The Atmosphere, Air Quality and Pollution Control Flashcards
1
Q
Smog
A
a mix of air pollutants from fossil fuel combustion; worse in mountainous areas where it becomes trapped and in sunny/high altitude areas where solar radiation is intense; worst issues in the United States in Los Angeles now
2
Q
Mexico City smog case study
A
once had the worst air in the world but in the 1990s combatted smog issues; shut down an oil refinery, pushed for natural gas usage, removed lead from gasoline, decreased the sulfur content of diesel, and used catalytic converters in new vehicles; implemented emissions testing, built air quality sampling stations and enforced cleaner taxis and city vehicles as the population was still growing; in 2007 created a 15-year plan to construct new subway system lines, fuel-efficient buses, electric buses/taxis, and car- and bicycle-sharing programs + restricted car traffic on Sundays in the main area of the city; most pollutants dropped 75% between 1991 and 2010-2015 but issues persist (rampant development, complacent politicians, hot and windless weather brings bad conditions back and smog still contributes to 4000 deaths per year)
3
Q
Atmosphere
A
the layer of gases that envelops a planet; in the case of Earth it moderates climate, provides oxygen, shields against meteors + solar radiation, and transports/recycles water + nutrients
4
Q
Content of Earth’s atmosphere
A
78% nitrogen, 21% oxygen, 1% other gases (argon, neon, helium, etc.); water vapor varies by time and place between 0-4%
5
Q
Proportion of Earth’s diameter taken up by the atmosphere
A
1/100
6
Q
Troposphere
A
the bottommost layer of Earth’s atmosphere where air movement drives weather and climate; 11 km average height; thin but contains 3/4 of the atmosphere’s mass (due to gravity); gets colder with increasing altitude
7
Q
Tropopause
A
the dividing area between the troposphere and the stratosphere
8
Q
Stratosphere
A
the second lowest layer of Earth’s atmosphere that is similar in composition to the troposphere but drier and less dense; 11-50 km above sea level; pollutants tend to last within it as there is little vertical mixing of gases; gets warmer with increasing altitude because of oxygen and ozone that absorb UV radiation
9
Q
Ozone layer
A
part of the atmosphere containing most atmospheric ozone; 17-30 km above sea level (so within the stratosphere); absorbs and scatters UV so less reaches the surface; life depends upon it
10
Q
Mesosphere
A
second highest layer of Earth’s atmosphere where meteors burn up; gets colder with increasing altitude
11
Q
Thermosphere
A
highest layer of Earth’s atmosphere; gets warmer with increasing altitude; extends up to 500 km above sea level before merging with space in the exosphere
12
Q
Percentage of solar energy absorbed vs. reflected
A
70% absorbed (by the atmosphere and the surface), 30% reflected
13
Q
Effects of radiation absorption by land and surface water
A
emit thermal infrared radiation as a result (and some water evaporates), making lower altitudes warmer and more moist
14
Q
Convective circulation
A
an air movement pattern controlled by radiation absorption on the Earth’s surface; warm air rises because it is less dense and creates vertical currents; in areas with lower pressure warm air expands and cools and its moisture condenses to rain; cool air descends and becomes denser + replaces warm rising air, then picks up heat and moisture (and the cycle continues)
15
Q
Weather
A
atmospheric conditions in a location over minutes, hours, days or weeks
16
Q
Climate
A
typical patterns of atmospheric conditions in a location over years, decades, centuries or millennia
17
Q
What characteristic of an atmospheric layer causes it to have vertical mixing?
