APES Ch 20 Study Guide Air Pollution
Air pollution- chemicals added to the air by nature or human activities in high enough concentrations
to be harmful
Primary air pollutant- a harmful substance released directly into the atmosphere
Secondary air pollutant- a harmful substance that forms in the atmosphere as a result of chemical
reactions between primary air pollutants
Particulates- solid or liquid particles suspended in the air
Hydrocarbons- compounds containing only hydrogen and carbon
Mobile sources- pollution from cars, trucks, planes and other sources of transportation
Stationary sources- sources from power plants, homes, industries, etc.
Photochemical smog- brownish-orange haze formed as a mixture of secondary pollutants from
chemical reactions involving sunlight, nitrogen oxide, and hydrocarbons
Temperature inversion (Thermal inversion)- when a layer of cold air is trapped beneath a layer of
warm air. The denser cold air cannot rise up through the warm air so air pollutants
accumulate close to ground level.
Emphysema- a progressive disease of the lungs in which the air sacs (alveoli) become damaged
reducing the exchange of gases and the efficiency of the lungs
Chronic bronchitis- chronic (long lasting) inflammation of the bronchi causing shortness of breath
and chronic coughing
Ultraviolet radiation- part of the electromagnetic spectrum with wavelengths that are just shorter than
visible light
Acid Deposition- rain, snow, sleet, hail or dry particles containing sulfur dioxide or nitrogen dioxide.
These react with water vapor to form sulfuric acid (H2SO4), nitric acid (HNO3) and nitrous
acid (HNO2).
Global distillation effect- the process whereby volatile chemicals evaporate from land as far away as
the tropics and are carried by air currents to higher latitudes where they condense and fall to
the ground.
Alpha particles- a type of ionizing radiation
1.
List the four most common gases in the atmosphere and the percentage of each.
Nitrogen (78%), oxygen (21%), argon (0.9%), and carbon dioxide (0.04%)
2.
Give the chemical equation for photosynthesis.
6CO2 + 6H2O + sunlight  C6H12O6 + 6O2 OR can be written without reducing as…
12CO2 + 6H2O + sunlight  C6H12O6 + 6O2 + 6H2O
How does this compare with the equation for cellular respiration?
It is the reverse
3.
Describe four ecosystem services performed by the atmosphere.
Shields Earth from deadly UV radiation; provides nitrogen for the nitrogen cycle;
Provides carbon dioxide for photosynthesis; moderates Earth’s climate; redistributes water
in the hydrologic cycle
4.
Give three examples of primary air pollutants.
Carbon oxides, nitrogen oxides (NO and NO2), sulfur dioxide, particulate matter, and
hydrocarbons
5.
Give three examples of secondary air pollutants
ozone, sulfur trioxide, nitric acid (HNO3), nitrous acid (HNO2), sulfuric acid (H2SO4), PANs,
hydrogen peroxide, most NO3- and SO4 2- salts;
Give four examples of particulates.
Soil particles, soot, lead, asbestos, sea salt, sulfuric acid droplets
6.
7.
Describe three problems that may be caused by particulates.
Reduce the amount of light reaching an area; the smaller particles PM-2.5 (particulate
matter less than 2.5 µm in diameter) can get lodged deep in the lungs and may carry other
toxins into the lungs; corrodes metals and erodes buildings when air is humid; contributes to
respiratory and heart disease
8.
Identify the three chemicals classified as nitrogen oxides.
Nitric oxide (NO); nitrogen dioxide (NO2), nitrous oxide (N2O)
9.
Describe six problems caused by nitrogen oxides.
Inhibit plant growth; aggravate asthma; involved in the formation of photochemical smog;
Involved in acid deposition; associated with climate change as nitrous oxide is a greenhouse
gas; depletes ozone in the stratosphere; causes metals to corrode and textiles to fade and
deteriorate
10.
Name two sulfur oxides.
Sulfur dioxide and sulfur trioxide
Which one is a primary pollutant?
Sulfur dioxide
Sulfur oxides are linked to what air major pollution problem?
Acid deposition
11.
What is the primary problem caused by carbon monoxide?
It bonds to hemoglobin and interferes with its ability to transport oxygen to body cells
12.
What is the primary problem caused by carbon dioxide?
It is a greenhouse gas
13.
What is the name and chemical formula of the simplest hydrocarbon? CH4
What problem is caused by this hydrocarbon? It is a greenhouse gas
14.
All hydrocarbons except for the simplest one identified in the previous question contribute to
the formation of ___photochemical smog_____.
15.
What is the chemical formula for ozone? O3
How does this compare with the chemical formula for the oxygen we breathe? O2
16.
