Master Basic EnvSci Notes PDF

Definition of “Environment” ENVIRONMENT means the physical factors of the surroundings of the human beings including land, water, atmosphere, climate, sound, odour, taste, the biological factors of animals and plants and the social factor of aesthetics. (Environmental Quality...

Definition of “Environment” ENVIRONMENT means the physical factors of the surroundings of the human beings including land, water, atmosphere, climate, sound, odour, taste, the biological factors of animals and plants and the social factor of aesthetics. (Environmental Quality Act, 1974)  OVERVIEW OF ENVIRONMENT & ITS RELATED ELEMENTS Environment Physical Chemical Biological Social Aesthetical o Water o Earth & o Ecological o Health & env. atmosphere concept o Socio-politic & o Sources & o Biogeochemical env. processes of cycle o Env. Education pollutants o Nat resources o Env. Regulation (rivers, wetland) & laws. o Biodiversity o Conservation Establishment of Department of Environment in Malaysia) Government approved the Environmental Quality Act as a law on 14 March 1974 and enforced on 15 April 1975. Division of Environment (BAS) was established on 15 September 1975 under the Ministry of Local Government and Environment. BAS was moved to Ministry of Science, Technology and Environment on March 1976. BAS upgraded to Department of Environment (JAS) on 1 September 1983. JAS was moved to the Ministry of Natural Resources and Environment on April 2006.  World Commission on Environment and Author Development Subject Sustainability Publisher Oxford University Press Publication 1987 date Pages 383 ISBN 019282080X Our Common Future, also known as the Brundtland Report, from the United Nations World Commission on Environment and Development (WCED) was published in 1987. Its targets were multilateralism and interdependence of nations in the search for a sustainable development path. The report sought to recapture the spirit of the Stockholm Conference - which had introduced environmental concerns to the formal political development sphere. Our Common Future placed environmental issues firmly on the political agenda; it aimed to discuss the environment and development as one single issue. The document was the culmination of a “900-day” international-exercise which catalogued, analysed, and synthesised: written submissions and expert testimony from “senior government representatives, scientists and experts, research institutes, industrialists, representatives of non- governmental organizations, and the general public” held at public hearings throughout the world. The Brundtland Commission's mandate was to: 1. “ re-examine the critical issues of environment and development and to formulate innovative, concrete, and realistic action proposals to deal with them; 2. strengthen international cooperation on environment and development and to assess and propose new forms of cooperation that can break out of existing patterns and influence policies and events in the direction of needed change; and 3. raise the level of understanding and commitment to action on the part of individuals, voluntary organizations, businesses, institutes, and governments” (1987: 347). “The Commission focused its attention in the areas of population, food security, the loss of species and genetic resources, energy, industry, and human settlements - realizing that all of these are connected and cannot be treated in isolation one from another” The Brundtland Commission Report recognised that human resource development in the form of poverty reduction, gender equity, and wealth redistribution was crucial to formulating strategies for environmental conservation, and it also recognised that environmental-limits to economic growth in industrialised and industrialising societies existed. The Brundtland Report claimed that poverty reduces sustainability and accelerates environmental pressures – creating a need for the balancing between economy and ecology. As such, the Report offered “[the] analysis, the broad remedies, and the recommendations for a sustainable course of development” within such societies (1987: 16). However, the Report was unable to identify the mode(s) of production that are responsible for degradation of the environment, and in the absence of analysing the principles governing market-led economic growth, the Report postulated that such growth could be reformed (and expanded); this lack of analysis resulted in an obfuscated-introduction of the term sustainable development. The publication of Our Common Future and the work of the World Commission on Environment and Development laid the groundwork for the convening of the 1992 Earth Summit and the adoption of Agenda 21, the Rio Declaration and to the establishment of the Commission on Sustainable Development. An oft-quoted definition of sustainable development is defined in the report as: "development that meets the needs of the present without compromising the ability of future generations to meet their own needs." In addition, key contributions of Our Common Future to the concept of sustainable development include the recognition that the many crises facing the planet are interlocking