Energy and the Environment Exam 3

What is the difference between point source and nonpoint-source polluters?

1. Point-source emitters = localized, stationary 

2. Non-point source emitters = mobile and widespread

What are the health impacts of PM2.5 exposure?

hardening and narrowing of arteries, common cause of heart attacks and strokes

Organic Carbon poses most risk for PM2.5 exposure

How is carbon monoxide and NOx produced during combustion?

1. Carbon Monoxide (CO): Due to incomplete combustion of fossil fuels. Due to insufficient oxygen in fuel-air mixture

2. NOᵪ compounds (NO & NO₂): Excess air (N₂) in fuel-air mixture —>N₂ oxides

When and how are the secondary pollutants produced in the daily smog cycle?

Midday

• Photochemical Reactions: The sun climbs higher, providing the energy needed for photochemical reactions. Primary pollutants react with sunlight to form secondary pollutants such as ozone (O₃), nitrogen dioxide (NO₂), and peroxyacyl nitrates (PANs). Increased Smog: The land/sea breeze cycle begins, pushing pollutants further inland and increasing smog levels

Afternoon

• Peak Concentrations: Ozone concentrations reach their highest levels. Onshore breezes can push smog far inland, sometimes over mountains into deserts

What is the atmospheric lapse rate?

1. Lapse rate = rate of temp decrease with altitude

   Winter = higher lapse rate, atmosphere cools rapidly with altitude (shallow line on graph)

   Summer = lower lapse rate atmosphere cools slowly with altitude (steep line on graph)

   Temperature inversion = layer of warm air sitting on top of a layer of cool air

What are the general chemical reactions that take place when acid deposition occurs on alkaline
soils?

1. Acidic soil water leaches CA & Mg from soil & drains into watershed (groundwater & surface).

2. Buffering capacity. Ph does not reach 4.5, no mobilization of Aluminum 

3. Overall effect = decrease in soil nutrients & increase in alkalinity & nutrients in freshwater

How are tree species like the Red Spruce and Sugar Maple affected by acid deposition?

Red Spruce: calcium leached from needle membrane, decreased cold tolerance, increased freezing injury

Sugar Maple: Calcium and magnesium leached from soil, aluminum taken up by tree, root function and nutrition impaired

What are the general chemical reactions that take place when acid deposition occurs on acidic soils?

1. Decreased soil nutrients

2. Plants exposed to Aluminum

3. Decreases water ph

4. Potential increase in water nutrients

5. Leaches Ca, Mg, Al

In aquatic ecosystems, which level of the food web is sensitive to low pH?

The lower level of the food chain

How are aquatic organisms in upper levels of the food web affected by acid deposition?

Reduced populations due to lack of nutrients and lack of biodiversity

How did the cap-and-trade system implemented under the Clean Air Act Amendments help reduce
SO2 emissions?

Set emissions cap for sulfur and NOx: 94% reduction of SO2 from power plants,

86% reduction of NOx from power plants

What is the definition of climate change?

Changes in average atmospheric conditions with decadal or longer timescales.

How do we know the excess carbon dioxide in the atmosphere started off as organic carbon and not
inorganic carbon (e.g., carbon from volcanoes)?

1. More ¹³C in sample vs standard 𝛅¹³C is positive 

2. Less ¹³C in sample vs standard 𝛅¹³C is negative

3. Organic carbon ¹²C →  more negative 𝜹¹³C

4. Inorganic carbon C (mineral form) more ¹³C than organic → more positive 𝛅¹³C

What are the definitions of emissivity, transmissivity, and reflectivity?

Emissivity: Relationship between rate of energy emitted and objects temperature

Transmissivity: fraction of incident light or radiation that passes through a material.

Reflectivity: fraction of incident light or radiation that is reflected by a surface.

Roughly speaking, what does the Stephan Boltzmann radiation law describe?

describes the relationship between the temperature of an object and the amount of thermal radiation it emits.

What is the relationship between Earth’s absorption spectrum and the greenhouse effect?

