Clean Air Act, Health Effects and Rule Overview

Laura McKelvey and Stephanie Karisny

Titles of the Clean Air Act

• Title I—National Ambient Air Quality Standards, Hazardous Air Pollutants– SIP, NSR and Technology Standards

• Title II—Mobile Sources• Title III— Emergency Powers and Tribal

Authority, Public Involvement• Title IV—Acid Deposition• Title V—Operating Permits• Title VI—Stratospheric Ozone

A Brief Overview of the CAA• The U.S. Environmental Protection Agency was created in

1970; the Clean Air Act (CAA) was passed in 1970; amendments were passed in 1990

• The goal of the Clean Air Act was to give the federal government the authority to address air pollution in the United States

• Since the inception of the Clean Air Act (in 1970):– There has been a 50% decrease in the criteria pollutants; criteria

pollutants include particulate matter (PM), ground-level ozone, carbon monoxide, sulfur oxides, nitrogen oxides and lead

– Air toxics from large industrial plants have been reduced by 70%– New cars are more than 90% cleaner– Production of ozone-depleting chemicals has ceased

Air Quality Management Process

Implement Control StrategiesEvaluate Air Quality

- Air Quality Assessments•Emissions Inventory Data

•Ambient Air Monitoring Data

Choose Control Strategies

-Voluntary programs / Outreach

-Some strategies may be regulatory

Determine NecessaryEmissions Reductions

Set Air Quality Goals

NAAQS

• National Ambient Air Quality Standards (NAAQS) – Primary standard set to protect public health – Secondary standard set to protect public and welfare

• State Implementation Plans – State plans to attain or maintain the NAAQS

• New Source Review and Prevention of Significant Deterioration (PSD) permits are part of the SIPs

• Title V Permits takes all the requirements from SIPs, technology standards, new source performance standards, etc. and combine them in one permit

Setting Air Quality Goals for Commonly Found “Criteria” Pollutants

• EPA sets limits for the amount (concentration) of pollutant that can be in the air for six commonly found pollutants:

– Particulate Matter (PM)– Ground Level Ozone (O3)– Carbon Monoxide (CO)– Sulfur Oxides (SOx)– Nitrogen Oxides (NOx)– Lead (Pb)

• These six pollutants are generally referred to as “criteria pollutants”

• These limits are called National Ambient Air Quality Standards (NAAQS)

• There are two types of NAAQS:– Primary standards are set at a level to protect public health – Secondary standards are set at a level to protect

ecosystems, the environment and other values

EPA’s Role in Setting Air Quality Goals• NAAQS set national levels for acceptable concentrations of these six pollutants in outdoor air

• EPA determines/designates all areas in the country as:– Clean or in “attainment”– Dirty (above the standard) or contributing to dirty air in a nearby location or “nonattainment” or– Not having enough information to determine the air quality status “unclassifiable”

• The CAA sets dates by which these pollution levels must be reached

• EPA provides guidance to the states on how to address air quality and reviews and approves (where appropriate) state air plans

• EPA and oversees implementation of plans and can enforce state requirements where necessary

• State plan for cleaning the air or keeping it clean to meet the national standards for these six “criteria pollutants” is called a State Implementation Plan (SIP)

• The criteria pollutants are also regulated through New Source Performance Standards (issued by EPA) which apply to certain new air pollution sources and SIPs and Permit requirements for sources must at least be as stringent as the NSPS but States can be more stringent then the NSPS

Ground-level Ozone is

• Primary component of smog

• Sometimes called “bad ozone” to distinguish it from “good ozone”

– Both types of ozone have the same chemical composition (O3)

– “Good ozone” occurs naturally in the upper portions of the earth’s atmosphere and forms a layer that protects life on earth from the sun's harmful rays

– “Bad ozone” at ground level is harmful to breathe

• Not emitted directly into air; forms when emissions of nitrogen oxides (NOx) and volatile organic compounds (VOCs) “cook” in sun

– Emissions from industrial facilities, electric utilities, motor vehicle exhaust, gasoline vapors, and chemical solvents are major man-made sources of NOx and VOCs

• Mainly a summertime pollutant, because sunlight and hot weather accelerate its formation

• Ozone levels can be high in both urban and rural areas, often due to transport of ozone, or the NOx and VOC emissions that form ozone

Ground-level Ozone (cont.)

