FINAL EXAM Flashcards
what are conventional fossil fuels?
the least expensive fuels to produce and supply nearly all of the energy provided by fossil fuels (coal, oil, natural gas)
what are unconventional fossil fuels?
more expensive to produce than coal, oil, natural gas, may eventually replace FF;oil shales and tar sands
what is the most widely used FF?
crude oil, then coal, natural gas
what is traditional biomass comprised of?
fuelwood, charcoal, agricultural residues, animal dung
what is the relationship between traditional biomass and agriculture?
its most widely used in rural areas where agriculture is the principal economic activity
why is coal production highest in china?
to generate electricity, power the rapid expansion of their economy
layers of the atmosphere in order
- troposphere
- stratosphere
- mesosphere
- thermosphere
characteristics of the troposphere
temperature declines with higher altitude (negative correlation between temp and altitude), lapse stops sealing in earth’s atmosphere
characteristics of the stratosphere
“just right” for ozone development, waste heat from ozone reactions warms temperature
what is the role of ozone in the stratosphere?
ozone is essential and most abundant here, where it absorbs solar energy (UV-B) that is harmful to organisms
describe the stratospheric cycle of ozone
it first forms when molecular oxygen absorbs solar energy and photodissociation occurs. ozone forms when the single oxygen atoms from photodissociation combine with molecular oxygen. the ozone gets split again when it absorbs ultraviolet radiation
stratospheric ozone vs tropospheric ozone
smaller amounts of ozone in the troposphere, but still harmful to human health and ecosystems; its considered a pollutant, it combines with NO and VOCs to form photochemical smog
how does the stability of the CFC molecule reduce stratospheric ozone
CFCs are inert chemicals meaning they do not break down easily and do not react with other chemicals; they eventually reach the stratosphere where the molecules are broken down by photodissociation, freeing chlorine, which causes a sequence of reactions in which a chlorine atom changes an ozone molecule into molecular oxygen, freeing the chlorine atom from chlorine monoxide, allowing that atom to destroy multiple atoms of ozone; O is also converted into O2 which reduces the amount of single oxygen atoms to form more ozone
what is the halogen depletion hypothesis?
- fugitive CFCs can make their way into the atmosphere
- photodissociation frees all the chlorine atoms from the og CFC molecule
- the chlorine atom reacts with O3 and O to reduce total O3 in the stratosphere
how was the halogen depletion hypothesis proved?
spy planes were turned into research vehicles equipped with special instruments and flown over the south pole where they found high concentrations of chlorine atoms in areas of low stratospheric ozone concentrations
what were the readily available forms of replacement for CFCs?
HFCs
what is lapse rate?
the rate at which temperature changes with altitude; raising a parcel of air will cause it to expand, thus cool
what is adiabatic lapse rate?
the default; a given parcel of air in which temperature change due to compression or expansion is associated with changes in altitude, but does not exchange heat with surrounding air; abt 1 degree celcius per 100 m
what is the process of cooling for the adiabatic lapse rate?
as air rises, pressure reduces, volume expands, fewer collisions between molecules occur, air cools (happens without any input)
what happens if the observed lapse rate is faster than the adiabatic lapse rate?
air parcels experience **more rapid cooling **and are cooler than surrounding air at higher altitudes, which means they are more dense and will sink back towards their og location
what happens if the observed lapse rate is slower than the adiabatic lapse rate?
air** does not cool** as quickly and becomes warmer than surrounding air at higher altitudes, making it less dense, meaning it can rise further and move away from its og location
what does the southern polar vortex do?
traps gases (CFCs)
forms polar stratospheric clouds (where the breakdown of CFCs is accelerated
how do the seasons affect the southern polar vortex?
- cold winter air forms vortex
- early spring brings increased solar radiation, photodissociation more Cl from CFCs
- in late spring, warmth returns, breaking up polar vortexes, throughout summer ozone levels increase again as polar air mixes with surroundings
why are polar vortexes less of an issue in the north pole?
