ess exam chapter 6

what does the atmosphere do?

what does the atmosphere do?

4 vital purposes:

• regulates temperature of planet surface

• protects from harmful solar radiation like ultraviolet - less than 2% of totality of photons coming from sun are deflected

• houses our oxygen and air

• provides environment for biogeochemical cycles - water, (N, C, and S)

what is the atmosphere made of?

78.08% nitrogen (harmless)

20.95% oxygen (keeps us alive - hemoglobin in our lungs grabs into it - we use it for respiration to function)

0.93% argon

0.04% trace gases including carbon dioxide, ozone, and methane

our atmosphere extends more than 120 km above earth’s surface, but over 80% of this gas is found in the first 10 km

atmospheric structure

1. troposphere

2. stratosphere

3. mesosphere

4. thermosphere

troposphere

• the majority of earth’s atmosphere and where all living things reside

• the majority of our planet’s weather occurs here (clouds, wind, rain, snow, etc.)

• the temperature of the troposphere decreases as altitude increases

stratosphere

• a layer of cold, thin air - has few clouds and no storms

• lack of weather is because air’s ability to hold water vapor is lower the colder the air gets

• the temperature of the stratosphere increases slowly with altitude

• increasing temperature is caused by the presence of a warm section within the upper stratosphere, called the ozone layer - mid to upper stratosphere

mesosphere

• as we move away from the ozone layer, temperatures decrease - in the bottom half of the mesosphere, as altitude rises, temperature decreases

• coldest temperature recorded in earth’s atmosphere is -112 degrees

• in the top half of the mesosphere, as altitude increases, temperature increases RAPIDLY

• meteors which enter our atmosphere rarely make it past the mesosphere before burning up

thermosphere

• the “changing sphere”

• the thermosphere is exposed to the full energy of the sun, ionizing particles and making it extremely hot

• record breaking temperatures as high as 1800 degrees F

• there is no clear boundary into space - atmosphere just becomes thinner and thinner until there is just no more gas

temperature inversion

• as altitude increases, temperature rises

• atmospheric condition in which warm air traps cooler air, and any pollutants trapped within the cool air near the earth’s surface - they cannot dissipate

• a person breathing these toxins can become ill

ozone layer

• mid to upper stratosphere

• 15 to 35 km above earth’s surface

• acts as barrier between earth and ultraviolet radiation

• absorbs, stores, and reflects about 98% of solar radiation

• like atmospheric water, the ozone cycle is considered a dynamic equilibrium because ozone is continuously added and removed - in both the formation and destruction of ozone radiation is absorbed

• radiation from sun making oxygen molecule production happen

what has happened to the ozone layer since the mid-1980s?

• gotten thinner

• chlorofluorocarbons (CFCs) when exposed to ultraviolet radiation, break into smaller molecules, including chlorine - chlorine rips apart ozone molecules

• thinned ozone layer above antarctica

• 90% of CFCs were released into atmosphere by industrialized countries in northern hemisphere

where are holes/thin patches most often discovered?

ozone holes - thinning and expanding patch of ozone layer

most often found at the two poles

what do we expect from this issue [montreal protocol] over the next 50 years?

• ozone layer will go back to its natural state

• hole over antarctica will shrink to less than 8 million square miles

greenhouse gasses

• ozone, carbon dioxide, methane, and water vapor are all considered greenhouse gases

• absorb and trap the sun’s radiation, warming our planet

• ever increasing amounts of these substances in our atmosphere, mostly from the burning of fossil fuels, (the result of a fossil fuel addicted society) is a major existential threat for life on this planet

changes in earth’s atmosphere

• the climate of this planet is not consistent or stable and has changed a great deal over geologic time

• this is due to Earth’s complex interaction of abiotic and biotic factors

  • abiotic factors: greenhouse gasses/temperature

  • biotic factors: all living things (human impact, trees)

• oxygen was extremely rare on earth and in no real abundance in earth’s early atmosphere

• 2.33 billion years ago (as of 2016), an organism evolved an amazing method of capturing energy from the sun and turning it into food

• 6CO2 + 6H2O  (light)→  C6H12O6 + 6O2

• early plant life changed our atmosphere, allowing animals lids to breathe oxygen-rich air

where does carbon dioxide come from?

anything that burns (volcanoes, fires/forest fires, animals, burning of fossil fuels)

what is the purpose of a greenhouse and what does it do? and why is the analogy appropriate when talking about the atmosphere?

