Air Pollution Overview Chapter 15 - PowerPoint Presentation

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Air Pollution OverviewChapter 15

Topics

:

1) Major Air Pollutants

2) Smog & Acid Deposition

Slide2

Our Atmosphere IS

a Resource

Atmospheric Composition

N2 78.08%O2 20.95%Argon 0.93%Carbon dioxide 0.04% (400 ppm)Ecosystem servicesBlocks UV radiationModerates the climateRedistributes water in the hydrologic cycle

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Air Pollution

Air pollution- the introduction of chemicals, particulate matter, or microorganisms into the atmosphere

at concentrations high enough to harm plants, animals, and materials such as buildings, or to alter ecosystems.

Global problem… air has no boundariesAtmosphere is a global commonsTragedy of the commons

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Defenses against Air Pollution

Your body has natural defenses against air pollution:

Nose hairs

Eyelashes and eye browsMucus in your nose and throatLiquid in your eyesThe smaller the particles, the more likely they are to get deeper into your lungsmost dangerous for the very young, the very old and people with compromised immune systemswith existing respiratory issues (asthma, emphysema, bronchitis) are at more risk from air pollution

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Natural Sources of Air Pollution

Volcanoes

Lightning

Forest firesPlants

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Anthropogenic Sources of Air Pollution

Transportation

Cars

TrucksPlanesBoatShippingFishingOil tankersPower plantsIndustrial processesWaste

disposal (incineration)

Human caused

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There are six Criteria Pollutantsthat are regulated by the Clean Air Act

under National Ambient Air Quality Standards (

NAAQS

)SO2 (Sulfur Dioxide) PrimaryNOx (Nitrogen Oxides) PrimaryCO (Carbon Monoxide) PrimaryPM (Particulate Matter) PrimaryO3 (Ozone) SecondaryPb (Lead) Primary

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Other air pollutants not on the NAAQS Six Criteria list, but also monitored:

Hg (Mercury)

VOC’s (Volatile Organic Chemicals)

CO2 (Carbon Dioxide)2007 – Supreme Court ruled pollutant under Clean Air Act2009 – EPA said they would implement in future2014 – in June Clean Power Plan 1st proposed to regulate green houses gases – especially from power plants2015 – in August, Clean Power Plan finalized by EPA2016 – in Feb, Supreme Court stayed implementation

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National Ambient Air Quality Standards (NAAQS)

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17_11.JPG

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Major Air Pollutants

Sulfur dioxide (SO

2

) and sulfuric acid:About 1/3 of SO2 occurs naturally volcanoes & firesAbout 2/3 from human sources mostly combustion of fossil fuels - coal and oil & metal productionS + O2 = SO2 (Primary Air Pollutant) Respiratory irritantSO

2

+ H

2

O = H

2

SO

4

(Sulfuric Acid –

Acid Rain

)

– secondary

SO

2

and soot contribute to

industrial, gray smog -

secondary

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Major Air Pollutants

Carbon oxides

:

Carbon monoxide (CO) is a highly toxic gas that forms during the incomplete combustion of carbon-containing materials.Tail pipes of carsGas heaters, generators – never use indoorsFire / fireplaces6,000 deaths in last 10 years, 60,000 exposuresCarbon dioxide (CO2) forms from complete combustion of most matter. As of 2013, burning fossil fuels has increased its concentration 43% above pre-industrial levels

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Major Air Pollutants

Suspended particulate matter (PM)

:

Consists of a variety of solid particles and liquid dropletsNatural sources: Volcanoes, fires, pollen, dustAnthropogenic sources: FF combustion, agricultureThe most harmful forms of PM are fine particles (“PM-10”, with an average diameter < 10 micrometers) and ultrafine particles (“PM-2.5”).PM causes ~60,000 premature US deaths per year

