Midterm 1 - Notes

Front 1

Environmental Chemistry (definition)

Back 1

Looking at the chemistry (both the processes and species) that contribute to our environment as we know it.

Front 2

"Sustainable" (definition)

Back 2

The industrial progress that meets the needs of the present without compromising the ability of future generations to meet their own needs.

Front 3

Industrial waste in the past (3 ways):

Back 3

1. Dumped on the ground

2. Drained into rivers

3. Up the smoke stack

Front 4

5 things we will focus on (spheres):

Back 4

1. Atmosphere - Air - 1st defense against the sun/high transport area.

2. Hydrosphere - Water - Interaction w/ atm and geosphere. High transport.

3. Geosphere - Soil and Rocks - Low transport

4. Biosphere - Life

5. Anthrosphere - Technology - Most recently defined/what we do that affects the env.

Front 5

Ecology (definition)

Back 5

The science that deals with the relationships between living organisms and their physical env.

Front 6

Pollution -- Pollutant (definition)

Back 6

Substance present in greater than natural quantities as a result of human activities that has a net detrimental effect upon its env.

** All pollutants are contaminants **

Front 7

Contaminant (definition)

Back 7

Causes deviation from normal composition of an environment.

Front 8

Definitions:

Source

Receptor

Sink

Back 8

- Origin of pollutant (ex: factory)

- Anything affected by the pollutant (ex: atm)

- Long time repository for a pollutant (ex: ground)

Front 9

Physical transport (examples)

Back 9

River flow, wind, land slide, animals, runoff, precipitation, convection

Front 10

Chemical pathways (examples)

Back 10

Biological uptake, surface chemistry, decomposition

Front 11

Mass Balance (definition)

Back 11

Matter can neither be created, nor destroyed, only changed.

Front 12

The atmosphere (definition)

Back 12

A layer of gases that surrounds our planet

N, O, Ar, CO2, Ne, He, CH4, Kr, N2O, H2, Xe, SO2, O3, NO2, H2O, etc.

78% N2 0.9% Ar

21% O2 0.04% CO2

Front 13

Components of Atmosphere (4 layers)

Back 13

1. Troposphere -- 15km

2. Stratosphere -- 50 km

3. Mesosphere -- 85 km

4. Thermosphere (ionosphere) -- 500 km

Front 14

What is bad in the atm today:

Hydrocarbons:

Back 14

1. Global warming (CO2, CH4)

2. Acid Rain (SO2, NO)

3. Acid Rain and Smog (NO2)

5. Health Hazards (CO)

- CH4, C2H6

Front 15

Definitions:

Meteorology

Weather

Climate

Humidity

Relative Humidity

Back 15

- The study of air movement & phenomena

- Short term variations in the state of the atmosphere

- Localized long term variation in the atm

- Vapor content in the air

- % max H2O the air can hold at a given temp

Front 16

Dew Point

Back 16

The temperature at which water starts condensing.

Front 17

Inorganic Oxides

Oxidants

Reductants

Organics

Photochemically active species

Acids

Bases

Salts

Unstable intermediates

Back 17

- CO, CO2, NO2, SO2...

- O3, H2O2, HO', ROO', NO3

- CO, SO2, H2S

- CH4, CnH2n+2, CnH2...

- NO2, CH2O

- HNO3, H2SO4

- NH2

- (NH4)2SO4, NH4SO4

- NO2*, OH'

Front 18

3 Types of reactive things in atm:

Back 18

1. Electronically excited species (*)

2. Ions (+/-) (more cations in atm b/c of sun)

3. Radicals (')

Front 19

5 types of light waves:

Back 19

1. UV = (200-400nm) Break bonds, ionize, electronic excitation

2. Vis = (400-700nm) Breaking bonds, electronic excitations

3. IR = (700-10,000nm) Vibrations, rotations (heat, causes movement)

4. Microwaves = (10,000nm)Rotations (spins molecules to create energy)

5. X-rays/Cosmic rays = (>200nm) Break bonds, ionize

Front 20

Organic

Inorganic

Back 20

- Carbon based/life, PAHs

- Everything else (metals, NOx, SO2, CO2)

Front 21

What we have done to make particles:

Back 21

1. Coal combustion - Chemical combustion/physical grinding, mulling, etc.

2. Sulfates, Nitrates - Industry, automobiles

3. Generation of aerosols - Smaller = worse

Front 22

Aerosol (definition)

Back 22

Colloidal-sized (not just one, a collection) atmospheric particle

Front 23

Definitions:

