AP Environmental Science Course Review Part 3 

6.2 Global Energy Consumption

• The use of energy resources is not evenly distributed between developed and developing countries

• The most widely used sources of energy are fossil fuels

• As developing countries become more developed, their reliance on fossil fuels for energy increases

Developed vs Developing Countries

• Developed nations use more energy on a per capita basis but developing nations use more energy in total (higher pop)

• Developing nations are still industrializing & pop is still growing rapidly

  • Also increase on per/person as countries industrialize + residents achieve higher standards of living

Fossil fuels

• Most common fuel source globally

  • oil>gasoline=main fuel for vehicles

  • coal=main fuel for electricity 

  • Natural gas=secondary fuel for electricity and main fuel for heating

• Hydroelectric energy (dams used to create electricity) are 2nd largest source of energy

  • Water spins a turbine which generates electricity

• nuclear energy is the 3rd largest source 

  • Uranium fission releases heat to turn water into steam to turn a turbine >generate electricity

Development increases Fossil Fuel Consumption

• Many residents of less developed countries depend on subsistence fuels (biomass that can be easily gathered/purchased and used)

  • Wood, charcoal, dried animal manure (can drive deforestation)

• Economic development>wealth>higher per capita GDP>energy use

• As developing nations develop, fossil fuel consumption increases

Factors that affect energy source

• Predominant energy source until 1875: wood>coal>1950s: nuclear>oil, natural gas, coal

• Availability: what fuels can consumers get?

• Price: supply and demand

• Governmental regulation: what fuels can consumers get?

6.3 Fuel Types and Uses

Subsistence fuels

• Biomass fuel sources that are easily accessible; often used in developing countries as a home heating or cooking fuel

• Wood (and charcoal) are the most common fuel sources in developing nations

  • Wood is free/cheap to cut down and utilize as fuel, can cause deforestation and habitat loss 

  • Charcoal is made by heating wood under low O2 conditions for long time

• Peat is partially decomposed organic matter (usually ferns or other plants) found in wet, aidic ecosystems like bogs and moors

  • Can be dried and used as a biomass fuel source

Coal formation

• peat>lignite>bituminous>anthracite

• Pressure from overlying and sediment layers compacts peat into coal over time

• Depper a coal reserve is buried, the more pressure from overlying rock layer>more energy dense

  • Anthracite is the most valuable form of coal

• Coal is burned to heat water into steam, to turn a turbine that generates electricity

• Peat (not a coal: partially decayed plant matter in swamps/bphs

• Lignite (brown coal): low heat content, low sulfur content, limited supplies in most areas

• Bituminous coal (soft coal: extensively used as fuel b/c of high heat content, high heat content

• Anthracite: best quality, high heating capacity, lowest sulfur content (CLEANEST) 

Mining Basics

• Ore: commercially valuable deposits of concentrated minerals that can be harvested and used as raw materials

• Metals: elements that conduct electricity, heat, and have structura properties for building ( found within ores)

• Reserve: known amount of a resource left that can be mined

  • Usually measured in years left of mining

• Overburden: soil, vegetation, rocks that are removed to get to an ore deposit below

• Tailings & Slag: leftover waste material separated from the valuable metal or mineral within ore (often stored in ponds @ mine site) MESS

Surface Mining

• Removal of overburdened to access ore near surface

• Different types of surface mining: Open pit, Strip mining, placer, mountaintop removal

  • Mountaintop removal: esp damaging to landscape and habitats, streams nearby

    • Removal of vegetation/ soil= topsoil erosion, habitat loss, increased stream turb, increased PM (particulate matter) in air

• Strip mining: removal of strips of soil/rock to expose ore

  • Remove material, extract resource, return mining spoils/tailings

    • Coal, sand

• Open-pit mining: uses a large visible pit/hole

  • Resource close to surface

    • copper

• Mountaintop removal: with explosives

  • Tailings deposited in nearby regions

• Placer mining: looking for minerals and metals in river sediments

  • Diamonds, tantalum, gold (CA gold rush)

Subsurface Mining

• More expensive due to high rinsurance/health care costs for workers

• Risks: poor ventilation>toxic gas exposure, mine shaft collapse, injury from falling rock, lung cancer, asbestos, fires, explosions

• Vertical “shaft” drilled down into ground 

  • Elevator to carry down workers & transport out resource

  • Often used for coal

• Increased used as surface coal deposits are depleted

Environmental Impacts of Mining

• Contamination of surface and groundwater with acidic mine drainage

• Habitat destruction

• Release of dust and harmful gases such as methane and H2S

• Rainwater carries sulfuric acid into nearby streams, infiltrates ground water

  • Lowers pH of water, making toxic metals like mercury/aluminum more soluble in water source (kills aquatic organisms)

• Methane release: coal mining releases methane gas (CH4) from rocks around coal

  • Vented out of mine to prevent explosion and continues seeping out after mine closes

    • GHG>>>CLIMATE CHANGE

• PM (particulate matter) release: coal mining especially releases lots of soot and other particulates that can irritate human and animal lungs

Mine Reclamation

• Process of restoring land to original state after mining has finished

• Includes

1. Filling of empty mine shaft/hole

2. Restoring original contours of land

3. Returning topsoil with acids, metals, and tailings removed

4. Replanting of native plants to restore community to as close to original state as possible

Mining Legislation

• Mining law of 1872 (general mining act): 

  • Allows individuals and companies to recover ores and fuels from federal lands

  • Few provisions for environmental protection

• Surface mining control and reclamation act (1977):

  • Land must be minimally distributed during coal mining and then reclaimed

• Related legislation: clean air act, clean water act, superfund act

Natural Gas

• Decaying remains of plants and animals (mostly marine life) are buried under layers of rock and converted by pressure into oil (petroleum) and natural gas over time

• Natural gas is mostly methane (CH4) and is found on top of trapped oil (petroleum) deposits

  • Forms when oil is trapped in a porous, sedimentary rock underneath a harder, impermeable rock layer that doesnt let the gas escape

• Considered the cleanest fossil fuel (produces the fewest air pollutants and least CO2 when burned)

