Deck 3: Earth’s Atmosphere

Question 1

At sea level,the pressure of the atmosphere is about kg/cm2.

A)1.0
B)2.6
C)8.2
D)6.7
E)5.0

Answer 1

A

Question 2

Based on composition,the atmosphere is divided into

A)one continuous region.
B)two broad classifications: homosphere and heterosphere.
C)two functional areas that absorb radiation from the Sun.
D)the troposphere and the stratosphere.
E)four regions based on temperature gradients.

Answer 2

B

Question 3

The region of the atmosphere that is so evenly mixed that it behaves as if it were a single gas is the

A)homosphere.
B)heterosphere.
C)exosphere.
D)thermosphere.
E)ionosphere.

Answer 3

A

Question 4

The solar constant is measured at

A)the outer boundary of the exosphere (32,000 km (20,000 mi)).
B)the top of the atmosphere (480 km (300 mi)).
C)the top of the stratosphere (50 km (31 mi)).
D)the top of the troposphere (12 km (8 mi)).
E)Earth's surface at the equator (sea level).

Question 5

Earth's first atmosphere likely formed from

A)water vapor condensed when Earth cooled.
B)photosynthetic activity of ocean bacteria.
C)outgassing from Earth's interior.
D)oxygen molecules absorbing sunlight and forming protective ozone.
E)respiration of early land mammals.

Question 6

The heterosphere is the layer of the atmosphere in which the gases are because of .

A)well mixed;thermal motions (i.e. ,convection)
B)well mixed;gravity causes gases of different weight to diffuse randomly
C)poorly mixed;thermal motions (i.e. ,convection)
D)poorly mixed;gravity causes gases of different weight to separate into layers
E)moderately mixed due to both thermal motion and separation by gravity

Question 7

Which of the following lists the correct sequence of gases,from most to least,in terms of percentage within the homosphere?

A)nitrogen,argon,oxygen,xenon,carbon dioxide
B)nitrogen,oxygen,argon,carbon dioxide,trace gases
C)oxygen,ozone,nitrogen,PAN,carbon dioxide
D)oxygen,nitrogen,neon,hydrocarbons,carbon dioxide
E)carbon dioxide,oxygen,nitrogen,argon

Question 8

Earth's fourth atmosphere likely formed from

A)water vapor condensed when Earth cooled.
B)photosynthetic activity of ocean bacteria.
C)outgassing from Earth's interior.
D)oxygen molecules absorbing sunlight and forming protective ozone.
E)respiration of early land mammals.

Question 9

Earth's second atmosphere likely formed from

A)water vapor condensed when Earth cooled.
B)photosynthetic activity of ocean bacteria.
C)outgassing from Earth's interior.
D)oxygen molecules absorbing sunlight and forming protective ozone.
E)respiration of early land mammals.

Question 10

Why are humans and other living things not crushed by the pressure of the atmosphere?

A)Atmospheric pressure increases with altitude and is,therefore,lowest near the Earth's surface.
B)While the atmosphere exerts pressure,it is a negligible amount.
C)They exert pressure outward,counterbalancing atmospheric pressure.
D)The tropopause serves as a buffer against the pressure exerted by the atmosphere.
E)The pressure exerted by the atmosphere is not great enough to crush them.

Question 11

The three stable (i.e. ,nonvariable)gases in the atmosphere,in order of abundance from most to least,are

A)carbon dioxide,argon,oxygen.
B)oxygen,carbon dioxide,argon.
C)argon,oxygen,nitrogen.
D)oxygen,argon,nitrogen.
E)nitrogen,oxygen,argon.

Question 12

Which of the following is false?

A)Air pressure decreases through the troposphere though increases in the stratosphere.
B)Air molecules exert air pressure through their motion,size,and number.
C)The atmosphere exerts an average force of 1 kg/cm2 at sea level.
D)Air pressure decreases with increasing altitude.
E)Over half of the total mass of the atmosphere lies below 5.5 km (3.14 mi).

Question 13

Air consists of

A)a mixture of gases that behaves like single gas.
B)unevenly mixed gases that act independently.
C)oxygen only.
D)mostly carbon dioxide and water vapor.
E)primarily oxygen and several trace gases,such as carbon dioxide.

Question 14

Half of the total mass of Earth's atmosphere lies below an elevation of _ meters.