• Ozone can penetrate deep into the lungs and can:– Make it more difficult for people working or playing outside

to breathe as deeply and vigorously as normal– Irritate the airways, causing: coughing, sore or scratchy

throat, pain when taking a deep breath, and shortness of breath

– Increase asthma attacks and use of asthma medication– Inflame and damage the lining of the lung by injuring the

cells that line the air spaces in the lung – Increase susceptibility to respiratory infection – Aggravate chronic lung diseases such as asthma,

emphysema and bronchitis

Ozone and Health

• Repeated exposure may cause permanent changes in the lung, leading to long-term health effects and a lower quality of life

Ozone Health Impacts: “ Pyramid of Effects”

Susceptible and vulnerable groups include

– People with lung disease such as asthma

– Children– Older adults– People who are more

likely to be exposed, such as outdoor workers

Proportion of Population AffectedProportion of Population Affected

Severity of Effects

A large number of scientific studies have linked ozone exposure to serious health outcomes such as emergency department visits, hospitalizations for respiratory causes, and mortality

Particulate Matter: What is It?

A complex mixture of extremely small particles and liquid droplets

Fine ParticlesCombustion, gases to particlesSulfates/acidsNitrateAmmoniumOrganicsCarbonMetalsWater

Sources:Coal, oil, gasoline, diesel, wood combustionTransformation of SOx, NOx, organic gases including biogenicsHigh temperature industrial processes (smelters, steel mills)Forest fires

Exposure/Lifetime:Lifetime days to weeks, regional distribution over urban scale to 1000s of km

Inhalable Coarse ParticlesCrushing, grinding, dustResuspended dusts (soil, street dust)Coal/oil fly ashAluminum, silica,iron-oxidesTire and brake wearInhalable Biological Materials (e.g., from soils, plant fragments)Sources:Resuspension of dust tracked onto roadsSuspension from disturbed soil (farms, mines, unpaved roads)Construction/demolitionIndustrial fugitivesBiological sourcesExposure/Lifetime:Coarse fraction (2.5-10) lifetime of hours to days, distribution up to 100s km

PM Components: fine and coarse

• Larger particles (> PM10) deposit in the upper respiratory tract

• Smaller, inhalable particles (≤ PM10) penetrate deep into the lungs

• Both coarse PM10-2.5 and fine PM2.5 can penetrate to lower lung

• Deposited particles may accumulate,

react, be cleared or absorbed

Particulate Matter

Heath Effects of Particle Pollution• Particles can cause both respiratory and cardio-vascular health

problems, including: – Aggravated asthma – Increases in respiratory symptoms like coughing and difficult or painful

breathing – Chronic bronchitis – Decreased lung function – Changes in heart rate and heart rate variability– Cardiac arrhythmias– Heart attacks– Premature death

• Types of studies:– Epidemiology/Field– Controlled human exposure– Animal

lung function changes, immune cell responses, heart rate or heart rate variability responses

Asthma attacks, medication use, symptoms

Doctor visits

Hospital Admissions

Death

PM Health Impacts: “Pyramid of Effects”PM Health Impacts: “Pyramid of Effects”

Some groups are at greater risk• People with heart or lung diseases

– Diseases make them vulnerable

– May include people with diabetes

• Older adults – May have undiagnosed disease

• Children– Bodies still developing

Sulfur Dioxide Health Effects• Short-term exposures to SO2, ranging

from 5 minutes to 24 hours• Respiratory effects including:

– bronchoconstriction– increased asthma symptoms

• These effects are particularly important for asthmatics while exercising or playing.

• Short-term exposure result in:– increased visits to emergency

departments and hospital admissions for respiratory illnesses

– particularly in at-risk populations including children, the elderly, and asthmatics    

• Emissions that lead to high concentrations of SO2 generally also lead to the formation of other Sox. 

• SOx can react with other compounds in the atmosphere to form small particles or PM2.5 discussed earlier.

• These particles penetrate deeply into sensitive parts of the lungs and can cause or worsen respiratory disease, such as emphysema and bronchitis, and can aggravate existing heart disease, leading to increased hospital admissions and premature death. 

• EPA’s NAAQS for particulate matter (PM) are designed to provide protection against these health effects.

