1Good things happen when the air clears

Module 7. Air Quality Solutions for the

Mid-Atlantic United States

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Did You Know?

You can buy one ton of sulfur dioxide emissions for $625?*

* May 4, 2006 market prices

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Activity: What Do You Think?1. Which solution to air pollution problems is the newest?

a) Regulationsb) Engineered control devicesc) Pollutant emission tradingd) Voluntary reductions

2. The CAIR targets which of the pollutants below?a) Sulfur dioxideb) Carbon dioxidec) Particulate matterd) Ozone

3. A baghouse controls which of the following pollutants?a) Sulfur dioxideb) Carbon dioxidec) Particulate matterd) Ozone

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Course GoalsBy the end of this course you will be able

to Understand the hierarchy of emission control solutions

and options being used in the Mid-Atlantic U.S. Pair emission control technologies with the pollutant(s)

they controlUnderstand the basics of air pollution markets

Participate in solutions to local air pollution problems

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Theory: Solution Options

Regulatory solutions?

Engineering solutions?

Market-based solutions?

Voluntary solutions?

expansion plans

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Application: Solution Options

The U.S. has a goal of non-deterioration of air quality. When a company wishes to build a new plant, or expand, a decision-making process must be used to determine the best emission control solution.

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Theory: Regulatory SolutionsThe Clean Air Act serves as the foundation

for U.S. air quality regulations and drives most solution optionsCAA, 1963CAAA, 1970CAAA, 1977CAAA, 1990CAA Revisions, 1997

Scientific evidence of air pollution

NAAQS and SIPs

NSPS, AQCR, PSD, BACT, LAER, RACT

MACT, HAPs, Titles I-VII

Ozone, PM2.5, Haze

Key elements>>>>>>>

>>>>>>>>>>>>

>>>>

>>>>>>>>

>>>>

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Theory: Regulatory SolutionsVia the CAA, the federal government sets the

operating bounds in order to protect all peopleThe state regulatory agencies are in charge of

implementation of the CAA (e.g. public hearings, permit granting) States have better understanding of local conditions

(e.g. geography, industry, demographic patterns) States can create stricter standards, if so desired State Implementation Plans (SIPs) which detail how

the state will meet the CAA are required for each state SIPs are tailored to how severe pollution is in the state

(marginal to extreme). Deadlines for cleaning the air are based on this starting point.

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Theory: Regulatory SolutionsThe 1990 CAAA included a federal permit program

for large sourcesA business applies for a permit; applications are reviewed

and permits issued by the state environmental regulatory agency

Permit coverage• Which pollutant(s) are being released• Allowable emissions• Control approaches to be used• Monitoring requirements• Permit fees

Permit applications and permits are available to the public

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Theory: Regulatory SolutionsClean Air Interstate Rule (CAIR)

Goal: reduce ozone and particulate levels Projected benefit-to-cost ratio = 25Cap-and-trade approach to SO2 and NOx for 450

Eastern U.S. counties Forecast: 70% and 60% emission reductions in SO2,

and NOx, respectively by 2015CAIR Milestone Deadline

CAIR rule promulgated 2005

SIPs due 2006

Phase I cap for NOx 2009

Phase I cap for SO2 2010

Phase II caps for NOx and SO2 2015

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Application: Regulatory SolutionsCAIR is expected to yield substantial air

quality improvements in the Mid-Atlantic U.S.

Source: USEPA 2005

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Analysis: Regulatory SolutionsQuestion: The U.S. has taken a regulatory

approach to drive most of the efforts to cleaner air. What are some advantages and disadvantages to this strategy?

Action: In a small group list two advantages and two disadvantages to a regulatory air quality control strategy.

Time: 5 minutes

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#2: Waste minimization

Theory: Engineering SolutionsProcess design

Engineering team conceptualizes the options available to control air emissions from the process/system

Four general options, in order of preference (and real costs)

process

raw materials

product

wasteemissions

#1: Pollution prevention

process

raw materials

product

emissions(minimized)

processrecoveryprocess

wasteemissionswaste

recycle

raw materials

product#3: Recovery & recycle

processcontrolprocess

wasteemissionswaste

raw materials

product#4: Destruction or disposal

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Theory: Engineering SolutionsIf the emissions must be controlled per state/federal rules

then it is important to understand the air stream before designing such control systems

Characterization of the emissions includes the following key propertiesCompositionConcentration Flow rateTemperature Pressure

} Identifying these helpsbound the design problem

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Theory: Engineering Solutions The control of emissions has met varied success,

depending on the compound and source. Ozone precursor (VOC, NOx) and

fine particle emission control are keyissues in the Mid-Atlantic U.S.

Mobile sources are problematicdue to increasing numbers and driving distances, and technologychallenges

Large point sources are easier to design for, subsequently many control technologies exist

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Gaseous control technologies are based on a variety of scientific principles. The approach depends on the pollutant targeted for control.

