1. New Source Review for Air Toxics November 2, 2005 Peter J. Moore Yorke Engineering 949-248-8490 x24

2. What is Toxics New Source Review (NSR)? Evaluation of the health risk impacts to nearby exposed individuals (receptors) Calculate health risk indices Health risk indices cannot exceed thresholds

3. When is Toxics NSR Applied? When a new or modified source causes an increase in Toxic Air Contaminants (TAC), Toxics NSR is required SCAQMD Rule 1401 – New Source Review of Toxic Air Contaminants Also Rule 219 permit-exempt equipment if health risk may exceed thresholds

4. Implications of Toxics NSR Permit denied if calculated health risk is too high Public notice required if cancer risk increase exceeds 1 in one million CEQA is triggered if combined project cancer risk increase exceeds 10 in one million May require Environmental Impact Report

5. Implications (continued) May set permit conditions Example: Natural Gas Engine Toxic Air Contaminants from internal combustion must be evaluated for Toxics NSR If health risk calculations show that a limit on operation is necessary to stay below health risk thresholds, a daily or monthly limit on natural gas use may become a permit condition Carefully consider all possible toxic emissions for any new source

6. What Toxics are Considered? Toxic Air Contaminants (TAC) are listed in Rules 1401 and 1402 Carcinogenic:153 compounds Acute:58 chemicals Chronic:125 chemicals Risk factors are assigned by the California EPA Office of Environmental Health Hazard Assessment (OEHHA) New TAC’s being added over time

7. Health Risk Index - MICR Maximum Individual Cancer Risk (MICR) Long term impact Probability that an individual will contract cancer over 70 years (resident receptor) or 40 years (commercial receptor) Must be < 1 x 10 -5 (10 in one million) for new equipment <1 x 10 -6 to avoid public notice

8. Health Risk Index - Chronic Chronic Hazard Index (HIC) Long term, non-cancer health effects Must be < 1.0 for all target organs

9. Health Risk Index - Acute Acute Hazard Index (HIA) Short term (1-hour average) health effects Must be < 1.0 for all target organs

10. What Are Target Organs? Specific systems in the human body that are affected by TACs SymbolDescriptionChronicAcute ALAlimentary system (liver) XX BNBones and teeth X CVCardiovascular system XX DEVDevelopmental XX ENDEndocrine system X EYEEye XX HEMHematopoietic system (blood) XX IMMImmune system XX KIDKidney X NSNervous system XX REPReproductive system XX RESPRespiratory system XX SKINSkin XX

11. Risk Assessment Tiers Tier 1: Screening Emission Levels Use Table 1A to check if emission rates are below thresholds Tier 2: Screening Risk Assessment Use Tables 2-10 to determine dispersion factors, etc. Tier 3: Screening Dispersion Modeling Use SCREEN3 to determine dispersion factors Tier 4: Detailed Risk Assessment Use HARP for highest fidelity model, full meteorology Less Conservative

12. Tier I Screening Evaluation Max Annual Controlled Emissions (tons/year) Max Hourly Controlled (lbs/hr) Look up tables in: “Risk Assessment Procedures for Rules 1401 and 212” Check for most recent version! If emissions are lower than screening levels, Rule 1401 is satisfied. If not, proceed to Tier II

13. Tier II Health Risk Assessment Max Annual Controlled Emissions (tons/year) Max Hourly Controlled (lbs/hr) Look up tables in: “Risk Assessment Procedures for Rules 1401 and 212” If health risk indices lower than thresholds, Rule 1401 is satisfied. If not, proceed to Tier III

14. Tier II Risk Assessment for MICR MICR = CP x DI x MP CP: cancer potency factor (mg/kg-day) -1 DI = Dose inhalation (mg/kg-day) DI = C air x DBR x EVF x 10 -6 Cair = concentration in air (µg/m 3) DBR = daily breathing rate (L/kg-day) EVR = Exposure value factor (unitless) 1 x10 -6 = convert µg to mg(10 -3 mg/µg), liters to cubic meters (10 -3 m 3 /l) C air = Q tons x X/Q x AF ann x MET Q tons = Emission rate (tons/year) X/Q = Dispersion Factor ((µg/m 3 )/(ton/yr) AF ann = Annual Averaging factor MET = meteorological correction factor (unitless) MP: multipathway factor (unitless) MICR = CP x ((Q tons x X/Q x AF ann x MET) x DBR x EVF x 10 -6 ) x MP

15. Chronic Index Equation HIC Chronic hazard index (calculated for each target organ)  TAC Sum of the contribution for each Toxic Air Contaminant (TAC) Qyr TAC Emission rate of each TAC (tons/year) X/QAnnual average dispersion factor (  g/m 3 )/(ton/year) REL TAC Chronic Reference Exposure Level (  g/m 3 ) for each TAC MPMulti-pathway adjustment factor (n.d.) METMeteorological correction factor (n.d.)

