Air Pollution

Question 1

characteristics of NOx

Answer 1

NO + NO2, forms ozone

Question 2

characteristics of O3

Answer 2

colourless + odourless, main component in smog

Question 3

what is combustion?

Answer 3

the burning of a substance in the presence of oxygen

Question 4

what happens with complete combustion?

Answer 4

carbon dioxide + water produced

Question 5

what happens with incomplete combustion?

Answer 5

carbon dioxide, water, and unwanted by-products produced

Question 6

combustion of coal

Answer 6

CO, NOx, SO2, PM2.5, heat

Question 7

what is fuel NOx?

Answer 7

reaction of oxygen with nitrogen in fuel

Question 8

what are the main culprits in smog formation?

Answer 8

NOx and VOCs

Question 9

sources of VOCs (3)

Answer 9

combustion - vehicles, construction
non-combustion - power plants, gas stations
natural - trees and plants

Question 10

formula for formation of ground-level ozone

Answer 10

NOx + VOCs + sunlight = O3, PM, organics (secondary pollutants)

Question 11

what pollutants are lung irritants and cause inflammation in the lungs?

Answer 11

NOx and O3

Question 12

what do catalytic converters do?

Answer 12

reduce CO and NOx

Question 13

when and where does the ozone hole appear?

Answer 13

Antarctica, every southern hemisphere spring (Sept-Nov)

Question 14

qualities of UV-B

Answer 14

medium energy, reaches surface a medium amount, responsible for short-term, partially absorbed by ozone

Question 15

qualities of UV-C

Answer 15

highest energy, doesn’t reach the earth’s surface, most dangerous, absorbed by compounds (mainly oxygen)

Question 16

what does ozone protect from?

Answer 16

UV-C radiation (completely) and UV-B radiation (partially)

Question 17

what was destroying stratospheric ozone? why?

Answer 17

CFCs and Halons, contain chlorine and bromine respectively

Question 18

what were CFCs introduced to the market as?

Answer 18

Freon

Question 19

how do CFCs destroy ozone? (explanation)

Answer 19

when CFC molecules are in the stratosphere, they react with UV light and break apart to release chlorine. this chlorine breaks ozone apart

Question 20

how do Halons destroy ozone? (explanation)

Answer 20

when Halon molecules are in the stratosphere, they react with UV light and break apart to release bromine. this bromine breaks ozone apart

Question 21

why is the ozone hole only in antarctica?

Answer 21

pollutants travel to the north and south poles, and artarctica is the only place cold enough for PSCs (polar stratospheric clouds) which contain ice crystals and act as a surface for ozone depleting reactions to occur

Question 22

what is another source of ozone depletion? how?

Answer 22

volcanoes - some eruptions are violent enough to spew particles and gases into the stratosphere. like PSCs, this provides a surface for ozone-destroying reactions to occur

Question 23

what do greenhouse gases do?

Answer 23

they absorb and re-emit thermal infrared radiation

Question 24

define back radiation

Answer 24

IR being pushed back to the surface

Question 25

is the greenhouse effect natural?

Answer 25

yes, it's natural and essential for human survival

Question 26

define anthropogenic global warming

Answer 26

increase in earth's temperature above what's from the natural greenhouse effect from human emissions

Question 27

how are ozone and greenhouse gases different?

Answer 27

ozone prevents harmful UV rays from reaching the surface whereas greenhouse gases keep IR from leaving

Question 28

greenhouse gases (most-least important) + aerosal

Answer 28

carbon dioxide, methane, nitrous oxide + black carbon

Question 29

does carbon dioxide absorb IR radiation better?

Answer 29

no, there's just more of it present, making it the most important greenhouse gas

Question 30

how much of current warming experienced on earth is due to CO2?

Answer 30

75%

Question 31

main source of CO2 and %

Answer 31

fossil fuel combustion, 80%

Question 32

fossil fuels that emit CO2 (highest-lowest emissions)

Answer 32

coal > gasoline > natural gas

Question 33

2nd largest source of anthropogenic CO2

Answer 33

deforestation

Question 34

why is deforestation a source of CO2 emissions?

Answer 34

trees store carbon so cutting them down releases CO2 into the atmosphere, it also means less trees to absorb the CO2 in the first place

Question 35

what are natural emission sources of CO2?

Answer 35

respiration, volcanoes, decomposition of dad matter, oceans

Question 36

2nd largest source of warming, %, and effectiveness at absorbing IR

Answer 36

methane, 20%, 25x better than CO2

Question 37

sources of methane from human activities

Answer 37

energy related: coal mining - natural gas deposits underground release CH4, natural gas production and transportation agriculture (cows, rice paddies) waste management

Question 38

sources of methane from natural sources

Answer 38

wetlands - microbes and bacteria produce CH4 termites - digestion oceans - decomposition of aquatic plants and fish by microbes

Question 39

2 worrisome future sources of methane

Answer 39

methane hydrates and permafrost

Question 40

what are methane hydrates?

Answer 40

they're solid cages of ice with HC4 inside found deep underground in polar regions and ocean sediments. these solid cages are melting and releasing CH4 into the atmosphere

Question 41

what is permafrost?

Answer 41

frozen soil in very cold areas (alaska, northern canada) are melting due to global warming and freeing trapped methane

Question 42

3rd largest source of warming + details

Answer 42

very little in the atmosphere, 300x more effective at absorbing IR

Question 43

is nitrous oxide a NOx molecule?

Answer 43

no

Question 44

what is the main source of nitrous oxide?

Answer 44

microbes that break down nitrogen in soil and oceans

Question 45

how are humans accelerating nitrous oxide emissions?

Answer 45

humans are adding fertilizer containing nitrogen to soil