollution close to the ground. It is usually highly toxic to humans and can cause severe sickness, shortened life or death.

Etymology

Coinage of the term "smog" is generally attributed to Dr. Henry Antoine Des Voeux in his 1905 paper, "Fog and Smoke" for a meeting of the Public Health Congress. The July 26, 1905 edition of the London newspaper Daily Graphic quoted Des Voeux, "He said it required no science to see that there was something produced in great cities which was not found in the country, and that was smoky fog, or what was known as 'smog.'"[2] The following day the newspaper stated that "Dr. Des Voeux did a public service in coining a new word for the London fog." "Smog" also appears in a January 19, 1893, Los Angeles Times article and is attributed to "a witty English writer."

Causes

Coal

Coal fires, used to heat individual buildings or in a power-producing plant, can emit significant clouds of smoke that contributes to smog. Air pollution from this source has been reported in England since the Middle Ages.[3] London, in particular, was notorious up through the mid-20th century for its coal-caused smogs, which were nicknamed 'pea-soupers.' Air pollution of this type is still a problem in areas that generate significant smoke from burning coal, as witnessed by the 2013 autumnal smog in Harbin, China, which closed roads, schools, and the airport.

Transportation emissions

Traffic emissions – such as from trucks, buses, and automobiles – also contribute.[4] Airborne by-products from vehicle exhaust systems cause air pollution and are a major ingredient in the creation of smog in some large cities.[5][6][7][8]

The major culprits from transportation sources are carbon monoxide (CO),[9][10] nitrogen oxides (NO and NOx),[11][12][13] volatile organic compounds,[10][11] sulfur dioxide,[10] and hydrocarbons.[10] These molecules react with sunlight, heat, ammonia, moisture, and other compounds to form the noxious vapors, ground level ozone, and particles that comprise smog.[10][11]

Photochemical smog

Photochemical smog was first described in the 1950s. It is the chemical reaction of sunlight, nitrogen oxides and volatile organic compounds in the atmosphere, which leaves airborne particles and ground-level ozone.[14] This noxious mixture of air pollutants can include the following:
All of these harsh chemicals are usually highly reactive and oxidizing. Photochemical smog is therefore considered to be a problem of modern industrialization. It is present in all modern cities, but it is more common in cities with sunny, warm, dry climates and a large number of motor vehicles.[15] Because it travels with the wind, it can affect sparsely populated areas as well.

Characteristic coloration for smog in California in the beige cloud bank behind the Golden Gate Bridge. The brown coloration is due to the NOx in the photochemical smog.

Natural causes

An erupting volcano can also emit high levels of sulphur dioxide along with a large quantity of particulate matter; two key components to the creation of smog. However, the smog created as a result of a volcanic eruption is often known as vog to distinguish it as a natural occurrence.

The radiocarbon content of some plant life has been linked to the distribution of smog in some areas. For example, the creosote bush in the Los Angeles area has been shown to have an effect on smog distribution that is more than fossil fuel combustion alone.[16]

Health effects


Highland Park Optimist Club wearing smog-gas masks at banquet, Los Angeles, circa 1954

Smog is a serious problem in many cities and continues to harm human health.[17][18] Ground-level ozone, sulfur dioxide, nitrogen dioxide and carbon monoxide are especially harmful for senior citizens, children, and people with heart and lung conditions such as emphysema, bronchitis, and asthma.[19] It can inflame breathing passages, decrease the lungs' working capacity, cause shortness of breath, pain when inhaling deeply, wheezing, and coughing. It can cause eye and nose irritation and it dries out the protective membranes of the nose and throat and interferes with the body's ability to fight infection, increasing susceptibility to illness. Hospital admissions and respiratory deaths often increase during periods when ozone levels are high.[20][21]

Levels of unhealthy exposure

The U.S. EPA has developed an Air Quality Index to help explain air pollution levels to the general public. 8 hour average ozone concentrations of 85 to 104 ppbv are described as "Unhealthy for Sensitive Groups", 105 ppbv to 124 ppbv as "unhealthy" and 125 ppb to 404 ppb as "very unhealthy".[19] The "very unhealthy" range for some other pollutants are: 355 μg m−3 - 424 μg m−3 for PM10; 15.5 ppm - 30.4ppm for CO and 0.65 ppm - 1.24 ppm for NO2.[22]

Premature deaths due to cancer and respiratory disease

The Ontario Medical Association announced that smog is responsible for an estimated 9,500 premature deaths in the province each year.[23]