Current National Ambient Air Quality Standards (NAAQS) as of March 2014

Pollutant Primary/Secondary Averaging Time Level Form

CO primary8-hour 9 ppm

Not to be exceeded more than once per year1-hour 35 ppm

Lead primary and secondary

Rolling 3 month average 0.15 μg/m3 Not to be exceeded

NO2

primary and secondary Annual 53 ppb Annual mean

primary 1-hour 100 ppb 98th percentile of 1-hour daily maximum concentrations, averaged over 3 years

O3

primary and secondary 8-hour 0.075 ppm Annual fourth-highest daily maximum

8-hr concentration, averaged over 3 years

PM2.5

primaryAnnual

12.0 μg/m3 annual mean, averaged over 3 years

secondary 15.0 μg/m3

primary and secondary 24-hour 35 μg/m3 98th percentile, averaged over 3 years

PM10

primary and secondary 24-hour 150 μg/m3 Not to be exceeded more than once per year on

average over 3 years

SO2

primary 1-hour 75 ppb 99th percentile of 1-hour daily maximum concentrations, averaged over 3 years

secondary 3-hour 0.5 ppm Not to be exceeded more than once per year

Primary (health-based) and secondary (welfare-based) standards. Units of measure are parts per million (ppm), parts per billion (ppb) or micrograms per cubic meter of air (μg/m3). For more information about the standards,

visit http://www.epa.gov/ttn/naaqs/.

“Everything is connected”

Permits

MonitoringPlanning &

Analysis

Statutory Authority

Resources: FTEs & $$

$

Compliance &

EnforcementRules &

Regulations

Emissions Inventory

What is a SIP?

What is a SIP?• Most air pollution control regulations in the US are

found in SIPs (State Implementation Plans)• States and have great leeway in developing SIPs• Implementation plans include information to

understand and track air quality like:– Emissions inventories (what sources are in the area) – Air quality monitoring– Modeling to show how the plan will achieve or maintain

good air quality• Control strategies for all the sources of pollution in

an area which can include– Voluntary programs to improve air quality, for example,

• Build High Occupancy Vehicle Lanes• Cash for clunkers

– Regulatory programs, for example• Impose limits on bus idling• Require sources to install air pollution control equipment

– Permit programs for new and modified sources• Development of these components generally

takes 3-4 years• CAA requires an area move to attainment with in

5-7 years.

SIPs Must Meet Minimum Requirements

• The Clean Air Act has many requirements for SIPs, including a requirement that non-attainment areas come into attainment as soon as possible

• SIPs must have:– Enforceable emission limits and control measures– An air monitoring program– Permit programs to control construction and modification of new

stationary sources– Measures to prevent one State from significantly contributing

to nonattainment in another State• SIPs are submitted to EPA for approval

– EPA must publish notice before approving a SIP (typically found in the Federal Register) and must give the public an opportunity to request public hearing and at least a 30-day comment period

Implementing Control Strategies

• Pre-construction and operating permits help with compliance and enforcement of the SIP– Permits contain requirements and

become enforcement tools– Before a permit is issued, the public

can request a public hearing and make comments on the draft permit

• Progress can be tracked through – Ambient monitoring– Reporting requirements contained in

permits and regulations• Enforcement is essential

SIP Process and Roles Opportunities for Input

SIP is now federally enforceable

Meet w/State SIP development team, join SIP stakeholder group, get on mailing list

Work w/Regional Office to provide input and community or tribal perspective

Attend and speak at public hearing, submit written comments

Work w/Regional Office to review and provide input

Attend and speak at public hearing, submit written comments

Work w/EPA and State to ensure controls are in place and working

State / local agencies start to develop SIP

State holds public hearing and comment period

State revises SIP to respond to public comment

State adopts & officially submits SIP to EPA Regional Office

EPA performs completeness review (EPA has 6 months)

EPA publishes proposed notice in Federal Register

EPA holds public comment period

EPA publishes final action responding to public comment

State modifies SIP based on EPA comments

State drafts SIP and submits to EPA for informal review

The State Implementation Plan Process

Stephanie KarisnyStaff Attorney

Great Lakes Environmental Law Center

• National Ambient Air Quality Standard (NAAQS) for SO2– Primary standard: Protection of human health

including "sensitive" populations such as asthmatics, children, and the elderly

• One-hour standard, 75 parts per billion (ppb)• Calculated as the three-year average of the 99th

percentile of the annual distribution of daily maximum 1-hour average concentrations

