ENV1m000 Ch 8 Notes

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Ocean County College *

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152

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Geography

Date

Oct 30, 2023

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docx

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Uploaded by PresidentThunder1633

So far we have discussed about life on earth, water and soil. They are the biosphere, hydrosphere and geosphere that is making up the Earth. Today is the last unit of the semester and we will cover the last part of the Earth system – the Atmosphere. The atmosphere is composed of several spherical layers. The layer of air directly above the surface is the troposphere, which supports life and the layer above this is the stratosphere, which contains the earth’s protective ozone layer. The troposphere contains the air we breathe and is composed mainly of nitrogen and oxygen – but also contains greenhouse gasses such as carbon dioxide and nitrogen monoxide. Troposphere extends roughly 11 miles above earth’s surface at sea level and 4miles over the poles. The stratosphere is similar in composition to the troposphere, but has much less water vapor and contains the ozone layer. Stratosphere extends from 11 to 30 miles up. Ozone is produced when oxygen molecules interact with UV radiation from the sun. This protective layer keeps 95% of the sun’s harmful UV radiation from reaching the surface. It also keeps oxygen in the troposphere from becoming ozone, a pollutant when found at the surface. Nitrogen (N2)is the most abundant gas in the Earth’s atmosphere making up about 78 %. Oxygen is the second most abundant making up about 21 %. As mentioned in last unit, the components making the Earth are very closely inter-related. In other words, the complex dynamic interaction and balance among biosphere, hydrosphere, geosphere, and atmosphere are the key factors on keeping the Earth sustainable. For example, living organisms are used as food sources and oxygen is utilized in most organisms that digest other organisms. Another example is chemical weathering of rocks which can cause oxides to form, locking up the oxygen with minerals. Oxygen is also released into the atmosphere by plants as they photosynthesize. Water in the atmosphere varies considerably and also cycles in the Hydrologic Cycle. Carbon Dioxide (CO2) makes up approximately 0.03 % of the Earth’s atmospheric gases. Carbon dioxide concentrations in the atmosphere is regulated by several processes. For example, CO2 is removed from the atmosphere as green plants fix the CO2 into carbohydrates, CO2 is exchanged between the atmosphere and the oceans, and chemical reactions between the atmosphere and limestone also controls the amount of carbon dioxide. It has been reported and evidenced that reduced ozone levels in the stratosphere coming from the widespread use of certain chemicals is allowing more harmful ultraviolet (UV) radiation to reach the earth. Ozone thinning stems from the overuse of harmful chlorofluorocarbons (CFCs) known as freons which are used for coolants/air conditioning. Ozone thinning causes more biologically damaging UV-A/UV-B radiation to reach earth’s surface, contributing to cataracts and skin cancer, and it also impairs/destroys phytoplankton. By not producing and using ozone depleting chemicals and adhering to international treaties that ban these chemicals, we can reverse ozone depletion. As we know atmosphere is essential and important to sustain life on earth. However, air pollution has become a significant environmental issue this century. Air pollution occurs when atmospheric chemicals exist in high enough concentrations to harm organisms, ecosystems, and alter climate. Outdoor pollution includes industrial smog caused by burning coal, photochemical smog generated from industrial emissions and cars, and acid deposition resulted from coal-burning power and industrial plant and cars. Industrial smog is generally a mix of sulfur dioxide, sulfuric acid, and particulates. Countries like China, India, Ukarine, Czech Republic, Bulgaria and Poland are major