  • Produces about 1/2 as much CO2 as coal when burned to generate electricity

  • Produces virtually no PM (ash/soot)

    • Produces less SO4, NO2 than coal/oil and no mercury

Crude Oil (petroleum)

• Decaying organic matter trapped under rock layers is compressed into oil over time

• Extracted by drilling a well through the overlying rock layers to reach the underground deposit and then pumping liquid oil out under pressure

• Can also be received from tar sands (combination of clay, sand, water, and bitumen)

  • Bitumen is a thick, sticky, semi-solid form of petroleum (not liquid)

  • Extracting & using oil from tar sand is extremely energy and water intensive

    • Lots of water needs to be heated (requiring energy) to create steam thats piped down into the tar sand to melt the bitumen into a liquid that can flow up a pipe

    • Lots more water is used to separate the oil from all of the impurities (sand, clay) at the refinery

6.4 Distribution of Natural Energy Resources

Fossil Fuel Products

• Crude oil (petroleum) is converted into lots of different products through the process of fractional distillation 

• Crude oil is burned in a furnace and water vapor passes into a column where different hydrocarbons are separated based on their boiling points

• hydrocarbons w/ lower boiling points gather at the top of the column, higher boiling points gather at bottom

• Different hydrocarbons within petroleum are used for different products

  • Petroleum gas (PUMPING OF VISCOUS LIQUID)

  • Gasoline (fuel for cars)

  • Naphtha (used to make plastic)

  • Jet fuel

  • Diesel fuel

  • Motor oil

  • Bitumen (asphalt for roads)

FF Energy Reserved

• Coal (100-150 years left)

  • US, Russia, China, Australia

• Natural Gas (50-60 years left)

  • Russia, iran, qatar, US, saudi Arabia

• Oil (50ish years left)

  • Venezuela, saudi arabia, iran, canada, iraq

Fracking and Shale Gas

• Hydraulic fracturing (aka fracking) is method of natural gas extraction that has extended access to natural gas

  • Gas trapped in semi-permeable sedimentary rock layers like shale is released by cracking the rock with pressurized water

  • Well is made; pipe is inserted; fracking fluid is inserted; gas flows out

• Fracking natural gas from shale rock increases/extended supply of natural gas

• Can contaminate water/destroy habitat; pipe is not lined properly, may contaminate water; fracking fluid has volatile organic compounds (VOCs); Leads to earthquakes from breaking rock and destabilizing the ground from the pressure

Shale Gas Reserves

• FF are non-renewable and will eventually be depleted, but short-term economic profit still drives extraction and use

  • Discovered but unharvested reserves rep economic benefit to countries

Tar/Oil Sands

• Bitumen deposits where crude oil can be recovered but with higher water & energy inputs

  • Canada: alberta region = world’s largest oil sands reserve

    • tar/oil islands extraction extends the world’s supply of crude oil

6.5 Fossil Fuels

Fossil Fuel Combustion

• Reaction between O2 and fossil fuels releases energy as heat and produced CO2 and H2O as products

  • Combustion is step in carbon cycle (Hydrocarbons -FFs- are burned to release energy and the carbon stored in them reacts w O2 in the air to form CO2

• Methane (natural gas), gasoline, propane, butane, coal are fossil fuels (hydrocarbons) that release energy in the same way

  • wood/biomass work same

FF to Generate Electricity

• The #1 source of electricity production globally is coal, then natural gas

• Heat> water into steam> steam turns a turbine, turbine powers generator> generator produces electricity

  • Coal, oil, natural gas, biomass, and trash acn all be burned to drive this same process and create energy

  • Nuclear energy works similarly, nuclear fission prodicing inital heat

Environmental Consequences>COAL

• Habitat destruction to clear land for mining

• Produces pollutants and relases CO@ (GHG> global warming)

  • Releases more CO2 than other FF when burned for electricity

  • Release PM (soot, ash) which can irritate respiratory system

  • Produces toxic ash contaminated w lead, mercury, and arsenic

    • Taken to landfills, stored in ash ponds which can leak into ground/surface water or into soil

  • Releases sulfur and nitrogen oxides which irritate resp systems and contribute to smog and acid precipitation

Generating Electricity

• Coal is 30% efficient for generating electricity

  • Nat. gas is 60% efficient

• Much of energy “lost” or not converted into electricity escapes as heat

• Cogeneration: when heat produced from electricity generation is used to provide heat (air and hot water) to a building

  • CHP (combined heat and power) systems are close to 90% efficient

Environmental consequences: tar sands

• Habitat destruction to clear land (biodiv loss)

• Ground or nearby surface water depletion (H20) needed  for steam and washing impurities from bitumen at refinery

  • Water contamination: tailing ponds can overflow and run into nearby surface waters or leach into groundwater

    • Carcinogen salts, acids, hydrocarbons, bitumens all toxic to plants/animals

  • CO2 released b machinery during extraction, transport, refinement

Environmental consequences: crude oil/petroleum

• Possibility of spill (from tanker ships or pipeline)

  • Spills in water= crude oil covering sun, clogging fish gills, suffocating ocean animals, sticking to bird feather

  • Spills on land= toxic to plant roots, surface, or groundwater contamination

• Habitat or fragmentation when land is cleared for roads, drilling equipment, pipelines

Fracking (Hydraulic Fracturing)

• Used to extract natural gas from sedimentary rock

• Vertical well is drilled down 

How is energy produced in a coal-fired power plant

• Coal is burned, creates steam through the boiling water, steam turns turbine, turbine turns generator, generator creates electricity

One environmental issue that can arise from combustion of fossil fuels

• Mining for resources, pulverized coal, water use, carbon dioxide production

6.6 Nuclear Energy

Nuclear fission and radioactivity

• A neutron is fired into the nucleus of a radioactive (unstable) element, such as uranium

  • Nucleus breaks apart and releases lost of energy (heat) and more neutrons that break more nuclei, releasing more energy (chain reaction)

• Radioactivity refers to the energy given off by a nucleus of a radioactive isotope (uranium-235)

