Multiple Air Toxics Exposure Study in the South Coast Air Basin MATES III FINAL REPORT. September 2008

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2 Multiple Air Toxics Exposure Study in the South Coast Air Basin MATES III FINAL REPORT September 2008 South Coast Air Quality Management District Copley Drive Diamond Bar, CA 91765

3 SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT GOVERNING BOARD Chairman: WILLIAM A. BURKE, Ed. D. Speaker of the Assembly Appointee Vice-Chairman: S. ROY WILSON, Ed. D. Supervisor, Fourth District Riverside County Representative MEMBERS: MICHAEL D. ANTONOVICH Supervisor, Fifth District, Los Angeles County Representative MICHAEL A. CACCIOTTI Councilmember, City of South Pasadena Cities Representative, Los Angeles County Eastern Region BILL CAMPBELL Supervisor, Third District Orange County Representative JANE W. CARNEY Senate Rules Committee Appointee RONALD O. LOVERIDGE Mayor, City of Riverside Cities Representative, Riverside County JOSEPH K. LYOU, PH.D. Governor s Appointee GARY OVITT Supervisor, Fourth District San Bernardino County Representative JAN PERRY Councilmember City of Los Angeles Representative MIGUEL PULIDO Mayor, City of Santa Ana Cities Representative, Orange County TONIA REYES URANGA Councilmember, City of Long Beach Cities Representative, Los Angeles County, Western Region DENNIS YATES Mayor, City of Chino Cities Representative, San Bernardino County EXECUTIVE OFFICER: BARRY R. WALLERSTEIN, D.Env

4 AUTHORS AND CONTRIBUTORS The following individuals contributed to the development, implementation, and reporting of this project. South Coast Air Quality Management District Executive Officer Barry R. Wallerstein, D.Env. Deputy Executive Officers Elaine Chang, Dr. PH Chung Liu, D. Env. Planning, Rule Development & Area Sources Science and Technology Advancement Assistant Deputy Executive Officers Laki Tisopulos, Ph.D., P.E. Henry Hogo Planning, Rule Development & Area Sources Mobile Source Division, Science and Technology Advancement AUTHORS Jean Ospital, Dr. PH Joe Cassmassi Tom Chico Health Effects Officer Planning and Rules Manager Program Supervisor CONTRIBUTORS Libby Ayers Dale Barber Steven Barbosa Tracy Basler Mark Bassett Rene Bermudez Roger Bond Malou Cartwright Wimol Chanjamsri Paul Chavez Tom Chico Alice Chen Corie Choa Amy Chun Kris Collins Monique Davis Alicia Diaz Jorge Diez Kevin Durkee Rudy Eden Lila Enriquez Philip Fine Jeremy Graham Meteorological Technician Temporary Air Quality Instrument Specialist I Principal Air Quality Chemist Temporary Laboratory Technician Air Quality Specialist Principal Air Quality Instrument Specialist Air Quality Chemist Laboratory Technician Chemist Senior Air Quality Instrument Specialist Program Supervisor Temporary Chemist Principal Air Quality Chemist Temporary Laboratory Technician Temporary Laboratory Technician Temporary Chemist Laboratory Technician Laboratory Technician Air Quality Specialist Senior Enforcement Manager, Laboratory Services Air Quality Instrument Specialist I Atmospheric Measurements Manager Air Quality Instrument Specialist I

