Types Of Pollution And Their Causes Environmental Sciences Essay

Types Of Pollution And Their Causes Environmental Sciences Essay Pollution  is the introduction of contaminants into a natural environment that causes discomfort to the  ecosystem  i.e. physical systems or living organisms.  Pollution can take the form of  chemical substances  or  energy, such as noise, heat, or light. Pollutants, the elements of pollution, can be foreign substances or energies, or naturally occurring; when naturally occurring, they are considered contaminants when they exceed natural levels. Pollution is often classed as  point source  or  nonpoint source pollution. POINT SOURCE POLLUTION A  point source of pollution  is a single identifiable  localized  source of  air,  water,  thermal,  noise  or  light  pollution. A  point source  has negligible extent, distinguishing it from other pollution source geometries. The sources are called  point sources  because in mathematical modeling, they can be approximated as a mathematical  point  to simplify analysis. Pollution point sources are identical to other  physics,  engineering,  optics  andchemistry  point sources except that their emissions have been labeled Water pollution from an  oil refinery  wastewater  discharge outlet Noise pollution from a  jet engine Disruptive  seismic  vibration from a localized seismic study Light pollution from an intrusive  street light Thermal pollution from an industrial process  outfall Radio  emissions from an interference-producing electrical device Types of air pollution sources which have finite extent are  line sources,  area sources  and  volume sources. Air pollution sources are also often categorized as either stationary or mobile. NON POINT SOURCE POLLUTION Non-point source (NPS) pollution  is  water pollution  affecting a water body from diffuse sources, such as polluted  runoff  from  agricultural  areas draining into a river, or wind-borne debris blowing out to sea. Nonpoint source pollution can be contrasted with  point source  pollution, where discharges occur to a body of water at a single location, such as discharges from a chemical factory,  urban runoff  from a roadway  storm drain, or from ships at sea. NPS may derive from many different sources with no specific solution to rectify the problem, making it difficult to regulate. It is the leading cause of water pollution in the  United States  today, with polluted runoff from agriculture the primary cause. Other significant sources of runoff include  hydrological  and  habitat modification, and  silviculture  (forestry). Contaminated stormwater washed off of  parking lots,  roads  and  highways, and  lawns  (often containing  fertilizers  and  pesticides) is called  urban runoff. This runoff is often classified as a type of NPS pollution. Some people may also consider it a point source because many times it is channeled into municipal storm drain systems and discharged through pipes to nearby  surface waters. However, not all urban runoff flows through storm drain systems before entering waterbodies. Some may flow directly into waterbodies, especially in developing and suburban areas. Also, unlike other types of point sources, such as industrial discharge, wastewater plants and other operations, pollution in urban runoff cannot be attributed to one activity or even group of activities. Therefore, because it is not caused by an easily identified and regulated activity, urban runoff pollution sources are also often treated as true nonpoint sources as municipalities work to abate t hem. MAJOR FORMS OF POLLUTION ::: The major forms of pollution are listed below along with the particular pollutants relevant to each of them: AIR POLLUTION Air pollution  is the introduction of  chemicals,  particulate matter, or  biological materials  that cause harm or discomfort to humans or other living organisms, or damages the  natural environment  into the atmosphere. The atmosphere is a complex dynamic 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 Earths  ecosystems. NOISE POLLUTION Noise pollution  (or  environmental  noise) is displeasing human, animal or machine-created sound that disrupts the activity or balance of human or animal life. The word  noise  comes from the Latin word  nauseas, meaning seasickness. The source of most outdoor noise worldwide is mainly  construction  and  transpHYPERLINK http://en.wikipedia.org/wiki/Transportortation systems, including  motor vehicle  noise,  aircraft noise  and  rail noise.  