A
cooler temperatures as altitude increases (since warm air rises)
18
Q
Temperature inversion (AKA thermal inversion)
A
a departure from a normal temperature profile where warm and cool layers of air are in the opposite order (cool below warm), such as in mountain valleys where the slopes block sunlight and keep low air shaded/cool or as with cooled ocean air moving inland; can cause pollutants to be trapped at low altitudes (usually mixing dilutes them and carries them upward)
19
Q
Inversion layer
A
a band of air where temperature increases with altitude (since the direction of temperature change is switched)
20
Q
Cool air characteristics (compared to warm)
A
denser, more stable, resists mixing; why inversions occur
21
Q
Hadley cells
A
convective cells of air at the equator where the sun is most intense; air warms, rises and expands, then releases moisture as heavy rainfall (as in tropical rainforests)
22
Q
Air at 30° north and south latitude
A
air that diverged from the equator and cooled/sank with rainfall (so now dry); line up with deserts
23
Q
Ferrel and polar cells
A
cells of air that lift up and create precipitation at 60° north and south latitude; descends again at the poles
24
Q
Characteristics of air from the equator to the poles
A
wet –> arid –> moist –> dry; explains (in conjunction with temperature variation) why biomes occur in latitudinal bands
25
Formation of global wind currents
due to the movement of cells of air and the Coriolis effect (how Earth's rotation affects the movement of things around it)
26
Coriolis effect
describes how regions of the Earth's surface near the equator move west to east more quickly than those near the poles due to the Earth's rotation; an observer on Earth finds that currents going north or south seem to be deflected from a straight path and are instead curved
27
Air pollutants
gases and particulate materials added to the atmosphere that can affect the climate and harm living things (including wood fires to coal-burning power plants)
28
Air pollution
the release of air pollutants
29
Outdoor air pollution (AKA ambient air pollution)
refers to air pollution taking place outside in the open atmosphere on larger scales; has mostly decreased in industrialized nations with public policy and technology changes but is still a major issue in developing and urban areas; includes greenhouse gases
30
World Health Organization's estimate of premature deaths per year due to health problems from outdoor air pollution
3.3 million
31
Natural processes that contribute to air pollution
fires (soot and gases from typically 60 million hectares per year), volcanic eruptions (particles + sulfur dioxide + ash), windblown dust and dust storms; some are worse due to human activity and land use policies (e.g., farming and grazing strip vegetation so dust storms increase, fires are used to clear forests, suppressing fires leads to fuel buildup so fires are more destructive, and fossil fuel use leads to warming and drought so dust storms and fires are more common)
32
Primary pollutants
released directly from a source
33
Secondary pollutants
formed by interactions between pollutants or a pollutant and the atmosphere (e.g., ozone from smog and acid precipitation from pollution/water/oxygen)
34
Residence time
how long a substance lasts in the atmosphere; some react or settle to the ground more readily than others; short = localized impact for a short period (e.g., car exhaust) and long = regional/global impact for long periods, even centuries (e.g., the pollution driving climate change or ozone depletion)
35
Clean Air Act
U.S. legislation from 1963 that funds pollution control research, sets air quality standards, encourages emissions standards for automobiles and stationary point sources, imposes limits on new sources, funds a nationwide monitoring system and enables citizens to sue parties that violate it; had the EPA set standards for the emissions of key pollutants and the concentrations of major pollutants in ambient air; required states to monitor and develop/enforce regulations, then submit their plans to the EPA (which can then take over if these are found to be inadequate and prevent states from receiving transportation project funding when the air is not clean enough)
36
Which 6 major pollutants do state and local agencies have to monitor and report about to the EPA?
carbon monoxide, sulfur dioxide, nitrous oxides, volatile organic compounds, particular matter and lead
37
About carbon monoxide as a pollutant
colorless and odorless gas; produced mainly by incomplete fuel combustion (especially in vehicles and engines in the U.S.) but also from industrial processes, waste combustion and residential wood burning; binds to hemoglobin in the blood and keeps it from binding with oxygen (poisonous)
38
About sulfur dioxide as a pollutant
pungent and colorless gas; mostly from the combustion of coal for electricity and industry (sulfur is a contaminant in coal and reacts with oxygen); can react to form sulfur trioxide and sulfuric acid in the atmosphere, leading to acid deposition
39
About nitrous oxides as pollutants
mostly come from diatomic oxygen and nitrogen in the atmosphere reacting at high temperatures in vehicle engine combustion; rest from industry and electrical utilities; contribute to smog, acid deposition and stratospheric ozone depletion
40
About volatile organic compounds (VOCs) as pollutants
emitted by engines, solvents, industrial processes, household chemicals, paints, perfumes, adhesives, pesticides, plastics and consumer items (also evaporate from furnishings, building materials, carpets, etc.); include benzene, acetone, formaldehyde, etc. (one anthropogenic group is the hydrocarbons); some are emitted naturally by plants; produce secondary pollutants; may be released in large amounts when an item is new or fresh and less with age or with each use of an item; can cause irritation and induce skin allergies
41
About particulate matter as a pollutant
refers to solid and liquid particles small enough to be suspended in the atmosphere; primary pollutants in this category include dust, soot, etc. and secondary pollutants include sulfates, nitrates, etc.; classified by size (PM₁₀ < 10 microns in diameter, mostly from road dust and PM₂.₅ < 2.5 microns in diameter, mostly from combustion); smaller particles can get deep into the lungs and tissues and cause organ damage
42
About lead as a pollutant
a heavy metal and a particle pollutant; tetraethyl lead and tetramethyl lead improve engine performance when used in gasoline but particles become airborne and are inhaled or end up on land/in water; accumulates in tissues once it enters the food chain and causes nervous system malfunction among other issues; leaded gas has mostly been phased out since the 1980s so the main source in developed areas now is industrial metal smelting
43
Social demand, policy and technology have greatly decreased the presence of the 6 major air pollutants despite what factors?
