Learning Objectives
By the end of this chapter the reader will be able to:
•Describe historically important air pollution episodes
•List health effects associated with air pollution
•Describe potential hazards linked to indoor air
•Enumerate the typical components of urban ambient
air pollution
•Discuss the concept of global warming
Air Quality
•Many European cities do not meet World Health
Organization (WHO) air quality standards for at least one
pollutant.
•In the US in 2016, about half of Americans lived in areas
that do not meet US air quality standards.
•Air pollution was not an issue until the Industrial
Revolution in the early 1900s
oThe term smog was coined in the mid-1900 after it was observed
oEpisodes of air pollution disaster have occurred over time that have
brought attention to how we were “dumping” pollutants in the atmosphere
oLed to the first Clean Air Act in 1963 and subsequent amendments, the
latest in 1990 (epa.gov)
Smog
•Smogdenotes “A mixture of pollutants, principally
ground-level ozone, produced by chemical reactions in
the air involving smog-forming chemicals.”
•Formed by anthropogenic and/or natural sources
•Smog Complex
oIrritation of the eyes and respiratory tracts, chest pains, cough,
shortness of breath, nausea and headache associated with
exposure to smog
•The following images show the smog (haze) in two major
cities. The lower image also shows a good example of
thermal inversion, discussed later.
Smog
Effects of Air Pollution
Health
•Some forms of cancer such as lung cancer and skin
cancer
•Damage to vital tissues and organs, such as the
nervous system
•Impairment of lung and breathing function
Environmental
•Causes property damage
•Reduces visibility in national parks
•Harms forests
•Harms lakes and other bodies of water
•Injures wildlife
Lethal Air Pollution
Episodes in History
•Meuse Valley in Belgium (1930)
o60 deaths in 20 years
•Donora, Pennsylvania (1948)
oAffected half of the town’s population and
caused 20 deaths
•London, England (1952)
o3,000 more deaths in that year
Air pollution
•Composition of Pure Air (by Weight)
oNitrogen (76%)
oOxygen (23%)
oArgon (1%)
oCarbon dioxide (0.03%)
oVariety of other gases in lesser amounts
oWater vapor
•When any thing else is added or trace elements
increase, air becomes polluted
Natural Sources of Air Pollution
•Wind storms that spread dust clouds
•Salt evaporation along the earth’s coasts
•Production of materials that have a biologic
origin (e.g., mold spores, pollen, organic
material from plants and animals)
•Forest fires
•Volcanic eruptions
Figure 10-6 Eruption of Mount
Saint Helens on May 18, 1980.
Source: Reprinted from
the Centers for Disease
Control and Prevention.
Public Health Image
Library. ID #4726.
Available at:
http://phil.cdc.gov/Phil/d
etails.asp. Accessed
March 22, 2010.
Anthropogenic Sources of
Air Pollution
Stationary sources
•Electric generating plants
•Factories and manufacturing complexes
•Oil refineries
•Chemical plants
•Incinerators
•Gasses from sewer systems
Anthropogenic Sources of
Air Pollution
Mobile sources
•On-road vehicles
oExamples: cars, trucks, buses
•Off-road vehicles
oExamples: dune buggies, snowmobiles
•Nonroadvehicles
oExamples: airplanes, ships, trains
•According to the EPA, motor vehicles produce nearly
halfof two major causes of smog -VOCs and NO
x-
almost 75% of carbon monoxide, and more than half of
emissions of toxic air pollutants.
Common Components
of Air Pollution
•Sulfur oxides
•Particulate matter
•Oxidants (ozone)
•Carbon monoxide
•Hydrocarbons
•Nitrogen oxides
•Lead
•Other heavy metals
Criteria Air Pollutants
•Used to describe “A group of very common air
pollutants regulated by EPA on the basis of
criteria (information on health and/or
environmental effects of pollution).”
•Criteria air pollutants are
oOzone
oNitrogen oxides
oCarbon monoxide
oSulfur dioxide
oParticulate matter
oLead
Overview table
next slide
Ozone
•Ozone occurs naturally and helps to protect us from the
sun’s harmful ultraviolet UV rays.
•In the lower atmosphere, ozone is the most pervasive
outdoor air pollutant in the United States.
oMajor component of smog
oFormed when pollutants released by cars, power plants, and
other sources react with sunlight.
oCan irritate the lungs and cause severe coughing, shortness of
breath, and pain when breathing.
oOzone exposure also can trigger asthma attacks
Nitrogen Oxides
•Automobile emissions and emissions from coal
burning power plants are the primary sources of
nitrogen oxides in the atmosphere.