1. Pout = Pout(atmosphere) + Pout(surface)

2. Pout = eₐσTₐ⁴ + (1-eₐ)σTₛ⁴

   Algebra! Pout = σTₛ⁴ - eₐσ(Tₛ⁴ - Tₐ⁴). eₐσ(Tₛ⁴ - Tₐ⁴) = greenhouse effect

Earth is absorbing more light that typical GHG absorb

What are the major reservoirs of carbon in the global carbon cycle?

Size: terrestrial < ocean< lithosphere

What do results from open air experiments tell us about the future capacity of the terrestrial
reservoir?

antagonistic effects of increase of temperature and CO₂, Slower or lower rate of biomass increase

Expect terrestrial net removal rate to be zero

What do results from soil experiments tell us about carbon saturation in soils?

we expect higher soil respiration rates (higher microbial decomposition rates) → (rate at which CO₂ is emitted out of the soil increases)

Expect terrestrial net removal rate to be zero

How is climate change expected to affect thermohaline circulation?

Down well rates decrease = reduced carbon transport

What is the link between chemical weathering and the lithosphere reservoir for carbon?

1. Step 1 chemical weathering of rocks at surface (carbonate acid H₂CO₃)

2. Step 2 dissolved ions runoff into oceans 

3. Ions precipitate as solid minerals & settle to sea floor 

4. Tectonic processes subduction seafloor to Earth's interior

5. Climate change Increases Temperature and increases precipitation → higher rates of chemical weathering (increase by 50% 0.2 GTC/yr to 0.3 GTC/yr)

What is solar radiation management (SRM) and commonly proposed SRM techniques?

large-scale actions aimed at reducing global warming by increasing the reflection of sunlight away from Earth.

Space Reflector, Atmospheric Aerosols, Surface albedo (desert or urban)

What are commonly proposed ways to perform carbon cycle management?

Enhanced Weathering, Sequestration, Ocean Fertilization

What is the premise behind ocean fertilization as a geoengineering technique?

 Prevent dilution of added nutrients by: Fertilized twice with 2 metric tons of FeSO4

Results: Plankton productivity increased, but not as much as expected due to other limiting nutrients such as SiO2. Carbon did not settle into the deep ocean, remaining in the top 150 m of water column. Why? Increased grazing consumer organisms & marine snow did not increase

What is the premise behind enhanced chemical weathering with olivine?

Olivine is very reactive to CO2 and would bind with it. If pulverised olivine, need 10 -20 Gtonnes of olivine per year → scale up olivine mining x 10,000

How does the extent of mining uranium compare to that of coal?

Coal: 17,000 Acres 5.5 mining deaths/year

Uranium: 1,900 Acres 0.1 mining deaths/year

How do the carbon dioxide emissions and air pollution of a nuclear power plant compare with those
of a coal power plant?

CO2 emissions for Coal: 1,000 tons/hour, 400,000 tons/year general emissions

Nuclear CO2 emissions: 2 tons/hour 6,000 tons/year general emissions

Iodine - 131 & cesium - 137 in steam (rare)

How did the Three Mile Island disaster impact the expansion of nuclear power in the U.S.?

81 orders for reactors were cancelled. Made people fearful of nuclear power. Marked beginning of 30-year period with minimal
construction of nuclear power plants in US.

What kind of reactor was used at Chernobyl?

Graphite reactor

How did the Fukushima Daiichi cooling systems lose power twice in 2011?

9.0 magnitude earthquake and subsequent
tsunami cutting power to cooling systems of 3
active reactors

What decisions were made during construction of the Fukushima Daiichi that made it more susceptible to damage from the 2011 Tohoku earthquake and tsunami?

Seismic hazard maps exhibit only a moderate risk of a strong shaking/moderate-heavy damage occurring in Fukushima

Seawall at Fukushima Daiichi was built at 5.7 m
based on tsunami size of 1938 earthquake (too low)

How is most of the nuclear waste in the U.S. stored?

100-year short-term dry cask storage units. Made of steel and concrete.

What geological characteristics of Yucca Mountain made it attractive for long-term nuclear waste storage?

1. Fine grained volcanic rocks (low permeability) 

2. 1000 feet below surface + 1000 feet above water table

3. Not tectonically active in last 12.5 million years