A 20-year American Cancer Society study found that cumulative exposure also increases the likelihood of premature death from a respiratory disease, implying the 8-hour standard may be insufficient.[24]

Smog and the risk of certain birth defects

A study examining 806 women who had babies with birth defects between 1997 and 2006, and 849 women who had healthy babies, found that smog in the San Joaquin Valley area of California was linked to two types of neural tube defects: spina bifida (a condition involving, among other manifestations, certain malformations of the spinal column), and anencephaly (the underdevelopment or absence of part or all of the brain, which if not fatal usually results in profound impairment).[25]

Smog and low birth weight

According to a study published in The Lancet, even a very small (5 μg) change in PM2.5 exposure was associated with an increase (18%) in risk of a low birth weight at delivery, and this relationship held even below the current accepted safe levels.[26]

Areas affected


Beijing air on a day after rain (left) and a smoggy day (right)

Smog can form in almost any climate where industries or cities release large amounts of air pollution, such as smoke or gases. However, it is worse during periods of warmer, sunnier weather when the upper air is warm enough to inhibit vertical circulation. It is especially prevalent in geologic basins encircled by hills or mountains. It often stays for an extended period of time over densely populated cities or urban areas, and can build up to dangerous levels.

Delhi, India

During the autumn and winter months, some 500 million tons of crop residue are burnt, and winds blow from India's north and northwest towards east.[27][28][29] This aerial view shows India's annual crop burning, resulting in smoke and air pollution over Delhi and adjoining areas.

Delhi is the most polluted[30] city in the world and according to one estimate, air pollution causes the death of about 10,500 people in Delhi every year.[31][32][33] During 2013-14, peak levels of fine particulate matter (PM) in Delhi increased by about 44%, primarily due to high vehicular and industrial emissions, construction work and crop burning in adjoining states.[31][34][35][36] Delhi has the highest level of the airborne particulate matter, PM2.5 considered most harmful to health, with 153 micrograms.[37] Rising air pollution level has significantly increased lung-related ailments (especially asthma and lung cancer) among Delhi's children and women.[38][39] The dense smog in Delhi during winter season results in major air and rail traffic disruptions every year.[40] According to Indian meteorologists, the average maximum temperature in Delhi during winters has declined notably since 1998 due to rising air pollution.[41]

Dense smog blankets Connaught Place, Delhi.

Environmentalists have criticised the Delhi government for not doing enough to curb air pollution and to inform people about air quality issues.[32] Most of Delhi's residents are unaware of alarming levels of air pollution in the city and the health risks associated with it.[35][36] Since the mid-1990s, Delhi has undertaken some measures to curb air pollution – Delhi has the third highest quantity of trees among Indian cities[42] and the Delhi Transport Corporation operates the world's largest fleet of environmentally friendly compressed natural gas (CNG) buses.[43] In 1996, the Centre for Science and Environment (CSE) started a public interest litigation in the Supreme Court of India that ordered the conversion of Delhi's fleet of buses and taxis to run on CNG and banned the use of leaded petrol in 1998. In 2003, Delhi won the United States Department of Energy's first 'Clean Cities International Partner of the Year' award for its "bold efforts to curb air pollution and support alternative fuel initiatives".[43] The Delhi Metro has also been credited for significantly reducing air pollutants in the city.[44]

However, according several authors, most of these gains have been lost, especially due to stubble burning, rise in market share of diesel cars and a considerable decline in bus ridership.[45][46] According to CSE and System of Air Quality Weather Forecasting and Research (SAFAR), burning of agricultural waste in nearby Punjab, Haryana and Uttar Pradesh regions results in severe intensification of smog over Delhi.[47][48] The state government of adjoining Uttar Pradesh is considering imposing a ban on crop burning to reduce pollution in Delhi NCR and an environmental panel has appealed to India's Supreme Court to impose a 30% cess on diesel cars.[49][50]

United Kingdom

London


Victorian London was notorious for its thick smogs, or "pea-soupers", a fact that is often recreated (as here) to add an air of mystery to a period costume drama

In 1306, concerns over air pollution were sufficient for Edward I to (briefly) ban coal fires in London.[3] In 1661, John Evelyn's Fumifugium suggested burning fragrant wood instead of mineral coal, which he believed would reduce coughing. The Ballad of Gresham College the same year describes how the smoke "does our lungs and spirits choke, Our hanging spoil, and rust our iron."