Poor  urban planning  may give rise to noise pollution, since side-by-side industrial and residential buildings can result in noise pollution in the residential area. Indoor and outdoor noise pollution sources include  car alarms, emergency service  sirens, mechanical equipment,  fireworks, compressed  air horns, groundskeeping equipment, barking dogs, appliances,lighting  hum, audio entertainment systems, electric  megaphones, and loud people. SOIL CONTAMINATION Soil contamination  (soil pollution) is caused by the presence of  xenobiotic  (human-made) chemicals or other alteration in the natural soil environment. This type of contamination typically arises from the rupture of  underground storage tanks, application of  pesticides, percolation of contaminated surface water to subsurface strata, oil and fuel dumping, leaching of wastes fromlandfills  or direct discharge of industrial wastes to the soil. The most common chemicals involved are petroleum  hydrocarbons,  solvents, pesticides, lead and other  heavy metals. This occurrence of this phenomenon is correlated with the degree of industrialization and intensities of chemical usage. The concern over soil contamination stems primarily from health risks, from direct contact with the contaminated soil, vapors from the contaminants, and from secondary contamination of water supplies within and underlying the soil. Mapping of contaminated soil sites and the resulting cleanup are time consuming and expensive tasks, requiring extensive amounts of  geology,hydrology,  chemistry  and  computer modeling  skills. It is in  North America  and  Western Europe  that the extent of contaminated land is most well known, with many of countries in these areas having a legal framework to identify and deal with this environmental problem; this however may well be just the tip of the iceberg with developing countries very likely to be the next generation of new soil contamination cases. RADIOACTIVE CONTAMINATION Radioactive contamination, also called  radiological contamination, is radioactive substances on surfaces, or within solids, liquids or gases (including the human body), where their presence is unintended or undesirable, or the process giving rise to their presence in such places. Also used less formally to refer to a quantity, namely the  activity  on a surface (or on a unit area of a surface). Contamination does not include residual  radioactive material  remaining at a site after the completion of  decommissioning. The term radioactive contamination may have a connotation that is not intended. The term radioactive contamination refers only to the presence of  radioactivity, and gives no indication of the magnitude of the hazard involved. Radioactive contamination is typically the result of a spill or accident during the production or use of  radionuclides  (radioisotopes), an unstable nucleus which has excessive energy. Contamination may occur from radioactive gases, liquids or particles. For example, if a radionuclide used in  nuclear medicine  is accidentally spilled, the material could be spread by people as they walk around. Radioactive contamination may also be an inevitable result of certain processes, such as the release of radioactive  xenon  in  nuclear fuel reprocessing. In cases that radioactive material cannot be contained, it may be diluted to safe concentrations.  Nuclear fallout  is the distribution of radioactive contamination by a  nuclear explosion. THERMAL POLLUTION   Thermal pollution  is the degradation of  water quality  by any process that changes ambient water  temperature. A common cause of thermal pollution is the use of water as a  coolant  by  power plants  and industrial manufacturers. When water used as a coolant is returned to the natural environment at a higher temperature, the change in temperature (a) decreases  oxygen  supply, and (b) affects  ecosystem  composition.  Urban runoffstormwater  discharged to surface waters from  roads  and  parking lotscan also be a source of elevated water temperatures. When a power plant first opens or shuts down for repair or other causes, fish and other organisms adapted to particular temperature range can be killed by the abrupt rise in water temperature known as thermal shock. SOURCES AND CAUSES Air pollution comes from both natural and man made sources. Though globally man made pollutants from combustion, construction, mining, agriculture and warfare are increasingly significant in the air pollution equation. Motor vehicle emissions are one of the leading causes of air pollution.  China,  United States,  Russia,  Mexico, and  Japan  are the world leaders in air pollution emissions. Principal stationary pollution sources include  chemical plants, coal-fired  power plants,  oil refineries,  petrochemical  plants,  nuclear waste  disposal activity, incinerators, large livestock farms (dairy cows, pigs, poultry, etc.),  PVC  factories, metals production factories, plastics factories, and other heavy industry. Agricultural air pollution comes from contemporary practices which include clear felling and burning of natural vegetation as well as spraying of pesticides and herbicides About 400 million metric tons of  hazardous wastes  are generated each year.  The  United States  alone produces about 250 million metric tons.  Americans constitute less than 5% of the  worldHYPERLINK http://en.wikipedia.org/wiki/Worlds_populationHYPERLINK http://en.wikipedia.org/wiki/Worlds_populations population, but produce roughly 25% of the worlds  COHYPERLINK http://en.wikipedia.org/wiki/Carbon_dioxide2,  and generate approximately 30% of  worlds waste.  