S2008 Chem Final

Front 1

the primary pollutants

Back 1

CO

NO

RH (hydrocarbons)

Front 2

RH =

Back 2

hydrocarbon

Front 3

the secondary pollutants

Back 3

NO2

O3

PAN

Front 4

SMOG REACTIONS

Back 4

CO + OH --> CO2 + H

H + O2 --> HO2

HO2 + NO --> NO2 + OH

NO2 + sun --> NO + O

O + O2 --> O3
-----------------------------

NET: CO + 2O2 --> CO2 + O3

Front 5

ozone hole occurs..

Back 5

antarctica

spring

(IE OCTOBER)

Front 6

ozone hole occurs @ what km

Back 6

15 - 20 km


antarctica/ spring/ (october)

Front 7

theories for ozone hole

Back 7

1- solar maximum

2- dynamics theory

3- chlorine from man-made CFCs

Front 8

SOLAR MAXIMUM

theory for ozone hole

Back 8

increase in solar activity raised NOx and destroyed more O3

Front 9

DYNAMICS THEORY

theory for ozone hole

Back 9

O3 poor air was transported into the polar vortex

Front 10

CHLORINE FROM MAN-MADE CFCs

theory for ozone hole

Back 10

increased Cl in polar stratosphere was causing O3 destruction

--missions found enhanced Cl and low NOx... proving theory is
***CORRECT***

Front 11

original Cl destruction cycle couldn't explain when/where hole was forming

--needed new mechanism:

Back 11

LOW O means that ClO reacts with
ANOTHER ClO
to regenerate Cl

Front 12

reservoir species for Cl

Back 12

reservoir species keep it from destroying O3

ClONO2 and HCl

**when NOx is high ClO reacts to form ClONO2
(= Cl DOESN't DESTROY ozone)

Front 13

PSCs Form

Back 13

low temp

in Antarctic Vortex

Front 14

PSCs ARE:

Back 14

water ice clouds

surfaces help ACTIVATE Cl

*ClONO2 + HCl --> HNO3 + Cl2

Cl2 destroys O3
HNO3 is rained out in clouds (which prvents more ClONO2 from forming)

Front 15

polar vortex importance for O3 loss

Back 15

circular winds over pole during winter (COLD)
isolates air and keeps new ozone from coming in

Front 16

ingredients for ozone hole

Back 16

Cl

Sunlight

PSCs (cold temps)

Front 17

ozone hole in arctic

Back 17

not as bad due to warmer winter temps

& weaker vortex

Front 18

CFCs replaced with

Back 18

HCFCs

H allows them to react with OH

Front 19

Bromine
v
Chlorine

Back 19

Bromine is WORSE than chlorine

(but less of it)

Front 20

order of ozone destruction power

Back 20

F << Cl < Br < I

Front 21

main source of Br

Back 21

CH3Br
methyl bromide

pesticide for strawberry plants

Front 22

global ozone loss comes from

Back 22

sulfuric acid particles

-- which are everywhere

(similar to PSC catalyst)

Front 23

photochemcial smog
from

Back 23

cars + sun

Front 24

primary pollutants
(definition)

Back 24

DIRECTLY emitted


(CO, NO, RH)

Front 25

secondary pollutants
(definition)

Back 25

formed from primary

(NO2, O3, PAN)

Front 26

CO comes from

Back 26

incomplete combustion

Front 27

CO properties

Back 27

peaks at rush hour

worse in winter

Front 28

CO is reduced by

Back 28

adding more oxygen to fuel

(ie ethanol, MTBE..)

BUT ^ this can increase O3 production
(or add toxic chems to the enviro)

Front 29

NO properties

Back 29

comes from engines

currently isn't regulated

when no RH present - reacts with O3 and destroys it

Front 30

NO when no RH present

Back 30

reacts with O3 and destroys it

Front 31

regulations of smog are meant to

Back 31

reduce O3

Front 32

O3 properties

Back 32

strong oxidant

harmful to people / plants / materials

peaks in afternoon

worse in summer

Front 33

why O3 peaks in afternoon

Back 33

needs sun

needs primary pollutants

needs time

Front 34

why O3 worse in summer

Back 34

more sun

Front 35

O3 forms from different reaction mechanisms

Back 35

1. CO and NO cycle

2. RH and NO cycle
("ozone engine")

Front 36

ozone "engine"

Back 36

RH and NO cycle

makes most of ozone

SO hydrocarbons are regulated

Front 37

which cycles makes most of ozone?

