Chapter 10Chapter 10

Air Quality

Learning ObjectivesLearning ObjectivesBy 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 QualityAir Quality• Many European cities do not meet World Health

Organization (WHO) air quality standards for at least one pollutant.

• 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 1900so The term smog was coined in the mid-1900 after it was observedo Episodes of air pollution disaster have occurred over time that have

brought attention to how we were “dumping” pollutants in the atmosphere

o Led to the first Clean Air Act in 1963 and subsequent amendments, the latest in 1990 (epa.gov)

SmogSmog• Smog denotes “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

o Irritation of the eyes and respiratory tracts, chest pains, cough, shortness of breath, nausea and headache associated with exposure to smog

SmogSmog

Effects of Air PollutionEffects of Air PollutionHealth•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 Lethal Air Pollution Episodes in HistoryEpisodes in History

• Meuse Valley in Belgium (1930)o 60 deaths in 20 years

• Donora, Pennsylvania (1948)oAffected half of the town’s

population and caused 20 deaths• London, England (1952)

o 3,000 more deaths in that year

Air pollutionAir pollution• Composition of Pure Air (by Weight)

oNitrogen (76%)oOxygen (23%)o Argon (1%)oCarbon dioxide (0.03%)o Variety of other gases in lesser amounts oWater vapor

• When any thing else is added or trace elements increase, air become polluted

Natural Sources of Air Natural Sources of Air PollutionPollution

• Wind storms that spread dust clouds• Salt evaporation along the earth’s coasts • Production of materials that have a

biologic origin • Forest fires• Volcanic eruptions

Figure 10-5 Figure 10-5 Eruption of Eruption of Mount Saint Helens on May Mount Saint Helens on May

18, 1980.18, 1980.

Source: Reprinted from the Centers for Disease Control and Prevention. Public Health Image Library. ID #4726. Available at: http://phil.cdc.gov/Phil/details.asp. Accessed March 22, 2010.

Anthropogenic Sources of Anthropogenic Sources of Air PollutionAir Pollution

Stationary sources•Electric generating plants•Factories and manufacturing complexes•Oil refineries•Chemical plants•Incinerators•Gasses from sewer systems

Anthropogenic Sources of Anthropogenic Sources of Air PollutionAir Pollution

Mobile sources•On-road vehicles •Off-road vehicles •Non-road vehicles

•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.

Common ComponentsCommon Componentsof Air Pollutionof Air Pollution

• Sulfur oxides• Particulate matter• Oxidants (ozone)• Carbon monoxide• Hydrocarbons• Nitrogen oxides• Lead• Other heavy metals

Criteria Air PollutantsCriteria 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 o Ozoneo Nitrogen oxideso Carbon monoxideo Sulfur dioxideo Particulate mattero Lead

OzoneOzone• 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 smogo 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 the lung. 

Nitrogen OxidesNitrogen 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 MonoxideCarbon 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

O2o Carboxyhemoglobin

Volatile Organic CompoundsVolatile 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 o Irritate the respiratory tract and eyes and cause

dizziness and headaches. • Long-term

o linked to cancer and a number of adverse neurological, reproductive, and developmental effects.

Particulate Matter (PM)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

annually (U.S.).

Sulfur Dioxide (SOSulfur Dioxide (SO22))• 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 cardiovascular diseases. 

Acid RainAcid Rain• 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.

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.

Figure 10-9 Acid rain formation.

Temperature InversionTemperature 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.

Temperature InversionTemperature Inversion

Diesel ExhaustDiesel Exhaust• 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 IndexThe 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 basis.

• It focuses on health effects you may experience within a few hours or days after breathing polluted air.

National Ambient Air National Ambient Air Quality Standards Quality Standards

(NAAQS)(NAAQS)• Federal standards for air pollution• The EPA reviews the scientific literature at 5-year

intervals and decides whether to revise each standard.

• 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 buildings.