crises that are elements of a single crisis of the whole and of the vital need for the active participation of all sectors of society in consultation and decisions relating to sustainable development. Our Common Future is also known as the Brundtland Report in recognition of former Norwegian Prime Minister Gro Harlem Brundtland's role as Chair of the World Commission on Environment and Development. (Source: Wikipedia) UN Conference on the Human Environment The United Nations Conference on the Human Environment was held in Stockholm, Sweden from June 5–16 in 1972. When the UN General Assembly decided to convene the 1972 Stockholm Conference, at the initiative of the Government of Sweden to host it, UN Secretary-General U Thant invited Maurice Strong to lead it as Secretary-General of the Conference, as the Canadian diplomat (under Pierre Trudeau) had initiated and already worked for over two years on the project. History Sweden first suggested to the United Nations Economic and Social Council ECOSOC in 1968 the idea of having a UN conference to focus on human interactions with the environment. ECOSOC passed resolution 1346 supporting the idea. General Assembly Resolution 2398 in 1969 decided to convene a conference in 1972 and mandated a set of reports from the UN secretary-general suggesting that the conference focus on "stimulating and providing guidelines for action by national government and international organizations" facing environmental issues. Stockholm Declaration The meeting agreed upon a Declaration containing 26 principles concerning the environment and development; an Action Plan with 109 recommendations, and a Resolution. Principles of the Stockholm Declaration: 1. Human rights must be asserted, apartheid and colonialism condemned 2. Natural resources must be safeguarded 3. The Earth's capacity to produce renewable resources must be maintained 4. Wildlife must be safeguarded 5. Non-renewable resources must be shared and not exhausted 6. Pollution must not exceed the environment's capacity to clean itself 7. Damaging oceanic pollution must be prevented 8. Development is needed to improve the environment 9. Developing countries therefore need assistance 10. Developing countries need reasonable prices for exports to carry out environmental management 11. Environment policy must not hamper development 12. Developing countries need money to develop environmental safeguards 13. Integrated development planning is needed 14. Rational planning should resolve conflicts between environment and development 15. Human settlements must be planned to eliminate environmental problems 16. Governments should plan their own appropriate population policies 17. National institutions must plan development of states' natural resources 18. Science and technology must be used to improve the environment 19. Environmental education is essential 20. Environmental research must be promoted, particularly in developing countries 21. States may exploit their resources as they wish but must not endanger others 22. Compensation is due to states thus endangered 23. Each nation must establish its own standards 24. There must be cooperation on international issues 25. International organizations should help to improve the environment 26. Weapons of mass destruction must be eliminated One of the seminal issues that emerged from the conference is the recognition for poverty alleviation for protecting the environment. The Indian Prime Minister Indira Gandhi in her seminal speech in the conference brought forward the connection between ecological management and poverty alleviation. Some argue that this conference, and more importantly the scientific conferences preceding it, had a real impact on the environmental policies of the European Community (that later became the European Union). For example, in 1973, the EU created the Environmental and Consumer Protection Directorate, and composed the first Environmental Action Program. Such increased interest and research collaboration arguably paved the way for further understanding of global warming, which has led to such agreements as the Kyoto Protocol and the Paris Agreement, and has given a foundation of modern environmentalism. (Source: Wikipedia) Water in the Environment 1 > Water Usage 2  Water Properties Unique physical & chemical properties make water suitable or “fit” for the support of life as we know it. Water plays so many & such important roles in the functioning of the Biosphere. Water is in unique abundance on our planet. The only material that exists in all three physical states at the earth’s surface ie. liquid, solid, and gas. > Water 3  DENSITY of H²O reaches a max at 277K (unlike that of most other liquids) NB. A no. of important ecological & env. Consequences may be attributed to the expansion of H²O as it freezes eg¹. the intiation of rock weathering by ice formation in small cracks & fissures (crystal of ice expand & enlarge cracks). Water expands when freezing. eg². Thermal stratification of lakes. The unusually low density of ice & of liquid water just above the melting pts. Is attributed to the open structure of water molecule. > Density 4 SURFACE TENSION