In 2007,  China  has overtaken the United States as the worlds biggest producer of CO2. In February 2007, a report by the Intergovernmental Panel on Climate Change (IPCC), representing the work of 2,500 scientists from more than 130 countries, said that humans have been the primary cause of global warming since 1950. Humans have ways to cut greenhouse gas emissions and avoid the consequences of global warming, a major climate report concluded. But in order to change the climate, the transition from fossil fuels like coal and oil needs to occur within decades, according to the final report this year from the UNs Intergovernmental Panel on Climate Change (IPCC). Some of the more common  soil  contaminants are  chlorinated hydrocarbons  (CFH),  heavy metals  (such as  chromium,  cadmiumfound in rechargeable  batteries, and  leadfound in lead  paint,  aviation fuel  and still in some countries,  gasoline),  MTBE,zinc,  arsenic  and  benzene. In 2001 a series of press reports culminating in a book called  Fateful Harvest  unveiled a widespread practice of recycling industrial byproducts into fertilizer, resulting in the contamination of the soil with various metals. Ordinary municipal  landfills  are the source of many chemical substances entering the soil environment (and often groundwater), emanating from the wide variety of refuse accepted, especially substances illegally discarded there, or from pre-1970 landfills that may have been subject to little control in the U.S. or EU. There have also been some unusual releases of  polychlorinated dibenzodioxins, commonly called  dioxins  for simplic ity, such as  TCDD. Pollution can also be the consequence of a natural disaster. For example,  hurricanes  often involve water contamination from sewage, and  petrochemical  spills from ruptured  boats  or  automobiles. Larger scale and environmental damage is not uncommon when coastal  oil rigs  or  refineries  are involved. Some sources of pollution, such as  nuclear power  plants or  oil tankers, can produce widespread and potentially hazardous releases when accidents occur. In the case of  noise pollution  the dominant source class is the  motor vehicle, producing about ninety percent of all unwanted noise worldwide. EFFECTS HUMAN HEALTH Adverse  air quality  can kill many organisms including humans. Ozone pollution can cause  respiratory disease,  cardiovascular disease,  throat  inflammation, chest pain, andcongestion. Water pollution causes approximately 14,000 deaths per day, mostly due to contamination of  drinking water  by untreated  sewage  in  developing countries. An estimated 700 million  Indians  have no access to a proper toilet, and 1,000 Indian children die of diarrhoeal sickness every day.  Nearly 500 million Chinese lack access to safe drinking water.  656,000 people die prematurely each year in  China  because of air pollution. In  India, air pollution is believed to cause 527,700 fatalities a year.  Studies have estimated that the number of people killed annually in the US could be over 50,000. Oil spills can cause  skin  irritations and  rashes. Noise pollution induces  hearing loss,  high blood pressure,  stress, and  sleep disturbance.  Mercury  has been linked to  developmental deficits  in children and  neurologic  symptoms. Older people are majorly exposed to diseases induced by air pollution. Those with heart or lung disorders are under additional risk. Children and infants are also at serious risk.  Lead  and other  heavy metals  have been shown to cause neurological problems. Chemical and  radioactive  substances can  cause  cancerand  as well as  birth defects. ENVIRONMENT Pollution has been found to be present widely in the  environment. There are a number of effects of this: Biomagnification  describes situations where toxins (such as  heavy metals) may pass through  trophic levels, becoming exponentially more concentrated in the process. Carbon dioxide  emissions cause  ocean acidification, the ongoing decrease in the pH of the Earths oceans as CO2  becomes dissolved. The emission of  greenhouse gases  leads to  global warming  which affects ecosystems in many ways. Invasive species  can out compete native species and reduce  biodiversity. Invasive plants can contribute debris and biomolecules (allelopathy) that can alter soil and chemical compositions of an environment, often reducing native species  competitiveness. Nitrogen oxides  are removed from the air by rain and  fertilise  land which can change the species composition of ecosystems. Smog  and haze can reduce the amount of sunlight received by plants to carry out  photosynthesis  and leads to the production of  tropospheric ozone  which damages plants. Soil can become infertile and unsuitable for plants. This will affect other  organisms  in the  food web. Sulphur dioxide  and  nitrogen oxides  can cause  acid rain  which lowers the  pH  value of soil. POLLUTION CONTROL :: Pollution control is a term used in  environmental management. It means the control of  emissions  and  effluents  into air, water or soil. Without pollution control, the waste products from consumption, heating, agriculture, mining, manufacturing, transportation and other human activities, whether they accumulate or disperse, will degrade the  environment. In the hierarchy of controls,  pollution prevention  and  waste minimization  are more desirable than pollution control. PRACTICES:: RECYCLING :::: Recycling  involves processing used  materials  (waste) into new products to prevent waste of potentially useful materials, reduce the consumption of fresh raw materials, reduce  energy  usage, reduce air pollution (from  incineration) and water pollution (from  landfilling) by reducing the need for conventional waste disposal, and lower  greenhouse gas  emissions as compared to virgin production.  