2 PollutionAir Pollution: the __________________________________________ into the atmosphereEmissions: ______________________(smoke and soot) or _______________ (sulfur dioxide and carbon monoxide)____________________________: the wind blows dust, volcanoes erupt, forest fires produce smoke, soot and gasses___________________________: most air pollution comes from fossil fuels introduce carbon monoxide
3 How Air Pollutants Affect Your Health Respiratory System Problems: ______________________________ ________________________________________________________. If people are exposed over and over they may develop asthma, bronchitis and emphysemaEffects of Carbon Monoxide: ________________________________ ________________________________________________________. This interferes with your bodies ability to deliver oxygen to cells. Causes headaches, tiredness and nausea. Over time this can damage the heart muscle.Cancer: Trace amounts of air pollutants may contribute to cancer
4 Smog________________________________: Rain can combine with the sulfur in the air and cause acid rainPhotochemical Smog: A process that needs light. ______________ ________________________________________________________. Atmospheric ozone is the most abundant pollutant in photochemical smog. Ozone can damage living tissue.
5 Temperature Inversions Recall that in the troposphere, air temperature usually decreases as altitude increases. Earth’s surface warms the air at low altitudes. Since warm air rises, any pollutants in the air are carried away from the surface and higher into the troposphere. This process removes pollutants from low altitudes and helps them disperse.The situation is different, however, when a temperature inversion occurs. A temperature inversion is the condition in the troposphere in which layer of cooler air is located beneath a layer of warmer air. Since cold air has a greater density than warm air, the air at Earth’s surface does not rise and mix with the air higher up. Therefore temperature inversions can keep air pollutants, including those found in smog, from going away.
6 Acid Rain________________________________________________________ ________________________________________________________ ________________________________________________________Sources: Mainly sulfur dioxide and nitrogen dioxide from burning fossil fuels.Effects: Harm to ecosystems and man made structures. If the pH in a lake falls to low the fish can’t survive. Acid rain erodes rock
7 Reduction in Air Pollutants Motor Vehicles: Introduction of a catalytic converter a device that reduces the amount of air pollutants in emissionsCleaner Gasoline: Gasoline once contained lead. The lead from the vehicle emissions would settle onto the ground and contaminate it. Lead has been outlawed in gasoline since 1973.Industries and Power Plants: Scrubbers have been added to many plants to remove pollutants of change them chemically before they leave the factory
8 Ozone: A Success StoryOzone Hole: first noticed in the late twentieth centuryChlorofluorocarbons: (CFC’s) are a chemical that had been predicted to cause the depletion in the ozone layer, by reacting with the ozone. Used in refrigerators and aerosol spray cans.The Montreal Protocol: Many nations began to restrict production of CFC’s. Today the production of CFC’s has dropped 95% since the late 1980’s. Evidence indicates that the ozone is beginning to recover. The levels of ozone has stabilized and scientists believe that they will soon begin to increase to their former levels.
9 The Greenhouse EffectIf Earth did not have an atmosphere, most of the energy from the sun would be reflected back into space. ________ _________________________________________________ _________________________________________________ _________________________________________________The gases that do this area called greenhouse gases. The major greenhouse gases are water vapor and carbon dioxide.The term greenhouse effect is a bit misleading. Greenhouses used for plants hold heat in place by preventing warm air from escaping. In contrast, greenhouse gas molecules in the atmosphere do not trap air or anything else. Instead they absorb heat and release is slowly.
10 Causes of Climate Change _______________________________________________– because the greenhouse gases in the atmosphere are the reason the Earth keeps warm, increased levels of greenhouse gases, mainly CO2 don’t allow heat to irradiate out from the earth, creating a shift in climate_______________________________________________– The main source of extra CO2 in the atmosphere is the burning of carbon-containing fuels, such as oil, natural gas, and coal for energy. These fuels are called fossil fuels because they formed millions of years ago, from the remains of living things._____________________________________________– Land-use changes, such as cutting of forests, have also caused an increase in greenhouse gases. Remember that plants, including trees, take in carbon dioxide. Therefore, the loss of forests contribute to an increase of carbon dioxide in the atmosphere
11 Evidence of a Warming Earth When scientists talk about global climate change, ________________ __________________________________________________________ _______________________________ The term global warming refers specifically to an increase in Earth’s average surface temperatureRising Temperature – The Intergovernmental Panel on Climate Change notes that the average atmospheric temperatures near Earth’s surface increased by 0.74⁰C between 1906 and ______ ________________________________________________________Changes in Precipitation – Changes in precipitation over the past 100 years have been complex. Some regions receiving more precipitation and others are receiving less. Meanwhile heavy rainstorms have increased in both dry and moist regionsMelting Ice – _____________________________________________ ________________________________________________________Raising Sea Levels – Both warming of sea water and melting of ice are contributing to the raising sea levels
12 Effects on Ecosystems and Organisms Shifting Habitats – As ecosystems on land become warmer, the locations in which some organisms live are changing.____________ ________________________________________________________ ________________________________________________________._________________________________– Many species of birds migrate every year. Some birds are starting their spring migration earlier. The change in temperature is probably sending signals to the birds to start their migration.__________________________________– During the last few decades, temperature changes have been greatest in the Arctic. Ice sheets are melting and sea ice thinning. As sea ice melts earlier and freezes later, it has become more difficult for polar bears to hunt seals to feed on.