EGEE exam study guide Chapter 4 4a 1 Introduction a There is a high dependence on fossil fuels within the US i approx 86 ii the 3 fossil fuels that we depend on are 2 Fossil fuel elements a fossil fuels are hydrocarbon comprised of 1 Coal 2 Natural gases 3 Petroleum i carbon and hydrogen ii sulfur iii nitrogen iv oxygen v mineral matter 1 turns into ash when burnt b the composition and the amount of the elements found change with each different fossil fuel i example from notes there is more hydrogen in liquid fuel than coal c combustion is the rapid exudation combining with oxygen of a fossil fuels elements that in turn generate heat i what products are formed from each element during combustion of coal 1 Carbon forms carbon dioxide and when there is not enough oxygen for complete oxidation carbon monoxide can form 2 Hydrogen when hydrogen oxidizes it forms water 3 nitrogen when oxidized it becomes nitrogen dioxide and nitric oxide 4 sulfur becomes sulfur dioxide 5 minerals turn into ash particles 3 products of combustion a some of the fuel might not burn completely during combustion and instead is released into the atmosphere b There are six products of combustion i Carbon dioxide CO2 1 main product of the combustion of fossil fuels a accounts of 60 90 of what we burn 2 the us is the largest emitter of CO2 emitting 23 of the worlds emissions a sources of CO2 emissions i commercial 17 ii residential 21 iii industrial 29 iv transportation 33 3 China is the second largest emitter of CO2 emitting 18 of the worlds emissions ii carbon monoxide CO colorless odorless gas that is lethal it is formed when carbon in fuel is not burned completely 1 Sources of CO emissions Industrial processes 4 a Fuel consumption 4 b c Misc 15 d Non road vehicles and engines 22 e On road vehicles 55 iii Sulfur dioxide SO2 abundant in raw materials like coal and crude oil SO2 can dissolve in water and form acid which interacts with other gases that can be harmful to people and the environment 1 Sources of SO2 a Highway vehicles 2 b Non road vehicles 3 c d Fuel combustion industrial and other 16 e Fuel consumption electrical utilities 70 Industrial processing 9 iv nitrogen oxides NOx form when a fuel is burned at extremely high temperatures 1 Sources of NOx emissions Industrial 5 a Misc 2 b c Fuel consumption 39 d Transportation 54 v Lead Pb 1 major sources have been motor vehicles and industrial sources vi Particulate matter PM the mixture of solid particles and liquid droplets in the air 1 Fine particles are 2 5 micrometers 2 Coarse particles are 2 5 micrometers but or 10 micrometers 3 Primary particles are formed from combustion and are directly emitted into the atmosphere 4 Secondary particles formed in the atmosphere from 4 health and environment effects of primary pollutants primary gas emissions a CO2 doesn t harm people s health but is a greenhouse gas which means that it absorbs infrared radiation that is escaping from the earth s surface and traps it in the air causing the atmosphere to warm up b CO at high levels CO can be lethal exposure to high levels of CO can result in visual impairment poor learning ability reduced work and mental capacity and sometimes death c SO2 short term exposure can result in temporary breathing difficulties Long term exposure can result in respiratory illness and or aggravation of existing cardiovascular diseases d NOx exposures may lead to respiratory problems in people Exposure of this element can also lead to changes in plant species composition and can acidify soils and water e PM fine particles are most likely to be linked to the more serious health effects that PM can cause f Pb lead accumulates in the body and can affect kidney function as well as the liver and nervous system 5 secondary pollutants a Pollutants emitted into the air as a result of combustion are called primary pollutants After being emitted into the atmosphere these primary pollutants combine with other gases to create secondary pollutants i example of a secondary pollutant the ozone 4B 1 Introduction a The earth is continuously receiving energy during the day and releasing energy at night something called the greenhouse effect 2 The greenhouse effect a The sun emits radiation which travels to earth over time Some of the gases are reflected back into space by clouds but the rest permeates the earth s atmosphere b Once in the atmosphere some of the radiation heats up and some of it will evaporate to the hydrological cycle At night the c CO2 that is in the atmosphere has the ability to trap the infrared radiation as it is trying to escape back into space which is in turn causing the earth s atmosphere to warm up i If this did not happen then all of the radiation the earth receives during the day would completely escape at night and the earth would be 0 degrees at night which would make earth inhabitable ii Therefore the greenhouse effect makes our planet habitable and is very important 1 However this greenhouse effect is also increasing global warning so although it is good it may also be detrimental 3 Greenhouse gases a The concentration of greenhouse gases has significantly increases b Scientists have confirmed that these increases are due primarily c The percentage that each gas comprises the total greenhouse over the past 150 years i CO2 has increased by 31 ii CH4 has increased by 151 iii N2O has increased over 17 to human activities emissions in the US i CO2 comprises 82 ii CH4 methane comprises 9 iii N2O nitrous oxide 5 iv Other gases 2 d The increase in green house gases between 1880 and 2000 is believed to be what caused an increase in global temperature i Since the industrial revolution the average increase in temperature has been 1 degree F 4 CO2 and the temperature fluctuations a Did the atmospheric CO2 concentrations and temperature fluctuate prior to the preindustrial period or only after i Some argue that the temp change is natural and cyclical The biggest difference is that more than 6 billion people live on earth and are contributing to the increases in the global temp 5 Global warming a Radiation from the sun can be affected by activity on the sun s surface such as sun spot which increase the radiation being emitted from the sun b There are many uncertainties when it comes to global warming such as the long term effects of global warming i However it is likely that the greenhouse gases contribute to global warming and it is know for certain that human activity changes the earth s