Addressing Hazardous Air Pollutants HAPs or Air Toxics in Wisconsin Overview of WI Program, Comparis

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Addressing Hazardous Air Pollutants (HAPs or Air
Toxics) in Wisconsin Overview of WI Program,
Comparison to the Federal Program and Current and
Future Risk Assessment Activities

• Jeff Myers
• Environmental Toxicologist
• Bureau of Air Management
• [phone]
• myersj_at_dnr.state.wi.us
• www.dnr.wisconsin.gov/org/aw/air/health/airtoxics/

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Wisconsin Facts

• Population 5.5 Million
• Most Residents in SE Part of State
• 36 of residents live in 7 SE counties
• Milwaukee County Population 940,000
• 18 of Total State Population
• Major WI Industries Agriculture, Tourism, Pulp
  and Paper, Wood Products, Printing, Foundries,
  Utilities (55 of power from coal)
• 1.4 Million Dairy Cows (14 of US Total)

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Wisconsin Facts Air Sources

• 1500 Permitted Sources
• 650 Title V Major Sources
• 2100 Sources Report to the Inventory
• We have sources that dont need permits that need
  to report to the inventory
• 240 New/Modified Construction
• Permits/Year

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Why Does Wisconsin Have its Own HAP Program?

• Federal HAP Program was not proceeding fast
  enough
• Citizens petitioned Department in early 1980s
  about the concern with slow progress over federal
  NESHAP program
• This led to task force and recommendation for
  rule
• Rule became effective in 1988 (2 years before
  1990 Clean Air Act Amendments)

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WI Air Toxics Rule Background (Contd)

• Rule was controversial and lawsuits were filed by
  some industry groups claiming it went beyond
  statutory authority
• 1990 Court decision upheld majority of rule
• 1995 Rule revised to incorporate use of US EPA
  reference concentrations for chronic non-cancer
  effects
• July 2004 Latest rule revision effective

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Basics of WI Air Toxics Rule (Ch. NR 445 Admin.
Code)

• Applies to new/modified and existing facilities,
  even those that do not need a permit
• About 438 chemicals listed originally
• Rule revised effective July 1, 2004 to cover a
  total of about 535 chemicals, including diesel
  exhaust and coal dust
• Sets ambient air concentrations (not to be
  exceeded beyond the property line, regardless of
  land use) for
• Acute non-carcinogens (based on ACGIH TLVs)
• Chronic non-carcinogens (based on US EPA
  reference concentrations (RfCs))
• Establishes control technology requirements for
  carcinogens (must be listed by BOTH IARC and NTP
  to be considered)

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Thresholds in WI Air Toxics Rule

• There are threshold tables in the rule that give
  a listing of emission rates that one can compare
  against
• Thresholds are based on modeling of a generic
  facility at 4 different stack heights, so as not
  to exceed a given standard or 10-5 risk for
  carcinogens - it is meant to filter out small
  emitters
• If non-exempt potential emissions are below these
  thresholds, then one documents their calculations
  and they are done
• If above thresholds, modeling or other compliance
  options available, or source must meet the
  Standard

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Risk Based Off-Ramps

• In July 2004 Revisions, we offered a risk-based
  off-ramp where sources can
• For Single Pollutant demonstrate lt10-6 risk
• Facility Wide demonstrate lt 10-5 risk
• Reason Historically many sources could
  demonstrate it was too costly to control risks
  and an expensive technology review would achieve
  no environmental benefit. This allows us to
  concentrate resources on higher risk sources

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Why Does the WI Rule Look the Way it Does Today?

• It looks this way because of the unique problems,
  social, economic and political landscapes in
  Wisconsin
• It is a hybrid of ambient standards for
  non-carcinogens and technology standards for
  carcinogens
• It tried to go beyond federal rules, to fix any
  health gaps in the federal HAP program, but is
  now required to be no more stringent than the
  federal program, thus WI program complements
  the 112 standards
• It is trying to focus resources on significant
  risks, rather than on all sources

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Comparison Wisconsin vs.. Federal HAP Program
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Concern in WI About Federal Program