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Particulates

Solid or liquid particles that are suspended in the air

Sources are varied and include: burning, fossil fuels, road dust, dust storms, pollen,

fires,and volcanoesHuman Health Impacts:The smaller the PM, the more dangerous (deeper into your lungs)Impacts vary depending on the particle, but PM increases asthma, irritates the respiratory system and can cause cancerEnvironmental impacts:Scatters and absorbs sunlight, reducing visibility and photosynthesisHigh levels can cause global coolingPM > 10 – filtered out by bodyPM10 – not filtered by body – deposited in lungsPM2.5 – not filtered by body – high toxic and deposited in lungs

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Major Air Pollutants

Nitrogen oxides

and

nitric acid: Nitrogen oxide (NO) forms when nitrogen and oxygen gas in air react at the high-temperature combustion in automobile engines and coal-burning plants. NO can also form from lightening and certain soil bacteria.NO reacts with air to form NO2. - primaryNO2 reacts with water vapor in the air to form nitric acid (HNO3) and nitrate salts (NO3-) which are components of acid deposition. - secondaryNOx + VOCs + sunlight → photochemical smog (ozone)

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Major Air Pollutants

Ozone (O

3

):Is a highly reactive gas that is a major component of photochemical smog.It is a secondary air pollutantIt can Cause and aggravate respiratory illness (soft tissues).Aggravate heart disease.Damage plants, rubber in tires, fabrics, and paints.

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Major Air Pollutants

Lead

Is a powerful neurotoxin.

Removed from gasoline over three decades agoConcentrations in the air have declined precipitously (yay!!!!)Mercury from coal fired power plants is now of greater concern than leadSources include: old pipes and paint

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Major Air Pollutants

Volatile organic compounds (VOCs)

:

Vaporize at room temp – strong odorsHydrocarbons emitted by the leaves of many plantsContribute to formation of Photochemical SmogMethane1/3 natural sources: plants, wetlands, termites, anaerobic respiration2/3 from human sources: landfills, oil & natural gas wells, cattle belching & flatulence, and rice paddiesOther VOCs: industrial solvents (trichlorethylene, benzene, vinyl chloride) and components of gasoline plastics, drugs, synthetic rubber.Long-term exposure to benzene can cause cancer, blood disorders, and immune system damage.

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Common VOCs

Compound

Sources

Impacts

Methane

Cows, leaky pipelines, landfills

Global climate change, suffocation at very high concentrations

Formaldehyde

Preservative found in paneling, particle board, furniture, carpeting, etc

Skin and eye irritant, increase in asthma, carcinogen: nasal and leukemia

Benzene

tobacco smoke, service stations, exhaust from motor vehicles, and industrial emissions

Carcinogen (leukemia), neurological damage, organ damage

Xylene

/Toluene

Tobacco smoke, magic markers, fossil fuels, paint thinners

Neurological damage, skin and eye irritation, organ damage

Perc

perchoroethylene

Dry cleaning fluid and paint strippers

Central nervous system depressant, carcinogen, skin irritant

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Smog

“

Smog” = smoke + fog

coined in 1905 to describe sulfur dioxide emissionsA mixture of oxidants and particulate matter that caused haze, reduced sunlight and health effects.Can come from natural and anthropogenic sourcesName: London smog(New York smog, gray smog) Photochemical smog(L.A. smog, Denver smog, brown smog)

Weather:

cool, damp

sunny

Content:

particulates, sulfur oxides

NO

x

, ozone, hydrocarbons.

Sources:

coal, etc.

gasoline, combustion.

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Industrial Smog

Gray smog or London smog

Smog from industrial fossil-fuel combustion

Contains: soot, SO2, SO42-, CO, CO2 Chemistry:Burning sulfur-rich oil or coal creates SO2, SO3, sulfuric acid, ammonium sulfate.Burning fossil fuels leads to CO2 ,CO, and Carbon particles (soot).In London in 1952, severe pollution killed over 4000 peopleMostly from POINT SOURCES like coal power plants and industry

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Photochemical Smog

Brown smog or LA type smog

Smog from reaction of sunlight with pollutants

Builds during daylight, less at nightHot sunny days in urban areas create perfect conditions.Trapped by inversion layers and mountainsNOx + VOCs + sunlight → photochemical smog (mainly O3)Mostly caused by car exhaust