  • Radioactive nuclei decay or breakdown and give off energy (radiation) without fission, nuclear fission releases tons of energy all at once

• Radioactive half life= amount of time it takes for 50% of a radioactive substance to decay (breakdown)

• 10 half-lives generally means saftey

  • Cobalt-60 takes 5.37 yrs to undergo half life

    • 20 g is the 100% and undergoes half-life (5.27 years)= 10 g left (50%)

      • Half life #2 is 5g (25%)

Generating electricity

• heat> water into steam>steam turns a turbine>turbine powers generator>generator produces electricity

• U-235 stored in fuel rods, submerged in water in reaction core, heat from fission turns H20>steam> turns turbine>powers generator> makes electricity

  • Control rods are lowered into reactor core to absorb neutrons and slow down reaction, preventing meltdown/explosion

  • Water pump brings in cool water to be turned into steam and cools reactor from overheating

Nonrenewable, but cleaner than FF

• Is nonrenewable b/c radioactive elements like uranium is limited

  • No air pollutants or CO2/CH4 released when electricity is generated, mining of uranium, plant construction stil release GHG

  • Only gases released from elec gen is water vapor (technically GHG but stays in atm briefly)

• Spent fuel rods: used fuel rods remain radioactive for millions of years and need to be stored in lead containers on site @ nuclear PP

• Mine tailing: leftover rock and soil from mining have radioactive elements to contaminate soil/water nearby

• Water use: nuclear PP require lots of water and can deplete surface/groundwater sources

• Thermal pollution: hot water from PP released back into surface water can cause thermal shock (decreased O2 and suffocation)

Nuclear meltdowns

• Three Mile island (US): partial meltdown due to testing error, radiation released but no deaths/cancer

• Fukushima (japan): earthquake and tsunami triggered cooling pump failure that led to meltdown (explosion of reactor core) and widespread radiation release

• Chernobyl (ukraine): stuck cooling valve during test elad to complete meltdowns, several deaths + widespread radiation release

  • Contaminated soil: radiation can remain in soil and harm plants and animals in the future

  • Radiation spread: radiation can be carried by the wind over long distances

6.7 Energy from Biomass

Biomass vs. Biofuels

• Biomass: organic matter (wood/charcoal, dried animal waste, dead leaves/brush) burned to release heat- mostly for heating gomes/cooking

  • Utilized primarily in developing world for heating homes/cooking

    • Easy to harvest, available, cheap/free (subsistence fuel)

• Can be burned in PP to generate electricity(less common than FFs)

• Biofuels: liquid fuels (ethanol, biodiesel)

  • Used as replacement fuel sources for gasoline, primarily in vehicles

Modern vs fossil carbon

• Biomass burning CO2 but does not increase atmospheric CO2 levels like FF burning

  • Burning biomass releases modern carbon (CO2 that was recently taken out of the atmosphere); FF burning releases fossil carbon that has been stored for millions of years

    • Biomass burning considered carbon neutral

Humanhealth and env consequences of biomass burning

• Releases CO, NO3, PM, VOCs-volatile organic compounds-(respiratory irritants)

  • 3 billion people globally cook an open biomass fires (developing world)

  • Biomass bruns indor worsens asthma, bronchitis, COPD, emphysema

• Environmental consequences=deforestation and air pollutants

Biofuels: ethanol and algae

• Corn and sugarcane are fermented into ethanol which is mixed w gasoline

  • Corn grain/sugar cane broken down and yeast ferments sugar>ethanol

• E85 or flex fuel= 51-83% ethanol + gasoline mix

  • Decreases oil consumption for transportation, but is less efficient than pure gasoline

• “Renewable” only to extent of production of corn is sustainable (sugar cane is a perennial= more sustainable)

• Environmental consequences= all the neg. consequences of monocrop org

  • Soil erosion, hab. Loss, GHG release (soils, tractors, fertilizers), H2O use

• Lots of corn needed, relative to petroleum, can compete w human consumption of corn

• Algae produce oils that can be used as biofuels more sustainably than corn

Biodiesel

• Liquid fuels produced specifically from plant oils (soy, canola, palm)

  • Palm oil biodiesel has been found to produce 98% more GHG than FF from clearing of forests for palm plantations

1. One resource that can be combusted to provide heat and describe a neg consequence that results

   1. Wood can be combusted to provide heat that results in deforestation depending on the location

2. Describe a potential solution to the negative consequence to part a

   1. Government regulation or efforts to regulate forest growth

3. One source of biofuel that causes loss of habitat and solution to produce biofuels with decreased habitat impact

   1. Brazil forests or in gee, solution cou

4. 
   

6.8 Solar Energy

Active vs Passive solar energy

• Passive: absorbing or blocking heat from the sun w/o use of mechanical electrical equip

  • Using sun’s heat to cook food in a solar oven

  • Orienting building design to block sunlight in warmer months and allow sunlight in during colder months

• Active: use of mechanical/electrical equip to capture sun’s heat (solar water heaters or CST- concentrated solar thermal) or convert light rays directly into electricity (PV cells)

  • Solar water heaters capture suns heat in water or circulating fluid and transfer heat to warm water for home

Photovoltaic Cells

• Aka solar panels; contain semiconductor (usually silicon) that emits low voltage electrical current when exposed to sun

  • Photons (particles carrying energy from sun) cause separation of charges between 2 semiconductors layers, electrons sep from protons and flow through circuit to load, delivering energy as electricity

• Drawback: intermittency (solar energy can only be generated during the say)

  • Could be solved by cheaper, larger batteries that can store energy generated during teh day for use at night (not currently available)

Concentrated Solar Thermal (CST)

• Heliostats (mirrors) reflects sun’s rays onto a central water tower to heat water to produce steam to turn turbines>electricity

  • Drawback: habitat destruction and light beams frying birds mis air

Solar Energy PROs

• No air pollutants (PM, SO, NO) released to gen electricity

  • No CO2 released when generating electricity

  • Renewable, unlike FF that will run out

  • No mining of fossil fuels for electricity production

Solar Energy Cons

• Semiconductor metals (silicon) need to be mined to produce PV cells (solar panels)

  • This can disrupt habitats, pollute water with mine tailing, air with PM

  • Silicon is a limited resource

  • Solar panel farms can displace habitats

6.8 FRQ

The increased tracking ability such as the one or two-axis tracking PV array allows for an increased energy production for one kilowatt of solar PV capacity in comparison to a fixed tilt solar panel. This is because the PV cells can further. 