Ozone in the __troposphere_______(name the layer of the atmosphere) is harmful because
___it is toxic and harmful to lung tissue; it damages lung tissue increasing the risk of
respiratory and heart problems; it is also damaging to plant tissue stressing them and reducing
growth rates__
17.
Ozone in the ___stratosphere___________ (name the layer of the atmosphere) is beneficial
because ___it shields us from much of the ultraviolet light that enters the atmosphere
so is essential to life__
18.
What layer of the atmosphere is the lowest? _____troposphere________________
19.
Classify ground level ozone as either a primary or secondary pollutant.
secondary
Identify the three industries that are the biggest producers of toxic air pollutants.
Chemical industry, metals industry, paper industry
20.
21.
Give one example of a natural source of air pollution.
Many plants produce release hydrocarbons from their leaves
22.
Describe the consequences of the Dec. 1952 episode of industrial smog event in London.
4000 Londoners died in Dec and an additional 8000 people died during the next 2 months
possibly due to the effects of the smog
23.
Explain how photochemical smog forms. Sunlight triggers a series of chemical reactions
involving nitrogen oxides and hydrocarbons. The products of photochemical smog include ozone
which in turn reacts with hydrocarbons and other air pollutants to form over 100 different secondary
pollutants including PANs (peroxyacyl nitrates) See Fig. 20.5 bottom of page 458
List four chemicals that are frequently part of the mixture called photochemical smog.
Ozone, PANs, nitric acid (HNO3), Formaldehyde and other aldehydes
24.
Why is photochemical smog primarily a problem during the summer?
It requires a minimum amount of sunlight to trigger the formation of the secondary pollutants
25.
What does VOCs stand for? Volatile organic compounds
List 3 sources of VOCs. Dry cleaners, paints, cleaning products, bakeris…
26.
What topographic features increase the risk of temperature inversions?
Cities located in valleys, near the coast or on the leeward side of mountains
27.
Why are temperature inversions linked to poor air quality?
During a temp inversion, a cool air mass near the ground lies trapped under a layer of warm
dry air. The cool air is denser so it can’t rise. Pollutants released into the air become trapped in
this cool, dense air. Concentrations rise as it can’t disperse.
28.
How has air quality in Los Angles changed during the last 50 years?
Improved substantially but still fails to meet state standards for ozone over 100 days/yr
29.
Air pollution is linked to __400,000___ premature deaths in China each year.
30.
Why does China have such poor air quality? Rapid industrialization, growing population,
growing number of cars, much electricity produced by coal, dust from construction
31.
List three respiratory diseases that are caused by or aggravated by air pollution.
Emphysema, chronic bronchitis, asthma
32.
Describe the toxic effects of carbon monoxide.
CO bonds to hemoglobin molecules in red blood cells. Forms a strong bond to make
carboxyhemoglobin. (O2 forms weak bonds with hemoglobin to form oxyhemoglobin. Bonds break
easily leading to oxygen being delivered to cells around the body as red blood cells circulate
throught the body.) The bonds between CO and hemoglobin do not break easily so the red blood
cells transport CO instead of oxygen and the body cells are deprived of oxygen.
Medium concentrations cause head ache, drowsiness. High level is fatal.
Studies have linked elevated CO concentrations to increases in hospital admissions for congestive
heart failure.
33.
Coal fired power plants are a major source of what air pollutants?
Sulfur oxides, particulates, mercury, hydrocarbons, carbon dioxide, nitrogen oxides
34.
Explain why children are especially vulnerable to air pollution.
Lungs are not fully developed and air pollution can restrict lung development; children have
higher metabolic rates than adults and need more oxygen so their respiration rates are higher
(breathing in about 2 times as much air per pound of body weight as an adult)
35.
How has overall air quality in the US changed since 1970?
Improved (see figure 20.13 on page 465)
36.
Describe how each of the following help to reduce air pollution. (How do they work? What
pollutants do they remove?) (See fig. 20.11 on p. 464)
Vapor recovery- phase I vapor recovery removes vapors from underground storage tanks at
gas stations while gasoline is being delivered to the tank. Phase II vapor recovery involves removing
gasoline vapors from car gas tanks as gasoline is pumped in. Removes gasoline vapors.
Electrostatic precipitator- an electrode negatively charges particulates in the smoke. The
negatively charged particles are attracted to the positively charged precipitator wall and then fall off
into the collector. Removes particulates. (Ionizing air purifiers used in the home are electrostatic
precipitators.)
Scrubber- mists of water traps particulates in the dirty gas washing them from the air before
it leaves the smoke stack. Removes particulates.
37.
Which federal agency oversees the Clean Air Act? EPA
38.
List the six criteria pollutants that receive the most attention under the Clean Air Act.
Lead, particulate matter, sulfur dioxide, carbon monoxide, nitrogen oxides, ozone
See http://www.epa.gov/air/urbanair/ for more info
39.