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South Asia’s Massive Brown Cloud

A huge dark brown cloud of industrial smog, caused by

coal-burning in countries such as China and India

, stretches over much of southeastern Asia.Respiratory ailments & deathsphotosynthesis is reduced interfering with crop development.Fine particles and droplets in the cloud appear to be changing regional climates (including rainfall).Acid rain on US west coasthttps://www.youtube.com/watch?v=qYYK-2sDN4U

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Chemistry of Photochemical Smog

Concentration of

NOx

and VOCs buildup from cars in the AMMidday UV rays increase catalyzation of photochemical reactions creating ozone and PANs (peroxyacyl nitrates)Levels stay high through the afternoon decreasing after sun setOzone - Formation

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Thermal Inversions make smog worse by trapping it under a layer of cold air

Areas with sunny climate, light winds, mountains on one side and an ocean on the other are susceptible to inversions

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a valley surrounded by mountains can trap air pollutants

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How Acid Deposition Develops

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ACID DEPOSITION

Figure 19-8

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ACID DEPOSITION

pH measurements in relation to major coal-burning and industrial plants.

Figure 19-7

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Acid deposition Effectscontributes to chronic respiratory disease can

leach toxic metals (such as lead and mercury) from soils and rocks

Damages statues, monuments, buildings

Kills fishDeclining Aquatic Animal Populations Harms crops & treesForest declineEx: Black forest in Germany (50% is destroyed)Is a regional problem downwind from coal-burning facilities.Thin-shelled eggsBecause calcium is unavailable in acidic soil

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Range of Tolerance

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Acid Deposition

Sources

Formation

Effects

Solutions

NOx – cars, industrial plants

SO

2

– coal power plants, fossil fuels, cars, industrial plants

NO

x

and SO

x

react with water in the air to form H

2

SO

4

and HNO

3

.

Acid is transported regionally

Dry deposition of sulfate and nitrate salts and SO2

Wet deposition of H

2

SO

4

and HNO

3

.

Humans

- respiratory diseases

- increases leaching of toxic metals into water

Structures

Dissolves marble, limestone, sandstone, metals and plastics

Ecosystems

-

acidic soil

 nutrient loss (P, N, Ca, Mg), plant loss, release of toxic metals

-acidic water  destroys all life

- Direct damage  reduced photosynthesis and growth

Prevention

- use low-sulfur coal, use less coal

Use pollution control devices to reduce emissions

Increase use of alternate energy

Tax SO2 emissions

Clean-up

- Add buffers to neutralize

- Add phosphate fertilizer

Slide38

Air Pollution – Part II

Topics:

Air Pollution Control Technology

Indoor Air PollutionOzone Layer Destruction & Recovery

Slide39

Air Pollution Around the World

Air quality is deteriorating rapidly in developing countries

China has an especially bad problem with Particulate Matter & smog

Developing countries have older carsStill use leaded gasoline5 worst cities in worldBeijing, China; Mexico City, Mexico; Shanghai, China; Tehran, Iran; and Calcutta, India

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Controlling Air PollutionHow successful has the Clean Air Act been?

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The Clean Air Act is Working!

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Air Quality is better in US; EPA estimates since 1970

Particulate Matter (PM) – down 78%

Carbon Monoxide (CO) – down 56%

Nitrogen Oxides (NOx) – down 30%Lead (Pb) – down 98%Sulfur Dioxide (SO2) – down 32%Ground level Ozone (O3) – down 14%VOCs – down 55%Air quality is worse in developing countries:Mexico City & Beijing: air exceeds WHO standards 350 days/year

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Environmental scientists point out several deficiencies in the Clean Air Act:U.S. rely

on cleanup rather than prevention.

The U.S. Congress has

delayed/failed to significantly increase fuel-efficiency (CAFE) standards for automobiles.Regulation of motorcycles and two-cycle engines inadequate.little or no regulation of oceangoing ships in American ports.Airports are exempt.does not regulate CO2.failed to deal with indoor air pollution.Need better enforcement of the Clean Air Act.Executives claim correcting these deficiencies would cost too much, harm economic growth, and cost jobs.