•At low levels of exposure, nitrogen oxides can
irritate the eyes, nose, throat, and lungs, and
may cause coughing, shortness of breath, and
nausea.
•High levels of exposure can seriously damage
tissues in the throat and upper respiratory tract
and trigger the build-up of fluid in the lungs.
Carbon Monoxide
•Colorless, odorless, poisonous gas produced by the
incomplete combustion of fossil fuels
•Exposure to high levels of CO can result in death or
serious health consequences
•Indoor sources include stoves, heaters, and tobacco
smoke
•Hemoglobin has as a greater affinity for CO than O
2
oCarboxyhemoglobin
Volatile Organic Compounds
•VOCs are organic compounds that easily form vapors at
room temperature.
•In outdoor air, VOCs are generated primarily by power
plants, automobiles, and industry.
•Indoors, VOCs are emitted by a number of household
items, such as paint, paint thinner, cleaning supplies,
glue, and markers.
•Short-term
oIrritate the respiratory tract and eyes and cause dizziness and
headaches.
•Long-term
olinked to cancer and a number of adverse neurological,
reproductive, and developmental effects.
Particulate Matter (PM)
•PM
10and PM
2.5
oParticles of both sizes cause
respiratory system irritation and
impact the lungs.
oProduced primarily by the
combustion of fossil fuels by
cars, power plants, and
industry
oPM is one of the nation’s
deadliest air pollutants.
•PM
2.5particles are capable of being inhaled deeply into the lungs.
•PM
2.5particles are not cleared readily from the body.
•PM
2.5 particles could beassociated with 60,000 deaths annually
(U.S.).
Sulfur Dioxide (SO
2)
•Released to the atmosphere mainly by the burning of
coal and oil and by industrial processes such as the
smelting of metallic ores.
•Produced in nature by processes such as decomposition
and volcanic eruptions, but human activities are the
primary contributor to SO
2pollution
•Electric utilities alone account for nearly two-thirds of
annual sulfur dioxide emissions.
•At high exposure levels, sulfur dioxide can cause
temporary breathing difficulty for people with asthma and
long-term exposure to high levels of SO
2can cause
respiratory illness and aggravate cardiovascular
diseases.
Acid Rain
•Refers to the precipitation of acidic compounds
formed when components of air pollution (e.g.,
SO
2and NO
x) interact with other components in
the air such as water, oxygen, and oxidants.
•Emissions of SO
2and NO
xare produced by
installations such as electric utility plants.
•Creates abnormally high levels of acidity that are
potentially damaging to the environment, wildlife,
and human health.
Figure 10.11 Acid rain pathway.
Reproduced from US Environmental Protection Agency.
What is acid rain? Available at:
https://www.epa.gov/acidrain/what-acid-rain.
Accessed June 6, 2017.
* Numbers shown in figure refer to the pathway for acid rain in our environment.
1
Emissions of SO2 and NOx are released into the air.
2
The pollutants are transformed into acid particles that may be transported long distances.
3
These acid particles then fall on earth as dust, rain, snow, and other materials.
4
The acid rain particles may cause harmful effects on soil, forests, streams, and lakes.
Temperature Inversion
•An atmospheric condition
during which a warm layer of
air stalls above a layer of cool
air that is closer to the
surface of the earth
•During a temperature
inversion, pollutants can build
up when they are trapped
close to the earth’s surface.
•Image next slide shows an
actual example of this.
Temperature Inversion
Diesel Exhaust
•A complex mixture of particles and gases; includes the
element carbon, condensed hydrocarbongases, and
polycyclic aromatic hydrocarbons (PAHs), the latter
suspected of being carcinogens.
•Other constituents are hundreds of organic and inorganic
compounds, some of which are regarded as toxic air
pollutants.
•Epidemiologic evidence suggests that in comparison
with nonexposed groups, two categories of workers
exposed directly to diesel exhaust have lung cancer
incidence rates that are 20% to 40% higher.
The Air Quality Index
•The Air Quality Index, determined by the EPA, is used to
provide the public with an indication of air quality in a local
area on a daily basis.
•It focuses on health effects you may experience within a
few hours or days after breathing polluted air.
National Ambient Air
Quality Standards (NAAQS)
•Federal standards for air pollution
•The EPA reviews the scientific literature at 5-year
intervals and decides whether to revise each standard.
•Primary standardsset limits to protect public health,
including the health of ‘sensitive’ populations such as
asthmatics, children, and the elderly.
•Secondary standardsset limits to protect public
welfare, including protection against decreased visibility,
damage to animals, crops, vegetation, and buildings.
