Air Toxics:

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Air Toxics Current Status, New Directions
Kenneth L. Mitchell, Ph.D. Chief Air Toxics
Assessment Implementation U.S. Environmental
Protection Agency Atlanta, Georgia
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Good Afternoon!

• What are Air Toxics?
• Program Overview
• Current Status
• Future Directions

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What do we mean by Air Toxics?
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Why are air toxics a problem?
Millions of Sources
Some Persist Bioaccumulate
Many are Highly Toxic
Sources/Populations Colocated
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WIND DIRECTION
TRANSFORMATION
WET DEPOSITION
DISPERSION
DRY DEPOSITION
EVAPORATION/REENTRAINMENT
IN AIR
CANCER
TARGET ORGAN/TISSUE
INGESTION
OTHER NON-CANCER ENDPOINTS
EXCRETION
INTAKE/UPTAKE
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There Are Sources Everywhere!
Courtesy of Sustaining the Environment and
Resources for Canadians
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Types of Sources
Major Sources 10 TPY or more of one HAP Or 25
TPY or more of a combination of HAPS
Area Sources Less than 10 TPY of one HAP Or Less
than 25 TPY of a combination of HAPS
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Types of Sources
Outdoor Air
Indoor Sources Not regulated but pose (on
average) 3-5 times the concentrations of outdoor
air
Mobile Sources On- and Off-road Engines, fuels,
and operation all contribute to pollution 21
MSATs
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THE NATIONAL AIR TOXICS PROGRAM (Stationary,
Mobile, and Indoor Air Sources)
Risk Assessment Methods for Facility Specific
Community-Scale
Risk Decision Criteria for Facilities and
Communities
Education and Outreach
Voluntary Reduction Options
SLT Program Structure Design
Regulatory Approaches
Achieve Meaningful Reductions At The Local Level
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Residual Risk Mandate from Congress

• Assess risks from stationary sources that emit
  air toxics after technology-based (MACT)
  standards are in place
• Set additional standards if MACT does not protect
  public health with an ample margin of safety
• Set additional standards if necessary to prevent
  adverse environmental effects

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Residual Risk Status

• Coke ovens April 2005
• March 2006
• Industrial cooling towers
• Magnetic tape
• Ethylene oxide sterilizers
• Gasoline distribution
• Dry cleaning July 2006
• HON December 2006
• Halogenated Solvents December 2006

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Residual Risk New Directions

• Develop total facility low-risk demonstration
  (TFLRD) rule
• Develop comprehensive or generic residual risk
  rule (GRRR)

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Area Sources Current Status

• The Integrated Urban Strategy was published July
  19, 1999
• Identified chemicals of concern
• Identified initial list of area source
  categories
• 70 source categories have been listed
• Listing completed in November 2002
• Source categories required to be subject to
  regulation
• 16 rules completed
• 4 under court order

20 of the 70 Standards
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Area Sources Recent Additional Court Ordered
Schedule

• Dec. 15, 2006 4 categories
• June 15, 2007 6 categories
• Dec. 15 2007 10 categories
• June 15, 2008 10 categories
• Dec. 15, 2008 10 categories
• June 15, 2009 10 categories
• 50 Categories
• 3 area source standards subject to CAA 112(c)(6)
  (related to PBT chemicals) must be promulgated by
  this date.

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Area Sources Future Directions

• National Rulemaking Approach
• Establish national standards for source
  categories that have a national level of concern
• Flexible Rulemaking Approach
• Enact a rule, covering a set of categories, that
  will regulate how categories are controlled at
  the local level based on local needs
• EPA will provide guidance on control approaches

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Mobile Source Air Toxics (MSATs) Current Status

• In March 2001, EPA published first MSAT rule
• Toxics emissions performance standard for
  gasoline
• Refinery-specific baselines to ensure no
  backsliding from 1998-2000 performance
• No additional standards for fuels or vehicles
• Identified data gaps and committed to additional
  research
• Committed to additional rulemaking to evaluate
  the need for and feasibility of additional
  controls

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Mobile Source Air Toxics Future Directions

• Proposed Rule signed on February 28, 2006
• Public hearing on April 12
• 60-day comment period (through May 30th)
• Final rule by February 9, 2007

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Mobile Source Air Toxics Future Directions

• Benzene content standard for gasoline
• Vehicle standards
• Exhaust emissions
• Evaporative emissions
• Gas can standards

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Diesel Exhaust Current and Future Directions

• Building on the successes of EPAs regulatory and
  voluntary efforts to reduce emissions from diesel
  engines, EPA has created the National Clean
  Diesel Campaign (NCDC)
• Successful implementation of the 2007 Highway
  Engine Rule and the Clean Air Nonroad Diesel Rule
• Develop new emissions standards for locomotive
  and marine diesel engines
• Promote reduction of emissions for existing
  diesel engines through cost-effective and
  innovative strategies, including use of cleaner
  fuels, retrofitting and repairing existing
  fleets, idling reduction among others

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Thanks for your attention!

• Dr. Ken Mitchell
• U.S. Environmental Protection Agency
• [phone]
• mitchell.ken_at_epa.gov
• http//www.epa.gov/region4/air/airtoxic/index.htm