Severe episodes of smog continued in the 19th and 20th centuries, mainly in the winter, and were nicknamed "pea-soupers". The Great Smog of 1952 darkened the streets of London and killed approximately 4,000 people in the short time of 4 days (a further 8,000[51] died from its effects in the following weeks and months). Initially a flu epidemic was blamed for the loss of life.

In 1956 the Clean Air Act started legally enforcing smokeless zones in the capital. There were areas where no soft coal was allowed to be burned in homes or in businesses, only coke, which produces no smoke. Because of the smokeless zones, reduced levels of sooty particulates made the intense and persistent London smog a thing of the past.

It was after this that the great clean-up of London began. One by one, historical buildings which, during the previous two centuries had gradually completely blackened externally, had their stone facades cleaned and restored to their original appearance. Victorian buildings whose appearance changed dramatically after cleaning included the British Museum of Natural History. A more recent example was the Palace of Westminster, which was cleaned in the 1980s. A notable exception to the restoration trend was 10 Downing Street, whose bricks upon cleaning in the late 1950s proved to be naturally yellow; the smog-derived black colour of the façade was considered so iconic that the bricks were painted black to preserve the image.[52][53] Smog caused by traffic pollution, however, does still occur in modern London.

Other areas

Other areas of the United Kingdom were affected by smog, especially heavily industrialised areas.
The cities of Glasgow and Edinburgh, in Scotland, suffered smoke-laden fogs in 1909. Des Voeux, commonly credited with creating the "smog" moniker, presented a paper in 1911 to the Manchester Conference of the Smoke Abatement League of Great Britain about the fogs and resulting deaths.[54]

One Birmingham resident described near black-out conditions in the 1900s before the Clean Air Act, with visibility so poor that cyclists had to dismount and walk in order to stay on the road.[55]

Mexico City, Mexico


Situated in a valley, and relying heavily on automobiles, Mexico City often suffers from poor air quality.

Due to its location in a highland "bowl", cold air sinks down onto the urban area of Mexico City, trapping industrial and vehicle pollution underneath, and turning it into the most infamously smog-plagued city of Latin America. Within one generation, the city has changed from being known for some of the cleanest air of the world into one with some of the worst pollution, with pollutants like nitrogen dioxide being double or even triple international standards.[56]

Photochemical smog over Mexico City. December 2010.

Santiago, Chile

Similar to Mexico City, the air pollution of Santiago valley, located between the Andes and the Chilean Coast Range, turn it into the most infamously smog-plagued city of South America. Other aggravates of the situation reside in its high latitude (31 degrees South) and dry weather during most of the year.

Tehran, Iran

In December 2005, schools and public offices had to close in Tehran, Iran and 1600 people were taken to hospital, in a severe smog blamed largely on unfiltered car exhaust.[57]

United States


A NASA astronaut photograph of a smog layer over central New York.

Counties in the United States where one or more National Ambient Air Quality Standards are not met, as of June 2007.

Smog was brought to the attention of the general US public in 1933 with the publication of the book "Stop That Smoke", by Henry Obermeyer, a New York public utility official, in which he pointed out the effect on human life and even the destruction of 3,000 acres (12 km2) of a farmer's spinach crop.[58] Since then, the United States Environmental Protection Agency has designated over 300 U.S. counties to be non-attainment areas for one or more pollutants tracked as part of the National Ambient Air Quality Standards.[59] These areas are largely clustered around large metropolitan areas, with the largest contiguous non-attainment zones in California and the Northeast.
Various U.S. and Canadian government agencies collaborate to produce real-time air quality maps and forecasts.[60]

Los Angeles and the San Joaquin Valley

Because of their locations in low basins surrounded by mountains, Los Angeles and the San Joaquin Valley are notorious for their smog. The millions of vehicles in these regions combined with the additional effects of the San Francisco Bay and Los Angeles/Long Beach port complexes frequently contribute to further air pollution. While strict regulations by numerous California government agencies overseeing this problem have decreased the number of Stage 1 smog alerts from several hundred annually to just a few, these geologically predisposed entrapment zones collect pollution levels from cars, trucks and fixed sources which still exceeds health standards and is a pressing issue for the more than 25 million people who live there.