Water has high surface tension. water molecules’ ability to form large no. of strong hydrogen bonds=>large surf tension. eg. Many insects able to walk on the surfaces of lakes& streams eg. Capillarity movement of awater in plant vessels & retention of it in bet. soil particles. The combination of tension & adhesion produces force that enhance circulation of water in plants, soils, and blood streams of the body. > Surface Tension 5 > A water strider on water surface 6 THERMAL PROPERTIES Water has large heat capacity (75.5 J/mol K) allows a given qty of heat to be stored with minimal temp change, & its large thermal conductivity allows for rapid transfer of heat to or from adjacent substances. eg. Organisms (eg man) require a narrow range of temp for their internal env have used this for excellent thermoregulation systems. eg. Entire Biosphere moderated by storage of solar energy in water or its phase changes. > High thermal capacity 7 LIQUID FORM Pure water is colorless, odorless, & transparent. These properties are necessary for maximum benefits, such as plant growth. For example, the transparency of water permits light penetration in streams & lakes so vital in sustenance for aqueous animals & plants. eg. photosynthesis > Colorless, odorless & transparent 8 Example: Thermal stratification of a lake. Lake stratification - separation of lakes into 3 layers: Epilimnion (top of the lake); Metalimnion or thermocline (middle layer); Hypolimnion (the bottom layer). > Water and thermal stratification 9 Example: Thermal stratification of a lake (Refer Fig.) If water behaved as most liquids, lakes would freeze solid in winter (where temp drops below 273K for extended periods). Fish & aquatic organisms would die due to water being frozen. Instead, a layer of water at 277K collects at the bottom of lakes while only the surf layer freezes. In summer the opposite situation: a layer of water warmed by solar radiation collects at the surf above colder, denser liquid at the bottom. In spring & fall, as the surf layer warms & cools, a point is reached at which the entire lake is nearly uniform in temp so that vertical mixing (turnover) can occur. This distributes dioxygen & nutrients throughout the water. > Water and thermal stratification 10 > Water and thermal stratification 11  Majority aquatic organisms are cold-blooded ie. They have v little control over their body temp. High heat capacity of water helps: a body of water able to gain or lose relatively large qty of heat without suffering correspondingly large changes in temp. Because of this, the organisms do not have the problem of their own body temp changing all the time. A gram calorie (cal.) is the amt of heat energy required to raise the temp of one gram of water from 14.5 oC to 15.5 oC. One kilocalorie (kcal. Or Cal.) is equal to 1,000 gram calories. Food Calories for human diets are usually measured in kilocalorie. > High thermal capacity of water 12 VISCOSITY Water has very low viscosity. This mobility allows easy transportation, as well as use as an avenue for movement of boats & ships. The buoyancy of the fluid enhances its effectiveness as a medium for transportation. > Viscosity 13  The Water Cycle When rainwater falls on land, some evaporates again into atmosphere, some is absorbed by plants or drunk by animals, some runs off the surf of land into streams and lakes, some percolates. The endless cycling of water maintains the various freshwater environments & supplies the vast quantities of water necessary for life on land/earth. Water is a renewable resource because of the hydrologic cycle. The water cycle is likewise a major factor in modifying temperatures, & it provides for the transport of chemical nutrients thru ecosystems. > Roles of water cycle 14 > Hydrological Cycle 15  Undesirable pollutants may be transported thru water cycle. Eg. sulphur (H2SO4) of acid rain in the atmosphere, toxic metals (Hg, As) & pesticides (DDT). These pollutants create env problems & some may be harmful to organisms & man. > Transportation of pollutants 16 > Water and acid rain 17 Water in the Environment 1  WATER Unique physical & chemical properties Suitable or “fit” the support of the life as we know it. Plays so many & such important roles in the functioning of the Biosphere. 2  DENSITY of H²O reaches a max at 277K (unlike that of most other liquids) NB. A no. of important ecological & env. Consequences may be attributed to the expansion of H²O as it freezes eg¹. Intiation of rock weathering by ice formation in small cracks & fissures. eg². Thermal stratification of lakes. The unusually low density of ice & of liquid water just above the melting pts. Is attributed to the open structure of water molecule. 3 SURFACE TENSION water molecule from large no.5 of strong hydrogen bonds=>large surf tension. eg. Many insects able to walk on the surfaces of lakes& streams eg. Capillarity movement of awater in plant vessels & retention of it in bet. soil particles. 