countries generating these type of smogs. Photochemical smog is generated by a mix of primary/secondary pollutants/chemicals formed in light activated reactions. Places like Los Angeles, Salt Lake City, Sydney, Sao Palo, Bangkok and Mexico City are major locations generating the photochemical smog. Indoor air pollution includes smoke and soot from wood and coal fires, cigarette smoke, and chemicals in building materials and cleaning products. Sources of these air pollutions could be either natural reactions or human activities. Natural air pollution sources include dust, wildfires, volcanoes, and plants while human activities including burning fossil fuels and car use are the major cause for air pollution. They can be classified as primary or secondary. Primary pollutants are the ones emitted directly into air whereas the secondary pollutants are the chemicals formed from primary pollutants. Human inputs of air pollution come from mobile sources (such as cars) and stationary sources (such as industrial, power and cement plants). Some primary pollutants react with one another and with other chemicals in the air to form secondary air pollutants. Examples of major outdoor air pollutants are carbon oxides, nitrogen oxides and nitric acid, sulfur dioxide and sulfuric acid, particulates meaning the suspended particulate matter, Ozone, and volatile organic compounds or referred as VOCs. VOCs include hydrocarbons, methane, benzene, and liquid solvents. VOCs are organic compounds that exist as gasses in the atmosphere or that evaporate from sources on the surface: especially from rice paddies, landfills, natural gas wells and pipelines, cows, industrial solvents, dry-cleaning fluids and various components of gasoline, plastics and other human made products. Outdoor air pollution can be reduced by several different methods. Settling of particles heavier than air, cleansing by rain/snow, salty sea spray from the oceans, wind dilution and removal, and chemical reactions in the atmosphere can all be the causes for reducing the outdoor air pollution. However, it can also be increased by urban structures that block winds, hills and mountains that block valley ventilation, high temperatures, emission of VOCs, grasshopper effect, and temperature inversions. Furthermore, acidic compounds like sulfuric acid, nitric acid vapor, acid-forming sulfate, and nitrate salts formed during wind dispersal of outdoor pollutants can result in far flung acid deposition which is a mix of wet and dry deposition of pollutants. Wet deposition include acid rain/snow/cloud vapor and happens slowly in distant downwind areas whereas dry deposition means acidic particles and happens quickly close to industrial sources. Acid deposition harms crops, reduces plant productivity, leaches essential nutrients from soil, damages buildings, contributes to human respiratory disease, and leaches toxic metals into the environment that get biomagnified into food webs. Prevention is the best solution to reduce or eliminate these pollutants from coal-fired power and industrial plants. In less-developed countries, mainly from indoor burning of wood, charcoal, dung, and coal in open fires/poorly vented stoves cause indoor air pollution. In more-developed countries, fumes given off by building materials/furniture are the major indoor pollutant. For example, 11 common air pollutants are higher inside U.S. buildings than outside. Air pollution inside cars in congested traffic can be almost 20 times higher than outside. WHO study finds indoor air pollution is the most serious pollution problem facing humans. And air pollution poses significant health hazards. Human bodies are made up to protect form naturally occurring pollutants. For example, our respiratory system has hairs in nose filter out large particles, mucus in upper respiratory tract traps smaller particles/dissolves some gaseous pollutants, sneezing/coughing expel contaminated air, and hair-like cilia in the upper

respiratory tract oscillate and transport mucus/pollutants to throat. However, prolonged or acute exposure to air pollutants can break down these natural defenses. The smallest particles are also a main problem – fine and ultrafine particulate matter gets lodged deep in the lungs and contributes to lung cancer, asthma, heart attack, and stroke – also chronic bronchitis and emphysema. WHO estimates that together indoor/outdoor air pollution kills 7 million people per year. How should we deal with air pollution? While there are many legal, economic, and technological tools that can help us fight air pollution, the best solution is prevention. Strengthen laws to make stringent prevention by further reducing and controlling emissions (especially for cars and motorcycles), setting stricter regulations for airports and reducing indoor air pollution, and authorizing/using emissions trading. Enactment/regulation/enforcement between 1980 & 2012 lowered the emissions of 6 major air pollutants by 67%.Between 1990 & 2012 emissions trading in the US reduced SO2 emissions from power plants by 76%. Under this system industrial/power plants are allotted a number of pollution credits. Plants that do use all of theirs can trade with plants that exceed their credits. However this idea is controversial. Proponents contend this emissions trading/cap-and-trade program is cheaper/more efficient then government regulation. Critics say that by allowing outdated, over-polluting plants to trade for credits they will not improve pollution controls and will continue to pollute. Reducing indoor air pollution can be achieved by transitioning from using open fires/poorly vented stoves in less- developed countries to more efficient clay/well vented metal stoves and solar cookers, banning indoor smoking and increase air circulation in commercial buildings/homes, setting stricter standards for emissions from products designed/made for indoor use, and using naturally based cleaning products. Unfortunately, scientific evidence indicates that atmospheric warming is happening at a rate that will likely lead to significant climate change. As the earth’s average atmospheric temperature rises, some areas get warmer, others get cooler. Over the earth’s 3.5 billion year history, climate has changed many times. For the last 100 thousand years, humans have lived/developed in a reasonably steady, inter-glacial (thawing) climate. However, over the last 200 years, atmospheric temperatures have risen with urban growth and the rate of climate change has been accelerating since 1978. AAAS (The American Association for the Advancement of Science) studies show that atmospheric warming is tied to rising levels of greenhouse gasses from human activities. While climate change has occurred throughout earth’s history the rate of change is now accelerating. The 2014 US National Climate Assessment shows that there is 97% scientific agreement that climate change is happening now and is caused by human activities, immediate and sustained action to curb climate change is possible, affordable and would bring major benefits to both humans and the environment, and the sooner we act, the lower the risks and costs of significant climate disruption. Greenhouse effect refers to lower atmospheric warming caused by the reflection and interaction of some of the earth’s incoming solar radiation with molecules in the air. Life on earth is dependent of this effect. CO2/heat uptake by oceans helps to moderate the earth’s average surface temperature and slows climate change, but cloud cover leads to atmospheric warming. Outdoor air pollution in the form of suspended microscopic droplets called aerosols and soot can both enhance/hinder the greenhouse effect and clod formation. Scientist do not think either will counteract or enhance projected climate change. The projected increases in atmospheric temperatures can have

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