– Secondary standard: Protection against environmental and property damage - e.g., protection against decreased visibility, damage to animals, crops, vegetation, buildings

• Three-hour standard, 0.5 parts per million (ppm)• Not to be exceeded more than once per calendar year

• Wayne is the only county in Michigan that is a designated nonattainment area for SO2 under the 2010 standard– “The area bounded on the east by the

Michigan-Ontario border, on the south by the Wayne County- Monroe County border, on the west by Interstate 75 north to Southfield Road, Southfield Road to Interstate 94, and Interstate 94 north to Michigan Avenue, and on the north by Michigan Avenue to Woodward Avenue and a line on Woodward Avenue extended to the Michigan-Ontario border”

• States are primarily responsible for ensuring attainment and maintenance of NAAQS once EPA has established them

• State needs to create a State Implementation Plan (SIP) that provides for the attainment and maintenance of NAAQS through control programs directed at sources of SO2

• SIP goes through public participation process (state level)

• USEPA has final say, approves or disapproves SIP (also public participation)

• SIPs due to USEPA by April 6, 2015• NAAQS for SO2 must be met by October 4, 2018

• General Nonattainment SIP Requirements:– Section 172 of the Clean Air Act (CAA) addresses

the general requirements for areas designated as nonattainment

– States with nonattainment areas must submit a SIP that shows the affected area will attain the standard by the applicable attainment date (10/4/2018)

– SIP must demonstrate that area will attain the standard as expeditiously as practicable, and provide for the implementation of all reasonably available control measures (RACM) including reductions in emissions from existing sources through adoption of additional control technologies

• What kinds of SO2 control options are available?– Switch to low-sulfur fuel (low sulfur coal)– Implement flue gas desulfurization

control technology• Dry FGD technologies• Wet FGD technologies

Overview

• Section 112 of the Clean Air Act– Overview– Emission standards– MACT program– Risk and technology review (RTR)

• Available Resources

• Status Updates on Rules

Section 112 of the Clean Air ActOverview

• Establishes requirements for setting national emission standards for hazardous air pollutants (NESHAP)

• A hazardous air pollutant is defined as “any air pollutant listed pursuant to subsection (b) of this section [CAA section 112]”

– There are currently 189 pollutants on the HAP list (the complete list is available online at: http://www.epa.gov/ttn/atw/overview.html)

• Stationary sources are broken down into two categories: major and area– A major source “means any stationary source or group of stationary sources located

within a contiguous area and under common control that emits or has the potential to emit considering controls, in the aggregate, 10 tons per year or more of any hazardous air pollutant or 25 tons per year or more of any combination of hazardous air pollutants”

– An area source “means any stationary source of hazardous air pollutants that is not a major source”

Regulation of Toxic Pollutants• The Clean Air Act listed 189 (now 183) toxic air pollutants

(that may cause cancer or serious health problems)

• There are literally thousands of sources of toxic air pollutants (also called hazardous air pollutants or HAPs)

• Sources range from gigantic oil refineries to the dry cleaner on the corner, as well as mobile sources (cars, trucks, planes, trains)

• Clean Air Act requires EPA to set standards for specific source types

Section 112 of the Clean Air ActEmission Standards

• Per section 112(d), “the Administrator shall promulgate regulations establishing emission standards for each category or subcategory of major sources and area sources of hazardous air pollutants listed for regulation pursuant to subsection (c) of this section in accordance with the schedules provided in subsection (c) and (e) of this section”

• Emission standards “require the maximum degree of reduction in emissions of the hazardous air pollutants…the maximum degree of reduction in emissions that is deemed achievable for new sources in a category or subcategory shall not be less stringent than the emission control that is achieved in practice by the best controlled similar source, as determined by the Administrator”– The above is speaking to the maximum achievable control

technology or MACT program

Section 112 of the Clean Air ActMACT Program

• Under the MACT program emission limits for existing sources are established by:– Examining “the average emission limitation achieved by the best

performing 12 percent of the existing sources (for which the Administrator has emissions information)… or by examining “the average emission limitation achieved by the best performing 5 sources (for which the Administrator has or could reasonably obtain emission information) in the category or subcategory for categories or subcategories with fewer than 30 sources)

• For area sources the Administrator may “elect to promulgate standards or requirements applicable to sources in such categories or subcategories which provide for the use of generally available control technologies or management practices by such sources to reduce emissions of hazardous air pollutants”