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Controlling Air PollutionWhat are some specific technologies to reduce emissions from cars, power plants, etc?

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Catalytic Converters

reduce NO

X

from tailpipes of cars

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“Fluidized Bed Combustion” technology

Mix coal with limestone before burning to

neutralize SO

2 before it is emitted

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Convert coal to Methane gas before burning to reduce SO

2

emissions

Removing Sulfur from Coalvia “gasification” technology

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Controlling Particulate Matter

Without Electrostatic precipitator

With Electrostatic precipitator

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Scrubbers

Capture PM in a “mist” after combustion

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Permits for Pollution Control

Cap and trade – SO

2

Turns the right to pollute into a commoditySet a number of allowances and buy and sell them in a free-market systemSO2 permit auction/trading: 23.5 million tonnes  10.3 million tonnes from 1982 to 2008

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Indoor Air PollutionHow do indoor air pollution issues differ for Developing and Developed countries?

What are the most common indoor air pollutants?

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Air Pollution is a Big KillerEach year, air pollution prematurely kills about

5

million people,

mostly from indoor air pollution in developing countries.

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Air Pollution is a Big Killer

premature

deaths from air pollution in

US.In the U.S., the EPA estimates that annual deaths related to indoor and outdoor air pollution range from 150,000 to 350,000.According to the EPA, each year more than 125,000 Americans get cancer from breathing diesel fumes.

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Developing Nations Indoor Air Pollution:

Wood, Dung, Coal to heat and cook

Poor ventilation

Women & Children at riskPM & CO pollutantsDamage to respiratory track: asthma, bronchitis, pnenomia, emphysema, lung cancer, suffication

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Indoor Air and Developing Nations

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Developed Countries Indoor Air Pollution:

People spend more time indoors

Buildings are “tighter”

Superinsulated to reduce energy consumption of heating/cooling – can trap pollutants inside!Leads to “Sick Building Syndrome”Materials made of plastics & other petroleum products out-gassing of VOCs (over time)

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INDOOR AIR POLLUTION- Developed Countries

Sick Building Syndrome (SBS)

1 in 5 commercial buildings considered “sick”

When 20% or more report symptoms when inside the building and/or report relief of symptoms when outsideExposes employees to health risks from unhealthy levels of indoor air pollutantsDizzyness, headaches, coughing, shortness of breath, nausea, burning eyes, sore throats, respiratory infections, flu-like symptoms, skin irritation, chronic fatigueBuildings at riskNewer – formaldehyde & other VOCs offgasses, also less gas exchange because more air-tightOlder – lead, asbestos, mold, mildew, poor ventilation, temperature, & humidity control

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Most

common indoor air pollutants in Developed Countries

:

Radon (product of Uranium decay; enters basements) cigarette smokecarbon monoxide nitrogen dioxideformaldehyde (a VOC from glues and furniture)pesticides

lead

cleaning solvents

ozone

and asbestos

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Major

indoor air pollutants

:

Radon is a radioactive gas that results from the decay of radium and uranium found in the bedrock under buildings. Responsible for tens of thousands of lung cancer deaths each year. Prevention: Remove radon by sealing or ventilating where radon enters the home.Molds and allergens are caused by moisture induced growth of mold and mildew and the release of animal dander and plant pollen. Prevention: filtration, humidity and dust control methodsCarbon monoxide can be released from tobacco smoke, space heaters that use fossil fuel and wood burning stoves. Causes headaches and dizziness. Prevention: Proper ventilationIndoor Air PollutionRadon

Molds & Allergens

Carbon Monoxide

Formaldehyde

Asbestos

Lead

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Major

indoor air pollutants

:

VOCs like formaldehyde that can be associated with new building material like furniture and carpeting. Causes irritation of eyes, nose, throat and lungs Prevention: Ventilation or alternative materialsAsbestos fibers are present in floor or ceiling tiles and insulation materials of older buildings. Long term inhalation can lead to lung disease or mesothelioma. Prevention: Removal or sealingLead can be found in old plumbing pipes and fixtures, older paints, and some ceramic glazes. Causes impaired mental and physical development. Prevention: alternative paints or plumbingIndoor Air PollutionRadon

Molds & Allergens

Carbon Monoxide

Formaldehyde

Asbestos

Lead

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Indoor pollutants affect cognitive function

Two studies,

published

in 2012 and 2015, suggest that indoor exposure to carbon dioxide can impair performance and decision-making. cognitive scores for poor ventilation (multiple pollutants) 61% higher on days with low concentrations of pollutants, 101% better on days with the most ventilation. cognitive function scores for CO2 15% lower with moderate CO2 — about 945 ppm50% lower with CO2 concentrations around 1,400 ppm.2,500 ppm produced ‘dysfunctional’ performance

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Solutions

Green Design/Building

materials

Increase ventilationFiltersIndoor plantsBiowall – living wallfunctional wall of plants that purifies indoor air12 varieties tropical plants grow in absence of soil. roots are embedded between two layers. Water is recirculated providing roots with nutrients Provides O2 - Absorbs CO2microbial communities on the plants’ roots function as a biofilter.bacteria and fungi break down volatile organic compounds (VOCs) capable of removing 60-90% of pollutants

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OzoneWhere is the “Ozone Hole”?

What effects does ozone depletion have?

What substances cause ozone depletion?

Will the ozone layer recover?

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Ozone – O3

Good Up High, Bad Nearby

Ozone in the

stratosphere protects us from harmful UV raysOzone in the troposphere is an air pollutant and health threat

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Atmospheric Layers

The stratosphere contains 99.9% of the ozone.

Ozone depletion occurs in the stratosphere.

The troposphere contains the weather, the majority of oxygen, and living organisms.Global warming and climate change occurs in the troposphere.Exosphere –satellites Northern LightsMeteorites burn up

Thickest layer

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OZONE DEPLETION IN THE STRATOSPHERE

Less ozone in the stratosphere allows for more harmful UV radiation to reach the earth’s surface

.

The ozone layer keeps about 95% of the sun’s harmful UV radiation from reaching the earth’s surface.Chlorofluorocarbon (CFCs) have lowered the average concentrations of ozone in the stratosphere.

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Effects of UV Radiation

health problems: sunburn, cancers and cataracts

decrease

in the productivity – disruption of photosynthesisPlants / forests / surface dwelling planktondisruption of food chainsLower crop yieldsimmune system suppression in animals increase in smog (photochemical smog)

Can affect climate

Melanoma skin cancer

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Increased UV-so what?

marine phytoplankton

(food webs)

amphibian populationsskin cancer (melanoma)Cataractsdamage to crops & forests

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Ozone Depleting ChemicalsChlorofluorocarbons (CFCs) were discovered in 1930Inexpensive to manufacture.

Odorless, unreactive, nonflammable,

seemed to be dream chemicals

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Chlorofluorocarbons

(

CFCs

) are used in:coolants in fridges and air-conditionerspropellants for aerosol cansstyrofoam insulation and packagingmedical sterilizersHalons are used in many fire extinguishers, soil fumigants/pesticides, and solvents.Methyl chloroform is

used to

degrease

metals

Methyl bromide

is

used as a

fumigant

Carbon tetrachloride

is

used in many

industrial

processes.

Ozone Depleting Chemicals

Discarded refrigerators leak coolant

Many aerosols use CFC propellants

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Discovering a problem

In 1973 Frank Sherwood Rowland and Mario Molina began studying the impacts of CFCs in the Earth’s atmosphere.