• LA is north of the equator, summer solstice is when it hits the earth the most which is why the energy production is the highest which is why it is about the same

• When the earth starts tilting and is not hit directly by the sun, the days shorten so there is less opportunity for solar panels to capture sunlight so the axis helps

6.9 Hydroelectricity

How it works

• Kinetic energy of moving water>spins a turbine with mechanical energy>turbine powers generator

  • Water moves with natural current of river/tides or vertically through dam channel

  • Largest renewable energy source

• Largest producers: China, Brazil, US

Water Impoundments (dams)

• Dams built in rivers create large artificial lake behind the dams (reservoirs)

  • Dams enable operators to control amount of water through the channel, increasing/decreasing electricity production

  • Also for control of flow downstream; prevention of season and prevent seasonal flooding

  • Reservoirs are source of reactional money (boating, tourism, increased prop values, fishing)

• IMPACTS: flooding of ecosystems behind dam and sedimentation (buildup of sediments behind dam)

River system and Tidal energy

• Dam diverts the natural current of a river through man-made channel

  • Less impactful to surround environment with no reservoir and no ecosystems being flooded

  • Doesnt stop natural flow of sediments; doesnt generate as much water and unavailable in warmer seasons when water levels are lower

Drawbacks of Hydrodams

• Ecological: reservoir flood habitats behind dams

  • Prevents upstream migration of fish like salmon that go to spawning ground to reproduce

  • Sedimentation causes upstream to be warmer (less O2) with more sediments and downstream loses sediment, decreased water level, loses steambed hab

• Environmental: FF combustion during dam construction; increased evap due to larger surface area of reservoir

• Economic impacts: humans homes and businesses must be relocated due to reservoir flossing

  • Initial construction is very expensive (does create long term jobs tho soo)

  • Potential loss of fishing revenue is salmon breeding is disrupted

Fish Ladders

• Cement “steps” or series of pools that migratory fish like salmon can use to continue migration upstream, around or over dams

  • Enables continued breeding for salmon, food sources for predators like birds, bears, dishing for humans

Benefits of Hydrodams

• No GHG emission when producing electricity (initial construction does require)

  • Jobs created to maintain dam

  • reservoir/dam can be tourist attractions

  • Reliable electricity source for nearby

  • No air pollutants

• Control of downstream seasonal flooding (use for hydroelectricity, recreation/scenic, flood control)

6.10  Energy

• Natural radioactive decay of elements deep in earth’s core gives of heat

  • Water piped down into ground, heated by this heat 

    • Hot water converted into steam>KINETIC ENERGY OF STEAM TURNS turbine> electricity or to heat homes directly

• The heat from magma turns water>steam which is forced through pipes to spin a turbine

• Water is cooled in cooling tower and returned to the ground to start process over

• Renewable b/c heat from earth’s core wont run out, only is groundwater is returned after use

Ground Source Heat Pump

• “” but technically heat does not come from from geologic activity FROM GROUND STORING HEAT FROM SUN

  • 10 ft down, ground stays consistent 50-60 degrees from holding heat from sun

    • Heat is absorbing fluid pumped through pipe into ground where it takes heat from ground (winter) or gives off heat into ground (in summer)

 heating

• Piping water deep into ground to be heated by magma and then transfering heat from water>building

  • 1000s of meters into ground to reach heater water reservoir

PRO

• Potentially renewable if water is piped back into ground for reuse

• Much less CO2 emission than FF 

• No release of (PM/SO/NO/CO)

CON

• Not everywhere has access to  energy

• Hydrogen sulfide can be released, lethal/toxic to humans and animals

• Cost of drilling deep into earth can be high initially (sometimes not worth it)

6.11 Hydrogen Fuel Cells

Hydrogen Fuel Cell Basics

• Hydrogen is a renewable, alternative fuel source to FF

  • H2 and O2 are inputs used to create electricity w H2O as waste product

• H2 gas enters fuel cell, split into protons (H+)and electrons by electrolyte membrane that only allows for protons to pass

  • Electrons take alternative route around the membrane>creates electrical current

  • O2 molecule break apart and combine w 2 hydrogens to create H2O byproduct

• VEHICLES: replaces gasoline with H fuel

Creating H2 Gas

• Have to obtain pure H gas (doesnt exists by itself as a gas naturally)

• Serapting H2 gas from other molecules like H2O or CH4 is energy intensive

  • Steam reforming: burning natural gas (CH4) and using steam to separate the H gas from methane

    • Emits CO2 and requires FF input

  • Electrolysis: electrical current is applied to water to break it into O2 and H2

    • No CO2 emission, requires electricity 

PROS

• Can be stored in pressurized tanks, easy transport for different locations (not like solar, hydro, wind where must be used as soon as generated)

• Used as fuel for vehicles (replacing gasoline) or ammonia for fertilizer

  • Gasoline replacement> EMITS NO AIR POLLUTANTS, ONLY H2O

  • Many industrial chemicals requires H2 gas

  • Can be stored as liquid/gas, easy for transport

  • H fuel cells are 80% efficient in converting chemical energy in H2 and O2 ino energy

CONS

• 95% of H2 production requires methane (CH4), based on nonrenewable source and CO2 releasing energy source

• H fuel stores in gas form in vehicles would require larger tanks than current gasoline tanks

Products H2 gas and Oxygen goes through first reaction layer into proteins/electrons

• Electrons produce electric current while protons flow through a membrane layer, on the other side they are combined with oxygen from the environment to create water vapor as the product

6.12 Wind Energy

Wind Turbine Electricity Generation

• Kinetic energy of wind spins turbine>generator converts mechanical energy of turbine >electricity

  • Avg wind turbine has 15-30% capacity factor of total possible energy it could generate