Theory: Engineering Solutions

Technology Principle Target pollutant(s)

Incinerator combustion VOCs, CO

Absorption tower air to water transfer NH3, SO2

Adsorption column air to solid transfer VOCs, SO2

Biofilter biological VOCs

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Theory: Engineering Solutions Process: Incinerator

Objective: convert organicsto carbon dioxide

Effective concentration: >100 ppmTarget compounds: VOCs, CO

• Works best if contaminant has significantenergy content (burnable)

• Catalysts are used when contaminants arelow on energy content

• Combustion products must not be moretoxic than original contaminant

wasteair stream

burnerpiping

treatedair

fuel(if needed)

catalyst

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Theory: Engineering SolutionsProcess: Absorption

Objective: remove soluble pollutantsEffective concentration: >200 ppmTarget compounds: SO2, NH3, Cl2

Transfer air pollutant into water• Air/water contact time is important• Engineered devices try to maximize time• Sometimes chemicals are added to water to enhance transfer

– Flue gas desulfurization (FGD)

wasteair stream

treatedair

dirtywater

media

€

SO2 +CaCO3 → CaSO4 +CO2

€

SO2 +CaOH( )2 → CaSO4 +H2OLimestone added to water:

Lime added to water:

Advantage: SO2 removal increased to 50-90%Disadvantage: CaSO4 produces sludge and scaling of unit

cleanwater

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Theory: Engineering SolutionsProcess: Adsorption

Objective: remove sorbable pollutantsEffective concentration: >200 ppmTarget compounds: VOCs, H2S, SO2

Transfer air pollutant onto sorbent• Sorbent (solid) must be matched to sorbate (gas)• Many different sorbents

– Activated carbon– Silica gel

• Limitations– Sorbents preferentially sorb water– Less effective at high temperatures– All sorption sites are eventually used– Must cycle through adsorption, desorption phases

Phase: Adsorptionwaste air stream

treated air

Air pollutant“sticks” tosorbent

………….………….………….………….………….………….………….………….………….………….………….………….………….………….………….………….………….………….………….………….………….………….………….………….

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Theory: Engineering SolutionsProcess: Biofilter

Objective: remove biodegradable air pollutants

Effective concentration: <200 ppmTarget compounds: VOCs, org-SBacteria consume air pollutant

• Contact time in reactor is critical• Air stream limitations

– Narrow temperature range,T=10-40° C

– Low particulate levels– Relatively low concentrations

• Advantages– Low capital costs– Low operating costs

wasteair stream

water

bio media

treated air

drainagewater

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Particle control technologies are based on a variety of scientific principles. The approach depends on the particle size targeted for optimal control.

Theory: Engineering Solutions

Technology Principle Targeted Particle Size

Settling chamber Gravity > 50 µm

Cyclone Centrifugal force > 10 µm

Baghouse Filtration > 1 µm

Electrostatic precipitator

Charge attraction > 0.1 µm

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Theory: Engineering Solutions

Process: Settling chamberObjective: remove large PM

Effective sizes: d>50 µm

Gravitational settling• Slow down horizontal velocity

• Provide time for settling

. ...

. ...........

. .

... .

..

. . ......

.. . .

.. . . . ...

...

.. . . . .

..

. . ..

.... . .....

.. . ..

dirtyair in

cleanair out

collectedparticles

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Theory: Engineering Solutions

Process: CycloneObjective: remove medium PMEffective sizes: d>10 µmCentrifugal force

• Particle inertia results in removalfrom air stream

• Particles accumulate along wall,slide out

dirtyair in

particlesout

cleanair out

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Theory: Engineering Solutions

Process: BaghouseObjective: remove small PMEffective sizes: d>1 µmFiltration

• Pass air through bags

• Particles retained within

dirtyair in

cleanair out

bags

collectedparticles

shaker

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Theory: Engineering Solutions

Process: Electrostatic PrecipitatorObjective: remove ultrafine PMEffective sizes: d>0.1 µmElectrostatic charge

• Charge plates

• Particles given opposite charge

cleanair out

collectedparticles

high voltagewires

plates

dirtyair in

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Application: Engineering Solutions Equipment selection is only a first step. Sizing the system,

and estimating costs are critical next steps. To assist in these preliminary design steps, EPA has an easy-to-use software tool, the Air Compliance Advisor.

Information used Source characteristicsEmission control methods Permit requirements Pollution regulations

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Analysis: Engineering Solutions Question: Why do we bother converting an air

pollution problem into a wastewater (e.g. via absorption or biofiltration) or solid waste problem (e.g. via baghouse or ESP)?

Action: In a small group, think about the trade-offs involved in this kind of “pollution swapping”.

Time: 5 minutes

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Theory: Market-Based SolutionsThe 1990 CAAA introduced market-based solutions to

give major sources flexibility to meet emission targets.Total allowable emissions, or cap, is determined (then

ratcheted down over time), and businesses then figure out the best way to meet that total.

