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Questions and Answers
What is the primary function of the atmosphere in nurturing life on earth?
Which layer of the atmosphere contains the ozone layer that protects us from harmful sunlight?
What occurs to temperature in the mesosphere as altitude increases?
Which component of the atmosphere is primarily responsible for protecting Earth from cosmic rays?
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What is the altitude range of the thermosphere?
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What major process is associated with the function of the atmosphere in the hydrologic cycle?
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At what altitude does the exosphere begin?
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What happens to pressure as altitude increases in the atmosphere?
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What type of smog is primarily formed from secondary pollutants such as NO, NO2, and ozone?
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Which of the following pollutants is NOT classified as a gaseous pollutant?
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What is a significant factor contributing to air pollution as mentioned in the content?
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Which of the following is a primary cause of industrial smog?
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What effect does acid rain primarily have on the environment?
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Which pollutants are specifically mentioned as contributing to photochemical smog formation?
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What type of health issues can air pollution cause according to the content?
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Which statement best describes the relationship between air pollution and ecosystem health?
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What process occurs when a molecule absorbs a photon of sufficient energy to remove an electron?
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Which gas is the most abundant in the atmosphere, constantly increasing to levels over 400 ppm and contributing significantly to global warming?
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What happens during photodissociation?
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What is the primary source of Carbon Monoxide (CO) in the atmosphere?
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Which reaction produces sulfuric acid (H2SO4) from sulfur trioxide (SO3)?
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What is one of the effects of carbon monoxide exposure during pregnancy?
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What is a significant health threat associated with Carbon Monoxide (CO)?
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Which oxides are primarily responsible for acid rain formation from burning fossil fuels?
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Which activity significantly contributes to the excess formation of carbon dioxide?
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Which statement describes a consequence observed between 1906 and 2005 according to climate reports?
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What is the significance of photolysis in atmospheric chemistry?
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What is projected to happen due to climate change effects according to the IPCC updates in 2010?
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Which of the following is NOT listed as an effect of global warming?
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What percentage likelihood does the IPCC give for the warming of the lower atmosphere being primarily human-caused?
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Which phenomenon is a result of climate change as indicated in the content?
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What causes volatile organic compounds (VOCs) to be released into the atmosphere?
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Which of the following compounds are classified as VOCs?
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What is the primary cause for the doubling of methane levels in the atmosphere over the last 250 years?
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Which statement about heavy metals is true?
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Which compound is noted for being a carcinogen that can harm both plants and humans?
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What role does atmospheric methane play in global warming compared to CO2?
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What are the primary sources of heavy metal emissions to the environment?
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Which of the following best describes temperature (thermal) inversion?
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Which type of organic compound includes formaldehyde and acetaldehyde?
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Study Notes
Our Atmosphere
- Atmosphere is essential for life on Earth, providing oxygen and protection from hostile environments
- It is a source of CO2 for photosynthesis, N2 for nitrogen fixation and plays a vital role in the hydrological cycle
Stratification of Atmosphere
- Temperature and pressure vary with altitude
- Pressure decreases with increasing altitude
Troposphere
- Closest to the Earth's surface, extending from 0 to 10 km
- Contains a homogeneous composition of major gases
- Temperature drops with altitude due to air expansion
- Top layer contains ice which prevents loss of hydrogen
Stratosphere
- Extends from 10 km to around 25 km
- Contains the ozone layer, which absorbs harmful UV radiation from the sun
- Temperature increases with altitude due to ozone's absorption of UV energy
Mesosphere
- Located above the stratosphere, ranging from 30 to 80 km
- Temperature decreases with increasing height due to less solar heating and more cooling by CO2
Thermosphere
- Highest layer of the atmosphere, ranging from 100 to 400 km
- Temperature increases with altitude due to absorption of solar radiation
- Most meteors burn up in this layer
Exosphere
- Uppermost layer of the atmosphere, extending from 500 km to 10,000 km
- Atmosphere thins out and merges with interplanetary space
Photochemical Reactions
- Photo-excited species can react through various pathways
- Photoionization and photodissociation are important processes in the atmosphere, particularly at high altitudes
- Photoionization is the ionization of molecules by radiation, while photodissociation is the breaking of chemical bonds by radiation
- Photolysis is important in gas phase and atmospheric chemistry
Gases Oxides in the Atmosphere