Recycling is a key component of modern waste reduction and is the third component of the Reduce,  Reuse, Recycle  waste hierarchy. Recyclable materials include many kinds of  glass,  paper,  metal,  plastic,  textiles, and  electronics. Although similar in effect, the  composting  or other reuse of  biodegradable waste   such as  food  or  garden waste   is not typically considered recycling.  Materials to be recycled are either brought to a collection center or picked up from the curbside, then sorted, cleaned, and reprocessed into new materials bound for manufacturing. In a strict sense, recycling of a material would produce a fresh supply of the same material-for example, used office  paper  would be converted into new office paper, or used  foamed polystyrene  into new polystyrene. However, this is often difficult or too expensive (compared with producing the same product from raw materials or other sources), so recycling of many products or materials involves their  reuse  in producing different materials (e.g.,  paperboard) instead. Another form of recycling is the  salvage  of certain materials from complex products, either due to their intrinsic value (e.g.,  lead  from  car batteries, or  goldfrom  computer  components), or due to their hazardous nature (e.g., removal and reuse of  mercury  from various items). Critics dispute the net economic and environmental benefits of recycling over its costs, and suggest that proponents of recycling often make matters worse and suffer from  confirmation bias. Specifi cally, critics argue that the costs and energy used in collection and transportation detract from (and outweigh) the costs and energy saved in the production process; also that the jobs produced by the recycling industry can be a poor trade for the jobs lost in logging, mining, and other industries associated with virgin production; and that materials such as paper pulp can only be recycled a few times before material degradation prevents further recycling. Proponents of recycling dispute each of these claims, and the validity of arguments from both sides has led to enduring controversy. PROCESS OF RECYCLING Collection A number of different systems have been implemented to collect recyclates from the general waste stream. These systems lie along the spectrum of trade-off between public convenience and government ease and expense. The three main categories of collection are drop-off centres, buy-back centres and curbside collection. Drop-off centres require the waste producer to carry the recyclates to a central location, either an installed or mobile collection station or the reprocessing plant itself. They are the easiest type of collection to establish, but suffer from low and unpredictable throughput. Buy-back centres differ in that the cleaned recyclates are purchased, thus providing a clear incentive for use and creating a stable supply. The post-processed material can then be sold on, hopefully creating a profit. Unfortunately government subsidies are necessary to make buy-back centres a viable enterprise, as according to the United States Nation Solid Wastes Management Association it costs on average US$50 to process a ton of material, which can only be resold for US$30. CURBSIDE COLLECTION Curbside collection encompasses many subtly different systems, which differ mostly on where in the process the recyclates are sorted and cleaned. The main categories are mixed waste collection, commingled recyclables and source separation.  A  waste collection vehicle  generally picks up the waste. At one end of the spectrum is mixed waste collection, in which all recyclates are collected mixed in with the rest of the waste, and the desired material is then sorted out and cleaned at a central sorting facility. This results in a large amount of recyclable waste, paper especially, being too soiled to reprocess, but has advantages as well: the city need not pay for a separate collection of recyclates and no public education is needed. Any changes to which materials are recyclable is easy to accommodate as all sorting happens in a central location. In a Commingled or  single-stream system, all recyclables for collection are mixed but kept separate from other waste. This greatly reduces the need for post-collection cleaning but does require  public education  on what materials are recyclable. Source separation is the other extreme, where each material is cleaned and sorted prior to collection. This method requires the least post-collection sorting and produces the purest recyclates, but incurs additional  operating costs  for collection of each separate material. An extensive public education program is also required, which must be successful if recyclate contamination is to be avoided. Source separation used to be the preferred method due to the high sorting costs incurred by commingled collection. Advances in sorting technology (see  sorting  below), however, have lowered this overhead substantially-many areas which had developed source separation programs have since switched to comingled collection. Sorting Once commingled recyclates are collected and delivered to a  central collection facility, the different types of materials must be sorted. This is done in a series of stages, many of which involve automated processes such that a truck-load of material can be fully sorted in less than an hour.  