Back 37

RH and NO cycle

Front 38

regulations of RH

Back 38

help in urban

not in rural

-- rural areas have many more trees - huge natural source of hydrocarbons

Front 39

denver brown cloud

Back 39

colorado has visibility problem with pollution

95% from particles

Front 40

particles forming the denver brown cloud

Back 40

soot -- primary particle emitted

NH4NO3 & (NH4)2SO4 -- secondary particles
... Formed from
cars (NO --> HNO3)

cows (NH3)

Front 41

how NH4NO3 and (NH4)2SO4
(secondary particles of denver brown cloud)
are formed

Back 41

from cars: NO --> HNO3

cows: NH3

Front 42

NO2 component of denver brown cloud

Back 42

can reduce visibility 5%

NO2 is BROWN

photolyzed by visible light

Front 43

pollutants of photochemical smog

Back 43

primary: CO, NO, & RH

secondary: NO2, O3, PAN

Front 44

main source of CO to atmosphere

Back 44

cars

Front 45

when / where are CO concentrations highest

Back 45

peaks at rush hour
@ location of emissions

Front 46

how oxy-fuels meant to lower CO concentration

Back 46

they contain oxygen

sooo help burn the fuel to CO2 (not CO)

Front 47

3 oxy-fuels

Back 47

methanol

ethanol

MTBE

Front 48

MTBE as oxy-fuel

Back 48

MTBE is toxic

possibly carcinogenic

--has shown up in h2o supplies

**have been efforts to phase out / ban MTBE's bc harmful to enviro

Front 49

methanol / ethanol as oxy-fuel

Back 49

tend to increase formaldehyde emissions

could lead to increased ozone

Front 50

dillemma with oxy-fuels

Back 50

can decrease CO

but increase ozone

Front 51

ozone engine
reactions

Back 51

RH + OH --> R + H2O

R + O2 --> RO2

RO2 + NO --> RO + NO2

NO2 + light --> NO + O

O + O2 --> O3

Front 52

the only way to make O atoms

Back 52

make O

then O will combine with O2 forming O3

Front 53

photolysis of NO2

Back 53

ie light + NO2

makes oxygen atoms!!!

(so can make O3)

Front 54

oxydation of hydrocarbons

Back 54

ie RH + OH --> R + H2O
R + O2 --> RO2

makes RO2 which can react with NO to form NO2

Front 55

in the ozone engine

NO2...

Back 55

is NOT used up

it cycles between two forms
NO and NO2

each time it cycles a new molecule of ozone is made

Front 56

when / where do ozone concentrations peak

Back 56

afternoon

downwind site of emissions

Front 57

what chem form are oxides of N emitted to atmosphere
in auto exhaust

Back 57

NO

(and is converted to NO2 in atmosphere)

Front 58

how does PAN (and related compounds) export nitrogen oxides to rural areas

Back 58

PAN is long lived (so can be transported out of urban areas)

when PAN decomposes it releases NO2

then the ozone engine can produce ozone when NO2 reacts with RH

(PAN decomposes and releases NO2
NO2 reacts with RH from trees, forming OZONE)

Front 59

in SouthEast US would you rather eliminate
RH or NOx emissions from cars

Back 59

NOx

bc 1/2 RH are from natural sources (trees)
so even 100% elimination of RH from cars wouldn't eliminate RH

Front 60

what atmospheric species most responsible for initiating reaction of pollutants (CO and RH)

Back 60

OH

Front 61

source of OH radicals in atmosphere

Back 61

O3 + UV --> O + O2
(O = oxygen atom with extra energy)

O + H2O --> 2OH

Front 62

main cause of denver brown cloud

Back 62

particles

soot

ammonium nitrate

ammonium sulfate

(brown gas, NO2 contributes to 5% of visibility reduction

Front 63

Denver / Boulder meeting federal CO and O3 standards

Back 63

MEETING CO standard

NOT meeting O3 standard

Front 64

what species in atmosphere causes reduced visibility

when does region suffer from worst visibility

Back 64

particles

winter - due to winter temp inversions

(metro area experiences poor visibility yr round)

Front 65

chapman mechanism

Back 65

O2 + UV --> O + O

O2 + O --> O3

O3 + light --> O + O2

O + O3 --> 2O2

Front 66

natural source of oxides of N to stratosphere

Back 66

N2O from bacteria

Front 67

time of yr / location of ozone hole

Back 67

spring

sourthern polar stratosphere

Front 68

ingredients for massive polar ozone loss

Back 68

Cl in atmosphere

low temps (form clouds)

light (for photochemistry)

Front 69

role of PSCs in ozone depletion

Back 69

heterogeneous reactions on PSCs convert
inert reservoir chlorine
to
photochemically active chlorine

Front 70

reaction that occurs on PSCs

Back 70

ClONO2 + HCl --> Cl2 + HNO3

Front 71

theory for global ozone loss involving H2SO4 aerosols

Back 71

heterogeneous chemistry (like ClONO2 + HCl --> Cl2 + HNO3 reaction)
may also occur on global sulfate aerosols