- Carbon monoxide (CO) is a serious health threat that prevents blood from transporting oxygen
- Carbon dioxide (CO2) is the most abundant greenhouse gas and is a major contributor to global warming
- Nitrogen oxides (NOx) enter the atmosphere as NO and are converted to NO2, which can form nitric acid (HNO3) contributing to acid rain
- Sulfur oxides (SOx) are released from burning fuels and coal, forming sulfuric acid (H2SO4) and contributing to acid rain
Carbon Monoxide
- Produced by incomplete combustion of carbon-containing materials like fossil fuels
- Binds irreversibly to hemoglobin, hindering oxygen transport
Sulfur Compounds
- Sulfur dioxide (SO2) is released during the combustion of oil and coal
- SO2 oxidizes to SO3, which reacts with water to form sulfuric acid (H2SO4)
- Over 30 million tons of SO2 are released into the atmosphere annually in the USA
- Sulfur is removed from fuel after combustion due to the expense of removing it beforehand
Nitrogen Oxides and Smog
- Industrial smog consists of SOx and particulates, primarily caused by industrial coal and oil burning
- Photochemical smog is composed of secondary pollutants, such as NO, NO2, and ozone
- Photochemical smog is characterized by a brownish haze, prevalent during midday in summer
- It is a result of auto exhaust, hydrocarbons, humidity, and sunlight
- It manifests as particulate matter and oxidants, particularly ozone
Air Pollution
- Defined as the presence of substances in the atmosphere that can harm human health, welfare, animal or plant life, property, or interfere with enjoyment of life and property
- Includes noxious gases and particulates like dust, mist, fume, smoke, and smog
Historical Background
- Humans have been affecting air quality by burning fuels and wood since discovering fire
- Significant air pollution is often linked to industrialization and urbanization
Air Pollutants
- Air pollutants can be classified into gaseous pollutants including H2S, SOx, NOx, CO, VOCs, O3 and other oxidants
- Particulate pollutants include dust, mist, fume, smoke, smog, and more
Effects of Air Pollution
- Health problems, primarily affecting respiratory systems
- Environmental issues like acid rain, smog formation, ozone depletion, global warming, and climate change
- Other effects include ecosystem damage, soiling, corrosion of buildings and structures, and discoloration
Air Quality
- Air quality is heavily influenced by pollution from various sources
- Carbon monoxide exposure during pregnancy can cause low birth weight, increased mortality, and nervous system damage in offspring
- Carbon monoxide is categorized as a Category 1 reproductive toxicant
Carbon Dioxide (CO2)
- Excess CO2 is caused by burning fossil fuels, decomposition of limestone, and cement manufacturing
- Deforestation disrupts the balance of CO2 levels
- CO2 is a major contributor to global warming
Human Activities Cause Global Warming
- According to the 2007 Intergovernmental Panel on Climate Change (IPCC) report:
- Average global temperature increased by about 0.74°C between 1906 and 2005, mostly since 1980
- Annual greenhouse gas emissions from human activities increased by 70% from 1970 to 2009
- The decade from 2000 to 2009 was the warmest on record since 1881
- Arctic temperatures have risen at almost twice the rate of the rest of the Earth over the past 50 years
- Glaciers are melting, and floating sea ice is increasing
- Sea levels have risen by 19 cm in the last 100 years
- The IPCC*
- Panel of scientists from 130 countries, updated its findings in 2010:
- Projected climate change effects are now 2-3 times higher than in 2007
- Ice melting is happening at a faster rate than previously estimated
- There is a 90-99% likelihood that the lower atmosphere is warming due to human-caused increases in greenhouse gas emissions
- Significant climate disruption is inevitable in this century
- Ecological, economic, and social disruptions are expected
Global Warming Effects
- Climate change
- Ice melting
- Sea-level rise
- Desertification
- Disease outbreaks
- Other effects
Projected Climate Disruption - Severe Consequences
- Tipping point and irreversible climate change
- Ecosystems collapsing
- Low-lying cities flooding
- Prolonged droughts and wildfires
- Destructive storms
- Shrinking glaciers and drying rivers
- Extinction of up to half the world's species
- The spread of tropical infectious diseases
- Declining streamflows, dry lakes, and lower water tables
- Other effects of prolonged water scarcity
Volatile Organic Compounds (VOCs)
- Released from incomplete combustion of fossil fuels, including gases and vapors like gasoline fumes and solvents
- Some VOCs are carcinogenic
- Harmful to plants, causing aging, tissue breakdown, and leaf shedding
Volatile Organic Compounds (VOCs) Include
- Biogenic organic compounds: methane, terpenes, esters
- Hydrocarbons: alkanes, alkenes, alkynes, PAHs, BTEX, etc.
- Carbonyl compounds: formaldehydes, acetaldehyde
- Oxygen-containing compounds: alcohols, phenols, ethers, solvents
- Organonitrogen compounds: amines, nitriles
- Organohalide compounds: THMs, PCE, TCE, CFCs, dioxin
- Organosulfur compounds: Dimethyl sulfide, methanethiol
- Organic particulate matter
Methane (CH4)
- Most abundant hydrocarbon in the atmosphere
- Generated from natural gas and fermentation of organic material
- Methane levels in the atmosphere have doubled over the last 250 years due to fossil fuel burning, agriculture, and fermentation of organic matter by anaerobic microorganisms
- Methane is a major contributor to atmospheric chemical processes, including global warming, and is more effective than CO2 per molecule
- Methane affects both troposphere and stratosphere chemistry
Heavy Metals
- A general term for metals and metalloids with an atomic density greater than 4 g/cm³
- They occur naturally in the Earth's crust, including cadmium, chromium, copper, mercury, lead, zinc, arsenic, boron, platinum, palladium, rhodium, ruthenium, osmium, and iridium
- They are emitted to the environment from both natural and anthropogenic sources
- Combustion processes are major sources of heavy metals, including power generation, smelting, incineration, and internal combustion engines
- Mercury (Hg) and lead (Pb) are the most prevalent heavy metals in the atmosphere
Temperature (Thermal) Inversion
- Certain atmospheric conditions can lead to temperature inversions, where temperature increases with altitude, instead of decreasing
- This creates stable atmospheric layers, trapping pollutants near the ground and exacerbating air pollution problems
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Description
Explore the layers of Earth's atmosphere and understand their significance for life. This quiz covers the characteristics of the troposphere, stratosphere, mesosphere, and more, emphasizing temperature, pressure, and essential atmospheric functions such as gas composition and protection from UV radiation.
