By the end of this chapter the reader will be able
• Describe historically important air pollution
• 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
• Many European cities do not meet World Health
Organization (WHO) air quality standards for at least
• In the U.S., about a quarter of the population lives in
areas that do not meet U.S. air quality standards.
• Air pollution was not an issue until the Industrial
Revolution in the early 1900s
o The term smog was coined in the mid-1900 after it was observed
o Episodes of air pollution disaster have occurred over time that
have brought attention to how we were “dumping” pollutants in
o Led to the first Clean Air Act in 1963 and subsequent amendments,
the latest in 1990 (epa.gov)
• Smog denotes “A mixture of pollutants, principally
ground-level ozone, produced by chemical
reactions in the air involving smog-forming
• Formed by anthropogenic and/or natural sources
• Smog Complex
o Irritation of the eyes and respiratory tracts, chest pains,
cough, shortness of breath, nausea and headache
associated with exposure to smog
Effects of Air Pollution
•Some forms of cancer such as lung cancer and
•Damage to vital tissues and organs, such as the
•Impairment of lung and breathing function
•Causes property damage
•Reduces visibility in national parks
•Harms lakes and other bodies of water
Lethal Air Pollution
Episodes in History
• Meuse Valley in Belgium (1930)
o 60 deaths in 20 years
• Donora, Pennsylvania (1948)
o Affected half of the town’s
population and caused 20 deaths
• London, England (1952)
o 3,000 more deaths in that year
• Composition of Pure Air (by Weight)
o Nitrogen (76%)
o Oxygen (23%)
o Argon (1%)
o Carbon dioxide (0.03%)
o Variety of other gases in lesser amounts
o Water vapor
• When any thing else is added or trace
elements increase, air become 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
• Forest fires
• Volcanic eruptions
Figure 10-5 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.
March 22, 2010.
Anthropogenic Sources of
•Electric generating plants
•Factories and manufacturing complexes
•Gasses from sewer systems
Anthropogenic Sources of
•According to the EPA, motor vehicles produce
nearly half of two major causes of smog - VOCs
and NOx - almost 75% of carbon monoxide, and
more than half of emissions of toxic air pollutants.
of Air Pollution
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
• 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.
o Major component of smog
o Formed when pollutants released by cars, power plants,
and other sources react with sunlight.
o Can irritate the lungs and cause severe coughing,
shortness of breath, and pain when breathing.
o Ozone exposure also can trigger asthma attacks,
aggravate chronic lung diseases like emphysema and
bronchitis, increase the body’s susceptibility to respiratory
infections, and cause permanent damage to the lining of
• Automobile emissions and emissions from
coal burning power plants are the primary
sources of nitrogen oxides in the
• 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.
• 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
• Hemoglobin has as a greater affinity for CO than O2
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.
o Irritate the respiratory tract and eyes and cause dizziness
o linked to cancer and a number of adverse neurological,
reproductive, and developmental effects.
Particulate Matter (PM)
• PM10 and PM2.5
o Particles of both sizes cause respiratory system irritation
and impact the lungs.
o Produced primarily by the combustion of fossil fuels by
cars, power plants, and industry
o PM is one of the nation’s deadliest air pollutants.
• PM2.5 particles are capable of being inhaled deeply
into the lungs.
• PM2.5 particles are not cleared readily from the body.
• PM2.5 particles are associated with 60,000 deaths
Sulfur Dioxide (SO2)
• 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 SO2 pollution
• 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 SO2
can cause respiratory illness and aggravate
• Refers to the precipitation of acidic
compounds formed when components of
air pollution (e.g., SO2 and NOx) interact with
other components in the air such as water,
oxygen, and oxidants.
• Emissions of SO2 and NOx are 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 10-9 Acid rain formation.
Source: Reprinted from US Environmental Protection Agency. AIRTrends 1995 Summary: Acid Rain. Available at:
http://www.epa.gov/air/airtrends/aqtrnd95/acidrain.html. Accessed March 22, 2010.
• 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
• A complex mixture of particles and gases; includes
the element carbon, condensed hydrocarbon
gases, 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 (truck drivers and railroad
crews) exposed directly to diesel exhaust have lung
cancer incidence rates that are 20% to 40% higher.
The Air Quality Index
• The Air Quality Index is used to provide the public with
an indication of air quality in a local area on a daily
• 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
• Primary standards set limits to protect public health,
including the health of ‘sensitive’ populations such
as asthmatics, children, and the elderly.
• Secondary standards set limits to protect public
welfare, including protection against decreased
visibility, damage to animals, crops, vegetation, and
Effects of Air Pollution
•Irritation of the eyes,
nose, and throat
Effects of Air Pollution
o Growing health problem world wide
o Irritates bronchial passageways
o Prevalence in the U.S. has increased over 34%
o Excessive mucus build-up over time causing a
o SO2 has a direct effect as well as cigarette
Effects of Air Pollution
Coronary Heart Disease
o Those with underlying conditions have a higher
risk for the aggravating effects of pollution
o Cigarette smoke and air pollution work
synergistically to aggravate lung disease
o General assumptions can be made but
research is challenged in finding a specific
o Individual 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
• We will cover this section in Green Building Design
later in the semester.