Effects of Air Pollution
Acute
•Irritation of the eyes,
nose, and throat
•Aching lungs
•Bronchitis
•Pneumonia
•Wheezing
•Coughing
•Nausea
•Headaches
Chronic
•Heart disease
•Chronic obstructive
pulmonary disease
•Lung cancer
Right lung and Left tracheobronchial tree
Effects of Air Pollution
Asthma
oGrowing health problem world wide
oIrritates bronchial passageways
oPrevalence in the U.S. has increased over 34%
Chronic bronchitis
oExcessive mucus build-up over time causing a
chronic cough
oSO
2has a direct effect as well as cigarette smoking
Effects of Air Pollution
Coronary Heart Disease
oThose with underlying conditions have a higher risk
for the aggravating effects of pollution
oCigarette smoke and air pollution work
synergistically to aggravate lung disease
Lung Cancer
oGeneral assumptions can be made but research is
challenged in finding a specific correlation.
oIndividual studies have shown health effects with
specific demographic areas once smoking has been
controlled as a variable.
Poor Indoor Air Quality
•Many People Spend 90% of Time Indoors
•Illness can occur if indoor air is not circulated at a regular
rate
•We will cover this section in Green Building Design later
in the semester.
Global Warming
•“An increase in the near surface temperature of the
Earth. . . . [is] predicted to occur as a result of increased
emissions of greenhouse gases.”
•“Scientists generally agree that the Earth’s surface has
warmed by about 1 degree Fahrenheit in the past 140
years.”
Causes
•Use of fossil fuels, including coal and petroleum-based
fuels
•Chlorofluorocarbon gases used in air conditioners
•Linked to the depletion of the ozone layer
Global Warming
•Exchange of Carbon (C) between the
biosphere and atmosphere
o78% N, 20.95% O
2, 0.93% Ar, 0.038% CO
2,
trace amounts of other gases, and <1% H
2O
(vapor).
oHistorically fluctuated between 200 and 270
ppm
oToday upwards around 390 ppm
oSources (next slide)
•Combustion of fossil fuels, burning, humans
oSinks
•Vegetation, oceans
•Impacts of urbanization (above) and deforestation
(below) have a major impact on sources and
sinks.
Greenhouse Effect
•UV rays that bypass stratospheric ozone reach the lower
atmosphere
•Some are reflected back into space by dust particles and
the earth’s surface
•Some is absorbed by water vapor and other components
to help maintain earth’s temperature
•However, more and more radiation is being absorbed
because of an increase in gasses in the atmosphere
•This trapped radiation can cause an increase in earth’s
temperature
Click to watch a brief overview of Greenhouse Gasses
Potential Impacts of
Global Warming
•HighCO
2 leads to:
oIncrease temps
oArid soils
•Accelerated evaporation
oIcemelts
oRising seas
oChange in seasons
•Migration/hibernation
effects
oMore destructive storms
Potential Impacts of
Global Warming
•Health Implications
oDirect Temperature affects
•Illness due to heat waves
oExtreme Weather Events
•hurricanes, floods, etc
oGrowth of vector-borne infectious disease
•Malaria, yellow fever, cholera, Lyme disease
oAsthma and Respiratory disease
•Increase in ozone and particulate matter
oIndirect through agricultural yields and production
Potential Impacts of
Global Warming
Air Pollution in the U.S.
•U.S. produces 23% of the earth’s emissions of greenhouse
gases.
•Major source of air pollution in the U.S. is combustion of
fossil fuels, particularly by coal-fired electric generating
plants and internal combustion engines.
•The U.S., with only about 4% of the world’s population, is
the second leading source of carbon dioxide pollution.
oChina is the current leader
Laws to Reduce Emissions
of Harmful Air Pollution
Clean Air Act (1970)
•Air pollution is regulated by the Environmental Protection
Agency (EPA) under authority granted by Congress in
the Clean Air Act (page 87)
•http://www.epa.gov/air/caa/
•Still 150 million people across the United States continue
to live in areas with unhealthful levels of air pollution in
the form of either ozone or particle pollution.
Improvements Since Clean Air Act
•Smog has been reduced by 12%
•Lead levels in the air have decreased by 89%
•SO
2levels have declined by 26%
•NO
2levels have dropped by 12%
•Particulate levels have decreased by 20%
Steps to Reduce Emissions
of Harmful Air Pollution
•Several mechanical devices are used to reduce
industrial emissions of particulate matter
oCatalytic converters
•Improves the combustion efficiency of petroleum products as to
reduce the amount of CO, NO, and hydrocarbons that enter the air
oGasification
•Removal of SO
2and conversion of coal to a gas form to reduce
sulfur oxides in the air
oBag House method
•Utilizes fabric bags to capture particulate matter before it enter the
air
•Inexpensive but not very effective
oElectrostatic Precipitators
•Charges particles low in a smoke stack so they would be electrically
attracted to metal plates further up the stack
Stabilizing Climate
•Kyoto Protocol was good but inadequate
•An international and legally binding compact that
was initiated in Kyoto, Japan, in 1997.