• to allow more total radiation or energy to enter than to escape

• maintains a controlled environment - provides an environment that is friendly to living things

• atmosphere maintaining a proper temperature and climate on earth's surface

define the greenhouse effect:

“the way in which heat is trapped close to Earth's surface by “greenhouse gasses”; These heat-trapping gasses can be thought of as a blanket wrapped around Earth, keeping the planet toastier than it would be without them”

pollution

gasses, liquids, and solids, present in high enough concentrations to harm humans, animals, and/or the environment

natural sources of air pollution

wind blow dust, volcanic activity, wildfires, hydrocarbons (like CH4) emitted by plants and animals (natural VOCs)

anthropogenic sources of air pollution

stationary sources (industry, agriculture, power generation), mobile sources (automobiles and other forms of fossil fuel powered transportation)

primary air pollutants

enter directly into the atmosphere in a harmful form

[CO, NO2, SO2] - bind more tightly to blood than oxygen, [Particulates, VOCs] - respiratory irritants

secondary air pollutants

harmful form created via chemical reactions with other substances in the atmosphere

ground level ozone, nitric acid, sulfuric acid, smog

criteria pollutants

ground level ozone, suspended particulate matter (SPM), lead, carbon monoxide, sulfur dioxide, nitrogen oxides

• CAA 1963 signed into law by LBJ

• CAA 1970 amended and signed into law by Nixon

• identified 6 pollutants as criteria air pollutants

• continue to be the official indicators of air quality in the US, although many indexes include volatile organic compounds (VOCs)

ground level ozone

“good up high, bad nearby”

colorless and highly reactive gas composed of three oxygen atoms (O3), good ozone is stratospheric and bad ozone is ground level

only secondary pollutant in criteria pollutants

source: created by chemical reactions between VOCs and nitrogen oxides - when chemicals released by industry, transportation, etc. react in presence of sunlight

• concentration depends on:

  • concentration and ratio of nitrogen oxides and VOCs

  • wind speed and direction

  • terrain

  • time of year and temperature (when colder (less molecular movement), ozone more easily created)

health effects: ozone effects breathing by constricting airway muscles and irritating or damaging the airways and lungs; respiratory irritant

environmental effects: high levels of ozone, when ingested by plants, can reduce photosynthesis, growth rate, and resistance to certain diseases or harm from other threats; causes issues with cellular reproduction

• contributes to the smog feedback loop

• agricultural crops are highly sensitive to effects of ground level ozone

suspended particulate matter (SPM)

mixture of solid particles (dust) and liquid vapor particles in the air

can be PM10 (inhalable) or PM2.5 (fine inhalable)

source: can be emitted from construction sites, fires, or industrial smoke stacks as direct sources

• can also form from chemical reactions from pollutants like sulfur dioxide and nitrogen oxides

health effects: articles can be breathed in and ingested into your lungs or bloodstream, and can cause issues such as serious heart problems or reduced lung function

environmental effects: the settling of these particles can result in the acidification of bodies of water, depletion of nutrients in water and soil, and acid rain effect

• reduces visibility by absorbing and scattering light, and acidic components can settle and corrode stone and metal material

lead

naturally occurring element in the environment; nuerotoxin

source: can get into the air through activities like metals processing, the use of leaded fuel, and waste incineration

• we used it for preserving things like paint and gasoline because it wouldn’t break down

• old fashion coal power plants with no filtering systems contribute lead into the atmosphere and environment

health effects: when lead gets into the body, it can get into the bones and blood, and cause problems in the nervous system, cardiovascular system, kidneys, and even the brain

• especially dangerous to young children

• also stays in the body for a long time because it takes a long time to break down and leave the body’s systems

• has negative effects on reproduction

environmental effects: lead is persistent and can get into soils and water sources from pollutant sources of lead - it can decrease growth of plants and have neurological effects on animals

carbon monoxide

gas that is released when things are burned - colorless and odorless

source: biggest source is fossil fuel-burning transportation vehicles

• air quality indoors can also be at risk because old heaters, stoves, furnaces and similar systems can release CO

• a product of incomplete combustion - there's too little oxygen

health effects: if large amounts are breathed in, it bonds to your hemoglobin more strongly than oxygen, therefore limiting your oxygen supply and putting your vital organs at risk 

environmental effects: highly concentrated CO levels would not likely occur outdoors, but animals would be affected similarly to humans - CO is only harmful to plants at extremely high levels

sulfur dioxide (and sulfuric acid)

the most largely present sulfur oxide in the atmosphere

• SO3 can react with H2O to form sulfuric acid, a secondary pollutant which is corrosive 

• SO2 is often used to represent the larger group of sulfur oxides, because most sources of SO2 pollution also release smaller amounts of other sulfur oxides, or can lead to the creation of them

source: largest source of atmospheric sulfur dioxide is industrial burning, especially of fossil fuels, but it can also be released naturally by things like volcanoes and wildfires

• can also react with other atmospheric compounds to create particles that add to SPM pollution in the air

health effects: affects the respiratory system and therefore breathing

environmental effects: high concentrations of sulfur oxides can harm plant growth and foliage as well as produce acid rain (sulfuric acid)

nitrogen oxides (and nitric acid)

nitrogen dioxide, like sulfur dioxide, is an indicator off all the nitrogen oxides in the atmosphere, including nitric acid

nitrogen dioxide is red-brown, other oxides are colorless

source: largest source just comes from all sources of burning fuel - transportation, power plants, etc.