Some plants can now sort the materials automatically, known as  single-stream recycling. A 30 percent increase in recycling rates has been seen in the areas where these plants exist. Initially, the commingled recyclates are removed from the collection vehicle and placed on a conveyor belt spread out in a single layer. Large pieces of  corrugated fiberboard  and  plastic bags  are removed by hand at this stage, as they can cause later machinery to jam. Next, automated machinery separates the recyclates by weight, splitting lighter paper and plastic from heavier glass and metal. Cardboard is removed from the mixed paper, and the most common types of plastic,  PET  (#1) and  HDPE  (#2), are collected. This separation is usually done by hand, but has become automated in some sorting centers: a  spectroscopic  scanner is used to differentiate between different types of paper and plastic based on the absorbed wavelengths, and subsequently divert each material into the proper collection channel.[4] Strong magnets are used to separate out  ferrous metals, such as  iron,  steel, and  tin-plated steel cans  (tin cans).  Non-ferrous metals  are ejected by  magnetic eddy currents  in which a rotating  magnetic field  induces  an electric current around the aluminium cans, which in turn creates a magnetic eddy current inside the cans. This magnetic eddy current is repulsed by a large magnetic field, and the cans are ejected from the rest of the recyclate stream.[4] Finally, glass must be sorted by hand based on its color: brown, amber, green or clear. GREEN HOUSE GASES AND GLOBAL WARNING Carbon dioxide, while vital for  photosynthesis, is sometimes referred to as pollution, because raised levels of the gas in the atmosphere are affecting the Earths climate. Disruption of the environment can also highlight the connection between areas of pollution that would normally be classified separately, such as those of water and air. Recent studies have investigated the potential for long-term rising levels of atmospheric carbon dioxide to cause slight but critical  increases in the acidity of ocean waters, and the possible effects of this on marine ecosystems. Global warming  is the increase in the  average temperature  of  Earths near-surface air and oceans since the mid-20th century and its projected continuation. According to the 2007  Fourth Assessment Report  by the  Intergovernmental Panel on Climate Change  (IPCC), global surface temperature increased 0.74  Ã‚ ±Ã‚  0.18  Ã‚ °C  (1.33  Ã‚ ±Ã‚  0.32  Ã‚ °F) during the 20th century. Global dimming, a result of increasing concentrations of atmospheric  aerosols  that block sunlight from reaching the surface, has partially countered the effects of warming induced by greenhouse gases. Climate model  projections summarized in the latest IPCC report indicate that the global  surface temperature  is likely to rise a further  1.1 to 6.4  Ã‚ °C  (2.0 to 11.5  Ã‚ °F)  during the 21st century.  The uncertainty in this estimate arises from the use of models with differing  sensitivity to greenhouse gas concentrations  and the use of differing  estimates of future greenhouse gas emissions. An increase in global temperature will cause  sea levels to rise  and will change the amount and pattern of  precipitation, probably including expansion of  subtropical  deserts.  Warming is expected to be  strongest in the Arcticand would be associated with continuing  retreat of glaciers,  permafrost  and  sea ice. Other likely effects include changes in the frequency and intensity of  extreme weather  events,  species extinctions, and changes in  agricultural yields. Warming and related changes will vary from region to region aroun d the globe, though the nature of these regional variations is uncertain.  As a result of contemporary increases in atmospheric carbon dioxide, the oceans have become  more acidic; a result that is predicted to continue. The  scientific consensus  is that  anthropogenic  global warming is occurring.  Nevertheless,  political  and  public debate  continues. The  Kyoto Protocol  is aimed at stabilizing greenhouse gas concentration to prevent a dangerous anthropogenic interference.  As of November 2009,  187 states had signed and ratified  the protocol. The  greenhouse effect  is the process by which  absorption  and  emission  of  infrared  radiation by gases in the  atmosphere  warm a  planets lower atmosphere and surface. It was proposed by  Joseph Fourierin 1824 and was first investigated quantitatively by  Svante Arrhenius  in 1896.  The question in terms of global warming is how the strength of the presumed greenhouse effect changes when human activity increases the concentrations of greenhouse gases in the atmosphere. Naturally occurring greenhouse gases have a mean warming effect of about 33  Ã‚ °C (59  Ã‚ °F).  The major greenhouse gases are  water vapor, which causes about 36-70 percent of the greenhouse effect;carbon dioxide  (CO2), which causes 9-26 percent;  methane  (CH4), which causes 4-9 percent; and  ozone  (O3), which causes 3-7 percent.  