Effects of chemicals on visibility - PowerPoint Presentation

1. Effects of chemicals on visibilityDr. Saadia Rashid TariqTenured Associate Professor Department of Chemistry, LCWU, Lahore

2. Reduction in visibility- HazeHaze is caused by the scattering and absorption of visibility light by particles and gases. Light is an electromagnetic wave, and just as a plane water wave is deflected by a barrier from its original direction, light waves are scattered when they encounter particles and gas molecules that are approximately the same size as the light’s wavelength. The sky is blue because particlefree  air also scatters light,  but the gas molecules are so small that they scatter the shorter wavelength blue  light more than they scatter the longer wavelength red light. Wildfires, dust storms, and other natural events will affect visibility on a case-by-case basis. 

3. Reduction in visibility-HazeThe most obvious manifestation of photochemical smog is a yellowish- brownish-gray haze that is due to the presence in air of small water droplets containing products of chemical reactions that occur among pollutants in air. This haze, familiar to most of us who live in urban areas, now extends periodically to once-pristine areas such as the Grand Canyon in Arizona. Particles whose diameter is about that of the wavelength of visible light, i.e., 0.4–0.8 micro m, can scatter light—reflect it in random directions— and consequently interfere with its transmission, thereby reducing visual clarity, long-distance visibility, and the amount of sunlight reaching the ground. A high concentration in air of particles of diameters between 0.1 cm and 1 mm produces a haze.Indeed, one conventional technique of measuring the extent of particulate pollution in an air mass is to determine its haziness.

4. HazeThe existence of smog in the air can often be determined by simply looking at buildings or hills in the distance, and seeing if their appearance is partially masked by haze. The widespread haze in the Arctic atmosphere in winter is due to sulfate aerosols that originate from the burning of coal, especially in Russia and Europe. The enhanced haziness in summertime over much of North America is due mainly to sulfate aerosols arising from industrialized areas in the United States and Canada. Haze over China, produced by air pollution, so reduces sunlight intensity that it may be cutting food production by as much as 30% across a third of the country.

5. Haze-reduction in visibilityFine particles are largely responsible for the haze in Los Angeles and other locations subject to episodes of photochemical smog. The smog aerosols contain nitric and sulfuric acids that have been neutralized to salts. Also present in these aerosols are organic carbon products that are formed in the photochemical smog reactions; however, intermediates formed from fuel molecules having short carbon chains usually have high enough vapor pressures that they exist as gases rather than condense onto particles.

6. Effects of chemicals on buildings and monuments One of the more costly effects of sulfur dioxide pollution is deterioration of building materials. Limestone, marble, and dolomite are calcium or magnesium carbonate minerals that are attacked by atmospheric sulfur dioxide to form products that are either water-soluble or composed of poorly adherent solid crusts on the rock’s surface, adversely affecting the appearance, structural integrity, and life of the building. Although both SO2 and NOx attack such stone, chemical analysis of the crusts shows predominantly sulfate salts.

7. Dolomite, a calcium/magnesium carbonate mineral, reacts with atmospheric sulfur dioxide as follows: CaCO3•MgCO3 + 2SO2 + O2 + 9H2O → CaSO4•2H2O + MgSO4•7H2O + 2CO2 An example of this is Taj Mahal in Agrah that is becoming yellow continously.

8. Pollution effects on buildings

9. Effect of chemicals on biodiversityBiodiversity can be defined as the variability and variety of life on our planet. This includes the variety in ecosystems, species and genetics. The level of Biodiversity usually increases with the temperature, meaning that it is higher in warm climate zones.

10. Why is Biodiversity Important?Support a variety of plant species: With greater Biodiversity, the variety of plants increases. This leads to more opportunities, especially for farmers, since they are able to plant a greater variety of crops and thus use their land more effectively.Ecosystem balance: Our ecosystems depend on complex processes. If only a small number of species die out, there can be a huge effect on the whole ecosystem since there are often chain effects which affect many other species. With the preservation of Biodiversity, it can be assured that the ecosystem stays in its natural balance.Freshwater resources: Through a variety of microorganisms and other creatures, it can be assured that freshwater resources are sustained.Nutrient storage: Plants and other forms of vegetation store nutrients of all sorts. When the plants are consumed by animals, these nutrients come back to the planet in a natural way. Biodiversity is important to sustain this natural nutrition-cycle.

11. Why is Biodiversity Important?Soil formation: A variety in plants contributes to soil formation. It also assures that there are enough minerals and other nutrients in the soil.Breaking down pollutants: Through the process of photosynthesis, plants help to break down pollutants and thus clean the air. In areas with a high wood and plant density, air quality tends to be much better than in areas with a low concentration of plants. Food resource: A greater variety of animals and plants is useful for humanity in the sense that it provides a big selection for food sources and thus supplies all nutrients necessary for human health. .