- land mass is unevenly distributed –> weaker vortex, trapping less air
- comparatively warmer temperatures: limiting formation of polar winds forming vortex & limiting formation of stratospheric clouds
how did policy solve the CFC problem?
companies agreed that if there was sufficient evidence of CFCs being harmful, they would stop/lessen production; basis of evidence found from research served for Montreal Protocol = 50% reduction in CFCs; HFCs become alternative
how is the CFC problem different from global anthropogenic climate change?
there were readily available alternatives, getting rid of CFCs is simpler because you can specifically eliminate specific type of refrigerants and in spray cans, not as much political lobbying passing disinformation
primary pollutants
enter atmosphere in form that is harmful to life & objects ex. Carbon monoxide, VOCs, NOx, SO2, aerosols
secondary pollutants
formed in atmosphere by interaction of primary pollutants with sunlight & other gases
ex. ozone formed by interaction of sunlight w/hydrocarbons & NOx, VOCs (benzine, formaldehyde), (secondary organic) aerosols, sulfuric acid
what is carbon monoxide & how are factors that contribute to its formation?
product of incomplete combustion of hydrocarbons, produced in combustion reactions where oxygen is insufficient, temp is too low, or air supply rate is too fast relative to insufficient oxygen, mixing in combustion chamber is insufficient;
why is carbon monoxide harmful?
binds to hemoglobin & disrupts transportation of oxygen
what are particulates?
solids or condensed liquids that are suspended or floating in the atmosphere; aerosols = mixtures of liquid & solid particles
ex. soot from fire
what are coarse particles?
PM10; between 10 and 2.5 microns; smaller than a cell, tend to settle more quickly, can be blocked by mucus and nose hairs, less dangerous
what are fine particles?
PM2.5
what are ultrafine particles?
PM0.1 below 0.1 microns, smaller than a virus, resists gravity settling but may be more likely to stick to larger particles or be deposited onto surface, exist in high concentrations closer to the surface, can be inhaled deeply and settle on lung surface leading to respiratory illness most dangerous
what are primary particulates?
emitted directly from some economic activity
what are secondary particulates?
formed by interaction of primary particulates with atmosphere
ex. nitrates
what is the weekend effect?
through nucleation, water droplets condense on particles, starting to form or seedling clouds. more rainfall and storm activity tends to happen toward the end of the week as a result of pollutants form work week, clouds form by weekend
characteristics of sulfur dioxide
sulfur aerosols form haze & clouds that reflect some sunlight –> cooling; FF combustion enhances flow of sulfur to atmosphere, primary pollutant, effects human respiration and plant growth, major reduction in emissions through cap and trade, respiratory irritant, can form acid rain
how does sulfur dioxide form a secondary pollutant?
SO2 reacts with atmospheric oxygen to form SO3, which in turn forms droplets (haze & clouds) along with sulfuric acid; removed from atmosphere as wet deposition aka acid rain
where is acid rain a problem?
downwind of appalachian mts, westerlies, from CA to NY, florida
where are the biggest sources of SO2?
where coal-fired electricity plants are
characteristics of NOx
NO, NO2; used in fertilizer, CAFOs, gasoline, lightning; generated during FF combustion, more of a problem for coal than oil than for natural gas, first produced as NO (harmless), oxidizes to NO2; NO is highly reactive –> can produce more secondary pollutants, cause pulmonary problems
what happens to nitrogen dioxide in the presence of hv?
dissociated to nitric oxide and an oxygen radical (highly reactive); the O radical in turn can react with oxygen to form ozone
characteristics of hydrocarbons
not all bad, some carcinogens; vocs are a subset, can arise from incomplete combustion or industrial processes, emitted by motor vehicles, also common in nature; geosmin, turpine; most aromatics and scents, important for plant-plant & plant-animal communication, some primary pollutants, can contribute to poor indoor air quality
what does volatile mean?
low point of evaporation
which hydrocarbons are harmful on their own?
benzene and formaldehyde
what happens when VOCs combine with NOx?
play role in photochemical smog, producing more ozone, particulates, and other secondary pollutants
what are concentrations of pollution shaped by?
emissions, the volume or air that they’re being emitted into, and their reaction & deposition removal processes from the air
emission sources –> atmospheric concentration –> reactions/deposition
what is vertical mixing layer?
