Kentucky Division for Air Quality Taimur Shaikh Ph.D. Air Toxics & Modeling Kentucky Division for Air Quality Taimur Shaikh Ph.D.

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

Air Toxics Implementation

401 KAR 63:020 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.”

Ambient Sampling VOC’s SVOC’s Metals/Metalloids (Future) EPA Method TO-15 Analyze for volatile organics Both grab and 24-hour composite samples SVOC’s 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

Air Toxics Modeling Consists of multiple tiers Usually performed: 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

ATRA Reference Library http://www.epa.gov/ttn/fera/risk_atra_main.html As part of the interpretation of 401 KAR 63:020, the Division uses EPA’s Air Toxics Risk Assessment (ATRA) Reference Library Volumes I, II, and III as the procedural direction for conducting risk evaluations.

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

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

The Tiered Risk Assessment Lookup tables Exposure = maximum offsite levels Simple dispersion modeling (MEI) No data – all assumptions Lower cost – high uncertainty Conservative results – consistently over-estimates risk Tier 1 (Screening Level) Exposure = residential air levels More refined dispersion & exposure modeling (MIR) Moderate cost Tier 2 (Moderate Complexity) Exposure = exposure assessment Detailed site-specific modeling (MIR) Complete study-specific data No assumptions Higher cost – lower uncertainty Tier 3 (High Complexity) A key component of future efforts to reduce air toxics is the Integrated Urban Air Toxics Strategy released by EPA in July 1999. The Strategy presents a framework to address air toxics in urban areas and builds on the substantial emission reductions already achieved from cars, trucks, fuels, and industries such as chemical plants and oil refineries.

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

Air Dispersion Modeling

Sample Projects Examples of incorporating modeling into Air Toxics: Toxics analysis – Dioxins & Furans Toxics analysis – Hydrazine Toxics analysis – HF modeling under 401 KAR 53:010 Modeling that belongs to Air Toxics by managerial default: NSR/PSD review Site evaluation of monitors for the Pb NAAQS.

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 (4.3*10-7 g/m3) exceeds 1*10-6 carcinogenic risk (6.4*10-8 g/m3) The facility is operational at the moment but has taken a production limit

Secondary Al Smelter (Dioxin 1 Hour Average) Please note that the scale is adjusted by two orders of magnitude.

Secondary Al Smelter (Dioxin Annual Average)

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 1:1,000,000 carcinogenic risk with cadmium driving the risk at 1:1,000 After our investigation, the facility choose to remove Cd, and Ni and reduce Pb and hydrazine emissions

Specialty Chemical Facility (Hydrazine Annual Average, Pre-reduction)

Specialty Chemical Facility (Hydrazine Annual Average, Post-reduction) Stack 17 is not emitting hydrazine at this point. They have gone to a closed system.

Ambient Air Quality Standards Toxics Analysis - HF 401 KAR 53:010 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 401 KAR 53:010 Ambient Air Quality Standards Averaging Period Concentration (μg/m3) 12 hour 3.68 24 hour 2.86 1 week 1.64 1 month 0.82

Ceramic Manufacturer (HF 12 Hour Average)

Ceramic Manufacturer (HF 24 Hour Average)

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) Primary Standard Secondary Standard Concentration Averaging Time Lead 0.15 mg/m3 Rolling 3-Month Average Same as Primary 1.5 mg/m3 Quarterly Average 10/15/2008 – Only rolling 3 month average Used 1 month and annual to get an idea for siting location

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

Coal Fired Power Plant (Pb Month Average)

Coal Fired Power Plant (Pb Annual Average)

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

Questions? Dr. Taimur Shaikh - Taimur.Shaikh@KY.gov Kentucky Division for Air Quality – (502)564-3999 ext. 4480