• less than 25% created by stationary sources which combust FF at high temperatures - more than 50% created by mobile transportation sources

• can react with other atmospheric compounds to produce particles and SPM pollution

• reacts with VOCs to produce ground level ozone

health effects: affects and can damage respiratory system, especially with long exposure

environmental effects: can form acid rain which harms ecosystems, and can affect nutrient balance in coastal ecosystems

• corrosive to metals

• has large effect on agricultural crops

volatile organic compounds (VOCs, hydrocarbons)

organic compounds that contain hydrogen and carbon

have “a high vapor pressure and low water solubility” - give off a lot of material

wide range of health effects - irritation to cancer

smog

high density, cloudy/blurry, air resulting from increasing concentration of atmospheric pollutants

industrial smog

consists of SMP pollutants, sulfur and nitrogen oxides, carbon monoxide, and sometimes ozone (“sulfur dioxide, suspended drops of sulfuric acid, suspended solid particles”)

rarely a problem in more developed countries, but is still an issue for currently industrializing countries where old fashioned/unregulated power plants burn FFs and where coal is still common fuel

photochemical smog

consists primarily of ozone pollution - occurs when nitrogen oxides react with VOCs in the presence of sunlight and produce SPM and ground level ozone (“light activated reactions within an airborne mixture of primary and secondary pollutants”);

found in large cities with warm climates - key are nitric oxide and VOCs

increased ground level ozone production despite warm temperature

What is a criteria pollutant? Where does this term come from?

A criteria pollutant is atmospheric pollutant that is an official indicator of air quality in the US. The term was coined in the Clean Air Act.

Name 3 primary pollutants

• Lead

• SPM

• Sulfur dioxide

• Carbon monoxide

• Nitric oxide

• Nitrogen dioxide

Name 3 secondary pollutants

• Ground level ozone (O3)

• HNO3 (nitric acid)

• H2SO4 (sulfuric acid)

• H2O2 (hydrogen peroxide)

distinguish between industrial smog and photochemical fog

• Industrial smog consists of sulfur dioxide, suspended drops of sulfuric acid, SPM, while photochemical smog is primarily consisting of ozone pollution produced by light activated reactions within an airborne mixture of primary and secondary pollutants - occurs when nitrogen oxides react with VOCs in the presence of sunlight and produce SPM and ground level ozone

• Industrial smog is rarely a problem in more developed countries, but is still an issue for currently industrializing countries where old fashioned/unregulated power plants burn FFs and where coal is still common fuel, while photochemical smog is a greater issue in large cities with warm climates.

2016 Kigali amendment

countries committed to cut the production and consumption of HFCs by more than 80 percent over the next 30 years

protocol successful

• had specific goal and combated the target of that goal

• acted extremely fast on the problem

• the most effective international climate treaty ever made

• 250 million cases of cancer have been averted

• almost completely phased out CFC production

• 2016 Kigali amendment - changes have been considered

protocol failure

• pesticide from methyl bromides, moving away from DDT - basically acts like CFCs

• nitrous oxide from fossil fuels and chemical production - largest ODS now, as well as third important greenhouse gas - will undermine effects of treaty

• global warming makes recovery slower - build up of greenhouse gasses prevent radiation from warming up the stratosphere

• have to make significant change to reach goal and make significant recovery of the ozone layer - based off of pattern of climate policy, this will not likely happen

protocol not enough time

• chemicals highly persistent - takes a while to break down over decades

• CFC production has not ceased completely

• have to be sure to say it’s a success

• HFC production - still extremely destructive like CFCs

  • hydroxyl production

• not every signatory does monitoring - protocol itself does not monitor

What does the catalytic converter on your car do and how does it work?

• uses chemical reactions to split harmful molecules in the gas exhaust produced by a car, before releasing the exhaust into the atmosphere

• within the catalyst, there are metal linings that cause both reduction and oxidation reactions when the engine emissions are blown through it

• nitrogen oxides are split into nitrogen and oxygen, and oxygen is added to carbon monoxide to release carbon dioxide

how would you classify CO2 (primary vs. secondary)?

primary pollutant due to it being lethal if it was the only thing breathed in and the excessive output of it is detrimental