Section 112 of the Clean Air ActRisk and Technology Review (RTR)

• Residual risk review and technology review required within 8 years of promulgation of MACT standards

• 2-step risk analysis1. Determine if risk is acceptable considering health information only, and if not

acceptable, tighten standards so risks are acceptable2. Determine if standards provide an ample margin of safety, which considers

health info, costs and feasibility

• Risk review includes inhalation risk assessment (cancer and non-cancer) and screens to assess multipathway, whole facility, acute and environmental risks

– Can perform refined multipathway assessments in limited cases if screens show potential multipathway human health risk

• Technology review takes into account new developments in practices, processes and control technologies considering cost and feasibility

• We also consider previously unregulated processes and HAP, and we make technical corrections

Available Resources• Overview of section 112 (this includes the list of HAPs):

http://www.epa.gov/ttn/atw/overview.html

• For further explanation of major and area sources and a list of source categories please visit:

http://www.epa.gov/ttn/atw/pollsour.html

• For a listing of all of the NESHAP/MACT final rules please visit: http://www.epa.gov/ttn/atw/mactfnlalph.html

• For an overview of the risk and technology review program please visit: http://www.epa.gov/ttn/atw/rrisk/rtrpg.html

• Plain English guide to Clean Air Act: http://www.epa.gov/air/caa/peg/

• State, local, tribal and federal partnerships: http://www.epa.gov/ttn/atw/stprogs.html

Status Updates on Rules

Startup Shutdown and Malfunctions • Historically, EPA’s air pollution rules require compliance with

standards at all times, but most rules allowed an exemption of the standard if it occurred during a malfunction or during periods of startup or shutdown

• In 2008, the D.C. Circuit Court ruled that such exemptions were not permitted

• EPA is addressing the court decision in its rules by removing the exemption for malfunctions; for start up and shutdown provisions, EPA considers whether it is viable for sources to comply at all times, or whether a separate provision is necessary to address start up and shutdown

Status Update on Rules (cont.)

Steel Sector• Steel mills are regulated under three different rulemakings

• Electric Arc Furnaces (EAF) – steel from recycled steel scrap– 88 facilities; mostly area sources (80 facilities) – 5 major stand-alone; 3 major co-located at integrated iron and steel facilities– Rule promulgated in 2007, included standards for mercury and PM limits

• Integrated Iron and Steel Plants – steel from taconite ore, coke– 16 facilities: 4 with sinter plants, 3 with EAF– 5 facilities with co-located coke plants– MACT rule promulgated in 2003, included PM and opacity limits

• Coke Plants – produces coke, a high-energy fuel used in steel production

– 19 facilities; 5 co-located at integrated iron and steel facilities – Most have multiple coke oven batteries – MACT rules were promulgated in 1993 and 2003 for various plant processes – RTR will be conducted for pushing, quenching and battery stacks– Coke oven rules include requirements for opacity and PM

Status Update on Rules (cont.)

43

Pollutant Limit

PM 27 milligrams per dry standard cubic meter (dscm)

Opacity 10 percent

Cadmium 0.040 milligrams per dscm

Lead 0.44 milligrams per dscm

Mercury 0.080 milligrams per dscm or 15 percent of the potential mercury emission concentration, whichever is less stringent

Sulfur dioxide 29 parts per million by volume (ppmv) or 25 percent of the potential sulfur dioxide emission concentration, whichever is less stringent

Hydrogen chloride  29 ppmv or 5 percent of the potential hydrogen chloride emission, whichever is less stringent

Dioxins/furans If facility uses ESP: 60 nanograms per dscmIf no ESP: 30 nanograms per dscm

Nitrogen oxides 205 ppmv (mass burn waterwall)

Carbon monoxide 100 ppmv (mass burn waterwall)

Federal plan emission limits for large MWCs constructed on or before 9/20/1994 (40 CFR Part 62 Subpart FFF)

Existing Large Municipal Waste Combustors

Status Update on Rules (cont.)Carbon Pollution Standards for Existing and Modified Power Plants

• The President in his directive to EPA under the Climate Action Plan stated that the agency should:

– Set flexible carbon pollution standards, regulations or guidelines, as appropriate, for power plants under section 111 of the Clean Air Act

– Focus on these elements when developing the standards:• Stakeholder engagement on program design