A)14,000
B)11,000
C)8,300
D)5,500
E)25,000

Question 15

Nitrogen (N2)is

A)a key component of life,integrated into our bodies directly from the air.
B)cycled through the environment via the activity of bacteria.
C)a product of the radioactive decay of a form of potassium in the crust.
D)now measured at 20.946% by volume in the homosphere.
E)the least abundant constant gas in the homosphere.

Question 16

The top of the Earth's atmosphere is approximately

A)3,200 km (1,988 mi)above the Earth's surface.
B)480 km (300 mi)above the Earth's surface.
C)2,000 km (1,243 mi)above the Earth's surface.
D)1,000 km (621 mi)above the Earth's surface.
E)10 km (6.21 mi)above the Earth's surface.

Question 17

The outermost region of the atmosphere,based on composition,is the

A)homosphere.
B)heterosphere.
C)troposphere.
D)thermosphere.
E)exosphere.

Question 18

Three criteria used for classification of the atmosphere are

A)structure,origin,temperature.
B)structure,origin,evolution.
C)composition,origin,evolution.
D)temperature,evolution,and function.
E)composition,temperature,and function.

Question 19

Which of the following is true of gases in the heterosphere?

A)The hydrogen,helium,oxygen and nitrogen are well mixed.
B)Hydrogen and helium occur at the top of the heterosphere and oxygen and nitrogen dominate in the lower heterosphere.
C)Oxygen and nitrogen occur at the top of the heterosphere and hydrogen and helium dominate in the lower heterosphere.
D)Nitrogen occurs at the top,followed in descending order by helium,oxygen and hydrogen.
E)Oxygen occurs at the top,followed in descending order by hydrogen,helium,and nitrogen.

Question 20

Earth's third atmosphere likely formed from

A)water vapor condensed when Earth cooled.
B)photosynthetic activity of ocean bacteria.
C)outgassing from Earth's interior.
D)oxygen molecules absorbing sunlight and forming protective ozone.
E)respiration of early land mammals.

Question 21

Which is true of the amount of CO2 in our atmosphere?

A)CO2 is the most abundant gas in the atmosphere.
B)The level of CO2 has been decreasing at the rate of 3.1% per year since 2000.
C)The level of CO2 in May 2016 was 408 ppm.
D)The level of CO2 has been much higher during the past 800,000 years than it is now.
E)The level of CO2 is at the lowest levels now it has been in the last 50 years.

Question 22

The high temperatures in the thermosphere occur because

A)infrared radiation from the ground heats this layer more than any other layer.
B)methane is such an effective greenhouse gas.
C)carbon dioxide has accumulated to very high levels in this layer.
D)it is in direct contact with high energy solar radiation.
E)high intensity solar radiation causes strong chemical reactions with ozone,and this heats the layer to very high temperatures.

Question 23

Based on temperature,the atmosphere is divided into

A)four regions,ranging from the troposphere to the thermosphere.
B)two broad regions.
C)two functional areas that absorb radiation from the Sun.
D)two regions based on composition.
E)four regions based on composition.

Question 24

Which of the following is not true of carbon dioxide?

A)It is critically important in regulating the temperature of the planet.
B)Present levels are higher than at any time in the past 800,000 years.
C)The steady increase of atmospheric CO2 is primarily from fossil fuel burning.
D)Overall,atmospheric CO2 has increased by 16% from 1992 to 2012.
E)It occurs in large amounts in the atmosphere relative to other gases.

Question 25

The thermopause is located

A)between the mesosphere and the thermosphere.
B)wherever -90°C (-130°F)is recorded.
C)on average,approximately 480 km (300 mi. )above Earth's surface.
D)at the bottom of the homosphere.
E)between the homosphere and the heterosphere.

Question 26

The highest temperatures in the atmosphere occur in the

A)troposphere.
B)stratosphere.
C)mesosphere.
D)thermosphere.
E)homosphere.

Question 27

Why does temperature increase with altitude in the stratosphere?

A)The increase is due to the effects of the normal lapse rate effect.
B)Chlorofluorocarbons increase ozone concentrations,which enhance temperature.
C)Ozone converts UV radiation from the sun into heat energy.
D)Ozone acts as a greenhouse gas which traps ultraviolet energy radiated by Earth's surface.
E)Temperatures actually decrease with altitude in the stratosphere.

Question 28

Which of the following is true of the mesosphere?

