Air pollution

Part B

SMOG…• Is worse on hotter days• Increases as traffic increases• Is more common in cities with sunny, warm

and dry climates with lots of cars like LA, Denver, Sydney (Australia), Mexico City, Jakarta (Indonesia) and Santiago (Chile)

A Model of How Pollutants That Make Up Photochemicals Are Formed

Several Factors Can Several Factors Can Decrease Air PollutionDecrease Air Pollution

• Outdoor air pollution may be decreased by– Settling of particles due to gravity–Rain and snow– Salty sea spray from the ocean–Winds –Chemical reactions • ex. SO2 reacts with O2 in atmosphere to form SO3

which reacts with water vapor to form H2SO4-falls out as acid rain

• Outdoor air pollution may be increased by– Urban buildings– Hills and mountains– High temperatures– Emissions of VOCs from certain trees and plants –

oaks, sweet gums, kudzu – Grasshopper effect-volatile pollutants transported by

evaporation and wind from tropical and temp. areas– Temperature inversions– Precipitation, wind

Several Factors Can Several Factors Can Increase Outdoor Air Increase Outdoor Air

PollutionPollution

Look at the temperature inversion diagram in your text

18.3 Acid Deposition Is a Serious Regional Air Pollution Problem

Acid deposition, acid rain Formation

1) sulfur dioxide (SO2) - forms H2SO4 (sulfuric acid)2) nitrogen oxides (NOx) - forms HNO3 (nitric acid)In the U.S., ~ 2/3 of all SO2 and ~ 1/4 of all NOx comes from

electric power generation that relies on burning fossil fuel Local versus regional problems-tall smokestacks Effects of prevailing winds: prevailing winds can blow acidic

compounds over hundreds of milesa) wet deposition: acidic rain, fog, and snowb) dry deposition: acidic gases and particles

Soils with limestone/calcium carbonate neutralize acid deposition

Where is the worst acid deposition? Asia!! China is biggest emitter of SO2

In 1872, Robert Smith coined the term acid rain.

Natural Capital Degradation: Acid

Deposition, Acid Rain

Acid Deposition Has a Number of Acid Deposition Has a Number of Harmful EffectsHarmful Effects

Human respiratory disordersHuman respiratory disorders

Aquatic ecosystems affectedAquatic ecosystems affected: Leach metals such as Pb and Hg into : Leach metals such as Pb and Hg into water and can accumulate in tissues of fish. EX: Mercury (Hg) water and can accumulate in tissues of fish. EX: Mercury (Hg) in fish in fish

Most fish cannot survive in water with pH < 4.5Most fish cannot survive in water with pH < 4.5

AlAl+3+3 and Hg become more soluble and Hg become more soluble

Acid Shock - Acid Shock - A sudden acidification of runoff waters from the spring melting of accumulated snow in the middle latitudes because of the winter deposition of acidic precipitation.

Many lakes in Norway and Sweden have no fishMany lakes in Norway and Sweden have no fish

Acid Deposition Has a Acid Deposition Has a Number of Harmful EffectsNumber of Harmful Effects

Harms crops Harms crops by making soil too acidic (< 5.1)by making soil too acidic (< 5.1)Damage waxy coat on leavesDamage waxy coat on leaves Impair germinationImpair germinationLeaches nutrientsLeaches nutrientsReduces plant productivity and the ability of Reduces plant productivity and the ability of

soils to buffer acidic inputssoils to buffer acidic inputsSynergistic effectsSynergistic effects

Acid Deposition Has a Number of Acid Deposition Has a Number of Harmful EffectsHarmful Effects

Affects forests Affects forests by leaching plant nutrients such as Ca, Mg by leaching plant nutrients such as Ca, Mg and releasing ions of Al, Pb, Cd and Hg which are toxic to and releasing ions of Al, Pb, Cd and Hg which are toxic to trees) trees)

promotes acid-loving mosses that kill trees.promotes acid-loving mosses that kill trees.

Tree foliage damaged, making trees more susceptible to Tree foliage damaged, making trees more susceptible to cold temps, diseases, insects, drought, fungicold temps, diseases, insects, drought, fungi

Hubbard Brook Studies- found that trees do not suffer Hubbard Brook Studies- found that trees do not suffer directly from acid rain, but from insufficient nutrients. In directly from acid rain, but from insufficient nutrients. In order for trees to recover, nutrients need to be order for trees to recover, nutrients need to be replenished- this can take decades if left to nature.replenished- this can take decades if left to nature.