Location

• Clustered in groups in flat, open areas (usually rural)

  • Locating them together makes service, repair, and building transmission lines to them easier

    • Can share land with agricultural use

• Offshore wind= wind farms in oceans/lakes

  • PROS:

    • Capitalized on the faster wind speeds

    • Environmental: Less damage due to decreased reliance on fossil fuels (less habitat destruction since there is less need for extracting natural gas and oil)

    • Economic: Increased creation of jobs such as construction, operation, and maintenance of the offshore wind project

    • Can also be used for tidal power:as the tides come in, propellers could be placed underwater to make energy

  • CONS:

    • Requires transmission lines built across long distances to reach land

Benefits

• Non-depletable

• No GHG emissions or air pollutants released when generating electricity

• No CO2 (climate change) or No/SO/PM 

• Can shae land use (doesnt destroy habitats or cause soil/water contamination)

Drawbacks

• Intermittency (isn't always available)

• Can kill birds and bats

• Considered eyesore or source of noise pollution by some

6.13 Energy Conservation

Small Scale Energy Conservation

• Lowering thermostat to use less heat/AC less often

• Conserving water (native plants instead of grass, low flow shower heads)

• Energy efficient appliances, better insulation to keep more heat home

Large Scale Energy Conservation

• Improving fuel efficiency

• Subsidizing (tax credits) for electric vehicles, charging stations, hybrids

• Increased public transport

• Green building designs

Sustainable home

• Using passive solar design to trap heat and decrease energy from heatings system

• Well insulated walls/attic trap heat in winter/cool air from AC in summer (decreases electricity used)

Water conservation

• Native plants require less watering than traditional lawns (increases biodiversity of pollinators, less fertilizer)

• Low-flow showers, toilets, dishwater use less total water

• Rain barrels allow rain water to be used for watering plants/cras

Transportation

• Improving fuel economy of US vehicles that conserve energy w less gasoline/diesel needed

  • CAFE (corporate average fuel economy) standards are set in US to require auto manufacturers to make cars that meet standards or pay penalties

• Hybrids have gasoline + electric engine

• Electric vehicles like tesla or LEAF use no gasoline, but still require electricity

• Public transit & carpooling

Buildings

• Green roof or walls decrease runoff, absorb sun’s heat = ;ess need for cooling building and surround area

• Sun lights on roof can decrease electricity used for lighting

• Recycled materials reduce energy required to produce new ones (glass, wood)

Unit 7: Atmospheric Pollution (Sunday, May 23rd)

7.1 Air Pollution Basics

Clean Air Act (1970) identified 6 criteria air pollutants that the EPA is required to set acceptable limits for, monitor, and enforce

• SO2 (sulfur dioxide): from coal combustion used for electricity OR naturally from coal and oil

  • Effects: respiratory irritant, smog, and acid precipitation

• NO & NO2 (Nitrogen Oxides): fossil fuel combustion OR forest fires, lighting, soil microbes in nature

  • Effects: formation of O3, photochemical smog, acid precipitation

• CO (carbon monoxide):  incomplete combustion, vehicle exhaust ( manure, charcoal, kerosene)

  •  Effects: O3, lethal to humans

• PM (particulate matter):fossil fuel and biomass combustion 

  • Effects:  respiratory irritant and smog

  • PM2.5: greatest health concern; lodges deeply in respiratory tract>>usually more toxic

  • PM10: too small to be filtered by respiratory tract>>health concern

• O3 (ozone troposphere): from the photochemical oxidation of NO2

  • Effects: respiratory irritation, formation of smog, damaging to plant stomata so it limits growth

• Pb (lead): metal plants, waste incineration (gasoline, paint in older buildings, toys and jewelry, pipes)

  • Effects: neurotoxicant

Air Pollutants vs. Greenhouse Gasses

• CO2 is NOT an air pollutant as part of the Clean Air Act

  • It does not directly lower air quality as it is not toxic to organisms to breathe, not damaging to lungs/eyes, and does not lead to smog/decreased visibility 

• CO2 is a GREENHOUSE GAS: it leads to earth warming and thus env and human health consequences 

  • Use fire air pollutants on FRQS: SO2, NOx, O3, PM

Coal Combustion

• Releases more air pollutants than other FFs: ~35% of global electricity

• Releases CO, CO2, SO2, NOx toxic metals (mercury, arsenic, lead), and PM (often carries toxic metals

  • Impacts of SO2:

    • Respiratory irritants

    •  sulfur aerosols block incoming sun=reduces visibility, photosynthesis

    • Forms sulfurous (grey) smog

    • Combines with water and O2 in atmosphere to form sulfuric acid>acid precipitation

Nitrogen Oxides (NOx)

• Released by combustion of FFs and biomass (NO and NO2)

  • NO forms when N2 combines with O2 (like during combustion)

  • NO can become NO2 by reacting with O3 or O2

  • Sunlight converts NO2 back into NO

• Env. and human health impacts:

  • Resp. irritants

  • Leads to tropospheric ozone (O3) formation>photochemical smog

  • Combines with water and O2 in atm. To form nitric acid>acid precip.

EPA and Lead

• Vehicles made after 1974 are required to have catalytic converters to reduce NOx, CO, and hydrocarbon emissions (aka known as neurotoxicant-damages nervous systems of humans)

Primary vs. secondary air pollutant

• Primary: Emitted directly from sources such as vehicles, power plants, factories, power plants, factories, or natural sources

  • NOx, CO, CO2**, VOCs, SO2, PM, hydrocarbons

• Secondary: primary pollutants that have transformed in presence of sunlight, water, O2

  • Occur more during the day b/c sunlight usually drives formation

  • Tropospheric O3 (ozone), sulfuric acid (H2SO4) & sulfate (SO42-). Nitric acid (HNO3) & nitrate (NO3-), acid rain, photochemical smog, 

7.2 Photochemical Smog

• Secondary form of pollution forming when NOx chemicals mix with VOCs in sunlight forming other pollutants

  • NOx form in the morning and peak in the afternoon (occurs more often in summer when sunlight is at its peak