refers to the altitude or “ceiling” to which pollutants are able to rise
what is horizontal movement?
refers to the distance pollutants are carried away from their source by the wind
what do diurnal changes in the mixing layer depend on?
solar radiation, albedo, clouds, seasons
what is advection?
horizontal movements** driven by pressure gradients (winds)**; moves pollution horizontally but not necessarily away from ppl
what is convection?
turbulent, vertical exchange of air; more convection means a larger (higher) mixing layer, is limited by stability of troposphere
when is the atmosphere unstable?
when the upper air is cooler than the ALR; an adiabatically rising air parcel near the ground is warmer than the env, causing it to rise
when is the atmosphere unstable?
when the upper air is cooler than ALR; an adiabatically rising air parcel near the ground is cooler than the environment, causing it to sink
radiation inversion
if temp rises with altitude, adiabatic air parcels wouldn’t rise; occur on warm clear nights when ground cools, can occur during day and trap pollutants underneath; LW radiation leaving the surface at night is absorbed by the troposphere, air very close to the ground is cooled by conduction with the cool ground (fog along ground = moisture trapped vertically)
what is a subsidence inversion?
occur as a large air mass sinks, causing it to heat up relative to the air underneath; 30 deg south is where most sinking of air occurs
what is mixing depth?
inversions cause downward mixing, unstable atmospheres allow upward mixing, stable atmospheres cause exahust to move downwind
what is fanning?
stable atmospheres cause exhaust to move downwind without much motion up or down only spreading out horizontally
what is looping?
unstable atmospheres allow upward mixing in waving pattern that indicates atmospheric convection is occurring (when the smoke moves up and down); good for us, carries pollution away
what is fumigation?
when inversions cause some downward mixing; bad cuz it keeps pollutants on our level
characteristics of the NAAQS
atmospheric concentration of pollutants have declined, established nationwide standards for max allowed concentration, forces firms to pay cost of compliance (externality) rather than ppl paying health cost of pollution, all states subject to same standards
what are the primary standards acc to the NAAQS?
protect public health, including sensitive populations such as children and the elderly and asthmatics
what are secondary standards acc to the NAAQS?
protect public welfare including visibility, damage to crops, vegetation, animals, property
how did the NAAQs internalize externalities?
established diff zones:
- class I (national parks) no increases allowed
- class II (most of US) increases allowed, but not up to the NAAQS
- class III where increases up to the NAAQS were permitted
what is a catalytic converter and how does it work?
exhaust emission control device that operates on exhaust to oxidize hydrocarbons and carbon monoxide to CO2 and reduce nitrogen oxides to N2
what factors determine atmospheric concentrations of primary pollutants?
mixing layer height (volume, higher mixing layer height more dispersal), emissions, advection, deposition, precipitation, gravity, wind, ways of flushing pollutants out of atmosphere, sink process
what affects the depth of the mixing layer?
convection
what determines ozone depletion?
CFCs
what affects secondary pollutants in the atmosphere?
ultraviolet radiation
where does coal originate vs oil?
coal - land vegetation
oil - aquatic organisms
what is the most common fuel in the US?
natural gas
what are considered renewable forms of energy?
biomass, biofuels, wind, solar, hydropower, biomass, geothermal
what country has the highest energy consumption?
china; US has highest per capita energy consumption by region
difference between service economy and industrial economy
industrial burns more FF
what are the conditions for the formation of FF?
lots of organic material available in small area that was cut off from aerobic decay
formation of FF in swamps
submerged organic material had little oxygen and accumulated in layers and trapped sediment as sea levels fluctuated = coal
FF formation in estuaries
dense systems of phytoplankton and zooplankton died and were quickly buried by sediment transported from river systems = oil and gas
what are concerns with coal?
dirtiest for local air pollution, contributes to acid rain from SO2, carbon monoxide, leads to creation of secondary pollutants (H2SO4, combine w NOx, VOCs –> aerosols), most carbon intensive, mines contain radioactive material and mercury, land clearing from surface mining, acidic mine drainage can erode nearby landscapes (soil and bedrock)
primary production/recovery of gas/oil
oil and gas flow up into a well from the internal pressure of the reservoir underground