3.1-3.7: air pollution Flashcards

1
Q

6 air pollutants in need of control measures:

A
  1. Carbon monoxide
  2. Sulfur dioxide
  3. Toxic organics
  4. Particulates
  5. Nitrogen oxides
  6. Volatile organic compounds
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2
Q

Radon

A

naturally occurring radioactive gas, contributes to lung cancer

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3
Q

CO peak emissions (US) = 1970 =

A

~185 million metric tons/year

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4
Q

Major source of CO =

A

transportation

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5
Q

Health hazards: CO @ high levels =

A

asphyxiating poison

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6
Q

asphyxiating poison

A
  • Displaces O2 bound to hemoglobin in blood proteins that transport O2 from lungs –> tissues
  • Iron-binding sites in hemoglobin bind CO 230 times more tightly than O2
  • normally = CO = 1% of hemoglobin binding sites
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7
Q

Air [CO] = 100 ppm = CO occupancy of hemoglobin binding sites =

A

16%

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8
Q

[CO] > 750 ppm =

A

loss of consciousness/death

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9
Q

main causes of CO poisoning

A

stoves/space heaters (poor circulation/malfunctions)

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10
Q

sulfur dioxide main sources

A

coal combustion, smelting metals (copper and nickel), transportation fuels (urban areas)

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11
Q

sulfur dioxide health hazards

A

Lung irritant/respiratory disease

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12
Q

Particulate matter-

A

SO2 as gas in air = H2SO4 attract water vapor –> droplets
- Secondary emissions from coal power plants

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13
Q

effects of sulfur dioxide

A
  • impair visibility
  • major contributor to acid rain (Corrodes artifacts, acidifies lakes/soils, dissolves limestone and stained glass, accelerates corrosion of iron/zinc)
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14
Q

Smokestacks

A

reduce sulfuric acid aerosols by dispersing plume
- Alleviates local problems
- Cause haze and acid rain downwind

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15
Q

Chemical scrubbers

A

remove SO2 by passing through limestone

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16
Q

Dry sorbent injection

A

injecting calcium hydroxide (Ca(OH)2) into combustion gas and a fabric filter collects particles
- ↓ volume CaSO3

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17
Q

Regenerable amine salt

A

scrubbing agent converts SO2 –> H2SO4 (commercial grade)
- Oxidized  fertilizer

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18
Q

Clean air act (1990) highlights ___ hazardous air pollutants and __ priority targets

A
  • 188
  • 33
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19
Q

3 inhalable organics

A

aldehydes, benzene, polycyclic aromatic hydrocarbons (PAHs)

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20
Q

Formaldehyde (H2CO) causes

A
  • eye/lung irritant (100 ppb)
  • drowsiness, nausea, headaches, respiratory diseases, nasal/nasopharyngeal cancer
  • Carcinogen to animals
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21
Q

sources of Formaldehyde

A

industrial and transportation, cigarettes, construction materials, carpets/fabrics

22
Q

Benzene (C6H6) = top 20 chemical produced in US (~7/6 million metric tons/year) AND is one of the top 20 most…

A

Top 20 most hazardous substances

23
Q

benzene is used in

A

petroleum, chemical/manufacturing industries
- 75% = chemical feedstock (styrene and phenol)
- 2% = gasoline

24
Q

Polycyclic Aromatic Hydrocarbons:

A

4+ C6H6 rings = carcinogens
- Activated by liver enzymes
- Cause cancer clusters

25
Q

Epoxide adducts

A

enzymes + compounds oxygen = alters DNA

26
Q

Sources of Polycyclic Aromatic Hydrocarbons:

A

carbon fuel combustion; soot particles and exhaust/smoke

27
Q

most serious air pollution health hazard =

A

Atmospheric particles
- Smallest particles = most dangerous

28
Q

Atmospheric particles cause

A
  • Penetrate lungs, block air passages = toxic
  • Causes: black-lung disease (coal miners), pulmonary fibrosis (asbestos workers), emphysema (everyone)
29
Q

PM 10 and PM 2.5 =

A

particulate matter w/ diameters < 10/2.5 µm = most dangerous
- Particles larger = caught by nose/throat

30
Q

Mesothelioma

A

cancer caused at low exposure to asbestos

31
Q

Crocidolite

A

most hazardous form of asbestos
- Tiny fibers
- Penetrate deep into lungs

32
Q

Chrysotile

A

most common form of asbestos
- Less hazardous (intercepted by upper airways)

33
Q

asbestos particles cause the highest __?

A

mortality of any gaseous pollutant

34
Q

current sources of asbestos

A

insulation, fireproofing, soot

35
Q

historical sources of asbestos

A

urban aerosols, diesel exhaust, transportation, electrical power, industrial (production of minerals), power plants, residential wood burning, railroads

36
Q

Toxic smog =

A

soot particles (coal fires) –> SO2 + sulfate aerosols

37
Q

Major part of photochemical smog

A

NOx (nitrogen oxides)

38
Q

effects of nitrogen oxide

A
  • Damage to ozone
  • Minor health effects
39
Q

Anthropogenic gases = destroying ozone in the ___ and creating ozone in the ___ (photochemical smog)

A
  • stratosphere
  • troposphere
40
Q

Stratospheric ozone

A

protects from harmful UV rays

41
Q

Ozone @ ground level

A

destroying plant, respiratory disease, eye irritation

42
Q

Ozone

A

strong oxidant, reacts rapidly w/ electron-rich molecules

43
Q

Electron-rich molecules = in …

A

rubber, green plants, membranes of lung’s air passages
- (why ozone at ground level destroys rubber, green plants, lungs)

44
Q

Oxidant molecules are formed in

A

photochemical smog

45
Q

Ozone (O3)- reactive molecule = ___ and causes it to be a ___

A

can be transported long distances
- Regional pollutant

46
Q

Ozone =

A

sunlight on NOx + hydrocarbons + CO
- ↑ NOx/hydrocarbon/CO pollutants = ↑ ozone
- NO = limiting resource for smog
- ↓ NO = ↓ smog/ozone

47
Q

causes of ozone

A

Transportation, fuel combustion, car exhaust, gasoline

48
Q

VOCs=

A

emitted by vegetation = major contributor to photochemical smog

49
Q

NOx feedback loop

A

↑ combustion temps = ↑ NOx formation

50
Q

Lowering NO and HC:

A

2 stages of combustion:
1. rich in fuel
2. rich in air
OR
remove pollutants from exhaust gases (3-way catalytic converter in cars)

51
Q

3-way catalytic converter in cars =

A

3 chambers
- 2 succession chambers + 1 reduction chamber
- Reduces automotive emissions

52
Q

Stationary power plants (new technology)

A

Converts NO back –> N2 w/ catalytic converters
- Ammonia = reductant
- Eliminating high temps that produce NO