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Proposed Costco Wholesale Redwood City GDF Expansion 7.A. - Page 200 Air Quality/Climate Change Analysis Appendix C: Modeling Assessment Updates Table C-4. Cumulative Health Risk Screening Analysis for Rail Corridor Near the Costco Wholesale Redwood City GDF. Cumulative Health Risk Screening Analysis for Diesel Exhaust Emissions from Locomotive Traffic. Ann.Ave. Inhalation Chronic Maximum Concentration Average Cancer Reference Estimated Non-cancer Rail Service in the at Peak Daily PM2.5 Potency Exposure Maximum Hazard Vicinity of the Receptor Emissions Factor Level(REL) Cancer Risk Index Costco Redwood City GDF (�ag/m3) (g/day) 1/(mg/kg-day) (�ag/m3) (per million) (HI) Caltrain(No Electrification) Before Rebuild 0.083 252.49 1.10E+00 5 3.23 0.0167 After Rebuild 0.033 101.00 1.10E+00 5 16.81 0.0067 Total Over 70 Years 20.05 0.0167 max Caltrain(Assuming Electrification) Before Rebuild 0.083 252.49 1.10E+00 5 3.23 0.0167 After Rebuild 0.033 101.00 1.10E+00 5 1.81 0.0067 Total Over 70 Years 5.04 0.0167(max) Reduction in Risk -15.00 -- Freight Rail Before Rebuild 0.019 56.85 1.10E+00 5 0.87 0.0038 After Rebuild 0.008 22.74 1.10E+00 5 3.73 0.0015 Total Over 70 Years 4.60 0.0038 max Dumbarton Passenger Rail 0.004 13.52 1.10E+00 5 2.25 0.0009 Notes: 1. Annual average peak receptor diesel particulate matter(PM)concentrations for rail service in the vicinity of the Costco Redwood City GDF are scaled from the annual average peak receptor diesel PM concentration from Draft TAC Analysis for 201 Marshall Road,Redwood City, Bay Area AQMD,December 2011,page 2. The Bay Area AQMD analysis evaluated the impact of existing diesel powered Caltrain locomotive emissions on a proposed residential project located 90 feet north of the nearest track. In the above table,the relative average daily PM 2.5 emissions(in grams per day),presented and documented in Table C-5,are used to scale the Bay Area AQMD modeled PM concentration to reflect PM concentrations associated with rail traffic in the vicinity of the Costco Redwood City GDF. Bay Area AQMD values: 0.066 micrograms per cubic meter(�ag/m3) 199.63 average daily PM2.5 emissions in grams per day(g/day) 2. Diesel exhaust inhalation cancer potency factor is from Technical Support Document for Cancer Potency Factors: Methodologies for Derivation,Listing ofAvailable Values,and Adjustments to Allow for Early Life Stage Exposures ,California Office of Environmental Health Hazard Assessment,May 2009,Appendix A(slope factor for diesel exhaust),available at www.oehha.ca.gov/air/hot_spots/ index.html(accessed July 23,2012). 3. Diesel exhaust chronic non-cancer Reference Exposure Level(REL)is from All OEHHA Acute, 8-hour and Chronic Reference Exposure Levels(chRELs),California Office of Environmental Health Hazard Assessment, December 18,2008,available at www.oehha.ca.gov/air/hot_spots/index.html(accessed July 23,2012). 4. Maximum cancer risk is estimated from the annual average PM concentration(peak residential receptor)using the following: Cancer Risk=Annual Average Concentration x(BR x ET x EF x ED x UCF)=AT]x CPF x ASF 5. The Bay Area AQMD recommends that cancer risk estimates should incorporate Age Sensitivity Factors(ASFs)to account for the increased susceptibility of infants and children to carcinogens. The District recommends the following ASFs: student receptors: 3; residential receptors: 1.7;and worker receptors: 1. Source: BAAQMD Air Toxics NSR Program Health Risk Screening Analysis (HRSA)Guidelines, Bay Area Air Quality Management District,January 2010,Section 2.3(Cancer Risk Calculations),available at www.baaqmd.gov/Divisions/Engineering/Air-Toxics/Review-of-Air-Toxics.aspx(accessed March 26,2012). 6. Maximum non-cancer chronic hazard index is estimated from the annual average peak residential receptor PM concentration using: Non-cancer Hazard Index=Annual Average Concentration=Chronic REL 7. Since funding commitments are not yet in place to allow electrification of the Caltrain system to proceed,the above table reflects estimates of cumulative health risks associated with Caltrain passenger rail service assuming that electrification does not occur,as well as cumulative health risks assuming that Caltrain electrification occurs. Caltrain electrification assumes that electrification will be completed by 2025 [Draft TAC Analysis for 201 Marshall Road,Redwood City, December 2011,Bay Area AQMD,page 3]. Residential Rece tor Ex osure Parameters Used in Cumulative Air Toxics Health Risk Screenin Anal sis. Breathing Exposure Exposure Exposure Units Averaging BAAQMD Rate BR Time Frequency Duration Conversion Time Cancer Risk Rail Daily Hourly (ET) (EF) (ED) Factor(UCF) (AT) Age Sensitivity Service (L/kg-day) (L/kg-hr) (hours/day) (days/year) (years) (mg-m3)/(�ag-L) (days) Factor(ASF) Caltrain Before Rebuild 302 12.6 24 350 5 1.00E-06 25,550 1.7 After Rebuild 302 12.6 24 350 65 1.00E-06 25,550 1.7 After Electrif. 58 Freight Rail Before Rebuild 302 12.6 24 350 6 1.00E-06 25,550 1.7 After Rebuild 302 12.6 24 350 64 1.00E-06 25,550 1.7 Dumbarton Rail 302 12.6 24 350 65 1.00E-06 25,550 1.7 Page 6 Date: 7/30/2012