12. Why is Biodiversity Important?Climatic stability: Since our natural system is balanced if do not intervene too much, Biodiversity protects the planet from global warming. For example, the rainforests store huge amounts of CO2, which is classified as a greenhouse gas. If by human actions like deforestation, this CO2 is released, it will have an adverse impact on our planet’s temperature. Thus, protecting a variety of plants and forests helps to stabilize our climate. Sustain recreation areas: Whether it is animals or humans, every species needs a place to rest. It is therefore crucial that we contain the natural variety of our planet in order to provide recreational areas where people and also animals can rest and recharge Source of drugs: Our nature, especially our plants, provide an immense variety of substances which are used for pharmaceutical processes. We would not be able to produce most of our drugs without extraction precious ingredients from a variety of plants.

13. Causes of loss of biodiversityDraughts: Draughts are one natural source for a loss in biodiversity. Since water is an essential prerequisite for all life on earth, a lack of water has serious consequences for all species. Plants which have not enough water will die off or will provide smaller crop yields. Animals will die since there organism is not able to work without water. If the draughts continue over a long period of time, there could be a severe loss in biodiversity. Floods: Floods are also harmful to the biodiversity of our planet. Animals and plants do need water to survive, however, too much of it may become deadly for them as well. Many organisms can simply drown in floods and the variety of animals and plants in the affected areas is therefore diminished.Wildfires: Wildfires are a severe problem to biodiversity since they can kill big areas of land. Thus, they destroy the natural food sources for animals, which have to move to other areas or they will die. Earthquakes: Earthquakes are another serious natural cause for a loss in biodiversity. They could kill large portions of the local wildlife. Position in the food chain: The position in the food chain is crucial for animals to determine their likelihood of extinction. If there are too many predators, the prey animals may almost have no chance to protect their species from extinction and thus biodiversity will be reduced. 

14. Causes of loss of biodiversityDegree of specialization: The more specialized as species is, the more likely it is to go extinct if environmental circumstances change since they will not be able to adapt to the new circumstances appropriately.Destruction of habitats: For many reasons, the habitats for animals and plants get destroyed by human intervention. We need more space for building houses. Moreover, we need more space for farming since we have to feed an increasing number of people. This leads to a destruction of the living environment of many species. They have to move or they will die. This problem is especially severe when it comes to the deforestation of the rainforests. Since 90% of all species on our planet live there, a destruction of this area will be extremely harmful to the variety in biodiversity.Excessive pollution: Pollution is another great man-made example causing a loss in biodiversity. There are several forms of pollution, including air and water pollution. Air pollution can lead to health issues for animals and even for humans, resulting in health diseases which in turn could diminish the variety of species. Moreover, water animals can be contaminated by toxic industrial by-products and thus go extinct. This problem is especially severe for water animals which react quite sensitive to changes in the natural environment and which are not able to adjust properly and fast enough.

15. Causes of loss of biodiversityOver-consumption: Another problem causing a loss in biodiversity is human over-consumption. Our consumption levels increase steadily. However, this leads to a higher level of pollution and to a destruction of natural environments, since for a higher level of production, more resources have to be extracted out of the ground. Thus, natural habitats are destroyed and the variety of animals and plants is diminished.Climate change: Through the emission of CO2 and other greenhouse gases in industrial processes and also in our daily lifes (like driving cars), we contribute to global warming. Global warming leads to a loss in biodiversity since animals and plants are usually quite sensitive to changes in their natural living conditions and thus many will go extinct when these conditions change. For example, if the ocean becomes warmer, the oxygen levels are likely do decrease. However, many fishes need a high oxygen concentration to survive. Thus, dropping oxygen levels can lead to the extinction of many fishes and other sea animals..

16. Causes of loss of biodiversityConflicts: Conflicts also lead to a decrease in the variety of species. In conflicts, large areas of land can be destroyed. Moreover, sometimes, even quite harmful chemicals are used. These chemicals have a serious adverse impact on the ecological system, which can lead to a decline in biodiversity. Invasive species: The introduction of invasive species can cause serious problems to the natural local ecosystems since they can carry diseases which may harm local species. Moreover, if the invasive species are able to adapt to the new conditions properly, they may also displace local species. Thus, the introduction of invasive species may lead to the extinction of part of the local species and therefore to a loss in biodiversity.Hunting: Hunting, especially the hunting of endangered species, can also lead to a loss in biodiversity. Often, animals are just hunted because of precious by-products of their existence. For example, elephants are often killed solely because of their ivory. Human greed can thus lead to an extinction of many species if we do not protect them properly

17. ConclusionsThus the presence of numerous chemicals present in environment have not only put the human health at stake but have also destroyed the environment in terms of:Causing hazeReducing biodiversityDegradation of soil flora and faunaReduction in crop yields and plant growthsDestruction of aquatic life

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