  • Water and oxygen in the atmosphere react with NOxs and form: Ozone; PANS (peroxyacyl nitrates, Acid Deposition

Precursors

• NO2 is broken by sunlight into NO + O 

• Volatile organic compounds that bind with NO and form photochemical oxidants

  • Carbon-based compounds that evaporate easy

  • Sources: gasoline, formaldehydrade, cleaning fluids, oil-based paints

• O3 forms when NO2 is broken by sunlight and free O binds to O2

  • Resp irr in troposphere

  • Damaging to plant stomata>limits growth

Conditions

• Sunlight drives O3 formation by breaking down NO2> NO + O then free O atom binds to O2

• Warm: hotter atm. Temp speeds O3 formation, evaporation of VOC and thus smog formation

Normal O3 formation

• Sunlights breaks NO3> NO + O2

• O binds with O2 to form O3

• At night, O3 reacts with NO to form NO2 and O2, O3 levels drop overnight

• O3 formation peaks in afternoon when sunlight is most direct and NO2 emissions from morning traffic have peaked

• Morning commute>high NO2 levels from car exhaust

Photochemical Smog Formation

• Sunlight breaks NO2> NO + O

• O bonds with O2 to form O3

  • VOCs bonds with NO to form photochemical oxidants

  • Without NO to react with O3, builds up instead of returning to O2 and NO2 overnight

• O3 combines with photochemical oxidants (NO + VOCs) to form photochemical smog

Factors that increase smog formation

• More sunlight (summer, afternoon) = more O3

  • Warmer temp speeds evap of VOCs that lead to O3

• Higher VOCs emissions (gas stations, laundromats, plastic factories, petrochem factories)

• Increased vehicle traffic; increases NO2 emissions and therefore O3 formation

Impacts of Smog

• Environmental: reduced sunlight>limits photosynthesis

  • O3 damages plant stomata and irritates animal resp tracts

• Humans: resp irritant, worsens asthma, bronchitis, COPD, irritates eyes

• Economic:  increased health care costs to treat asthma, bronchitis, COPS

  • Lost productivity due to sick workers missing work or dying

  • Decreased ag. Yields due to less sunlight reaching crops and damage to plant stomasa

Reduction of SMOG

• Vehicles: decreasing the # of vehicles on the road decreases NO2 emissions

  • Fewer vehicles = less gas= less VOCs

  • Carpooling, public transport, biking, walking, working from home

• Energy: increased electricity production from renewable sources that don't emit NO (solar, wind, hydro)

  • Nat gas power plants release for less NO than coal

7.3 Thermal Inversion

Urban Heat Island Effect

• Urban areas tend to have higher surface and air temp than surrounding suburban and rural areas due to:

  • Lower albedo: concrete and asphalt absorb more of sun’s energy than areas with more vegetation (absorbed sunlight is given off as IR radiation-heat)

    • Snow is higher albedo>keeps cooler

  • Less evapotranspiration: water evaporating from surfaces and transportation from surfaces and transpiration from plants carries heats from surface into the atmosphere

    • This cools off rural and suburban areas which have more vegetation

Thermal Inversion

• NORMALLY, the atmosphere is warmest at earth’s surface and cools as altitude rises

  • Warm air rises> air convection carries air pollutants away from earth's surface and distributes them into higher into the atmosphere

• During thermal inversion>> cooler air mass becomes trapped near earth's surface

  • Due to warm front OR due to hot urban surfaces coling overnight whole IR radiation absorbed during day is still being released

  • CITIES MOST PRONE DURING WINTER: HAVE TO BE FAR ENOUGH N/S TO HAVE DISTINCT WINTER

• Cold air at the surface is trapped beneath the warmer mass above, convection doesnt carry pollutants up and away

Effects of Thermal Inversion

• Air pollutants (smog, PM, ozone, SO2, NO2, PM10, PM2.5, Woodsmoke) trapped closer to earth

• Respiratory irritation: asthma flare ups>hospitalization, worsened COPD, emphysema

• Decreased tourism revenue

• Decreased photosynthetic rate

Regulations

• Increased public transportation

• Limited vehicle permits

• Emission testing for personal and commercial vehicles

• Restrictions on agricultural burning, waste-burning, coal-burning power plants

• Educational and incentive programs

Los Angeles is a highly populated city with much car traffic. It also sits next to the Pacific Ocean and receives cool prevailing winds that are trapped by nearby mountains. This cool air is much denser in comparison to the hot surface air found over the land. As a result, the cool air sinks below the warm air.

7.4 Atmospheric CO2 and PM

Natural Sources of Air Pollutants

• Lightning strikes: convert N2 in atm. to NO

• Forest fires: CO, PM, NO

  • Combustion of biomass also releases CO2 and H20 vapor

• Plasts (esp conifers): plants emit VOC

• Volcanoes: SO2, PM, CO, NO

Natural Sources of CO2 and PM

• Respiration: all living things release CO2 through respiration

• Natural PM sources: sea salt, pollen, ash from forest fires and volcano dust

  • Leads to haze

• Aerobic decomposition: decomposition of organic matter by bacteria and decomposers in the presence of oxygen>> releases CO2

• Anaerobic decomposition: decomposition of organic matter by bacteria and decomposers in low or oxygen -free conditions> releases CH4/methane

PM10 vs PM2.5

• Particulate matter: solid or liquid particles suspended in air

• PM10 (<10 micrometers)

  • Particles or droplets like dust, pollen, ash, mold

  • Too small to be filtered by nose hairs and trachea cilia

    • Nose hairs and mucous secretions in our nose and throat trap larger particles and prevent larger particles from getting to our lungs

    • Can irritate respiratory tract and cause inflammation

• PM2.5 (<2.5 micrometers)

  • Particles from combustion (esp vehicles) smaller dust particles

  • Most likely to travel deep into the lungs due to smaller size

  • Associated with chronic bronchitis and increased risk of lung cancer

7.5 Indoor Air Pollutants

Developing vs. Developed Countries

• Developing nations use more subsistence fuels like wood, manure, charcoal

  • Release CO, PM, NOx, VOCs, cause deforestation

  • Often combusted indoors with poor ventilation=high concentrations

• Developed nations use more commercial fuels (coal, oil, natural gas) supplies by utilities