Effects of Air PollutionEffects of Air PollutionAcute•Irritation of the eyes, nose, and throat•Aching lungs•Bronchitis•Pneumonia •Wheezing•Coughing•Nausea•Headaches

Chronic•Heart disease•Chronic obstructive pulmonary disease •Lung cancer

Effects of Air PollutionEffects of Air PollutionAsthma

o Growing health problem world wideo Irritates bronchial passagewayso Prevalence in the U.S. has increased over 34%

Chronic bronchitiso Excessive mucus build-up over time causing a

chronic cougho SO2 has a direct effect as well as cigarette

smoking

Effects of Air PollutionEffects of Air PollutionCoronary 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

Lung Cancero General assumptions can be made but research

is challenged in finding a specific correlation.o Individual studies have shown health effects

with specific demographic areas once smoking has been controlled as a variable.

Poor Indoor Air QualityPoor 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 WarmingGlobal 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

Global WarmingGlobal Warming• Exchange of Carbon (C) between the

biosphere and atmosphereo 78% N, 20.95% O2, 0.93% Ar, 0.038%

CO2, trace amounts of other gases, and <1% H2O (vapor).

oHistorically fluctuated between 200 and 270 ppm

o Today upwards around 390 ppm• Sources and Sinks?

o Combustion of fossil fuels, burning, humanso Vegetation, oceans

Greenhouse EffectGreenhouse 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

Potential Impacts of Potential Impacts of Global WarmingGlobal Warming

• High CO2 leads to:o Increase tempso Arid soils

• Accelerated evaporation

o Icemeltso Rising seaso Change in seasons

• Migration/hibernation effects

o More destructive storms

Potential Impacts of Potential Impacts of Global WarmingGlobal Warming

• Health Implicationso Direct Temperature affects

• Illness due to heat waveso Extreme Weather Events

• hurricanes, floods, etco Vector-borne infectious disease

• Malaria, yellow fever, cholera, Lyme diseaseo Asthma and Respiratory disease

• Increase in ozone and particulate mattero Indirect through agricultural yields and

production

Potential Impacts of Potential Impacts of Global WarmingGlobal Warming

Air Pollution in the U.S.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 leading source of carbon dioxide pollution.

Clean Air Act (1970)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)

• 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.

ImprovementsImprovements• 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%

Clean-upClean-up• 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 other source.

o Power plants emit more toxic metals that harm pregnant women and children (mercury) than any other source.

Stabilizing ClimateStabilizing 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. 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%.

Stabilizing ClimateStabilizing 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 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, 2005.

• The U.S. did not ratify.

Copenhagen Accord, Copenhagen Accord, 20092009

• 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

Technological ControlsTechnological Controls• 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

o Gasification• Removal of SO2 and conversion of coal to a gas form to

reduce sulfur oxides in the airo Bag House method

• Utilizes fabric bags to capture particulate matter before it enter the air

• Inexpensive but not very effectiveo Electrostatic Precipitators

• Charges particles low in a smoke stack so they would be electrically attracted to metal plates further up the stack

Stabilizing ClimateStabilizing Climate• Look to sources other than coal• Increasing power needs for increasing

populationo Improve efficiency standards for household

applianceso Stringent residential air conditioning efficiency

standardso Raising commercial air conditioning standardso Using tax credits and energy codes to improve

new building standardso Review and improve current building efficiency

o Coal closures set

Stabilizing ClimateStabilizing Climate• The measures on the previous slide would

decrease the need for up to 600 coal burning plants

• Incandescent lamp replacement with compact fluorescent lampso Greater longevity and lower energy usage

• Shift to gas-electric hybridso Price of gas?

• Redesign Urban Transport

Stabilizing ClimateStabilizing Climate• 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, Germanyo Cheap, abundant, inexhaustible, widely-

distributed, clean, climate benigno Almost down to generating electricity at 2

cents per kilowatt• Shell, GE, and BP

Stabilizing ClimateStabilizing Climate• Solar power

oUp to 6000 Megawatts to over 9000 next year

oMostly for water heating and electricity needs

o Tapping into grids

Stabilizing ClimateStabilizing Climate• Geothermal

o inexhaustibleo Japan – 69,000 megawatt capacityoCalifornia – 5-10% of its energy is

produced by thiso Iceland – 93% of homesoMore than 30 countries tap into

geothermal for heat

Energy Conservation Steps Energy Conservation Steps to Reduce Air Pollutionto 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.