Emission cap-and-trade markets SO2 for U.S. since 1994NOx for Eastern U.S. since 2003Greenhouse gases currently in

proposal stage (although there is a voluntary US/EU carbon market in existence)

Year GHG Cap

Until 2011 Today’s levels

2011-2015 -0.5%/yr

2016-2020 -1.0%/yr

Proposed U.S. GHG Caps

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Application: Market-Based SolutionsThe Acid Rain Program instituted a SO2 emissions

trading programSO2 allowances (1 ton) are available for sale or

purchase Price is set by market forcesAllowances can be traded among sources Sales are by major sources not emitting as much as state

permit allows (could also bank) Purchases

• By major sources emitting more than permit allows• By other interested investors

Continuous emissions monitoring are critical for verification

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Application: Market-Based SolutionsSO2 market to date

Initial price: $140/allowance (Jan. 1995)High price: $1630/allowance (Dec. 2005)Low price: $75/allowance (Feb. 1996)Current price: $600/allowanceCumulative allowances transferred (to end of 2003): ~250

million 335 facilities reduced emissions (by 6.3 million tons, 1990

versus 2000-2002) 282 facilities increased emissions (by 1.2 million tons,

1990 versus 2000-2002)

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Application: Market-Based SolutionsMeasured results

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Application: Market-Based SolutionsNOx Budget Trading

Program (NBP) targets summertime ozone precursor reductions from major sources in (and upwind of) the Mid-Atlantic U.S.

Initial results are promising 230,000 allowances traded

between companiesEmissions are decreasing

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Analysis: Market-Based Solutions

Question: Are there air quality problems where a market-based approach would not be appropriate?

Action: Discuss this in a group, identify any pollutants that a market-based strategy could make problems worse.

Time: 5 minutes

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Theory: Voluntary SolutionsVoluntary solutions can be effective, due to the

inherently different motivationPublic efforts

• Participatory approaches– Become educated on major sources in your community– Attend public hearings on permits– Sue the government or air pollution source’s owner to get action– Request action by the state or EPA against sources suspected of

violating permits

• Lifestyle choices to reduce air pollution emissionsCorporate efforts

• Pollution prevention/minimization programs• Employee incentive programs

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Application: Voluntary SolutionsA difficult problem in many cities

is fine particle pollution. In some locations a major source in winter can be the collective emissions from fireplaces. While some municipalities have instituted bans, most have setup programs for replacing fireplaces with modern wood-burning stoves. Ultimately, the public will choose to be part of the problem or solution.

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Application: Voluntary SolutionsBank of America Hybrid Program

Encourages employees to buy hybrid cars$3000 reimbursementFor employees living within 90 miles of

Charlotte, Boston, or LAAvailable to full and part-time (>20 hr/wk)

employees

The hybrid program expands our commitment to theenvironment and helps our associates in making a difference while cutting down on their commuting costs.-- Bank of America

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Application: Voluntary Solutions3M has a company mission to consider environmental

impacts in its product designs. It has made substantial reductions in air emissions over the past decade through conventional control technology, but also through two voluntary programs: Pollution Prevention Pays is an employee-driven program that

solicits ideas to minimize air emissions, among other environmental impacts

Development of solvent-less technologies

Results 95% reduction in VOC emissions since 1990

(255 million to 14 million pounds)

“The idea that preventing pollution, rather than costly treatment after the fact, plus extensive employee involvement by those who know the processes best, turns out to be the wisest environmental approach,” 3M vice president

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Analysis: SolutionsQuestion: You are the environmental manager of

a utility company in West Virginia needing to serve more customers. What options could you exercise so your SO2 emissions do not increase?

Action: In a small group, think of one solution within each of the four types (regulatory, engineering, market-based, voluntary).

Time: 10 minutes

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Activity: What Do You Think?1. Which solution to air pollution problems is the newest?

a) Regulationsb) Engineered control devicesc) Pollutant emission tradingd) Voluntary reductions

2. The CAIR targets which of the pollutants below?a) Sulfur dioxideb) Carbon dioxidec) Particulate matterd) Ozone

3. A baghouse controls which of the following pollutants?a) Sulfur dioxideb) Carbon dioxidec) Particulate matterd) Ozone

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Further Learning

Air Compliance Advisor, emissions control technology decision-making tool, http://www.epa.gov/ttn/ecas/costmodels.html

Code of Federal Regulations (CFR), description of air quality regulations can be found in Title 40, http://www.access.gpo.gov/nara/cfr/

Evaluating Ozone Control Programs in the Eastern United States, focus on the NOx Trading Program, http://www.epa.gov/airtrends/2005/ozonenbp.pdf

Clean Air Interstate Rule, summary description, http://www.epa.gov/air/interstateairquality/basic.html

A Guide to Mid-Atlantic Regional Air Quality, Part VI: Closing Thoughts, pp. 67-69. http://www.marama.org/reports/Guide-MidAtlantic_RegAQ_Final.pdf

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A Moment to Reflect

Which air quality solution do you feel has the greatest effectiveness?

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Thanks for making this a great class!

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Designed and created by:©2007 Prof. Kurt Paterson, Ph.D., P.E.paterson@mtu.edubigmac.cee.mtu.edu/marama.html

www.mtu.edu

Funding provided by:Mid-Atlantic Regional Air Management Association