4 5 Water Cycle 6 Water and acid rain 7 Atmospheric Science & Pollution 1  What is air pollution ? Air pollution may be defined as the presence in the air (outdoor atmosphere) of one or more contaminants or combinations thereof in such quantities and of such durations as may be or tend to be injurious to human, animal or plant life, or property, or which unreasonably interferes with the comfortable enjoyment of life or property or conduct of business. 2  Primary pollutants – Emitted directly into the environment e.g. CO, NOx and HC from motor vehicle exhaust Secondary pollutants – Formed by reaction in the environment E.g. O3 and PAN formed in photochemical smog from reaction of above primary pollutants 3  Major Pollutants Pollutants Minor Secondary Pollutants Pollutants Pollutants 4  Sulfur oxides (SOx) especially sulfur dioxide are emitted from burning of coal and oil. Nitrogen oxides (NOx) especially nitrogen dioxide are emitted from high temperature combustion. Can be seen as the brown haze dome above or plume downwind of cities. Carbon monoxide is colourless, odourless, non-irritating but very poisonous gas. It is a product by incomplete combustion of fuel such as natural gas, coal or wood. Vehicular exhaust is a major source of carbon monoxide. Carbon dioxide (CO2), a greenhouse gas emitted from combustion. 5  Volatile organic compounds (VOC), such as hydrocarbon fuel vapors and solvents. Particulate matter (PM), measured as smoke and dust. PM10 is the fraction of suspended particles 10 micrometers in diameter and smaller that will enter the nasal cavity. PM2.5 has a maximum particle size of 2.5 µm and will enter the bronchies and lungs. Toxic metals, such as lead, cadmium and copper. Chlorofluorocarbons (CFCs), harmful to the ozone layer emitted from products currently banned from use. 6  Ammonia (NH3) emitted from agricultural processes. Odors, such as from garbage, sewage, and industrial processes Radioactive pollutants produced by nuclear explosions and war explosives, and natural processes such as radon. Peroxyacetyl nitrate (PAN) similarly formed from NOx and VOCs. 7  Local – e.g. heat island Regional – e.g. acid rain Global – e.g. depletion of ozone layer, global warming Major environmental issues related to > atmosphere 8  An urban heat island (UHI) is a metropolitan area which is significantly warmer than its surrounding rural areas. The temperature difference usually is larger at night than during the day and larger in winter than in summer, and is most apparent when winds are weak. > What is heat island ? 9 > Urban heat island profile 10 > > Thermal Inversion (from heat island) 13 Temperature inversion 14  In the presence of a temperature inversion, the air near the surface is trapped and cannot move upward. In this case gases emitted at the surface do not dilute, and the concentration of pollutants increases. Temperature inversions happen in cities that are in valleys such as Denver and Mexico City. In this case the inversion happens because of radiative cooling from the surface. At night the surface cools by emission of infrared radiation, so that the coldest air is adjacent to the Earth’s surface and the air temperature increases with altitude. This inversion generally persists until the surface is warmed again the next morning by absorption of sunlight. Thermal inversions are also common in areas near mountain ranges such as in southern California. In this case, the temperature increases because of air that warms up as it descends down the mountain slope. > 15 Inversion Layer 16 > The changes 17  Heat islands form as cities replace natural land cover with pavement, buildings, and other infrastructure. These changes contribute to higher urban temperatures in a number of ways: – Displacing trees and vegetation minimizes the natural cooling effects of shading and evaporation of water from soil and leaves (evapotranspiration). – Tall buildings and narrow streets can heat air trapped between them and reduce air flow. – Waste heat from vehicles, factories, and air conditioners may add warmth to their surroundings, further exacerbating the heat island effect. > What is heat island ? 18 Displacing trees and vegetation minimizes the natural cooling effects of shading and evaporation of water from soil and leaves (evapotranspiration). 19 Urban heat island profile 20  Tall buildings and narrow streets can heat air trapped between them and reduce air flow. Heat island in urban area 21  Waste heat from vehicles, factories, and air conditioners may add warmth to their surroundings, further exacerbating the heat island effect. > Emission 22  Wearing out (reduction) of the amount of ozone in the stratosphere. > What is depletion of ozone layer? 23 24 25 26  Exposure to ambient ozone, even at low levels, may trigger a variety of health problems, especially in vulnerable populations such as children, the elderly, and those with pre-existing respiratory disease. Because wind can carry ozone and its precursors hundreds of miles, even residents far away from urban centers and sources of pollution can be at risk. There are specific health effects associated with ozone exposure. The specific health effects include: > Health Effects Associated with Ozone Exposure 27  Ozone can irritate lung airways and cause inflammation; Repeated exposure to ozone pollution for several months may cause permanent lung damage; Even low-level exposure can result in aggravated asthma, reduced lung capacity, and increased susceptibility to respiratory illnesses; and Studies have linked hospital admissions and emergency room visits to ground- level ozone exposure. > 28 > Do you want to be like this ? 