– States– Leaders in the power sector– Labor leaders– Non-governmental organizations– Tribal officials– Members of the public

• Flexibilities in program design– Market-based instruments, performance standards, others

• Costs– Tailor regulations and guidelines to reduce costs

• Continued importance of relying on a range of energy sources• Other regulations that affect the power sector

Status Update on Rules (cont.)Carbon Pollution Standards for Existing and Modified Power Plants• EPA’s Task:

– Develop carbon pollution standards, regulations or guidelines, as appropriate, for:

• New power plants• Modified and reconstructed power plants• Existing power plants

• Per the President’s Directive, EPA will issue proposed carbon pollution standards, regulations or guidelines, as appropriate, for modified, reconstructed and existing power plants, by no later than June 2014– EPA will issue final standards, regulations or guidelines as appropriate

by no later than June 2015– EPA will include in the guidelines addressing existing power plants a

requirement that States submit to EPA the implementation plans by no later than June 2016

Status Update on Rules (cont.)Carbon Pollution Standards for Existing and Modified Power Plants• EPA has been conducting a robust stakeholder engagement

process– Participated in meetings with over 300 utility, labor and

environmental groups since June 2013– Developed video webinar about the Climate Action Plan and

CAA section 111(d); this video has been viewed more than 3,800 times

– Held 11 public listening sessions around the country• 3,300 people attended• More than 1,600 people offered oral statements

• Engagement process has given EPA several key insights and takeaway messages

Petroleum Refinery Sector Risk and Technology Review

Presentation to the U.S. EPA Science Advisory BoardJuly 19, 2013

Developing Exposure Estimates• We use the EPA Human Exposure Model (HEM) risk modeling

system to estimate exposure, which contains:– AERMOD dispersion model (EPA’s approved local-scale model)

– 2010 Census data at census block resolution (about 10 households)

– Terrain elevation data

– Meteorological data

• Uses historical (2011) data from weather stations nationwide

• Exposure estimates are conservative– We assume that there is a person at the centroid of census block who is

continually exposed for 70 years

• If the highest concentration is at residence closer to the facility than the centroid, we use that concentration as our exposure estimate

– This reflects the Clean Air Act mandate to assess risks to the ‘individual most exposed’

Inhalation Risk Outputs

• Chronic – Cancer: Maximum Individual Risk (MIR) – highest cancer risk (in a

million) at a location where people live (census block centroid or nearest residence)

– Noncancer: Hazard Index (HI) – highest noncancer risk at a location where people live (census block centroid or nearest residence)

– Annual cancer incidence (cases/year)

– Cancer risk bin distributions (>100 in a million, 10 in a million…)

– Source category and facility wide risks

– Process level risk contributions

• Acute– Maximum off-site impact: pollutant-specific highest 1-hour Hazard

Quotient (HQ) outside estimated facility fenceline• Default factor of 10x time the annual emissions rate unless source category

specific information is provided• Can be refined with site-specific boundary conditions

Development of Emission Inventories• The purpose of the risk and technology review is to evaluate the

MACT standards to determine if:– It is necessary to tighten the standards to protect human health and the

environment with an “ample margin of safety”

– There are advancements in practices, processes or technologies that warrant tightening the standards

• Risk and technology review requires emission inventory data• Emission inventories are developed to satisfy state requirements

– EPA provides guidance in the form of AP-42 emission factors, but does not mandate their use

– Inventories are not consistent among states

– Speciation and completeness of data for air toxic pollutants vary

– EPA houses state inventories in the Emission Inventory System (EIS)

Refinery Emissions Inventory• EPA was petitioned in 2008 under the Data Quality Act to improve emission factors from

refineries

– In response, EPA developed a refinery emissions estimation protocol, which was put through two rounds of public notice and comment in 2010

• http://www.epa.gov/ttn/chief/efpac/protocol/index.htm

• Refinery Emissions Estimation Protocol

– Provides consistent set of methods for estimating emissions (criteria pollutants and air toxics)

– Requires speciation of air toxic pollutants

– Describes what refinery emission sources should have pollutant emission estimates

– No new sampling is required

– Ranking of methodologies depending on available data

– More detailed and comprehensive than AP-42 emission factors

• 2011 Refinery ICR required refiners to use the Refinery Emissions Estimation Protocol to develop their inventory

• Refinery inventory submitted in response to the ICR will be used to perform the risk and technology review of the MACT standards