What is a nonattainment area? An area where air pollution levels persistently exceed National
Ambient Air Quality Standards, or that contributes to ambient air quality in a nearby area that fails
to meet standards. Designating an area as nonattainment is a formal rulemaking process, and EPA
normally takes this action only after air quality standards have been exceeded for several consecutive
years.
40.
How do companies like Zipcar and Flexcar help to reduce air pollution.
People pay a membership fee and can use a car in the Zipcar fleet when they need it instead of
having their own personal car….it reduces the number of cars on the road
41.
What is stratospheric ozone thinning? A reduction in the concentration of ozone in the
stratosphere
When does this seasonal event occur? During the spring (Antarctica from Sept. to Nov. and
in the Arctic from Jan to April)
Where does it occur? Over the Antarctic and to a lesser extent the Arctic; the conditions are
created by increasing sunlight and a strong circumpolar vortex which isolates polar air masses from
other regions. When the circumpolar vortex finally breaks up it allows the ozone-depleted air to
spread out away from the poles causing ozone levels to drop in the stratosphere over higher latitude
regions like Australia, New Zealand, southern S. America, northern Europe and northern N. America
42.
Ozone depletion is caused by certain ___chlorine___ and ____bromine___containing
chemicals , especially chlorofluorocarbons.
43.
Describe at least three uses for chlorofluorocarbons. Air conditioner and refrigerator
coolants, once widely used as propellants for aerosol cans; foam-blowing agents for insulation and
packaging; solvents for the electronics industry
44.
Halons are another class of ozone depleting chemicals. List at least two uses of halons.
Fire retardants, pesticides, industrial solvents
45.
What is a circumpolar vortex? Mass of cold air that circulates around the polar regions,
isolating the polar air from the rest of the atmosphere. This vortex is strongest during the winter
when there is the greatest temperature gradient between polar air and middle latitude air
46.
Describe three human health problems linked to ozone depletion.
Skin cancer, cataracts, weakened immune systems
47.
Describe at least two problems linked to ozone depletion that are not directly related to human
health.
Inhibits photosynthesis in phytoplankton; increase rate of mutations observed in fish eggs and
larvae; damage crops and forests. Some effects may be positive such as the inhibition of fungi that
damage wheat crops. Most effects are negative…. Ex: physical damage to leaves reducing
photosynthesis and plant yields.
48.
What is the Montreal Protocol? International agreement resulting from a 1987 meeting in
Montreal, Canada to reduce CFC production 50% by 1998. Later modified to further limit CFC
production as studies showed reduced stratospheric ozone concentrations over heavily populated
midlatitudes of the Northern Hemisphere.
49.
How is the concentration of ozone depleting chemicals in the atmosphere changing?
The HCFCs (hydrochlorofluorocarbons) that replace CFCs still deplete ozone but not as much.
(Unfortunately they are also greenhouse gases.) They are viewed as a short term solution until less
harmful chemical replacements are developed. Production of CFCs, carbon tetrachloride and
methyl chloroform were phased out in the US and other highly developed countries in 1996 except
for some that was manufactured here to sell to developing countries. Developing countries phased
out CFC use in 2005.
Measurement of ozone-depleting chemicals in the stratosphere started to decline in the 1997.
Measurement of the rate of stratospheric ozone showed it was decreasing in the early 2000s.
50.
Explain why the problem of ozone depletion is not one that will be totally reversed right away
even if we stop all use of ozone depleting chemicals.
They are catalysts so each molecule of ozone depleting chemical can trigger the breakdown of
thousands of molecules of ozone AND they are highly stable molecules so will continue to effect the
atmosphere for at least 50 years. Full recovery is not expected until some time after 2050.
51.
A substance with a pH less than 7 is ___acidic__. A substance with a pH of 7 is
__neutral__. A substance with a pH greater than 7 is ___alkaline or basic_______.
52.
Each whole number decrease in pH represents a __10__-fold increase in acidity.
53.
Which solution is more acidic, one with a pH of 3 or one with a pH of 6? __3___
How many times more acidic is it? __1000____
54.
Another word for basic is ___alkaline____.
55.
What are the major sources of nitrogen oxide emissions? Motor vehicles and power plants
that burn fuel (coal, natural gas, oil, wood)
56.
What are the major sources of sulfur dioxide emissions?
Coal fired power plants
57.
Why was the height of smokestacks increased in the past?
To disperse the pollutants …old idea “dilution is the solution to pollution”
What were the consequences of increasing the height of smokestacks?
Reduced pollution locally but just increased pollution downwind..midwestern coal fired
power plants, steel mills etc “exported” their pollution to New England and Canada
58.
Explain how acid deposition affects aquatic ecosystems.