population growth, increased energy use, increased miles traveled by vehicle and higher GDP
44
Examples of technology in factories, power plants and refineries that chemically convert or physically remove pollutants before they are emitted in smokestacks
baghouse filters, electrostatic precipitators and scrubbers
45
Catalytic converter
an automotive part inside of which exhaust components like hydrocarbons, carbon monoxide and nitrous oxides are converted into carbon dioxide, water and atmospheric nitrogen using metals (catalysts)
46
Examples of factors that have decreased sulfur dioxide and nitrous oxides in the atmosphere
lower lead use/concentration, the EPA's Acid Rain Program and emissions trading system, clean coal technology
47
How do scrubbers work?
spray nozzles shoot a mist of water and lime or other active chemicals to capture and wash pollution out of the air (the water is later treated)
48
How effective are scrubbers?
can remove at least 90% of the particles and gas pollutants from air
49
Criteria pollutants
six major pollutants that are measured by the EPA and the states to judge outdoor air quality; can pose substantial health risks
50
What are the six criteria pollutants?
carbon monoxide, sulfur dioxide, particulate matter, lead, nitrogen dioxide, tropospheric ozone
51
Nitrogen dioxide
a foul-smelling, highly reactive and reddish-brown gas that contributes to smog and acid deposition; often results from nitrogen monoxide reacting in the atmosphere but can also be a primary pollutant
52
Tropospheric ozone
separate from the stratospheric ozone layer; accumulates from human activity and from reactions with nitrous oxides and VOCs in sunlight; AKA ground-level ozone; a major component of photochemical smog; colorless; readily splits to atmospheric oxygen and a free oxygen atom that can injure living tissue and cause respiratory issues; the pollutant with a concentration most frequently above defined standards
53
Air quality monitoring stations
provide data from hourly and daily air samples; over 4000 in the U.S.
54
Air Quality Index (AQI)
a method for measuring air quality used at each site covered by monitoring stations; each pollutant (CO, NO2, SO2, O3, and both PM ranges) gets its own with a value between 0 and 500 where < 100 is satisfactory and > 100 is unhealthy; highest is reported as the overall for the day in weather broadcasts and online
55
U.S. air quality concerns in present day
generally lesser since all criteria pollutants are now below the EPA standards (once a bigger and wider issue); outdoor air is typically cleaner than indoor; new pollutants are appearing, greenhouse gas emissions continue and many communities (especially low-income) are still experiencing unhealthy levels of pollution
56
Smog
one of the most prevalent types of air pollution; general term for a mix of pollutants from fossil fuel combustion; primarily in industrial and urban areas with heavy traffic
57
Industrial smog
a problem since the Industrial Revolution; parts of coal and oil are completely combusted to CO2, parts are partially combusted to CO and some are left unburned as soot (C) plus coal contains contaminants like mercury and sulfur, all of which make this up; can blanket whole areas in certain conditions
58
Worst case of industrial smog in the U.S.
1948 in Donora, PA mountain valley; came from a steel and wire factory; air cooled overnight and made it so sunlight couldn't warm the area, leading to a temperature inversion that trapped the smog; 21 people passed away and about half the town fell ill
59
Worst case of industrial smog in the world
1952 in London; a high-pressure system over the city for days trapped pollution from factories and coal-burning stoves; killed between 4,000 and 12,000 people
60
Industrial smog in industrializing vs. developed urban areas
lax control and continued use of coal, remains high vs. more regulation and mostly from exhaust, lower
61
Photochemical smog
results when sunlight drives chemical reactions between primary pollutants and the atmosphere, leading to 100+ different chemicals (tropospheric ozone usually the most abundant)
62
What made Mexico City prone to air quality issues from smog?
vehicles were responsible for substantial proportions of major pollutants; hot, sunny and windless weather plus hilly topography meant frequent inversions; presence of some secondary pollutants that led to photochemical smog (peroxyacyl nitrates/PANs and aldehydes)
63
Health hazards of smog
irritates the eyes, nose and throat; over time can lead to asthma, lung damage, heart problems, decreased infection resistance and cancer
64
What tactics have worked to reduce smog?
