chapter 18

Question 1

atmospheric pressure

Answer 1

• measure of mass per unit of air
• decreases with altitude

Question 2

density

Answer 2

varies throughout the atmosphere due to gravitational forces
- air at sea level has higher density than air at the top of a mountain

Question 3

atmosphere

Answer 3

thin layer of gases that surrounds the earth; classified into layers characterised by changes in temperature
- 78% nitrogen
- 21% oxygen
- .9% argon
- .1% water vapour, carbon dioxide, neon, helium, trace gases

Question 4

troposphere

Answer 4

• earth to 10km up
• 75-80% of atmospheric gases
• short-term weather patterns & long-term climate occurs here

Question 5

stratosphere

Answer 5

• 10km to 50km above earth
• ozone layer is here; absorbs the majority (95%) of uv radiation from the sun

Question 6

mesosphere

Answer 6

• 50km to 80km above earth
• colest layer of the atmosphere (as low as -90deg C)

Question 7

ozone

Answer 7

• bad in the troposphere, good in the stratosphere
• oxygen molecules + uv radiation = o3

Question 8

thermosphere

Answer 8

• 80km into space
• ionosphere: lower layer, 80km to 550km; reflects radio waves back to earth; cannot reflect shorter tv waves
• exosphere: upper layer, blends into the vacuum of interplanetary space

Question 9

primary pollutants

Answer 9

pollutants emitted directly into the air

Question 10

secondary pollutants

Answer 10

formed when primary pollutants react together or with the atmosphere

Question 11

major air pollutants

Answer 11

• carbon oxides
• nitrogen oxides
• particulaates
• vocs
• ozone
• radon 222, plutonium 239

Question 12

outdoor air pollution

Answer 12

• comes mostly from natural sources (dust particles, organic chemicals from plant decay, forest fires) and burning fossil fuels (vehicles, industrial plants, urban areas)
• pollution from natural sources rarely reach harmful levels

Question 13

outdoor primary pollutants (examples)

Answer 13

soot, carbon monoxide, nitric oxides

Question 14

outdoor secondary pollutants (examples)

Answer 14

nitric acid

Question 15

indoor air pollutants

Answer 15

come from infiltration of outside air & chemicals used/produced inside buildings

Question 16

photochemical smog

Answer 16

• nitrogen oxides or vocs + heat and sunlight = pc smog & other pollutants (more than 100)
• some no2 reacts with hydrocarbons to produce a mixture of ozone, nitric acid, aldehydes, PANs, etc.

Question 17

temperature inversion

Answer 17

when cool air is trapped below warm air
- can prevent outdoor pollutants from rising & dispersing
- dense, colder air becomes stagnant and accumulates more pollutants
- cities in valleys surrounded by mountains & areas with sunny climate, light winds, mountains, and lots of vehicles
- e.g. los angeles basin

Question 18

industrial smog

Answer 18

• mixture of sulphur dioxide, droplets of sulphuric acid, and suspended solid particles (emitted by burning coal & oil)

Question 19

reducing outdoor air pollution

Answer 19

• precipitation, sea spray, winds
• heavy particles settle out of the atmosphere due to gravity
• chemical reactions of pollutants
• these methods remove pollutants from the air & deposit them elsewhere

Question 20

increasing outdoor air pollution

Answer 20

• urban buildings
• mountains
• high temperatures

Question 21

air pollution control

Answer 21

• catalytic converters
• wet & dry scrubbers
• electrostatic precipitators
• vapour recovery nozzle
• afterburners

Question 22

catalytic converter

Answer 22

used in automobiles to convert co, NOx, and hydrocarbons to less harmful gases (like co2)

Question 23

wet & dry scrubbers

Answer 23

gases in smokestacks are passed through CaO (lime) or CaCO3 (calcium carbonate) to remove SO2, accumulating in a sludge
- smokestacks can reduce local pollution, but increase regional pollution

Question 24

electrostatic precipitators

Answer 24

removes particulates using an induced electrical charge

Question 25

vapour recovery nozzle

Answer 25

on a gasoline pump, minimises gas fumes from escaping

Question 26

afterburners

Answer 26

an additional combustion process

Question 27

acid deposition

Answer 27

- SOx, NOx, and particulates react in the atmosphere to produce acidic chemicals - these chemicals travel long distances before coming back to earth - big problem in areas downwind from coal-burning facilities & urban areas

Question 28

wet vs dry deposition

Answer 28

wet: acidic rain, snow, fog, vapour with pH less than 5,6 dry: adicic particles

Question 29

sick-building syndrome

Answer 29

- buildings with particularly poor air quality - caused by tobacco smoke, fromaldehyde, gasoline, radon gas, abestos, CO, VOCs, fungi, bacteria

Question 30

radon 222

Answer 30

colourless, odourless, radioactive gas - produced by decay of uranium 238

Question 31

clean air acts

Answer 31

- epa established naaqs (national ambient air quality standards) - epa established national emission standards for roxic air pollutants - 2003 clear skies initiative: reduced the effectiveness of the clean air act

Question 32

neutralising acid lakes

Answer 32

- adding limestone or lime to water or soil - adding a small amount of phosphate fertiliser - reducing SO2, NOx, and particulates - use of low-sulphur coal (pros and cons)

Question 33

deficiencies of clean air act

Answer 33

- continued reliance on pollution cleanup vs prevention - failure to sharply increase fuel efficiency for vehicles - no strict emission standards for fine particulates - municipal trash incinerators are given 30-year permits - weak standards for incinerators - weak standards for emissions of CO2 and other GHGs

Question 34

indoor air pollution statistics

Answer 34

- common pollutants are 2-5x greater inside homes & buildings than outside - inside cars in traffic-clogged areas, the pollution may be 18x higher than outside - health risks are magnified bc people usually spend 70-98% of their time indoors or in vehicles - as many as 2.8mil people die prematurely per year from breathing in high levels of indoor smoke & particulates

Question 35

four most dangerous indoor air pollutants

Answer 35

- cigarette smoke - formaldehyde - radioactive radon-222 gas - small fine & ultrafine particles

Question 36

formaldehyde

Answer 36

chemical used to manufacture common household materials; taxidermy; vaping

Question 37

radon-222

Answer 37

found in soils & rocks; can seep into homes & increase risk of lung cancer - produced by the radioactive decay of U-238 - thought to be 2nd leading cause of lung cancer deaths each year in the usa remedies: sealing cracks in foundation & walls, increase ventilation, use a fan for cross ventilation

Question 38

how the respiratory system protects from air pollution

Answer 38

- hairs in the nose filter out large particles; sticky mucus lines the respiratory trap to capture smaller particles & dissolved gases - sneezing/coughing to expel contaminated air & mucus

Question 39

disease & dangers from air pollution

Answer 39

- prolonged/acute exposure to air pollutants can break down natural defences - asthma, lung cancer, chronic bronchitis, emphysema - people with respiratory diseases, the elderly, infants, pregnant women, and people with heart disease are especially vulnerable