Fog

Haze

Smog

Mist

Smoke

Back 23

- Increased H2O

- Decreased visibility due to particles

- A photochemically oxidizing atmosphere

- Liquid particles

- Incomplete combustion

Front 24

CO

Back 24

- 0.1 ppm, 2/3 comes from CH4 + O2 -- COH2, 20% from degradation of chlorophyls, 6% from humans

- 50-100 ppm in urban areas

- Above 70 ppm is hazardous

- Can prevent by increasing air/fuel, which produces more CO2 instead

- In atm: CO + HO' -- CO2 + H

H + O2 + M -- HOO' + M

- Soil micro can consume CO -- CO2

Front 25

SO2

Back 25

- Sulfur can also exist in atm as H2S, SO3, (CH3)2S, sulfates

- Primary source is fossil fuels (pyrite in coal)

SO2 -- SO4,2- or H2SO4

- Photochemically inert in troposphere (wavelength of light not sufficient)

- Contributes to smog (hydrocarbons + NOx + UV light -- oxidation of SO2 to SO3 and SO4

- [SO2] > 1ppm can be harmful, occurs in urban areas and valleys

Front 26

SO2 (continued)

Back 26

- Can harm plants when dissolved in soil

- Acid rain - damage to buildings & structures

- Can trap SO2 by oxidizing to SO4,-2 and trap with Ca/Mg to make a salt (gas phase)

- Liquid phase - make acid

Front 27

Nitrogen

Back 27

- N2O, NO, NO2, NO3' -- All contribute to smog, acid rain and ozone depletion

Front 28

N2O

Back 28

- Not very reactive

N2O + O -- N2 + O2 or 2 NO

O3 + hv -- O2 + O (rxn reverses at night)

- Ozone depletion when O reacts with N2O instead

Front 29

NO and NO2 - NOx

Back 29

- Sources: Biological, lightning, cars

- NO + O3 -- NO2 + O2 (depletes ozone)

- Makes Smog:

2NO2 + O -- N2O5

N2O5 + H2O -- 2HNO3

HO' + NO2 - HNO3

- NO2 - health impacts - inflamed lungs, death

Front 30

Prevention

Back 30

1. Modify conditions to limit production

- Decrease O2, lower T

2. Treat exhaust to remove NOx

- Biofilters?

Front 31

NH3

Back 31

- Base: NH3 + HNO3 -- NH4NO3

- React with acid to produce corrosive salts

Front 32

F, Cl

Back 32

- HF and F2 used in aluminum manufacturing

- Highly toxic to humans

- Make radicals that attack ozone

- SF6 - Greenhouse gas 23,900x worse than CO2

Front 33

H2S

Back 33

- Looks like H2O

- Oxidizes quickly to SO2

- Very harmful to humans

- Common source = natural gas wells ("sour")

- Aids in oxidation of other substances

Front 34

What have we done to mitigate particles?

Back 34

- Fabric filter

- Settling (tall smoke stacks)

- Inertia - ex: centrifuge (set up spiral air motion, so they are trapped on the walls)

- Electrostatic filter

- Scrubbers

Front 35

Direct vs Indirect effects

Back 35

- Cancer vs. smog, O3 decrease, etc.

Front 36

3 types of hydrocarbons

Back 36

- Alkanes - CnH2n+2

- Alkenes =

- Alkynes - triple bond

Can enter the atmosphere directly, or as a byproduct of incomplete combustion (unsaturated/more reactive)

Front 37

Things that can attack double bonds and make chemistry happen

Back 37

OH', O2, NO, NO2

Front 38

Chromophores

Back 38

- A part of a molecule that absorbs light

Front 39

Alcohols

Phenols

Ethers

Carboxylic Acids

Back 39

- CH3OH, C2H5OH -- Are either absorbed or reacting w/ HO'

- Dissolve in H2O, react with OH'

- Gas additives - Oxidize into carbonyls

- Water soluble + precipitate

Front 40

Amine

Amide

Nitrile

Halides/Organohalides

Back 40

- Bases, smell of rotten fish, H bonding, decrease vapor pressure

- Similar to carbonyl chemistry

- Rubber production

- Has F, Cl, Br, I attached - Manufacturing and biological sources (ocean)

Front 41

Smog (definition)

Back 41

- Photochemically oxidizing atmosphere

- Large conc. of oxidants

- >0.15ppm oxidants that persist for 1hr+

- Hydrocarbons + UV light + NOx

Front 42

Harmful effects of Smog

Back 42

1. Human Health

2. Atmospheric changes

3. Plant life (acid rain)

4. Corrosion/damage to materials