vehicle inspections, regulating traffic into city centers, paying drivers to turn in their old cars for cleaner ones, lowering the sulfur content of gasoline, converting buses to natural gas, increasing public awareness (e.g., with billboards reporting current pollutant levels), restricting emissions from power plants/oil refineries; also lowered gasoline subsidies, rationed fuel and expanded subways as cars and people continue to grow in number
65
What made the California Air Resources Board noteworthy?
first state agency to regulate air quality (now in more than half of all U.S. states); requires inspections of vehicle exhaust and repairs when pollution is excessive; decreased emissions by 30%
66
How can altitude contribute to health issues caused by pollution?
air is "thinner" and deep breaths are needed to get enough oxygen, meaning more pollution enters the lungs
67
What were the findings of the research done by Isabelle Romieu and her colleagues in Mexico City (2007)?
studied the effects of growing up in polluted air; lung function was correlated with the presence of ozone and nitrogen dioxide; more pollution was associated with a decreased ability to breathe deeply, smaller/weaker lungs, and worse asthma
68
What are less expected health issues created by air pollution?
problems with heart rate, blood pressure, clotting and blood vessels; correlation with pollution and atherosclerosis plus emergency room visits for heart attacks/failure, chest pain or related problems; tiny particles can enter the bloodstream and interfere with blood flow or the heart's rhythm; dead bacteria on particles can trigger an inflammatory response by the heart which can become chronic if the pollution lasts; death rates increase after severe pollution exposure especially when it includes particles; brains are also affected based on studies comparing dogs from areas with different levels of pollution (amyloid beta protein plaques in dogs from more polluted locations signal Alzheimer's and caused disorientation and lethargy) as well as children (increased lesions on the prefrontal cortex + decreased cognitive skills) and mice (PM2.5 does pass through tissue and harm the brain)
69
Where is the worst tropospheric ozone in U.S. metropolitan areas?
Los Angeles; above the standard for 90+ days/year and contributes to thousands of early deaths
70
Reasons why pollution is worsening in industrializing nations
increases in driving and the number of factories/plants, continued use of traditional fuel sources (wood/coal/charcoal), use of outdated and inefficient technology that pollutes a lot because it is cheaper and quicker to build, urban poverty prevents solutions
71
About China's major air pollution issue
leads to 1.2 million early deaths per year; westerlies carry pollution to the north which has led to an average life expectancy 5 years shorter in the north than the south; have closed factories/mines, decreased subsidies for polluting industries, implemented pollution controls in plants, subsidized electric heaters to replace coal stoves, made cleaner gas and diesel, increased standards for fuel efficiency and emissions, increased mass transit options, increased natural gas/wind/solar/nuclear energy usage
72
What was the SCOTUS ruling in 2007 regarding the Clean Air Act and the EPA?
the EPA (which received pushback especially from coal-mining/petrochemical companies and certain states) could regulate greenhouse gases as air pollution under the Clean Air Act
73
2015 Clean Power Plan
applied to existing power plants and allowed states to choose how they decrease their emissions (could upgrade technology, switch from coal to natural gas, increase efficiency or renewable energy, or use carbon taxes/cap-and-trade programs); benefits were worth billions per year and would save thousands of lives but was challenged again such that SCOTUS prevented its implementation until lawsuits were resolved (later Republicans dismantled it)
74
Halocarbons
human-made compounds from simple hydrocarbons (hydrogen is replaced with halogens); the main ozone-depleting substance; includes chlorofluorocarbons
75
Chlorofluorocarbons (CFCs)
a halocarbon used frequently in refrigerants, fire extinguishers, polystyrene foam and air conditioning units in the 1970s that lingers in the stratosphere for 100+ years where UV rays break its bonds and release chlorine atoms that can split ozone molecules
76
What makes CFCs such a major issue?
in a two-step reaction involving ozone, they generate "endless" chlorine atoms that can continuously break apart more ozone molecules
77
When was the ozone hole first noticed?