  • Typically burned in closed, well ventilated furnaces, stoves, etc

  • Major indoor air pollutants come from chemicals in products; adhesives in furniture; cleaning supplies; insulation; lead paint

PM & Asbestos

• Particulates are a common indoor air pollutant (ex. Smoke, dust, asbestos)

• Asbestos is a long, silicate particle previously used in insulation (linked to lung cancer & asbestosis)

  • Out of use but remains in older buildings

  • Not dangerous until insulation is disturbed and asbestos particles enter air & resp tract

  • Should be removed by trained professionals with proper respiratory equipment, ventilation in area its being removed from, plastic to seal off area from rest of building

CO (Carbon Monoxide)

• Produced by incomplete combustion of any fuel (not all fuel combusted w low O2 or temp)

• CO is an asphyxiant: causes suffocation due to CO binding to hemoglobin in blood, displacing O2

  • Lethal to human in high concentrations, esp with poor ventilation (odorless/colorless)

  • Developed nations: CO released into home by malfunctioning natural gas furnace ventilation (detected by carbon monoxide detectors)

  • Developing nations: CO emitted from indoor biomass combustion for heating/cooking

VOCs (volatile organic compounds)

• Compounds or molecules that vaporize and become airborne at low temperatures

  • MUST CONTAIN CARBON

• Chemicals used in variety of home products that easily vaporize, enter air, irritate yes, lungs, bronchioles

  • Natural VOC: volcanoes/forest fires release benzene

• adhesives/sealants: chemicals used to glue carpet down, hold furniture together, seal panels

  • Formaldehyde is a common adhesive in particle board and carpet glues

• Cleaners: common household cleaners and deodorizers like febreeze

• Plastics and fabrics: both can release VOCs or from adhesives used in production

Radon Gas

• Radioactive gas released by decay of uranium naturally found in rocks underground (esp granite)

  • Usually enters homes through cracks in foundation, disperses up from basement/foundation through home

    • Can seep into groundwater sources + enter body through drinking water

  • 2nd leading cause of lung cancer after smoking

    • EPA recommends testing homes with airborne radon monitor

    • Sealing cracks in foundation can prevent it from entering/increasing ventilation in home can disperse if its detected

Dust and Mold

• Natural indoor air pollutant that can worsen asthma, bronchitis, COPD, emphysema

  • Dust settles in homes naturally, distrubed by movement, enters air and then resp tract

• Mold develops in dark, damp areas that aren't well ventilated

  • Black mold releases spores into air; harmful to resp. system

  • Can be removed physically cleaning mold out + fixing water leak/ventilation issue that led to mold formation

Lead

• Found in paint in old homes (EPA banned lead paint in 1978)

• Paint chips off walls/windows and is eaten by children or inhaled as dust

  • Lead water pipes also release lead into drinking water sources, less common than lead paint

  • Damages central nervous system of children due to smaller size + developing brain

  • Can be removed by strippnig lead paint, replacing with non-lead based paint; lead water pipes replaced with copper pipes

7.6 Reduction of Air Pollutants

Reducing emissions=reducing air pollutants

• Drive less, walk/bike/bus more

• Conserve electricity (smart appliances)

• Eat more plants, less meat

• Renewable, non-pollution emitting energy

Laws/Regulation

• Clean Air Act: allows EPA to set acceptable levels for criteria air pollutants

  • Monitor emission levels from power plants and other facilities

  • tax/sue/fine corporation that release emissions above levels

• CAFE Vehicle standards: (corporate average fuel economy) standards require the entire US fleet of vehicles to meet certain average fuel

  • Requires vehicle manufacturers to work to make more efficient vehicles

  • More efficient vehicles burn less gasoline and release less NOx, PM, CO, CO2

• Pollutant Credits: similar to ITQs for fish

  • Companies that reduce emissions well below EPA-set levels earn pollution credits

    • They can sell these to companies that release more than acceptable levels

Reducing Vehicle Air Pollutant

Vapor Recovery Nozzle: captures hydrocarbon VOCs released from gasoline fumes during refueling

• Separate tube inside nozzle captures vapors, returns them to underground storage tank beneath gas station

  • Reduces VOCS(reduce smog, resp irritants), benzene (carcinogen)

Catalytic Converter: required on all vehicles after 1975

• Contains metals (platinum & palladium) that binds to CO & NOx & hydrocarbons to convert into CO2, N2, O2, H2O

Reducing SOx & NOx

Crushed Limestone (SO2): used to reduce SO2 from coal power plants

• Crushed coal mixed w limestone before burned in boiler

  • Calcium carbonate in limestone + SO2 = calcium sulfate >reduced SO2 emitted

  • Used for gypsum wallboard or sheetrock 4 home foundations

Fluidized Bed Combustion (NOx): fluidizing jets of air pumped into combustion bed

• Jets of air bring more O2 making combustion more efficient + bringing more SO2 into contact w calcium carbonate in limestone

  • Allows coal to be combusted at lower temp>emits less NOx

Wet & Dry Scrubbers

Dry Scrubbers (NOx, SOx, VOCs): large column/pipe w chemicals that absorb or neutralize oxides (NOx, SOx, VOCs) from exhaust streams

• Calcium oxide is a common dry scrubber additive, reacts w SO2 to form calcium sulfite

Wet Scrubbers (NOx, SOx, VOCs, PM): involves chemical agents that absorb or neutralize NOx, SOx,VOCs, mist nozzles that trap PM in water droplets

• Mist droplets with pollutants and PM trapped in fall to bottom of scrubber or get trapped @ top by mist eliminator

  • Sludge collection system traps polluted water for disposal

Reducing PM

Electrostatic Precipitator: power plant/factory emissions passed through device with a neg. charged electrode gives particles a neg charge

• Neg. charged particles stick to pos charged collection plates, trapping them

  • Plates discharged occasionally so particles fall down into collection hopper for disposal in landfills

Baghouse Filter (PM): large fabric bag filters that trap PM as air from combustion/industrial processes pass through

• Shaker device knocks trapped particles loose into collection hopper below

  • PM collected & taken to landfill

Difference between “good” ozone and “bad” ozone

Function of the ozone layer?