A)It contains rare clouds that are visible at night.
B)Temperatures are uniform through the zone.
C)It is the warmest layer of the atmosphere.
D)It has the greatest vertical extent of all atmospheric layers.
E)It is within the heterosphere.

Question 29

About half of Earth's crust consists of compounds containing

A)nitrogen.
B)argon.
C)carbon dioxide.
D)oxygen.
E)ozone.

Question 30

Which stable (nonvariable)gas in the atmosphere is inert and unusable in life processes?

A)oxygen
B)nitrogen
C)argon
D)carbon dioxide
E)neon

Question 31

Atmospheric Temperature Temperatures within the stratosphere

A)decrease with altitude according to the normal lapse rate.
B)remain about the same from the tropopause to the stratopause.
C)increase with altitude because of the absorption of ultraviolet radiation.
D)decrease with altitude due to radiation losses.
E)increase with altitude due to increased atmospheric pressure.

Question 32

Despite its high temperatures,why would the thermosphere feel cold to humans?

A)The number of molecules is not high enough to transfer heat to human's skin.
B)Humans would die due to pressure changes before they could experience the intense heat.
C)The atmosphere is denser in the thermosphere and this pressure reduces heat transfer.
D)The average kinetic energy is actually less in the thermosphere than the troposphere.
E)The high density of individual molecules in the thermosphere have a cooling effect.

Question 33

Increasing atmospheric carbon dioxide since 1950.Monthly average CO2 measured at Mauna Loa Observatory in Hawai''i.The highest and lowest months (usually May and October)are plotted for each year;black line shows the 5-year running average. Which is true of the level of CO₂ in our atmosphere?

A)CO2 is reached 400 ppm in approximately 2013.
B)The rate of increase leveled out in 1976.
C)The level of CO2 was much higher in 1955 than today.
D)The level of CO2 is decreasing at 3.1% per year.
E)The levels of CO2 have greatly fluctuated over the past 50 years.

Question 34

The high temperature in the upper thermosphere

A)is produced by the absorption of UV radiation.
B)is more a measure of sensible temperature than kinetic energy.
C)would feel cold to humans due to few molecules for heat transfer.
D)produces a tremendous amount of heat transfer.
E)is produced primarily by the increased molecular activity of argon and helium.

Question 35

Oxygen (O2)is

A)a gas which principally originates from volcanic sources.
B)a by-product of photosynthesis.
C)one of the gases from Earth's earliest atmospheres.
D)now measured at 78.084% by volume in the homosphere.
E)not essential to life on the planet.

Question 36

The tropopause altitude is highest because of the .

A)at the equator;air expansion from intense heating at the surface
B)at the poles;diffuse solar radiation
C)during the summer;increased atmospheric pressure
D)during the winter;Sun's direct rays hitting the Tropic of Capricorn
E)in the midlatitudes;the constant movement of the subsolar point

Question 37

Which of the following is true of nitrogen?

A)The human body obtains the nitrogen it needs from the air.
B)There is very little nitrogen in the atmosphere.
C)Nitrogen originates principally from volcanic sources.
D)Nitrogen is a variable gas.
E)Nitrogen fixed by bacteria rarely returns to the atmosphere.

Question 38

Which of the gases listed below has accumulated in the atmosphere as a result of biological processes?

A)argon
B)oxygen
C)neon
D)water vapor
E)xenon

Question 39

Atmospheric Temperature Which of the following best describe conditions in the mesosphere?

A)Temperatures rapidly increase with altitude in the mesosphere.
B)It contains the coldest portion of the atmosphere along its outer boundary.
C)The mesosphere is completely within the heterosphere.
D)The mesosphere is located between the troposphere and the stratosphere.
E)The mesosphere corresponds with the ozonosphere.

Question 40

Which atmospheric zone supports the biosphere and is the region of principle weather activity?

A)thermosphere
B)mesosphere
C)stratosphere
D)troposphere
E)exosphere

Question 41

Which of the following is not true about the troposphere?

A)The altitude of the upper limits of the troposphere (the tropopause)varies with season and latitude.
B)Approximately 90% of the total mass of the atmosphere is within the troposphere.
C)Temperatures increase with altitude in the troposphere because the higher in altitude,the closer to the sun.
D)The bulk of all water vapor occurs in the troposphere.
E)An average temperature of -57°C (-70°F)defines the tropopause.