16. Acute Index Equation HIA Acute hazard index (calculated for each target organ)  TAC Sum of the contribution for each Toxic Air Contaminant (TAC) Q hr TAC Emission rate of each TAC (lb/hour) X/Q hr Hourly average dispersion factor (  g/m 3 )/(lb/hour) REL TAC Acute Reference Exposure Level (  g/m 3 ) for each TAC

17. Cancer Burden Calculation Only Needed if MICR >10 -6 Estimate Area (km 2 ) with Risk >10 -6 Multiply Area by 4,000 - 7,000 persons/ km 2 Multiply Total Persons by MICR If Burden >0.5 More detailed calculations or modeling required

18. Tier III Health Risk Assessment Similar to Tier II Use SCREEN3 to determine dispersion factors (X/Q) instead of from tables Exhaust temperature and velocity are included Simple building downwash effects Single source Equation is the same If health risk indices lower than thresholds, Rule 1401 is satisfied. If not, proceed to Tier IV

19. Tier IV Health Risk Assessment Most detailed health risk assessment Requires details of building dimensions, local topography, and local meteorology Use Hot Spots Analysis and Reporting Program (HARP) to calculate dispersion factors and health risk indices Free download from CARB website www.arb.ca.gov/toxics/harp/harp.htm Multiple sources in different locations

20. TAC’s from Natural Gas Ventura County APCD did testing of internal & external combustion equipment in 1995 for TAC’s “Ventura Factors” can be used for emission factors for external combustion only Use EPA’s AP-42 emission factors for internal combustion

21. TAC’s from External Combustion *As determined by Ventura APCD

22. TAC’s from Internal Combustion EPA: AP-42 Emission Factors, Table 3.2-3 Toxic Air ContaminantMICRHICHIA 1,1,2,2-Tetrachloroethane X 1,1,2-Trichloroethane X 1,1-Dichloroethane X 1,3-Butadiene XX Acetaldehyde XX Acrolein XX Benzene XXX Carbon Tetrachloride XXX Chlorobenzene X Chloroform XXX Ethylbenzene X Ethylene Dibromide XX Ethylene dichloride (1,2-dichloroethane) XX Formaldehyde XXX Methanol XX Methylene Chloride XXX n-Hexane X Naphthalene XX PAHs (w/o naphthalene) X Phenol XX Styrene XX Toluene XX Vinyl Chloride X X Xylene XX

23. Rule 1401 Limitations MICR of 1 X 10 -6 Without T-BACT * MICR of 1 X 10 -5 With T-BACT Cancer Burden, excess cancer cases in the population subject to a risk greater than (1 x 10 -6 ), of 0.5 Acute and Chronic Hazard Index of < 1 * T-BACT Criteria Similar to Existing BACT

24. Rule 1401 Exemptions Emergency Internal Combustion Engines Modifications with no increase in toxic emissions Functionally identical replacement Contemporaneous Risk Reductions No MICR increase at any location >1x10 -6, and Reduction occurs within 100 m of new equipment Alternative Hazard Index <10

25. Example Facility adding three large, natural-gas fueled, cogeneration engines Four existing emergency diesels Nearby residents Each engine passed Rule 1401 with MICR of 9 in one million CEQA triggered due to combined MICR of 27 in one million

26. Example (continued) We calculated that cogeneration engines resulted in less usage of diesel backup engines Diesel health risk is high Contemporaneous health risk reduction allowed project to proceed without requiring an Environmental Impact Report

27. Risk is Dependent On: Source and Receptor Location Emission Rate Emission Species Meteorology Stack Parameters Operating Schedule

28. Strategies Locate equipment away from adjacent residents or workers Raise stack height Perform detailed modeling to determine risk impacts to specific receptors Source test for actual toxic emissions Tests showed high destruction of PAH across catalyst