Major incidents in the US

Ulaanbaatar, Mongolia

In the late 1990s, massive immigration to Ulaanbaatar from the countryside began. An estimated 150,000 households, mainly living in traditional Mongolian gers on the outskirts of Ulaanbaatar, burn wood and coal (some poor families burn even car tires and trash) to heat themselves during the harsh winter, which lasts from October to April, since these outskirts are not connected to the city's central heating system. A temporary solution to decrease smog was proposed in the form of stoves with improved efficiency, although with no visible results. Coal-fired ger stoves release high levels of ash and other particulate matter (PM). When inhaled, these particles can settle in the lungs and respiratory tract and cause health problems. At two to 10 times above Mongolian and international air quality standards, Ulaanbaatar's PM rates are among the worst in the world, according to a December 2009 World Bank report. The Asian Development Bank (ADB) estimates that health costs related to this air pollution account for as much as 4 percent of Mongolia's GDP.[65]

Southeast Asia

Singapore's Downtown Core on 7 October 2006, when it was affected by forest fires in Sumatra, Indonesia

Smog is a regular problem in Southeast Asia caused by land and forest fires in Indonesia, especially Sumatra and Kalimantan, although the term haze is preferred in describing the problem. Farmers and plantation owners are usually responsible for the fires, which they use to clear tracts of land for further plantings. Those fires mainly affect Brunei, Indonesia, Philippines, Malaysia, Singapore and Thailand, and occasionally Guam and Saipan.[66][67] The economic losses of the fires in 1997 have been estimated at more than US$9 billion.[68] This includes damages in agriculture production, destruction of forest lands, health, transportation, tourism, and other economic endeavours. Not included are social, environmental, and psychological problems and long-term health effects. The second-latest bout of haze to occur in Malaysia, Singapore and the Malacca Straits is in October 2006, and was caused by smoke from fires in Indonesia being blown across the Straits of Malacca by south-westerly winds. A similar haze has occurred in June 2013, with the PSI setting a new record in Singapore on June 21 at 12pm with a reading of 401, which is in the "Hazardous" range.[69]

The Association of Southeast Asian Nations (ASEAN) reacted. In 2002, the Agreement on Transboundary Haze Pollution was signed between all ASEAN nations.[70] ASEAN formed a Regional Haze Action Plan (RHAP) and established a co-ordination and support unit (CSU).[71] RHAP, with the help of Canada, established a monitoring and warning system for forest/vegetation fires and implemented a Fire Danger Rating System (FDRS). The Malaysian Meteorological Department (MMD) has issued a daily rating of fire danger since September 2003.[72] Indonesia has been ineffective at enforcing legal policies on errant farmers.[citation needed]

Pollution index


Smog in São Paulo, Brazil

The severity of smog is often measured using automated optical instruments such as Nephelometers, as haze is associated with visibility and traffic control in ports. Haze however can also be an indication of poor air quality though this is often better reflected using accurate purpose built air indexes such as the American Air Quality Index, the Malaysian API (Air Pollution Index) and the Singaporean Pollutant Standards Index.

In hazy conditions, it is likely that the index will report the suspended particulate level. The disclosure of the responsible pollutant is mandated in some jurisdictions.

The Malaysian API does not have a capped value; hence its most hazardous readings can go above 500. Above 500, a state of emergency is declared in the affected area. Usually, this means that non-essential government services are suspended, and all ports in the affected area are closed. There may also be prohibitions on private sector commercial and industrial activities in the affected area excluding the food sector. So far, state of emergency rulings due to hazardous API levels were applied to the Malaysian towns of Port Klang, Kuala Selangor and the state of Sarawak during the 2005 Malaysian haze and the 1997 Southeast Asian haze.

Cultural references


Claude Monet made several trips to London between 1899 and 1901, during which he painted views of the Thames and Houses of Parliament which show the sun struggling to shine through London's smog-laden atmosphere.
  • The London "pea-soupers" earned the capital the nickname of "The Smoke". Similarly, Edinburgh was known as "Auld Reekie". The smogs feature in many London novels as a motif indicating hidden danger or a mystery, perhaps most overtly in Margery Allingham's The Tiger in the Smoke (1952), but also in Dickens's Bleak House (1852) and T.S. Eliot's "The Love Song of J. Alfred Prufrock."
  • The 1970 made-for-TV movie A Clear and Present Danger was one of the first American television network entertainment programs to warn about the problem of smog and air pollution, as it dramatized a man's efforts toward clean air after emphysema killed his friend.[73]
  • The history of smog in LA is detailed in Smogtown by Chip Jacobs and William J. Kelly.[74]

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