•Goal is to reduce emissions of greenhouse
gases that are believed to be the cause of recent
climate changes.
•Requires developed countries to reduce their
emissions by targeted amounts.
oFor example, the U.S. would be required to cut emissions by 7%
and European countries by 8%.
Stabilizing Climate
•In order for the Kyoto Protocol to come into
effect, it needed to be ratified by a sufficient
number of industrialized countries that in
combination produce at least 55% of the world’s
total CO
2emissions.
•By February 2005, 141 nations including Russia
had ratified the protocol, meaning that it could
be implemented.
oThe Kyoto Protocol went into force on February 16, 2005.
oThe U.S. did not ratify.
oThis, along with the Copenhagen Climate Change Conference
(next slide), has made the world aware that there are issues with
air quality.
Stabilizing Climate
Copenhagen Accord, 2009
•Spearheaded by the U.S., China, and several other
countries
•Sought to curb greenhouse gases and keep global
temperature increase below 2 degrees Celsius between
2010 and 2040
•Talks became deadlocked
Stabilizing Climate
Paris Agreement, December 2015
•A legally binding agreement
•Adopted by 195 countries
•Sought to limit global temperature rise during the current
century to 2 degrees Celsius
•United States announced withdrawal from the agreement
on June 1, 2017
Stabilizing Climate
•Look to sources other than coal, or at least,
improve the efficiency of coal plants
•Increasing power needs for increasing population
oImprove efficiency standards for household
appliances
oStringent residential air conditioning efficiency
standards
oRaising commercial air conditioning standards
oUsing tax credits and energy codes to improve new
building standards
oReview and improve current building efficiency
oCoal closures set
Stabilizing Climate
•The measures on the previous slide would decrease the
need for up to 600 coal burning plants
•Use energy-efficient designs in home construction and
electrical appliances; try to reduce dependence on
appliances.
oIncandescent lamp and compact fluorescent lamps replaced with LEDs
•Greater longevity and lower energy usage
•Increase the fuel efficiency of motor vehicles.
oFully electric
oHybrid gas-electric
oOther high-mileage designs
•Redesign Urban Transport
•Use bicycles.
Stabilizing Climate
•Harnessing the wind
oHas seen significant increases in use (below)
oCheap, abundant, inexhaustible, widely-distributed,
clean, climate benign
oAlmost down to generating electricity at 2 cents per
kilowatt
•Shell, GE, and BP
Stabilizing Climate
Country Windpower Production % of World Total
United States 140.9 26.4
China 118.1 22.1
Spain 49.1 9.2
Germany 46.0 8.6
India 30.0 5.6
United Kingdom 19.6 3.7
France 14.9 2.8
Italy 13.4 2.5
Canada 11.8 2.2
Denmark 10.3 1.9
(rest of world) 80.2 15.0
World Total 534.3TWh 100%
Source:Observ'ER–Electricity Production From Wind Sources [2012]
[60]
Stabilizing Climate
•Solar power
oContinually growing in energy production
oMostly for water heating and electricity needs
oTapping into grids is still an issue
Electricity Generation from Solar
Year Energy (TWh) % of Total
2004 2.6 0.01%
2005 3.7 0.02%
2006 5.0 0.03%
2007 6.8 0.03%
2008 11.4 0.06%
2009 19.3 0.10%
2010 31.4 0.15%
2011 60.6 0.27%
2012 96.7 0.43%
2013 134.5 0.58%
2014 185.9 0.79%
Source:BP-Statistical Review of World Energy, 2015
[23][24]
Stabilizing Climate
•Geothermal
oinexhaustible
oJapan –69,000 megawatt capacity
oCalifornia –5-10% of its energy is produced
by this
oIceland –93% of homes
oMore than 30 countries tap into geothermal
for heat
Energy Conservation Steps
to Reduce Air Pollution
•Increase the efficiency of older power plants.
•Develop more renewable and alternative energy
sources, e.g., wind turbines and solar panels.
•Use energy-efficient designs in home construction
and electrical appliances; try to reduce
dependence on such appliances.
•Increase the fuel efficiency of motor vehicles as in
the use of hybrid gas-electric and other high-
mileage designs.
•Increase the use of public transportation.