Damages exterior paint on cars and houses, Damages exterior paint on cars and houses, deteriorates roofing, marble statues, historic deteriorates roofing, marble statues, historic buildings, stain glass windows- costs $5 buildings, stain glass windows- costs $5 billion/yr in USbillion/yr in US

Is a regional problem that affects areas that Is a regional problem that affects areas that are downwind from large car-dominated are downwind from large car-dominated cities and from polluting coal-burning cities and from polluting coal-burning facilities (acidic components remain in air for facilities (acidic components remain in air for a few days)a few days)

Acid Deposition Has a Number of Acid Deposition Has a Number of Harmful EffectsHarmful Effects

Damage to buildings, statues, and monuments

effects of acid rain

Fig. 18-14a, p. 481

Emissions

SO2 H2O2 PANs

NOxAcid deposition O3

Others

Direct damage to leaves and bark

Reduced photosynthesis and growth

Increased susceptibility to drought, extreme cold, insects, mosses, and disease organisms

Soil acidification Tree death

Leaching of soil nutrients

Release of toxic metal ions

Root damage

Reduced nutrient and water uptakeAcids

Lake

Groundwater

Natural Capital Degradation: Air Pollution Damage

to Trees

We Know How to Reduce Acid Deposition

• Prevention approaches that reduce or eliminate emissions from SO2, nitrous oxide, and particulates. Remove S from coal before it is burned, use low-S coal, remove NOx from car exhaust. Tax emissions, improve energy efficiency.

• Reduce coal use? Expensive and cost passed on to consumers. Alternative energy sources? Areas affected are often far from sources.

• Clean up– Add lime to neutralize acidified lakes and soil

We Know How to Reduce Acid Deposition

• Prevention approaches that reduce or eliminate emissions from SO2, nitrous oxide, and particulates. Remove S from coal before it is burned, use low-S coal, remove NOx from car exhaust. Tax emissions, improve energy efficiency.

• Reduce coal use? Expensive and cost passed on to consumers. Alternative energy sources? Areas affected are often far from sources.

• Clean up– Add lime to neutralize acidified lakes and soil

18-4 Indoor Air Pollution Is a Serious 18-4 Indoor Air Pollution Is a Serious ProblemProblem

• Developing countries– Indoor burning of wood, charcoal, dung, crop residues

and coal– Poor suffer the greatest risk– Few, if any, regulations– Is the most serious air pollution problem

• Developed countries– Indoor air pollution poses a greater threat than

outdoor air pollution.

Indoor Air Pollution Is a Indoor Air Pollution Is a Serious ProblemSerious Problem

• Why? We spend up to 70-98% of our time indoors or inside our cars!–11 of the common air pollutants are at

higher levels inside than outside–Greater inside vehicles than outside–Health risks magnified because pollutants

are magnified indoors.

Indoor Air Pollution Is a Serious

Problem

• Who is at greatest risk from indoor air pollution?– Children under 5 and the elderly– Sick– Pregnant women– People with respiratory disorders or heart problems– Smokers– Factory workers

Indoor Air Pollution Is a Serious Problem

• Four most dangerous indoor air pollutants– Tobacco smoke– Formaldehyde(CH2O) – found in plywood, particle board,

paneling, drapes, furniture, carpet and wallpaper adhesives Estimated that 1/5,000 people who live in manufactured homes for more than 10 an lead to Lou Gehrig’s disease (kills nerve cells)

– Radioactive radon-222 gas- colorless, odorless, radioactive gas that is produced by the natural radioactive decay of U-238.

– Very small particles

Sources of these pollutants-brought in on shoes, pesticides, paints, sprays, living organisms (bugs), mold

Human health risks-sore throat, headache, chronic breathing problems, rash (flu-like systems)

Indoor Air Pollution Is a Serious Problem

Other possible indoor air pollutantsPesticide residuePb particlesLiving organisms and their excrements

E.g., Dust mites and cockroach droppingsAirborne spores of molds and mildews

Sick-building syndrome

What exactly is a sick building?• Term that refers to a building in which a number

of people report adverse health effects that they believe are related to the time they spend in the building

• A building in which occupants suffer persistent symptoms that disappear when they go outside

• A building which contains unhealthy levels of indoor air pollutants

How do you know if a building is really “sick”?