5 Tracy Goss Sam Guo Refaat Hanna Sheri Hanizavareh Sandra Hom Dan Houghton Tai-Ching Hu Judy Hwa Eddie Hwang Laura Julius Aaron Katzenstein Bong Mann Kim Cindy Kirkpatrick Mike Koch Sally Kou Jong Hoon Lee Sang-Mi Lee Kay Liu Eddie Lui Jason Low Joe Macias Satoru Mitsutomi Ricardo Morales Chris Nelson Kevin Orellana John Parrack II Richard Parent Tom Parsons Tuyet-le Pham Ed Ruffino Ken Sanchez David Sawyer Mike Shu Steve Taw Na Mon Trinh Solomon Teffera Lyovit Usares Brian Vlasich Thy Vo Jill Whynot Paul Williamson Sumner Wilson Robert Yi Xinqiu Zhang Program Supervisor Air Quality Chemist Air Quality Instrument Specialist II Student Intern Senior Air Quality Chemist Air Quality Chemist Senior Air Quality Chemist Air Quality Chemist Temporary Laboratory Technician Air Quality Inspector II Senior Air Quality Chemist Air Quality Specialist Temporary Laboratory Technician Air Quality Instrument Specialist I Air Quality Chemist Air Quality Specialist Air Quality Specialist Air Quality Chemist Temporary Laboratory Technician Quality Assurance Manager Temporary Air Quality Instrument Specialist I Program Supervisor Air Quality Instrument Specialist I Senior Staff Specialist Air Quality Inspector II Assistant Air Quality Chemist Air Quality Instrument Specialist II Atmospheric Measurements Manager (retired) Air Quality Specialist Air Quality Instrument Specialist II Air Quality Chemist Principal Air Quality Instrument Specialist Air Quality Chemist (retired) Laboratory Technician Laboratory Technician Principal Air Quality Chemist Air Quality Inspector II Air Quality Instrument Specialist II Temporary Chemist Director of Strategic Initiatives Air Quality Chemist Principal Air Quality Instrument Specialist Air Quality Chemist Air Quality Specialist

6 MATES III Technical Advisory Group Member Name: Greg Adams Robert Blaisdell Steven Cadle Judith Chow Steve Colome Bob Devlin Rob Farber Dennis Fitz John Froines Dan Greenbaum Debra Kaden Dean High Mike Lakin Bill LaMarr Angelo Logan Fred Lurmann Rod Merl Dale Shimp Shankar Prasad Bill Quinn Constantino Sioutas Samuel Soret Mel Zeldin Affiliation: L.A. County Sanitation Districts Cal EPA Office of Environmental Health Hazard Assessment General Motors Desert Research Institute Integrated Environmental Sciences U.S. Environmental Protection Agency Southern California Edison Center for Environmental Research and Technology University of California, Los Angeles Health Effects Institute Health Effects Institute Consultant Engine Manufacturers Association California Small Business Alliance East Yard Communities for Environmental Justice Sonoma Technology City of Santa Monica California Air Resources Board California Air Resources Board California Council for Environmental and Economic Balance University of Southern California Loma Linda University Consultant

7 Table of Contents Table of Contents EXECUTIVE SUMMARY... ES-1 1. INTRODUCTION Background Objective MATES III MONITORING PROGRAM Substances Monitored Siting of Monitoring Stations Ambient Sampling Schedule Monitoring Sites Monitoring and Laboratory Analysis Findings Cancer Risk Estimates EMISSIONS INVENTORY DEVELOPMENT Introduction Overview Point Sources Area Sources On-Road Mobile Sources Off-Road Mobile Sources Summary of Toxic Emissions Selected Emissions and Air Quality Changes Since MATES II References REGIONAL MODEL EVALUATION Introduction Background MATES III vs. MATES II: Key Modeling Assumptions Modeling Results Estimation of Risk Evaluation References MICROSCALE STUDY Introduction Site Selection Microscale Sites and Sampling Periods i

8 Table of Contents 6. SUMMARY FINDINGS AND DISCUSSION Improvements to Ambient Monitoring Improvements to Air Toxics Modeling Key Findings Discussion and Policy Implications ii

9 Table of Contents List of Tables Table No. Description Page No. ES-1 Substances Measured in MATES III ES-2 ES-2 ES-3 CMB Estimate of Diesel Particulate Compared to Emissions Inventory Ratio Methods Modeled Air Toxics Risk Comparisons Using the CAMx Model ES-3 ES Substances Monitored in MATES III MATES II Fixed Site Locations Sampling and Analysis Methods for MATES III Emissions of Diesel PM and EC, lbs./yr Estimates of Average Diesel PM, µg/m Commonly Used Spatial Surrogates Broad Vehicle Classes Considered by EMFAC Vehicle Activity Information for the Counties in the Basin Annual Average Day Toxic Emissions for the South Coast Air Basin 3-5 Cancer Potency Weighted Species Apportionment for 2005 Emissions 3-6 Selected Emissions and Air Quality Changes Since MATES II 4-1 Summary Comparison of Key Modeling Considerations Between MATES III and MATES II 4-2 Compounds Simulated and Measured: Six-Station Annual Average Concentrations 2005 MATES III and CAMx RTRAC Analyses MATES III 2005 EC 2.5 Model Performance Basin and Port Area Population-Weighted Risk 4-16 iii