Air Toxics Emissions From Refineries

Refinery Emission Sources• Point sources (vents or stacks)

– Emissions generally well understood and well characterized, and some test data available where pollutants were directly measured

– Examples include vents at catalytic cracking, fluid coking, delayed coking, catalytic reforming, sulfur recovery, hydrogen plants

– As part of risk and technology review, EPA is amending rules to require electronic submission of performance test data; will be used to periodically update emission factors

• Flares

– Destruction of pollutants in an open flame

– Difficult to directly measure pollutants

– Flare studies available to develop correlations for parameters that affect flare destruction efficiencies (2012 peer review)

– September 2012 NSPS flare amendments will require all flares to eventually have monitors to measure waste gas flow

– Flare operational requirements ensure good combustion and provide information (waste gas composition and flare destruction efficiency) that can be used to estimate emissions from flares

• Fugitive emission sources

– Tend to be open sources or not emitted through a stack or vent, thus difficult to directly measure pollutants

– Examples include equipment leaks and pressure relief devices, tanks and transfer operations and wastewater handling and treatment

– Emission models and estimates are used to predict pollutant emissions

– An emission standard at the fenceline can help ensure fugitive emission standards are being met

Fenceline Monitoring• Fugitive emission sources may not be well characterized in the inventories but are likely

significant contributors to overall emissions

• Fugitives from process piping

• Wastewater sources

• Pressure relief events

• Tanks

• Highest concentrations of these fugitive emission sources outside the facility likely occur by the property boundary near ground level

• Air monitoring at the property boundary can provide a direct measure of the annual average concentrations of air toxics directly surrounding the refinery

• Benzene is a refinery risk driver and also primarily emitted from fugitive sources; 85% of benzene emissions from refineries is from fugitive, ground-level sources, so reducing emissions of benzene from fugitive sources will reduce emissions of other toxic pollutants

• Perimeter or fenceline monitoring provides an indicator of the level of emissions at refineries and is a way to ground-truth fugitive emission estimates

Low-cost sensor

networks

Low-cost sensor

networks

Different technologies and approaches to detect and measure pollutants over extended areas and time

Mobile inspection

systems

Mobile inspection

systems

Monitoring for Assessment of Fugitives

Leak detection power and feasibility of widespread deployment

Ana

lytic

al p

ower

and

impl

emen

tatio

n co

st

Current open-path and auto

GC systems

Current open-path and auto

GC systemsLower cost

optical systems

Lower cost optical

systems

0.2 0.5 2 5 10 (µm)0.2 0.5 2 5 10 (µm)

UV DOAS FTIRTDL FLIR

UV Diff. Optical Absorption

Spectroscopy

Tunable Diode Laser (scanning)

Forward-Looking InfraRed (leak imaging)

Fourier Transform InfraRed

(scanning)

Open-path optical

systems

Open-path optical

systems

Open-Path Instruments

N

Low-Cost Sensors Can Provide 24-7 Observation & Enable New Regulatory Approaches

Facility fenceline monitoringPassive sampling

Low-cost sensor

networks

Low-cost sensor

networks

• Locate passive samplers around the perimeter of each refinery

• Calculate annual average concentration

• If rolling average concentration exceeds benzene concentration standard (the action level), initiate tiered approach to positively identify facility contribution and conduct corrective action to reduce emissions

Developments in Lower-Cost Time-Resolved Monitoring to Support Time-Integrated Passive Sampler Fenceline Measurements

Mobile inspection systems

Mobile inspection systems

SECONDARY MIRROR

PRIMARY MIRROR

SEALED UV WINDOW

BEAM SPLITTER

DETECTORS

FOCUSING LENS

Lower cost open-path

optical systems

Lower cost open-path

optical systems

Deep UV optical sensor

Drive-by leak inspection

Drop-in-place sensor packages

Prototype PID sensor package (pres. temp. , RH., VOC)

Combining senor and wind data

Combining senor and wind data

New leak-location algorithms

Low-cost stand-alone

sensors

Low-cost stand-alone

sensors

Wind

April 2013 passive sampler and GMAP demo with a cooperating refineryMobile inspection detected benzene leak at location of the highest passive sampler

reading

Passive sampler

Geospatial measurement (GMAP) mobile benzene

survey

Passive sampler fenceline and mobile inspection demonstration