Question 42

In which two atmospheric zones does temperature increase with altitude?

A)troposphere and mesosphere
B)troposphere and stratosphere
C)stratosphere and mesosphere
D)stratosphere and thermosphere
E)mesosphere and thermosphere

Question 43

The Montreal Protocol

A)established a framework to address acid precipitation.
B)aims to reduce and eliminate all ozone depleting substances.
C)only addresses CFCs.
D)created the Intergovernmental Panel on Climate Change.
E)is ineffective because so few countries have ratified it.

Question 44

Which of the following are affected by the loss of ozone?

A)crop yields
B)phytoplankton populations
C)immune systems
D)eye tissues
E)crop yields,phytoplankton populations,immune systems,and eye tissues

Question 45

Why is stratospheric ozone loss a concern?

A)Stratospheric ozone is a major greenhouse gas;its loss will contribute to the cooling of the planet.
B)Stratospheric ozone absorbs harmful ultraviolet radiation (UVB and UVC).
C)Stratospheric ozone is a component of photochemical smog.
D)Stratospheric ozone contributes to the brilliant auroras.
E)Stratospheric ozone is necessary for the transmission of long distance radio waves.

Question 46

Atmospheric Temperature Which of the following is true?

A)The thermosphere and ozonosphere are the same.
B)The ozonosphere stretches from the Earth's surface to approximately 50 km (30 mi. ).
C)All but 0.001 percent of the atmosphere is accounted for within the stratosphere.
D)The ozonosphere corresponds with the stratosphere.
E)Noctilucent clouds occur in the ozonosphere.

Question 47

The ozonosphere is critical to life because it

A)affects temperatures.
B)absorbs visible light wavelengths.
C)strengthens GPS signals that must pass through it.
D)produces the auroras.
E)absorbs most ultraviolet wavelengths.

Question 48

Directly above the midlatitudes,the tropopause (-57°C)occurs on average at approximately

A)1 km.
B)12 km (8 mi. ).
C)50 km (30 mi. ).
D)100 km (62 mi).
E)wherever +32°F is recorded as the temperature.

Question 49

In 1974,Dr.Rowland and Dr.Molina made what observation vis-à-vis ozone (O3)?

A)The photochemical interactions of chlorofluorocarbons and O3.
B)Automobile exhaust and sunlight were producing photochemical smog.
C)Anthropogenic O3 releases were a major culprit in global warming.
D)Ground-level O3 irritates human eyes and respiratory systems.
E)O3 is of little importance to humans.

Question 50

In terms of incoming solar radiation (insolation),which is the correct order?

A)troposphere,stratosphere,mesosphere,thermosphere
B)thermosphere,mesosphere,stratosphere,troposphere
C)mesosphere,thermosphere,troposphere,stratosphere
D)stratosphere,troposphere,thermosphere,mesosphere
E)troposphere,thermosphere,mesosphere,stratosphere

Question 51

Temperature,altitude and average lapse rate in the troposphere Which of the following is correct regarding lapse rates in the troposphere?

A)The term "normal (average)lapse rate" refers to the actual lapse rate in effect at any particular time.
B)The environmental lapse rate refers to the actual lapse rate,which varies in space and time.
C)The normal lapse rate is always the same as the dry adiabatic rate (DAR).
D)Temperatures generally increase with altitude in the troposphere.
E)The average lapse rate is 5°C/km (2.7°F /1000 ft. ;1.5°C/1,000 ft. ).

Question 52

Which of the following is true of chlorofluorocarbons?

A)The CFC molecules react with ultraviolet light to release carbon which then destroys ozone.
B)The CFC molecules react with ultraviolet light to release fluorine which then destroys ozone.
C)The CFC molecules react with ultraviolet light to release chlorine which then destroys ozone.
D)Most of the CFC-induced ozone destruction is occurring near the equator,rather than near the poles.
E)CFCs production will be phased out by 2026,but still continues in China and the U.S.

Question 53

In which two atmospheric zones does temperature decrease with altitude?

A)troposphere and mesosphere
B)troposphere and stratosphere
C)stratosphere and mesosphere
D)stratosphere and thermosphere
E)mesosphere and thermosphere

Question 54

Which of the following is true regarding the depletion of ozone in the ozonosphere?