Sulfur dioxide and nitrogen oxides react with water to form sulfuric acid (H2SO4), nitrous
acid (HNO2), and nitric acid (HNO3). This may kill fish eggs and larvae, some invertebrates, allows
toxic metals such as aluminum to dissolve more readily into water entering aquatic ecosystems and
food webs.
59.
How does acid deposition affect birds? Reduced the calcium in soils as it becomes more
soluble and washes away with little left for plant roots to absorb. This reduces the Ca in plant
tissues and the tissues of animals higher in the food chain. Adequate calcium in the diet is needed to
produce eggs with strong shells.
60.
How does acid deposition affect the concentration of each of the following in soil?
Calcium- reduces it
Potassium- reduces it
Nitrogen- increases it (nitric acid and nitrous acid are sources of nitrogen)
Aluminum- normally available in only very low concentrations because it is normally tightly
bound to rocks but it becomes more soluble in acidic soils and becomes more available for
absorption by plants which is a problem as it is toxic in higher concentrations
Manganese- same as aluminum
61.
Explain how multiple stressors may contribute to changes in forest health.
Exposure to multiple stressors such as acid deposition, ground level ozone, increased UV
radiation, insect pests, drought etc may leave a tree weakened. One stressor alone is much less likely
to kill a tree than a combination of stressors.
62.
Which of the pollutants contributing to acid deposition have been reduced most significantly
in the US? Sulfur dioxide
63.
What needs to be done if we want to cause significant further reductions in acid deposition?
Nitrogen oxide emissions need to be more significantly reduced which is a challenge as cars
are a major source and the number of cars on the road is increasing which can offset improvements
in air pollution control technology of cars
64.
Describe three reasons why many developing countries have serious and growing air pollution
problems? Environmental quality is often a low priority; outdated technologies are often
adopted; air pollution control laws (where they exist) are often not enforced; growing populations
and number of cars per capita; heavy reliance on coal in some countries (such as China)
65.
What is the global distillation effect? The long distance transportation of certain pollutants
resulting from the evaporation of volatile pollutants at lower latitudes and the movement of the
pollutants in the atmosphere to higher latitudes where eventually they condense and fall to the
ground.
Why is the global distillation effect likely to become an increasingly challenging problem in
the future? Air pollution does not respect international borders so pollution in one nation
will affect other nations even in remote areas far from the source
66.
Why are illnesses caused by indoor air pollution often not recognized?
The symptoms are often vague and are symptoms of many other illnesses not related to air pollution
67.
List at least six different indoor air pollutants and their sources.
(See fig. 20.21 on page 478) ammonia from household cleaners; carbon monoxide from cars
left running in attached garages, space heaters, gas stoves….; radon from uranium containing
bedrock; pesticides from garden products; para-dichlorobenzene from moth balls;
tetrachloroethylene from dry cleaning fluids; formaldehyds form furniture and carpeting made with
synthetic fibers, particle board, foam insulation…; asbestos from pipe insulation… ; fungi; tobacco
smoke
68.
Explain why indoor air pollution is a significant economic problem.
EPA estimates annual medical costs for treating health problems from indoor air pollution exceeds
$1 billion. When this is added to costs for lost work time and reduced productivity, total costs may
be $50 billion annually
69.
How has the incidence of asthma changed since 1970? doubled
70.
List at least six health problems linked to cigarette smoking. Asthma, lung cancer,
emphysema, heart attacks, strokes, impotence, cancers of bladder, mouth, throat, pancreas, kidney,
stomach, voice box and esophagus.
71.
How does passive smoking affect infants and young children? Doubles the risk of infants
developing pneumonia or bronchitis during its first year of life; leads to lower birth weights; smaller
head circumferences…
72.
How does radon gas enter buildings? Produced by the radioactive decay of uranium found in
very low concentrations in bedrock. Radon gas rises and enters homes through cracks in foundations
and basement floors, unsealed basement floors, and through plumbing (well water may contain
dissolved radon gas which enters the home during showers….)
What problems may be caused by exposure to radon gas?
Increased risk of lung cancer (perhaps 12% of lung cancers). Acts synergistically with cigarette
smoke…. 90% of radon-related lung cancer is among current or former smokers.
73.
What is one step that can be taken to reduce radon levels in homes? Seal cracks in basement
floors, increase ventilation in crawl spaces and basements
74.
Improving energy efficiency can lead to tighter homes that have higher concentrations of
indoor air pollutants. Describe how we could have efficient homes that have lower
concentrations of indoor air pollutants. Choosing materials that produce fewer
pollutants…avoiding vinyl products, synthetics, stain repellents, moth balls, more environmentally
friendly paints, using plants which help purify the air; air-to-air heat exchangers; not smoking…….