• Some MACTs result in higher residual risks than
  we would like to see and it is unclear how
  residual risk will work and how long it will take
• Some standards limit the amount of federally
  listed HAPs in a coating and some federally
  acceptable compliance options would allow use of
  these coatings
• As more coatings is used, it could exceed health
  benchmarks for carcinogens and non-carcinogens
• Non-federal HAPs can also be used in such
  coatings, because they comply with federal rules

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WI Emissions Inventory

• Since 1994, Annual Emissions Inventory required
  for all stationary sources with actual emissions
  of gt3 tons volatile organic compounds (VOC) or gt5
  tons particulate matter (PM)
• All HAPs (federal and state) and criteria
  pollutants are listed with thresholds for
  reporting
• WI supplements point source inventories with area
  source and mobile source emissions data for
  National Air Toxics Assessment (NATA) and Great
  Lakes Commission Inventories

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HAP Monitoring in WI

• Currently WI has 3 air toxics monitoring sites
• Milwaukee
• Madison
• Mayville (rural background site)
• Typically Metals, Organics, Semivolatiles
• Historically monitoring in several other
  locations (Green Bay, Wood County, Special
  Studies)
• Federal PM2.5 Speciation Monitors for metals (7
  locations)
• Resources not available to conduct wide spread
  monitoring
• Would like to obtain funding to address hot
  spots found from modeling, permits and evaluate
  mobile sources

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What is the Role of Risk Assessment in the WI Air
Program?

• WI standards for carcinogens are technology based
  and risk is not a consideration, by rule
• However, the addition of risk based off-ramps in
  our rule and the federal residual risk program in
  112(f) suggests that risk assessment will become
  more prevalent
• The most important reason we do risk assessment
  is because we need to know what results from our
  permitting decisions

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What is Cancer Risk Modeling and Why is it Used?

• What An analysis of cancer risk remaining after
  controls are in place
• Why Used
• As a compliance option in the revised rule
• To evaluate program effectiveness (in spite of
  fact WI rules for sources are not risk based, we
  still need to know) Are we doing our job of
  protecting WI citizens from air toxics?
• To help choose between alternative control
  devices in terms of removal required, costs,
  and stringency

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How is Risk Screening Done?

• Permit Engineer supplies potential (sometimes
  also actual) emissions estimates to air
  dispersion modeler
• Modeler uses US EPA regulatory air model - ISCST3
  (AERMOD in future) - to calculate annual average
  concentrations (usually using worst year of 5
  years)
• Calculation Annual avg. concentration X unit
  risk factor is lifetime excess cancer risk
  estimate. Multiple carcinogens - risk assumed to
  be additive
• Note For workload reasons, we keep this analysis
  simple - 70 years 20 M3/day - we dont used
  refined approaches, such as Monte Carlo exposure
  assessments and typically only use inhalation
  route

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Overall Findings of WI Risk Inhalation Screenings

• 15 years experience database of 346 analyses
  shows rule technology standards (BACT/LAER) are
  working most of the time
• 1 or 2 chemicals tend to drive the risk
  assessment
• Mainly larger sources paper mills, foundries,
  utilities, but some important exceptions (e.g.,
  diesel exhaust (8 out of 10 highest risk
  sources), yeast manufacturer)
• Formaldehyde, chloroform, benzene, dioxins,
  metals and diesel exhaust are main actors
• In spite of no DNR risk based authority, some
  sources have made voluntary reductions

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Why Consider Diesel Emissions in a HAP Program?
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WI Policy for Acceptable Risk

• Based on 1987 WI DNR Air and Waste Division Risk
  Guidance
• General goal is to be below 10-5 risk, except
  when cost and feasibility dictates higher risks
• EPA guidance through Federal Register and court
  cases defines range as 10-4 to 10-6

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Future Directions

• Using Integrated Models and Geographic
  Information Systems (GIS) to analyze cancer and
  non-cancer risks from multiple chemicals,
  multiple sources and multiple routes of exposure,
  including mobile sources
• Current project in Milwaukee using Regional Air
  Impact Modeling Initiative (RAIMI) developed by
  USEPA Region 6 - Jeff Yurks Group

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Milwaukee County
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Milwaukee County, WI
EPA National Air Toxics Assessment (NATA) (1996
Emissions Data)
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Milwaukee Study Area
Study Area (purple rectangle) is about 5.6 Km by
4.1 Km
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Stationary Air Pollution Sources in Study Area
and Buffer
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