A)The depletion is restricted to the Arctic and Antarctic regions.
B)It results from chemical reactions with chlorine derived from CFCs.
C)It results from the burning of fossil fuels.
D)The notion that ozone is being depleted as a result of human activity has little scientific evidence to support it.
E)Ozone depletion is of little concern to humans,though it can damage plants.

Question 55

Which of the following is not true of chlorofluorocarbons?

A)They have been used as propellants in spray cans.
B)They are used in refrigeration systems.
C)They are used to make foam products.
D)CFCs are stable under conditions at Earth's surface.
E)CFCs role in depleting ozone has yet to be confirmed.

Question 56

Which of the following is true of the ionosphere?

A)It primarily absorbs harmful infrared wavelengths.
B)All radio signals pass through this region virtually unaffected.
C)Radio waves from GPS are strengthened in the ionosphere.
D)It is being depleted through interactions with human-produced chlorofluorocarbons.
E)The region principally absorbs gamma rays,X-rays,and interacts with the solar wind.

Question 57

Why is the hole in the ozone greatest over Antarctica?

A)The ozone hole is a natural phenomenon related to high polar stratospheric clouds.
B)South American countries have not ratified the Montreal Protocol and continue to release ozone-destroying CFCs.
C)Chlorine freed from CFCs elsewhere migrate to the Antarctic region,where they are trapped by the polar vortex.
D)Ozone,a greenhouse gas which traps ultraviolet energy radiated from the Earth's surface,has highest concentration in Antarctica.
E)Melting permafrost releases ozone destroying methane.

Question 58

How does the ionosphere affect GPS?

A)GPS satellites orbit the Earth in the ionosphere.
B)GPS ground stations lose contact with geosynchronous satellites orbiting near the poles.
C)GPS signals must pass through the ionosphere,whose gases weaken the signal.
D)Positively charged ions in the ionosphere speed up the GPS signal,causing signal error.
E)Ionosphere gases strengthen GPS signals,improving locational accuracy.

Question 59

Which of the following is not true of UV exposure?

A)UVA radiation accounts for about 95% of all UV radiation reaching the Earth's surface.
B)Only exposure to UVA is a concern,not exposure to UVB and UVC.
C)UV radiation is potentially harmful and individuals should take appropriate precautions depending on the UV index.
D)UV radiation varies spatially according to the season,local weather conditions,and overhead ozone depletion.
E)UVB alters plant physiology and can lead to decreased agricultural productivity.

Question 60

Based on function,the atmosphere has

A)five regions beginning with the outermost thermosphere.
B)two zones that absorb radiation from the Sun.
C)one continuous zone that functions as a whole.
D)the troposphere and the stratosphere.
E)three zones,which are similar in function,but vary with altitude.

Question 61

Which of the following is not a result of acid deposition?

A)acidification of lakes
B)release of aluminum from soils
C)soil nutrient loss
D)increase in nutrients in forest ecosystems
E)loss of aquatic life in streams,lakes,and wetlands

Question 62

Protochemical reactions and pollutants from cars The main ingredients in photochemical smog are

A)ozone,PAN,and nitric acid.
B)PAN,nitric acid,and carbon monoxide.
C)ozone,particulate matter,and carbon monoxide.
D)PAN,carbon monoxide,and particulate matter.
E)VOC and sulfur oxides.

Question 63

Which of the following is true?

A)Natural sources of air pollution are not a concern in terms of human health.
B)Natural sources of air pollution are a relatively new occurrence.
C)Natural events,such as volcanoes and wildfires,produce air pollution and may cover large areas.
D)There is no reason to be concerned about natural sources of air pollution.
E)By definition,natural events cannot produce pollution,only humans can.

Question 64

What two pollutants react with water to produce acid rain?

A)sulfur oxides and nitrogen oxides
B)sulfur oxides and ozone
C)nitrogen oxides and ozone
D)sulfur oxides and PAN
E)ozone and VOCs

Question 65

With regards to carbon monoxide (CO),which of the following is false?

A)Anthropogenic CO is principally produced by automobiles.
B)Exposure to too much CO can lead to illness and even death.
C)Few effects of CO on humans have been identified.
D)It is a colorless,odorless and tasteless gas.
E)CO combines with the hemoglobin of the human body,displacing oxygen.

Question 66

In the lower atmosphere,H2SO4

A)is also called black soot.
B)is related to the problem of acid deposition.
C)is a problem that only occurred during the first half of this century.
D)forms by a combination of O2 and NO2.
E)only occurs in exceptionally polluted areas.