• When people report relief of symptoms when they go outside

• When 20% or more of the occupants report some adverse health effect when inside the building

• When occupants report any of the following symptoms: chronic respiratory problems, sinus infection, sore throat, asthma, shortness of breath, depression, forgetfulness, headaches, eye irritation

What type of building can be sick?

• Old– Asbestos and lead

• New– Formaldehyde or VOC’s

• Houses with wood-burning stoves– Carbon monoxide

Some Important Indoor Air Pollutants

Radioactive Radon Gas• Colorless, odorless, radioactive gas

• Sources: natural radioactive decay of Uranium-238 (rocks and soil)

• Human health risks-damage to lung tissue-cancer

• Testing for radon - detectors

• Correcting a radon problem: – Sealing cracks in walls and foundation,

increase ventilation

Sources and Paths of Entry for Indoor Radon-222 Gas

It’s a fantastic house with the exception of

the radon gas.

Your Body’s Natural Defenses against Air Your Body’s Natural Defenses against Air Pollution Can Be OverwhelmedPollution Can Be Overwhelmed

• Respiratory system protection from air pollutants– Role of cilia, mucus, sneezing, and coughing

• Effect of smoking and prolonged air pollution exposure– Chronic bronchitis– Emphysema– 6% of people in US suffer from asthma

Major Components of the Human Respiratory System

Lung Attack

Air Pollution Is a Big Killer

• 3 Million deaths per year world-wide– Mostly in Asia– Main causes-indoor air pollution– In US, more than 150,000 die each year from air pollution

• EPA: proposed stricter emission standards for diesel-powered vehicles– Reduce emission by 90%– Car makers hope they can delay

• Link between international trade and air pollution– Cargo ships and pollution

Premature Deaths from Air Pollution in the U.S.

Laws and Regulations Can Reduce Outdoor Air Pollution

• United States– Clean Air Acts: 1970, 1977, and 1990

• EPA – National ambient air quality standards (NAAQs) for 6

outdoor criteria pollutants• Carbon monoxide, nitric oxides (NOx), sulfur dioxide,

ozone, lead, and suspended particulate matter (SPM)• Primary Standard-Human health• Secondary Standard-environmental and property

damage

–National emission standards for 188 hazardous air pollutants (HAPs)•Mainly toxic metals, VOCs, and

chlorinated hydrocarbons• Toxic Release Inventory (TRI)-for power

plants, refineries which requires by law for release of info about chemical releases and waste management

• Good news in U.S.– Decrease in emissions 49% from 1980-2006

– Use of low-sulfur diesel fuel• Cuts pollution

• Developing countries– More air pollution

Laws and Regulations Can Reduce Outdoor Air Pollution

We Can Use the Marketplace to Reduce Outdoor Air Pollution

• Emission trading or cap-and-trade program• “Pollution Credits”– Mixed reactions to program– SO2 emissions down significantly– NO2 will be tried in the future– Mercury from coal plants-does not break down-

must set limits

There Are Many Ways to Reduce

Outdoor Air Pollution • 1980 –2006– SO2 emissions from U.S. electric power plants

decreased by 66%– NOx emissions by 41%– Particulate emissions by 28%

• Older plants not governed by the same regulations

• New cars have better emissions

Reducing Indoor Air Pollution Should Be a

Priority

• Greater threat to human health than outdoor pollution

• What can be done? – Prevention– Cleanup

We Need to Put More Emphasis on Pollution Prevention

• Output approaches

• New shift to preventing outdoor and indoor pollution– Pressure from citizens

Air Pollution…

• Global climate change, ozone depletion, acid rain, photochemical smog, and indoor air pollution are some of the most significant environmental problems faced by humanity. All of these problems/issues emphasize how important a healthy atmosphere is.

ON THE AP EXAM…• Don’t just state something “causes

pollution”. At least state that the activity causes “air pollution” or “water pollution”. Most likely, though, graders will want more specific information such as “this activity releases sulfur dioxide into the atmosphere”.