SO increases in Cl and sulfate aerosols can partially explain ozone losses

Front 72

how does H2SO4 get into stratosphere

Back 72

1- major volcanic eruptions

2- releases of longlived sulfur gases (like OCS)

Front 73

primary pollutants peak at

Back 73

7AM

Front 74

secondary pollutants peak

Back 74

downwind .. 1 PM

Front 75

CO peaks in (season)

Back 75

winter

.. cars don't run as well in winter
and smaller space

Front 76

ozone forceful oxidant due to

Back 76

extra O

Front 77

PAN

Back 77

eye irritant

O3 + RH + NO -sun-> PAN

PAN -UV-heat-> NO2
(PAN destroyed by UV / warm weather)

*creates ozone even if no pollution (travel to rural areas where natural RH)

Front 78

natural source of RH

Back 78

trees

Front 79

SMOG

morning / midday / later

Back 79

MORNING:
NO
CO
RH

MIDDAY:
NO2
CO
HC

LATER:
O3
CO
PAN
Haze

Front 80

colorado worries about

Back 80

CO

NO

Haze

Front 81

colorado has _ problem in past

Back 81

CO

partially due to cold temps / cars run inefficiently

**OXY-FUELS brought CO down**

Front 82

CO from incomplete combustion

v complete combustion

Back 82

2C + O2 --> 2CO

complete:
C + O2 --> CO2
****enough oxygen****

Front 83

formula for fuel

Back 83

octane

C8H18

Front 84

most commonly used oxy-fuel

Back 84

ethanol

Front 85

methanol as oxyfuel makes

Back 85

CH2O
and a ton of ozone

Front 86

MTBE decreases / increases

Back 86

decreases CO

increases NO

INCREASES OZONE

Front 87

only place that still has CO problem

Back 87

S. Cali

Front 88

only 1 gas contributes to decreased visibility

Back 88

NO2

(bc its brown)

Front 89

particles decreasing visibility

(primary or secondary?)

Back 89

soot = 1

NH4NO3 = 2

(NH4)2SO4 = 2

Front 90

active chlorine is

Back 90

radical

Front 91

2 main reservoir species for Cl in strat

Back 91

ClONO2

HCl

*don't react together in gas phase*

Front 92

ClONO2

HCl

Back 92

reservoir species for Cl

don't react in gas phase

only react on ICE particles
ClONO2 + HCl --> Cl2 + HNO3

HNO3 (nitric acid) stays on cloud particles

*clouds shift Cl out of reservoir phase into active phase

Front 93

Antarctic
v
Arctic

Back 93

Antarctic
land surrounded by ice / ocean
= GOOD VORTEX

Arctic:
Ice surrounded by land
-can't make strong vortex
-not as cold

Front 94

_ catalyzes Cl activation reaction

Back 94

PSCs

Front 95

HCl
HBr
HI

Back 95

HCl (holding hands)
easily parted - Cl destroys O3

HBr (barely touching)
Br readily destroyed O3

HI (not touching)
I always ready to destroy O3

Front 96

PSCs also form in

Back 96

Northern Winter

Front 97

Arctic Ozone

Back 97

similar trend


but less O3 loss

Front 98

Arctic Ozone in 2070

Back 98

lower levels of CFCs

Colder temps due to GHGs

LARGE OZONE LOSS even w lower Cl

Denitrification on large PSCs (NAT) has big effect

Front 99

sulfuric acid particles in atmosphere

Back 99

come from sulfur reactions in atmosphere

sulfur is from:
- OCS (natural in ocean)
- S in fuel
- S from volcanos

Front 100

MTBEs in US

Back 100

phased out in 2005

use exemptions increased since 2003

US now responsible for 40% of global MTBE

Front 101

how many countries have enough fissionable material to make at least 1 nuclear weapon

Back 101

40

Front 102

fissionable solids present at nuclear power plants

Back 102

U and Pu

Front 103

size of current nuc weapons

Back 103

can be carried by a few ppl

Front 104

majority of smoke comes from after nuc weapon dropped in urban area

Back 104

burning buildings

Front 105

albedo of smoke

Back 105

near 0

Front 106

smoke alters temp at earth's surface

Back 106

lowers temp

Front 107

pause in increased global temp in 70s 80s (global dimming) due to

Back 107

particle pollution

Front 108

ozone loss following nuclear occurs bc

Back 108

faster O3 loss in strat bc of high temps

Front 109

rising smoke from nuclear bomb carries GAS leading to ozone loss

Back 109

N2o

Front 110

if india pakistan nuc war what parts earth experience ozone loss

Back 110

all areas of globe except tropics

Front 111

if solar maximum caused ozone hole what species would be elevated during ozone hole

Back 111

NO

Front 112

PSCs are made of

Back 112

H2O

Front 113

ClONO2 reacts w/ what on PSCs

Back 113

HCl

Front 114

HCl
HI
HF
HBr
STRONGEST BOND?

