E10 Smog Hl

Front 1

What are the two types of smog?

Back 1

photochemical and reducing Smog

Front 2

The term smog comes from the words...

Back 2

smoke and fog

Front 3

What are the characteristic of contaminated air

Back 3

Yellow/brown color

Front 4

What does photochemical smog consists of

Back 4

mixture of secondary pollutant chemicals, air and water

Front 5

Where is reducing smog found?

Back 5

In coal burning cities with cold, wet winters, where thermal inversion can trap cold, still air close to the Earth's surface.

Front 6

Where do the primary pollutants for smog come from?

Back 6

internal combustion engines-automobiles

Front 7

What are the prefect conditions for smog to form

Back 7

bowl shaped cities (lack of wind) and high density of population (lot's of combustion engines)

Front 8

What is thermal inversion

Back 8

The abnormal temperature arrangement of air masses

Front 9

What are the primary sources of smog?

Back 9

VOCs, NOx (especially NO)

Front 10

How many types of smog exist? Name them.

Back 10

2, reducing smog and photochemical smog

Front 11

Desribe photochemical smog

Back 11

When a layer of warm air acts like a lid on the cold air which traps pollutants

Front 12

is photochemical smog oxidizing or reducing?

Back 12

oxidizing

Front 13

What effect does wind have on smog?

Back 13

under normal circumstance wind disperses the smog forming chemicals and smoke. without wind these pollutants collect and begin to form smog with the help of thermal inversion

Front 14

Which conditions are optimal for thermal inversion?

Back 14

windlessness, bowl-shaped cities, warm, dry and cloudless skies, as the UV light can easily reach the Earth

Front 15

What is necesary for the reactions in photochemical smog???

Back 15

UV light from the sun

Front 16

Where does smog occur?

Back 16

Smog typically occurs where there is temperature inversion

Front 17

When do pariculates, VOCs and NO peak and why?

Back 17

In the morning rush hours because they come from the car's engine

Front 18

Name one environmental condition that can promote photochemical smog

Back 18

Therma/temperature inversion

Front 19

Termination of proxide and nitrogen dioxide free radicals

Back 19

ROO• + •NO2 --> ROONO2

Front 20

What is thermal inversion?

Back 20

Thermal inversion is the increase in temperature in a layer of warm, still air, between the cold/clean air (higher altitudes) and the cold/polluted air (lower altitudes)

Front 21

Free radical produced when photochemical oxidants oxidise VOCs

Back 21

ROO• , a peroxide free radical

Front 22

What is it called when a layer of warmer air is trapped between two layers of colder air?

Back 22

Thermal inversion

Front 23

Stages of smog during the day

Back 23

1. release of VOC's, NOx 2.Increase in NO concentration and its oxidation to brown NO2 3. this dissociates with sun radiation into NO+•O 4. free radical O initiates reactions to form secondary pollutants 5. Photochemical oxidants oxidize VOC's to form secondary pollutants.

Front 24

What are PAN's?

Back 24

Peroaxyacyl nitrates

Front 25

What happens during early morning hours with with hydrocarbons and NOx

Back 25

N2+O2 --> NO2+N NO2+UV -->NO+N

Front 26

What is the propagation of free radicals?

Back 26

One free radical is used up but another is formed

Front 27

Oxidisation of NO

Back 27

Either 2NO+O2-->2NO2 or NO+O3-->NO2+O2

Front 28

What is the role of VOCs and particulates during formation of secondary pollutants?

Back 28

They act as catalysts and reactants in the formation of secondary pollutants.

Front 29

When does termination of free radicals take place?

Back 29

When two free radicals combine

Front 30

What are some secondary pollutants formed in photochemical smog?

Back 30

ozone, hydroxyl free radicals, aldehydes, peroxacyl nitrates (PANs)

Front 31

equation for formation of nitrogen oxide, from N2 and oxygen

Back 31

N2 + O2 --> 2NO

Front 32

Formation of hydroxide radicals

Back 32

O• + H2O --> 2OH•

Front 33

Formation of low altitude ozone

Back 33

O• + O2 --> O3

Front 34

Formation of nitric acid is the atmosphere

Back 34

OH• + NO2 --> HNO3

Front 35

What can ozone and hydroxyl free radicals do?

Back 35

act as photochemical oxidants

Front 36

Reaction to form brown NO2

Back 36

2NO+O2--->2NO2 or NO+O3--->NO2+O2

Front 37

Formation of peroxide radical

Back 37

ROO•

Front 38

Formation of PANs

Back 38

ROO• + NO2 --> ROONO2

Front 39

Formation of peroxides, aldehydes and ketones.

Back 39

OH• + RH --> R• + H2O