29  Summary Chemicals in the atmosphere that deplete the Ozone layer are CFCs and related compounds in the atmosphere i.e. Chlorofluorocarbons (CFCs) and other halogenated ozone depleting substances (ODS) are mainly responsible for man-made chemical ozone depletion. CFCs were used in air conditioning and cooling units, as aerosol spray propellants prior to the 1970s, and in the cleaning processes of delicate electronic equipment. > Effects of depletion of ozone layer 30  Summary Consequences of ozone layer depletion: Increased UV Biological effects (i) Basal and squamous cell carcinomas. The most common forms of skin cancer in humans, basal and squamous cell carcinomas, have been strongly linked to UVB exposure. (ii) Malignant melanoma. Another form of skin cancer, malignant melanoma, is much less common but far more dangerous, being lethal in about 15–20 percent of the cases diagnosed. > Effects of depletion of ozone layer 31 (iii) Cortical cataracts. Epidemiological studies suggest an association between ocular cortical cataracts and UVB exposure. (iv) Increased tropospheric ozone. Increased surface UV leads to increased tropospheric ozone. Ground-level ozone is generally recognized to be a health risk, as ozone is toxic due to its strong oxidant properties. (v) Increased production of vitamin D. Vitamin D is produced in the skin by ultraviolet light. Thus, higher UVB exposure raises human vitamin D in those deficient in it. > 32 (vi) Effects on animals. A November 2010 report by scientists at the Institute of Zoology in London found that whales off the coast of California have shown a sharp rise in sun damage. The findings suggest "rising UV levels as a result of ozone depletion are to blame for the observed skin damage, in the same way that human skin cancer rates have been on the increase in recent decades. (vii) Effects on crops. An increase of UV radiation would be expected to affect crops. A number of… > 33 ……economically important species of plants, such as rice, depend on cyanobacteria residing on their roots for the retention of nitrogen. Cyanobacteria are sensitive to UV radiation and would be affected by its increase. "Despite mechanisms to reduce or repair the effects of increased ultraviolet radiation, plants have a limited ability to adapt to increased levels of UVB, therefore plant growth can be directly affected by UVB radiation. (Source: Wikipedia) > 34  Acid rain is rain or any other form of precipitation that is unusually acidic. It has harmful effects on the environment and on structures. It is mostly caused by emissions due to human activity of sulfur and nitrogen compounds which react in the atmosphere to produce acids. In recent years, many governments have introduced laws to reduce these emissions. > Acid Rain 35  Natural Phenomena – The principal natural phenomena that contribute acid- producing gases to the atmosphere are emissions from volcanoes and those from biological processes that occur on the land, in wetlands, and in the oceans. The major biological source of sulfur containing compounds is dimethyl sulfide. – The effects of acidic deposits have been detected in glacial ice thousands of years old in remote parts of the globe. > 36  Human activity – The coal-fired – The principal cause of acid rain is sulfur and nitrogen compounds from human sources, such as electricity generation, factories and motor vehicles. Coal power plants are one of the most polluting. > 37 CO2 Emission - countries 38 Global CO2 - What is our action ? 39 Acid rain formation 40  Acid rain was first found in Manchester, England. In 1852, Robert Angus Smith found the relationship between acid rain and atmospheric pollution. Though acid rain was discovered in 1852, it wasn't until the late 1960s that scientists began widely observing and studying the phenomenon. Canadian Harold Harvey was among the first to research a "dead" lake. > History of Acid Rain 41  normal rainwater has a pH of about 5.7 (Coates, 1981). lowers the pH of soil, killing soil organisms, leaching nutrients from soil, decreasing soil’s ability to support crops > pH 42  Surface runoff of acid rain lowers the pH of streams and lakes, threatening valuable ecosystems. If pH drops below 5.0, fish usually disappear completely and plant life is drastically altered. Fish eggs extremely sensitive to slight drops in pH. Induce the corrosion of solids. Damage to sculptures, cathedrals, and other stone or metal structures. A common chemical reactions combines sulphuric acid in rain with limestone or marble (CaCO3): > Effects of acid rain 43  CaCO3 + H2SO4 + H2O → CaSO4.2H2O + CO2  Corrosion of limestone by acid, produces gypsum. Tiny amts of gyp crystallize in small interstices of stone as it drys out. Thus, accelerates nat. weathering (pressures exerted by growing crystals cause cracks in rock). > 44 > Effects of acid rain to environment 45 > 46 Why people are keep talking about Global Warming ? > Global Warming 47 > Is it real ? 