Question 67

The single major source for photochemical reactants in the United States are

A)steel mills and the agricultural industry.
B)electrical generation stations.
C)automobiles.
D)rapid transit,buses,and excessive use of light rail systems.
E)solar panels and wind turbines.

Question 68

Nitrogen oxides (NOx)

A)inflame the human respiratory tract,destroy lung tissues,and damage plants.
B)are yet to be of consequence in North America.
C)are produced only after photochemical reactions.
D)are more of a concern in nonurban areas than urban.
E)are unrelated to acid deposition.

Question 69

The reaction of automobile exhaust and ultraviolet light

A)produces photochemical smog.
B)produces industrial smog.
C)is affecting the stratospheric ozone concentration.
D)forms smoke and fog.
E)is considered beneficial because of the production of O3.

Question 70

Peroxyacetyl nitrates (PANs)in the lower troposphere

A)are principally related to sulfur dioxides.
B)are formed by particulates such as dust,dirt,soot,and ash.
C)damages and kills plant tissue and is an irritant to people.
D)are emitted from the tail pipes of automobiles;i.e. ,it comes directly from automobile exhaust.
E)may damage plants,forests,and crops,but have no adverse effects on humans.

Question 71

Photochemical smog became prevalent with the advent of

A)coal burning stoves.
B)the industrial revolution.
C)smelting of ores.
D)widespread,deliberately set forest fires.
E)automobiles.

Question 72

Which of the following statements about ozone (O3)is false?

A)Ozone in the stratosphere protects human health.
B)Ozone in the lower atmosphere protects human health.
C)Stratospheric ozone absorbs harmful radiation.
D)Tropospheric ozone is a component of photochemical smog.
E)Tropospheric ozone can damage plants.

Question 73

At CO levels of 100 ppm or less in the bloodstream

A)humans might develop a headache and have losses in vision and judgment.
B)there is no noticeable health effects.
C)the human bloodstream is unaffected.
D)carbon monoxide has only minor health effects.
E)no physiological disruptions will be noticed.

Question 74

Acid deposition results from

A)carbonic acids dissolved from atmospheric carbon dioxide.
B)nitric acid and sulfuric acid,formed from nitrogen oxides and sulfur dioxide.
C)hydrocarbons,nitrogen dioxide,and carbon monoxide.
D)hydrochloric acid.
E)tropospheric ozone.

Question 75

Chemical reactions and pollutants from industrial smog Industrial smog is

A)composed primarily of O3 and PANs.
B)principally associated with coal-burning industries and electrical generation.
C)a relatively recent problem that developed during the latter half of this century.
D)principally associated with transportation.
E)unrelated to the phenomena of acid deposition.

Question 76

O3 in the lower troposphere

A)forms acid rain.
B)is not associated with transportation.
C)causes lung irritation,asthma,and susceptibility to respiratory illness in humans.
D)has not been found to cause any damage to crops and plants.
E)is considered beneficial in trapping UV radiation.

Question 77

Which of the following is true regarding acid deposition?

A)Hundreds of lakes are incapable of supporting life due to high acidity.
B)Acid deposition is deposition that measures more than 7.0 on a pH scale.
C)No lakes or streams have been damaged by acid precipitation.
D)Soil processes generally are not affected by acid precipitation.
E)Natural precipitation typically falls between pH 7.5 and 8.0.

Question 78

The lower the pH of a liquid,

A)the more acidic it is.
B)the more basic (alkaline)it is.
C)the more neutral it is.
D)the more chemical reactive it is.
E)the more ammonia present.

Question 79

Sources of natural variable pollutants and materials include all of the following except

A)volcanoes.
B)forest fires.
C)plants and decaying plants.
D)industrial activity.
E)windblown dust.

Question 80

Which of the following best describes air pollution?

A)Both natural and anthropogenic gases,particles,and other substances in amounts that cause damage to the environment or are harmful to humans.
B)Solely anthropogenic gases,particles,and other substances in amounts that cause damage to the environment or are harmful to humans.
C)Solely natural gases,particles,and other substances in amounts that cause damage to the environment or are harmful to humans.
D)A distinct class of gases,particles,and other substances that the EPA has deemed worthy of regulating.
E)The release of certain gases,particles,and other substances to the air in quantities that exceed local,state,federal,and international laws.