Air Toxics

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Air Toxics Modeling

• Kentucky Division for Air Quality
• Taimur Shaikh Ph.D.

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Introduction

• Air Toxics Implementation
• Ambient Sampling
• Modeling
• Risk Assessment
• Air Toxics Modeling
• Scope
• Sample Projects
• Various Toxics Modeled Facilities
• Pb NAAQS Modeled Facility

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Air Toxics Implementation
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401 KAR 63020

• Potentially hazardous matter or toxic substances
  regulation
• No owner or operator shall allow any affected
• facility to emit potentially hazardous matter or
• toxic substances in such quantities or duration
  as
• to be harmful to the health and welfare of
• humans, animals and plants.

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Ambient Sampling

• VOCs
• EPA Method TO-15
• Analyze for volatile organics
• Both grab and 24-hour composite samples

• SVOCs
• EPA Method TO-13A
• Analyze for Poly-Aromatic Hydrocarbons
• 24-hour composites samples

• Metals/Metalloids (Future)
• PM10 including metals speciation
• 24-hour (or greater) composite samples

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Air Toxics Modeling

• Consists of multiple tiers
• 1st tier Screening via Screen3, conducted by
  permit reviewers
• 2nd tier AERMOD modeling using pertinent
  meteorological data and LULC data
• 3rd tier Same as 2nd tier but can require
  validated stack test emission rates, mass
  balances, and other data
• Usually performed
• For new facilities/major modifications
• In addition to sampled data
• As a follow-up to citizen complaints

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ATRA Reference Library
http//www.epa.gov/ttn/fera/risk_atra_main.html

• As part of the interpretation of 401 KAR 63020,
  the Division
• uses EPAs Air Toxics Risk Assessment (ATRA)
  Reference
• Library Volumes I, II, and III as the procedural
  direction for
• conducting risk evaluations.

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Risk Assessment

• Air Toxics Reference Library (ATRA)
• Tiered Risk Assessment
• Three distinct tiers
• The higher tiered assessments involve more
  complexity and have more rigorous data
  requirements
• 1st tier Risk is based on Screen3 output
• 2nd tier Risk is based on annual average from
  AERMOD (chronic assessment)
• 3rd tier Risk is based on ambient sampling data
  in addition to modeled values, at impacted
  individual, includes a more complex exposure and
  toxicity assessment
• Based on EPA guidance documents
• Most often, the data requirements limits the
  scope of the assessment

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The Tiered Risk Assessment
Complete study-specific data, no assumptions -
higher cost, lower uncertainty
Add quantitative uncertainty / variability
analysis More refined exposure assessment More
refined dispersion exposure modeling Simple
dispersion model Lookup Table
MORE REFINED Tiers 2 3
SCREENING Tier 1
No data, all assumptions - lower cost, high
uncertainty
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The Tiered Risk Assessment
Tier 3 (High Complexity)
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Air Toxics Domain

• All higher-level (tiers 2 3) risk assessments
• As directed by DAQ Management, risk assessments
  involving
• Unlisted pollutants
• Acute health effects
• Bioaccumulation
• Cumulative risk
• Carcinogenic risk
• Target organ specific hazard index
• Emissions from multiple sources
• Environmental damage

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Air Dispersion Modeling
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Sample Projects

• Examples of incorporating modeling into Air
  Toxics
• Toxics analysis Dioxins Furans
• Toxics analysis Hydrazine
• Toxics analysis HF modeling under
• 401 KAR 53010
• Modeling that belongs to Air Toxics by managerial
  default
• NSR/PSD review
• Site evaluation of monitors for the Pb NAAQS.

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Toxics Analysis Dioxins Furans

• Secondary Aluminum Smelter
• Emissions of Dioxin and Furans covered under
  Subpart RRR NESHAP for Secondary Aluminum
  Production
• Facility could not demonstrate capture efficiency
  due to deviations from RRR
• Modeled annual average (4.310-7 ?g/m3) exceeds
  110-6 carcinogenic risk (6.410-8 ?g/m3)
• The facility is operational at the moment but has
  taken a production limit

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Secondary Al Smelter (Dioxin 1 Hour Average)
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Secondary Al Smelter (Dioxin Annual Average)
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Toxics Analysis Hydrazine

• A specialty chemical facility manufacturing
  organic and organometallic compounds
• The facility was permitted to emit Ni, Cd, Pb,
  and hydrazine
• After initial modeling with AERMOD, modeled
  ambient concentrations exceeded 11,000,000
  carcinogenic risk with cadmium driving the risk
  at 11,000
• After our investigation, the facility choose to
  remove Cd, and Ni and reduce Pb and hydrazine
  emissions

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Specialty Chemical Facility (Hydrazine Annual
Average, Pre-reduction)
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Specialty Chemical Facility (Hydrazine Annual
Average, Post-reduction)
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Toxics Analysis - HF

• 401 KAR 53010 is the Kentucky Ambient Air
  Quality Standards which include standards for HF
• These are not to be exceeded more than once per
  year
• A ceramic and tile manufacturing facility was
  modeled to show compliance

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Ceramic Manufacturer(HF 12 Hour Average)
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Ceramic Manufacturer(HF 24 Hour Average)
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Pb NAAQS

• The modeling was used in site selection criteria
  for a Pb monitor in conjunction with the new Pb
  National Ambient Air Quality Standard (10/15/2008)

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Pb From a Coal Fired Power Plant

• Used air dispersion modeling of a coal fired
  power plant to site a monitor for the Pb NAAQS
• The NAAQS is based on a 3-month rolling and
  quarterly average
• Compared the one month and annual averages to
  choose the site for the monitor

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Coal Fired Power Plant (Pb Month Average)
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Coal Fired Power Plant (Pb Annual Average)
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Conclusions

• Air dispersion modeling
• Features prominently in the KY Air Toxics
  strategy
• Is applied in situations where monitoring is not
  feasible due to cost or time involved
• Can be binding from a regulatory standpoint
• Yields useful information for risk assessment

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Questions?
Dr. Taimur Shaikh - Taimur.Shaikh_at_KY.gov Kentucky
Division for Air Quality [phone] ext. 4480