• “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.”
• Use of fossil fuels, including coal and petroleumbased fuels
• Exchange of Carbon (C) between the
biosphere and atmosphere
o 78% N, 20.95% O2, 0.93% Ar, 0.038% CO2,
trace amounts of other gases, and <1%
o Historically fluctuated between 200 and
o Today upwards around 390 ppm
• Sources and Sinks?
o Combustion of fossil fuels, burning, humans
o Vegetation, oceans
• UV rays that bypass stratospheric ozone reach the
• 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
• This trapped radiation can cause an increase in
Potential Impacts of
• High CO2 leads to:
o Increase temps
o Arid soils
o Rising seas
o Change in seasons
o More destructive
Potential Impacts of
• Health Implications
o Direct Temperature affects
• Illness due to heat waves
o Extreme Weather Events
• hurricanes, floods, etc
o Vector-borne infectious disease
• Malaria, yellow fever, cholera, Lyme disease
o Asthma and Respiratory disease
• Increase in ozone and particulate matter
o Indirect through agricultural yields and
Air Pollution in the U.S.
• U.S. produces 23% of the earth’s emissions of
• 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 leading source of carbon dioxide 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 84)
• 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
• Smog has been reduced by 12%
• Lead levels in the air have decreased by 89%
• SO2 levels have declined by 26%
• NO2 levels have dropped by 12%
• Particulate levels have decreased by 20%
• These "grandfathered" power plants are exempt from the
Clean Air Act, despite reasonably priced technologies
that could dramatically reduce their pollution levels.
o Power plants emit more deadly soot (sulfur dioxide) than any other source,
causing asthma attacks, respiratory disease, and premature death.
o Power plants are the single largest source of acid rain-forming pollution (sulfur
dioxide and nitrogen oxides).
o Power plants are the second largest source of the pollution that triggers "ozone
smog alert" days, asthma attacks, and lung disease (nitrogen oxides) – second
only to the combined emissions of the 200 million vehicles in the US fleet today.
o Power plants emit more global warming pollution (carbon dioxide) than any
o Power plants emit more toxic metals that harm pregnant women and children
(mercury) than any other source.
• Kyoto Protocol was good but inadequate
• An international and legally binding
compact that was initiated in Kyoto, Japan,
• 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. For
example, the U.S. would be required to cut
emissions by 7% and European countries
(Switzerland, Central and Eastern Europe,
and the European Union) by 8%.
• 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 CO2 emissions.
• By February 2005, 141 nations including
Russia had ratified the protocol, meaning
that it could be implemented. The Kyoto
Protocol went into force on February 16,
• The U.S. did not ratify.
Copenhagen Accord, 2009
• Spearheaded by the U.S., China, and several other
• Sought to curb greenhouse gases and keep global
temperature increase below 2 degrees Celsius
between 2010 and 2040
• Talks became deadlocked
• Several mechanical devices are used to reduce
industrial emissions of particulate matter
o Catalytic converters
• Improves the combustion efficiency of petroleum products as
to reduce the amount of CO, NO, and hydrocarbons that
enter the air
• Removal of SO2 and conversion of coal to a gas form to
reduce sulfur oxides in the air
o Bag House method
• Utilizes fabric bags to capture particulate matter before it
enter the air
• Inexpensive but not very effective
o Electrostatic Precipitators
• Charges particles low in a smoke stack so they would be
electrically attracted to metal plates further up the stack
• Look to sources other than coal
• Increasing power needs for increasing
o Improve efficiency standards for household
o Stringent residential air conditioning efficiency
o Raising commercial air conditioning standards
o Using tax credits and energy codes to improve
new building standards
o Review and improve current building efficiency
o Coal closures set
• The measures on the previous slide would decrease
the need for up to 600 coal burning plants
• Incandescent lamp replacement with compact
o Greater longevity and lower energy usage
• Shift to gas-electric hybrids
o Price of gas?
• Redesign Urban Transport
• Harnessing the wind
o End of 2006 world producing energy from
wind is up to 74,000 megawatts
• Most of which is in Denmark , Spain, Germany
o Cheap, abundant, inexhaustible, widelydistributed, clean, climate benign
o Almost down to generating electricity at 2
cents per kilowatt
• Shell, GE, and BP
• Solar power
o Up to 6000 Megawatts to over 9000 next
o Mostly for water heating and electricity
o Tapping into grids
o Japan – 69,000 megawatt capacity
o California – 5-10% of its energy is
produced by this
o Iceland – 93% of homes
o More 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
• 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.