Calculated that CFCs were lowering concentration of ozone in stratosphere

Major conclusionsRemain in troposphere because they are insoluble in water. Here they act as greenhouse gasesOver 11-20 years rise into stratosphere where UV radiation releases a Cl atom. This accelerates the normal breakdown of ozoneEach CFC molecule can last in stratosphere for 65-385 years.CFC industry (DuPont) attacked conclusions and delayed 14 years before admitting CFC deplete ozone in 1988In 1995 Rowland & Molina received a Nobel Prize in Chemistry

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OZONE DEPLETION IN THE STRATOSPHERE

Since 1976, in Antarctica, ozone levels have markedly decreased during

October

and November. – (Southern Hemisphere Spring)Figure 20-20

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OZONE DEPLETION IN THE STRATOSPHERE

During four months of each year

up to half of the ozone

in the stratosphere over Antarctica is depletedA smaller amount over the Arctic is depleted.Figure 20-19

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In 2000, the extent of the

ozone hole

over Antarctica was the largest ever.

The ozone ‘hole’ is defined as a region with lower than 220 Dobson units. The ozone hole is most evident in the Antarctic Spring (October)The Ozone Hole

Antarctic Ozone Hole, Minimum Values

The dark blue area indicates <200DU

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The Ozone Hole

Slide80

Fig. 20-18, p. 486

A free oxygen atom pulls

the oxygen atom off the chlorine monoxide molecule to form O2. Ultraviolet light hits a chlorofluorocarbon (CFC) molecule, such as CFCl3, breakingoff a chlorine atom and leaving CFCl2.Sun

Repeated

many times

The chlorine atom

and the oxygen atom

join to form a chlorine monoxide molecule (ClO).

Summary of Reactions

CCl

3

F + UV

Cl

+ CCl

2

F

Cl

+ O

3

ClO

+ O

2

ClO

+ O

Cl

+ O2

UV radiation

The chlorine atom attacks

an ozone (O3) molecule,

pulling an oxygen atom off

it and leaving an oxygen

molecule (O2).

Once free, the chlorine atom is off

to attack another ozone molecule

and begin the cycle again.

Cl

Chlorine is a catalyst

1

Cl

atom can destroy 100,00 ozone molecules

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Ozone Chemistry

Slide82

The Montreal Protocol is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances believed to be responsible for ozone

The phase out management plan included two phases:

Chlorofluorocarbons phase out management plan &

hydrochlorofluorocarbon phase out plan.Montreal Protocol 1987Copenhagen Protocol 1992Amendment to accelerate the phaseout of key ozone depleting compounds

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Laws and Treaties

Montreal Protocol, 1987

One of the most effective environmental efforts

Originally agreed to scale back CFC production 50% by 2000Amended to phase out ozone depleting chemicals in developed countries by 2000 and in developing countries by 2010.halt CFC production by the end of 2005Copenhagen Protocol, 1992Adopted to accelerate phase out OTHER ozone depleting compoundsHalons and HBFCs (fire extinguishers), methyl bromide (fumigant), and carbon tetrachloride (solvent)

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Montreal Protocol

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Since 1987, nations have cut their

consumption of ozone-depleting

substances by 70%.

Free chlorine in the stratosphere peaked around 1999 and is projected to decline for more than a century. Ozone loss is projected to diminish gradually until around 2050, but will peak in 2020 and then decline until the polar ozone levels will return to 1975 levels.It will take another 100 yearsfor full recovery (to pre-1950 levels).Ozone Recovery

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Human Health

• Worse sunburn

• More eye cataracts• More skin cancers• Immune system suppressionFood and Forests

• Reduced yields for some crops

• Reduced seafood supplies from reduced phytoplankton

• Decreased forest productivity for UV-sensitive tree species

Wildlife

• Increased eye cataracts in some species

• Decreased population of aquatic species sensitive to UV radiation

• Reduced population of surface phytoplankton

• Disrupted aquatic food webs from reduced phytoplankton

Air Pollution and Materials

• Increased acid deposition

• Increased photochemical smog

• Degradation of outdoor paints and plastics

Global Warming

• Accelerated warming because of decreased ocean uptake of CO2 from atmosphere by phytoplankton and CFCs acting as greenhouse gases

Effects of Ozone Depletion

Natural Capital Degradation