1985 (over Antarctica during the southern hemisphere's spring)
78
Extent of the ozone hole
reaches its lowest concentration every spring; maximum extent in 2006
79
Why is the ozone hole located where it is?
from June to August icy clouds containing nitric acid form in the stratosphere, causing chlorine atoms to break off of compounds like CFCs and accumulate in clouds after being trapped by wind currents; in spring a large amount of chlorine is released at once and reactions with ozone are catalyzed and sped up by solar radiation; in December the warmth weakens air currents and ozone-depleted air diffuses away while ozone-rich air flows in
80
Why is the ozone hole a problem?
increased exposure to UV radiation means increased skin cancer, crop damage and killed phytoplankton (the base of the marine food chain); associated with year-round and global risks
81
1987 Montreal Protocol
an international agreement to cut CFC production in half by 1988 that also led to further cuts/timetables and decreased other ozone-depleting substances (most of which have now been replaced with other chemicals); halted depletion and kept the ozone hole from growing although it is not expected to fully recover until after 2060 (and much of the CFCs in the troposphere didn't reach the stratosphere until around 2020)
82
Relationship between ozone and greenhouse gases
ozone depletion doesn't cause significant warming/cooling and global warming doesn't affect ozone concentrations much, but many ozone-depleting substances are greenhouse gases
83
Acid deposition
the deposition of acidic or acid-forming pollution from the atmosphere to Earth's surface (i.e., a type of atmospheric deposition), often via acid precipitation (rain/snow) but also fog, gases and dry particles
84
What primarily causes acid deposition?
the emission of sulfur dioxide and nitrous oxides, especially from fossil fuel combustion (cars, electric utilities, industrial facilities), allows for reactions between these gases and water vapor + oxygen + oxidants in the atmosphere to produce sulfuric acid and nitric acid (which remain suspended in and travel through the troposphere for days to weeks before descending)
85
Negative effects of acid deposition
leaches nutrients (Mg, Ca, K) out of topsoil and into inaccessible subsoil which impacts plants and soil organisms; makes toxic metal ions (Al, Zn, Hg, Cu) soluble and mobile which damages plant roots/uptake; ultimately means less food for larger organisms; enters waterways and damages fish gills, salt balance, breathing and circulation; damages crops, stone buildings, vehicles, tombstones and monuments
86
Where does the worst acidification usually occur?
downwind from industrial sources (effects can be far-reaching)
87
Acid Rain Program
part of the Clean Air Act of 1990; created an emissions trading (cap-and-trade) system for sulfur dioxide; encouraged a switch to low-sulfur coal and air-purifying technology; offered flexibility and generated similar systems for other pollutants; benefits outweighed costs 40:1 (though some argue that pollution decreased due to lower costs for cleaner fuel and regulated emissions cuts, plus command-and-control regulation in Europe has been more effective than cap-and-trade programs)
88
2011 Cross-State Air Pollution Rule
designed to limit the spread of pollution from upwind to downwind states
89
Indoor air pollution's impacts on health are greater than those of outdoor air pollution.
true
90
Outdoor air generally has a higher concentration of pollution than indoor air.
false
91
Percentage of time the average American spends indoors exposed to indoor air
90% (often surrounded by many products that use synthetic materials that haven't been comprehensively tested which release volatile chemicals into the air)
92
Relationship between energy-efficient habits and indoor air quality
increased efficiency (e.g., by sealing off or decreasing ventilation so heat cannot escape) = worsened air quality
93
Where does indoor air pollution have the biggest impact?
in developing countries - many people use wood, charcoal, dung or crop waste for cooking and heating without sufficient ventilation (and thus inhale soot, carbon monoxide, etc. regularly)
94
Health risks posed by indoor air pollution
pneumonia, bronchitis, lung cancer, asthma, allergies, sinus infections, cataracts, emphysema and heart disease
95
What are the major indoor air pollutants in developed countries?
cigarette smoke and radon
96
About radon as an indoor air pollutant
colorless, odorless, radioactive gas that comes from the decay of uranium in soil, rock or water; seeps up from the ground and can penetrate buildings; linked to 15% of global lung cancer cases; only identified with a test kit; estimated 6% of U.S. homes are above the safety standard
97
Living organisms as indoor airborne hazards
include dust mites, fungi spores and airborne bacteria (also pet dander, though nonliving itself); can trigger asthma and allergies or cause disease; heating and cooling systems may provide an ideal breeding ground for microbes with moisture, dust, foam insulation, and air currents to carry them
98
Sick building syndrome
refers to a kind of building- or indoor pollution-related illness with an unknown cause and nonspecific symptoms; affects millions
99
Ways to reduce indoor air pollution
using low-toxicity materials, monitoring air quality, keeping rooms and air ducts clean, using adequate ventilation, avoiding cigarette smoke, limiting exposure to new plastics and treated wood + pesticides and cleaning fluids (can be kept in a shed or garage), testing for carbon monoxide + mold + radon, and using cleaner-burning fuels/stoves