48 > Or you just want to wait ? 49 > Do you ? 50 > Global warming “melting” the earth ? 51 > Everybody experience global warming ? 52 > “Everyone” enjoy the global warming ? 53 > Even Malaysia experience the global warming 54 > Global Warming – Local perspective 55  An increase in the average temperature of the Earth Recent debate, but has been looked at by scientists for centuries > So what is GLOBAL WARMING ? 56 > Changes in global temperature 57  Future Now > How about in the future ? 58 > Greenhouse phenomenon 59 > 60 Human Impacts: Greenhouse Gases: CO2 Methane Nitrous oxide Fluorinated compounds > What causes it? 61  Natural Impacts – Volcanoes – Water Vapor – Cloud > What causes it? 62  Burning of fossil fuels is main cause US is leader in greenhouse gasses Human impacts are changing the composition of the atmosphere > Who’s Responsible? 63 > Greenhouse gasses 64 Ice melting 65 Land-based glaciers are retreating nearly everywhere around Earth: Triftgletscher Glacier, Switzerland. Since the 1850s ice cover in European alpine regions has decreased From 4,472 km2 to 2,272 km2. Photos: Michael Hambrey; Data: World Glacier Monitoring Service 2006 66 Observed changes in global climate parameters since 1970, (solid lines), compared to IPCC projections (broken lines with grey ranges): (a) Atmospheric CO2 concentration (b) Annual global mean surface temperature (land + oceans) (c) Sea level data from tide gauges (red line) and satellite altimeters (blue line) From: Rahmstorf et al. 2006 67 > 68 > 69  Rising sea level 1 Changes of precipitation pattern, local climate and acid 2 rain Expansions of desert 3 More Intense rainstorms 4 Not all long term effects can be determined 5 Effects of Air Pollution and Global Warming 70  What Is Being Done: Alternatives Renewable Energy Sources Solar Energies Wind Power Biomass Geothermal 71  Changes In Vehicle Systems Hybrid Fuel Cell Battery-Electric 72 73  Responsibility to improve environmental conditions lies upon all of us as individuals Concentrate on preventing environmental degradation before it starts > What you have to do ? 74 > 75  References Johnson, R. & Morrell, P. (1982). Environmental Science. Blackie & Son, London. > What you have to do ? 76  The Atmosphere 1. Atmosphere’s Structure.  There is considerable variation of temperature with height which forms the basis for the classification of the atmosphere into layers.  Temperature Profile – controlled mainly by degree of absorption of solar radiation in the various region.  Ozone contributes to the warming of the stratosphere.  Another source of heat is absorption of visible radiation by the earth’s surface and by clouds in the lower troposphere, that leads to the profile of decreasing temp with height observed up to an altitude of 10 km.  Temp profile – importance in determining the stability and degree of mixing of the atmosphere as a whole as well as those small parts of it in contact with cities or other high pollution areas.  Because its density is smaller, warm air rises above cold at the same pressure. In the atmosph., however pressure decreases significantly with altitude, allowing rising warm air to expand. Because air is poor conductor of heat its expansion is usually adiabatic and its temp must decrease by an amount equivalent to the work it does by expanding. If the rising air cools sufficiently, it will reach the same temp and density as its  surroundings and its rise will therefore halted. If the temp profile of the surroundings is such that at higher altitudes they are cooler than the rising body of air, the latter can continue upward.  In the troposphere much water vapour is present which can condense and release heat as rising air expands. This reduces the cooling effect.  Although vertical mixing may be absent at specific times and places, the general behavior of the troposphere is such that pollutants will be dispersed and diluted. On the other hand, the stratosphere exhibits stable atmospheric behavior. Because its temp- altitude profile has a positive slope vertical mixing is very slow. Material injected into the stratosphere tends to remain at a given altitude for years, eventhough it may be carried many times around the globe by jet-stream winds. A good example, a thin band of(NH4)2SO4 aerosol which has been discovered at an altitude of 20 km. [Source: Environmental Chemistry, JW Moore & EA Moore, 1976]. 2. Temperatute Inversion and Air Pollution.  Lapse rate, defined as the change in temp with increasing altitude.  A temp-altitude profile: When the lapse rate is positive and temp increases with altitude, even for only a short distance, a temperature inversion is said to exist.  Stable atmospheric conditions prevent vertical motion within the inversion layer; thus, gases and suspended matter become trapped and cannot rise past the altitude at which temp begins to increase. If an inversion occurs above a city or industrial region, pollutants which normally disperse throughout the troposphere cannot do so. This is important in a valley or among skyscrapers in a city where horizontal transport of hazardous substances is also cut off.