• To absorb the sun’s harmful UV rays, allowing just enough for life on earth

Ozone Layer Formation

• Step 1: O2 + ultraviolet rays = O + O

• Step 2: O + O2 = O3

CFCs:

• Chlorofluorocarbons

• Nontoxic, nonflammable

• Contain C, Cl, F

• Found in refrigerants, propellants (aerosols), foam, and packing materials

1. UV causes a chlorine atom to break away from the CFC molecule

2. Free chlorine atom hits an ozone molecule

3. The chlorine atom pulls 1 oxygen atom away

4. A free oxygen atom hits the chlorine monoxide molecule

5. Results in another free chlorine atom

6. Free chlorine will continue to deplete ozone in the stratosphere

• Montreal protocol: limited/banned CFCs in many countries

7.7 Acid Rain

Sources of NOx & SO2

• SO2: coal fired power plants. Metal factories, vehicles that burn diesel fuel

• NOx: vehicle emissions, diesel generators, coal power plants

Limiting Acid Rain (decreased after clean air act)

• Reducing NOx & SO2 emissions reduce acid deposition

  • Higher CAFE standards

  • More public transit

  • Renewable energy sources

  • More efficient electricity use

• NOx & SO2 react with O2 and H20 in the atmosphere, forming nitric and sulfuric acid

  • Sulfuric acid and nitric acid dissociate in the presence of water into sulfates and nitrate ions and hydrogen ions (H+)

• Acidic rain water (higher H+ conc) decreases soil and water pH

  • Limits tree growth in forests down wind from major SO2 and NOx sources

Env. effects of Acid Rain

• acidity= higher H+ ion concentration, lower pH

soil/water acidification:

• H+ ions displace or leech other pos. Charge nutrients (Ca2+, K+) from soil

• H+ ions make toxic metals like aluminium & mercury more soluble in soil and water

  • Slows growth or kills plants and animals living in the soil or water

pH tolerance:

• As pH decreases outside optimal range for species, pop. declines

  • When pH leaves range of tolerance, they cannot survive due to aluminium toxicity, disrupted blood osmolarity (Na+/Cl- balance disrupted at low pH)

• Indicator species can be used to determine conditions of an ecosystem (soil, water, etc.)

Mitigating Acid Rain

• Limestone (calcium carbonate) is a natural base to neutralize acidic soil/water

• Limestone: calcium carbonate reacts with H+ ions = HCO3 + Ca 2+

  • Neutralizes acidic water/soil, moving pH closer to 7

• Regions with limestone bedrock have natural buffering of acid rain (humans can also add crushed limestone to soils/waters to neutralize)

  • Acid rain can corrode human structures, esp made of limestone

• Limiting SO2 & NOx: decreasing primary pollutants that drive acid rain to reduce

  • Renewable energy sources, decreasing coal comb; fluidized bed combustion & lower burning temp. For existing coal power plants; dry or wet scrubbers

7.8 Noise Pollution

Urban noise pollution: any noise at great enough volume to cause physiological stress(dif hearing, headaches, confusion) or hearing loss 

• Construction: jack hammers, trucks, concrete pouring

• Transportation: cars, buses, trains

• Industrial activity: manufacturing plants

• Domestic activity: neighbor’s music, lawn mowing, home projects

Wildlife Effects (land)

• Noise pollution can disrupt animal communication, migration, and damage hearing

• Physiological stress: caterpillar hearts beat faster when exposed to stimu;ated highway noise pollution

  • Could drive pollinator species decline

• Hearing: can prevent predators from hearing prey and vice versa; can prevent mats from locating each other (decreases chances of survival)

Wildlife Effects (aquatic)

• Aquatic noise pollution comes from the noise of ship engines, military sonar, and seismic air blasts from oil and gas surveying ship

• Physiological stress: hearing loss, disrupted communication, mating calls, predator and prey navigation

  • Whales are especially prone to having migration routes disputed as vocal communication is disrupted

  • animals that rely on sonar or sound for navigation, feeding and communication can be disoriented by mechanical sounds and sonar used by humans.

• Seismic surveying: ships send huga air blasts down into the water, searching for oil by recording how the echo is returned from ocean floor

  • So loud that researchers off the coast of virginia cn detect blasts from coast of brazil

Explain one way that you can modify this procedure to better determine the impact of fossil fuel combustion on sulfur dioxide levels.

• Maybe burn some coal: lignite, bituminous, and anthracite to allow for a wider variety as coal is a fossil fuel, and the combustion of coal is an anthropogenic source of sulfur dioxide which will allow to make better conclusions

• Adjust the temperature the fossil fuels are being burned

• Change volume of the burning

Locations with the highest levels of tropospheric ozone? Dallas, Texas because it is bright/sunny

Describe the relationship between the max daily temperature and max daily ground level ozone that is shown by this data

• As the maximum ground level ozone increases, the temperature increases as a exponential relationship  

a. Describe the trend that you observe in the figure between altitude B and C

• Between B and C, the altitude is increasing as the temperature is increasing positively in which the directionality is different from before and after

B. Identify one pollutant that would increase in concentration due to the temperature anomaly between B and C.

•  One pollutant that would increase in concentration would be tropospheric ozone, O3, 

c.  explain how the trend you obsessed in a could lead to increased effects of the pollution you identified in b

• There is a temperature inversion occurring in which the trend is going against the normal trend of temperature decreasing with the increasing altitude. The thermal inversion traps pollution closer to the ground and as the cold air is trapped beneath the warmer mass above, the convection does not carry the pollutants away

a.  Explain the method that will be used to collect and analyze data

• To collect particulate matter density, a card wi

b. Describe the variables in the investigation 

• The independent variable is; how will it be manipulated?

• The dependent variable is; how will it be measured

c. describe the factors that will be controlled in the study

• What are being constant and why