1. Current Status, New Directions
Air Toxics:
Current Status, New Directions
Kenneth L. Mitchell, Ph.D.; Chief
Air Toxics Assessment & Implementation
U.S. Environmental Protection Agency
Atlanta, Georgia

2. Good Afternoon! What are Air Toxics? Program Overview Current Status
Future Directions

3. What do we mean by “Air Toxics?”
Six“Criteria”
Pollutants
O3, NO2, SO2, Pb
CO, PM
The Federal
Clean Air Act
Mobile Source
Pollutants
21 Chemicals &
Mixtures
Hazardous
Air Pollutants
(Air Toxics)
187 Chemicals &
Compounds

4. Why are air toxics a problem?
Millions of Sources
Cancer
Kidney, Liver Damage
Skin Rashes
Birth Defects, Miscarriages
Nervous System Damage
Developmental Problems in Children
Cough, Throat Irritation
Asthma, Chronic Bronchitis
Many are Highly Toxic
Some Persist & Bioaccumulate
Sources/Populations Colocated

5. EVAPORATION/ REENTRAINMENT OTHER NON-CANCER ENDPOINTS
WIND DIRECTION
WIND DIRECTION B A
TRANSFORMATION
WET DEPOSITION
DISPERSION
DRY DEPOSITION
EVAPORATION/ REENTRAINMENT
IN AIR
BIOACCUMULATION
IN FOOD
CANCER
TARGET ORGAN/TISSUE
INGESTION
INHALATION
DERMAL
OTHER NON-CANCER ENDPOINTS
EXCRETION
INTAKE/UPTAKE

8. There Are Sources Everywhere!
_________________________________________________________________
Courtesy of Sustaining the Environment and Resources for Canadians

9. Types of Sources Major Sources Area Sources 10 TPY or more of one HAP
_________________________________________________________________
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

10. Engines, fuels, and operation all contribute to pollution;
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

11. THE NATIONAL AIR TOXICS PROGRAM
(Stationary, Mobile, and Indoor Air Sources)
Regulatory
Approaches
Risk Assessment
Methods for
Facility Specific &
Community-Scale
Risk Decision
Criteria for
Facilities and
Communities
Voluntary
Reduction
Options
Education
and
Outreach
SLT
Program
Structure
Design
_________________________________________________________________
Achieve Meaningful Reductions
At The Local Level

12. 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

13. 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

14. Residual Risk – New Directions
Develop “total facility low-risk demonstration (TFLRD)” rule
Develop comprehensive or generic residual risk rule (GRRR)

15. 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

16. Area Sources – Recent Additional Court Ordered Schedule
Dec. 15, categories
June 15, categories
Dec * 10 categories
June 15, categories
Dec. 15, categories
June 15, categories
50 Categories
*3 area source standards subject to CAA 112(c)(6) (related to PBT chemicals) must be promulgated by this date.

17. 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

18. 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 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

19. 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

20. Mobile Source Air Toxics – Future Directions
Benzene content standard for gasoline
Vehicle standards
Exhaust emissions
Evaporative emissions
Gas can standards

21. Diesel Exhaust – Current and Future Directions
Building on the successes of EPA’s 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

22. Thanks for your attention!
Dr. Ken Mitchell
U.S. Environmental Protection Agency
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