Clouds also affect the radiation balance, but they are composed of liquid water or ice and so have  different effects on radiation  from water vapor. Human activity since the  Industrial Revolution  has increased the amount of greenhouse gases in the atmosphere, leading to increased  radiative forcing  from CO2,  methane, tropospheric  ozone,  CFCs  andnitrous oxide. The  concentrations  of CO2  and methane have increased by 36% and 148% respectively since 1750.  These levels are much higher than at any time during the last 650,000 years, the period for which reliable data has been extracted from  ice cores.  Less direct geological evidence indicates that CO2  values higher than this were last seen about 20 million years ago.[41]  Fossil fuel  burning has produced about three-quarters of the increase in CO2  from human activity over the past 20 years. Most of the rest is due to land-use change, particularly  deforestation. Over the last three decades of the 20th century,  GDP  per capita  and  population growth  were the main drivers of increases in greenhouse gas emissions.  CO2  emissions are continuing to rise due to the burning of fossil fuels and land-use change.  Emissions scenarios, estimates of changes in future emission levels of greenhouse gases, have been projected that depend upon uncertain economic,sociological,  technological, and natural developments.  In most scenarios, emissions continue to rise over the century, while in a few, emissions are reduced.  These emission scenarios, combined with carbon cycle modelling, have been used to produce estimates of how atmospheric concentrations of greenhouse gases will change in the future. Using the six IPCC  SRES  marker scenarios, models suggest that by the year 2100, the atmospheric concentration of CO2  could range between 541 and 970 ppm.  This is an increase of 90-250% above the concentration in the year 1750. Fossil fuel reserves are sufficient to reach these levels and continue emissions past 2100 if  coal,  tar sands  or  methane clathrates  are extensively exploited. The destruction of  stratospheric  ozone by  chlorofluorocarbons  is sometimes mentioned in relation to global warming. Although there are a few  areas of linkage, the relationship between the two is not strong. Reduction of stratospheric ozone has a cooling influence.  Substantial ozone depletion did not occur until the late 1970s.  Ozone in the troposphere  (the lowest part of the  EarthHYPERLINK http://en.wikipedia.org/wiki/Atmosphere_of_EarthHYPERLINK http://en.wikipedia.org/wiki/Atmosphere_of_Earths atmosphere) does contribute to surface warming. 8 most polluted cities in India ::: Sukinda, Orissa Number of people affected:  2,600,000 Type of pollutant:  Hexavalent chromium and other metals   Source of pollution:  Chromite mines and processing Hexavalent chromium is: a nasty heavy metal used for stainless steel production and leather tanning that is carcinogenic if inhaled or ingested. In Sukinda, which contains one of the largest open cast chromite ore mines in the world, 60% of the drinking water contains hexavalent chromium at levels more than double international standards. An Indian health group estimated that 84.75% of deaths in the mining areas where regulations are nonexistent are due to chromite-related diseases. There has been virtually no attempt to clean up the contamination. Sukinda has been listed in the Top 10 most polluted places in the world by the US-based Blacksmith Institute. Labourers work at a road construction site near Vapi Vapi, Gujarat Number of people potentially affected:  71,000 Type of pollutant:  Chemicals and heavy metals Source of pollution:  Industrial estates If Indias environment is on the whole healthier than its giant neighbor Chinas, thats because India is developing much more slowly. But thats changing, starting in towns like Vapi, which sits at the southern end of a 400-km-long belt of industrial estates. For the citizens of Vapi, the cost of growth has been severe: levels of mercury in the citys groundwater are reportedly 96 times higher than WHO safety levels, and heavy metals are present in the air and the local produce. Its just a disaster, says Fuller. Vapi has been listed in the Top 10 most polluted places in the world by the US-based Blacksmith Institute. Mandi Gobindgarh, Punjab Number of people affected:  155,416 Type of pollutant:  High dust and smoke particulate Source of pollution:  Industrial units Gobindgarh in Punjab, also known as Loha mandi, recorded suspended particulate matter (microscopic particles in the air such as dust and smoke) level of 252 micrograms per cubic metre in 2007, 320 percent higher than the national standard level of 60 micrograms. Known for its iron and steel factories, it is one of the most polluted city in the country. The population in Gobindgarh shows a higher prevalence of symptoms of angina and cardiovascular disease. A ragpicker rows boat in polluted Gomti river in Lucknow Lucknow, UP Number of people affected:  30 lakh Type of pollutant:  High dust and smoke particulate Source of pollution:  Industrial units, vehicles Vehicular emissions are the main cause of air pollution in Lucknow. In recent years there has been a rapid rise in vehicular