Back 114

HF

Front 115

coldest stratospheric temps

antarctic summer
or
arctic winter

Back 115

ARCTIC WINTER

Front 116

sulfuric acid + sugar = what color?

Back 116

black

Front 117

polar vortex stronger in

Back 117

ANTARCTIC

Front 118

allotropes

Back 118

two different forms of the same element

(O2 and O3)

Front 119

O2 molecule split to O

Back 119

O2 + UV => O

highly reactive .. diffuse down to strat and react with O2 / forming O3

Front 120

thinkness of ozone layer varies with

Back 120

latitude

season

Front 121

more clouds containing ice occur in antarctic when?

Back 121

antarctic winter

(JUNE - AUGUST)

thus ozone levels decrease

Front 122

CFC reaction to destroy ozone

Back 122

CF2Cl2 + UV --> CF2Cl + Cl

Cl + O3 --> ClO + O2

ClO + O --> Cl + O2

Front 123

HFC's

Back 123

break down before reaching strat

Front 124

ice caps melting not problem?

Back 124

water expands when warms neway

Front 125

atmosphere divided based on

Back 125

temp

Front 126

troposphere contains __ mass of atmosphere

Back 126

90%

Front 127

troposphere air mixed

Back 127

vertically

so gasses released on earth = MIXED WELL

rises, expands (less pressure), cools (bc expanded)

if new temp is higher than the surrounding air - will continue to rise (unstable air)
..
if new temp is lower than surrounding air.. balloon descends to original position (stable air)

Front 128

why does stratosphere temp increase with alt

Back 128

bc of absorption of light energy by ozone

Front 129

strat = giant inversion layer

Back 129

warm air above cold air

Front 130

actual amt of ozone is stratosphere

Back 130

small!

Front 131

chemical comp of strat
v
trop

Back 131

water concentration lower
bc water condenses in trop clouds and rains out

only few clouds in strat

Front 132

molecules released on earth don't reach strat

Back 132

bc water soluble ... and return to surface in rain or are broken down by chem reactions

HCl and NaCl,
hydrocarbons

Front 133

*only molecules that reach strat are

Back 133

insoluble and unreactive

N2O

OCS

CH4

CFCs

and halons (C based molecules containing Br

**once reach strat they absorb UV and break apart

Front 134

photolysis

Back 134

aka photochemical reactions

when molecules absorb light and break apart

Front 135

UV-C

Back 135

200-280 nm

most damaging to DNA

absorbed by O2 and O3

Front 136

UV-B

Back 136

280 - 320 nm

damaging to DNA

sensitive to O3 changes

Front 137

UV-A

Back 137

320-400 nm

sundan region

least DNA damage

Front 138

visible light

Back 138

400-700 nm

seen w eye

Front 139

ozone absorbs radiation between nm and nm

Back 139

200 - 300 nm

Front 140

NOx ozone destruction

Back 140

catalytic cycle
doesn't use up any NOx -- can keep going!

NO + O3 --> NO2 + O2
O + NO2 --> NO + O2

NET: O + O3 --> 2 O2

Front 141

NOx natural source

Back 141

N2O by bacteria
and micro organisms in ocean

Front 142

NOx anthro source

Back 142

N2O from fertilization

Front 143

Cl catalytic ozone cycle

Back 143

Cl + O3 --> ClO +O2
O + ClO--> Cl + O2

O + O3 --> 2O2


eventually Cl atoms react with CH4 to form HCl .. temporarily ending Ozone destruction cycle

Front 144

main source of Cl oxides

Back 144

Cl + Cl0 (= ClOx)

Front 145

air entering strat from trop

Back 145

air rises thru tropical tropospause...
enters strat

then spread to N and S strat

Front 146

PSCs

Back 146

bc little water vapor reaches strat temps must be VERY COLD to form ice on clouds
*IN WINTER*

may contain water ice particles or
crystals of HNO3 and ice
(form at slightly higher temps)
**more common and form every winter above both poles**

Front 147

polar vortex importance for ozone depletion

Back 147

forms each winter above antarctica

isolates strat air

allows air to become colder in winter

reduces flux of ozone rich air from tropics

**breaks down in late spring / early summer.. allowing ozone from lower latitudes to fill hole

Front 148

why no ozone hole over arctic?

Back 148

warmer over arctic
temps only occasionally low enough

more nitric acid / ice PSCs form than pure ice

^^ not as affective at removing nitric acid from stratosphere