10 Table of Contents 4-5 County-Wide Population-Weighted Risk MATES III Risk from Simulated Individual Toxic Air Contaminants 4-7 Comparison of Network Averaged CAMx RTRAC 2005 Modeled Risk to Measured Risk at Eight MATES III Sites 5-1 Comparison of Observed Concentrations for the Microscale and Fixed Site Pair of Commerce and Huntington Park 5-2 Comparison of Observed Concentrations for the Microscale and Fixed Site Pair of Indio and Rubidoux 5-3 Comparison of Observed Concentrations of the Microscale and Fixed Site Pair of San Bernardino and Inland Valley San Bernardino 5-4 Comparison of Observed Concentrations for the Microscale and Fixed Site Pair of Sun Valley and Burbank 5-5 Comparison of Observed Concentrations for the Microscale and Fixed Site Pair of Santa Ana and Anaheim iv

11 Table of Contents List of Figures Figure No. Description Page No. ES-1 Map of MATES III Monitoring Sites ES-8 ES-2 MATES III Average Monitored Air Toxics Risk ES-9 ES-3 MATES III Monitored Air Toxics Risk by Site ES-9 ES-4 MATES III Model Estimated Risk ES-10 ES-5 Change in CAMx RTRAC Air Toxics Simulated Risk (per million) from Using Back-Cast 1998 Emissions and MM5 Generated Meteorological Data Fields ES MATES III Monitoring Locations Average Concentrations of 1,3-Butadiene Average Concentrations of Benzene Average Concentrations of Perchloroethylene Average Concentrations of Methylene Chloride Average Concentrations of Formaldehyde Average Concentrations of Acetaldehyde Average Concentrations of Arsenic in TSP Average Concentrations of Cadmium in TSP Average Concentrations of Lead in TSP Average Concentrations of Nickel in TSP Average Concentrations of Hexavalent Chromium Average Concentrations of PM 10 Elemental Carbon Average Concentrations of PM 2.5 Elemental Carbon Average Monitored Naphthalene Concentrations for MATES III Year v

12 Table of Contents 2-16 Average Concentration of PAHs for MATES III Year Estimated 70-Year Risk from MATES III Year 1 Monitoring Data 2-18 Estimated 70-Year Risk from MATES III Year 2 Monitoring Data 2-19 PM 2.5 Mass from MATES III and EPA Collocated Samplers at Los Angeles 2-20 PM 2.5 Mass from MATES III and EPA Collocated Samplers at Rubidoux Flow Diagram for On-Road Emissions Processing Cancer Potency Weighted Source Apportionment for Cancer Potency Weighted Emission Comparison of MATES II and MATES III MATES III Modeling Domain Annual Average Concentration Pattern for Diesel PM Annual Average Concentration Pattern for Benzene Annual Average Concentration Pattern for 1,3 Butadiene Annual Average Concentration Pattern for Total Formaldehyde MATES III CAMx RTRAC Simulated Air Toxic Risk MATES II CAMx RTRAC Simulated Air Toxic Risk 4-8 Change in CAMx RTRAC Simulated Air Toxics Risk from to MATES III 2005 Simulated Air Toxic Risk- No Diesel Ports Area MATES III Simulated Air Toxic Risk Central Los Angeles MATES III Simulated Air Toxic Risk 4-18 vi

13 Table of Contents Mira Loma/Colton MATES III Simulated Air Toxic Risk Central Orange County MATES III Simulated Air Toxic Risk West Los Angeles MATES III Simulated Air Toxic Risk MATES III Simulated versus Measured Concentrations for Non-Diesel Air Toxics Risk vii

14 Table of Contents List of Appendices (Separate Document) Appendix I II III IV V VI VII VIII IX X Title List of Substances and Their Associated Risk Factor List of MATES III Technical Advisory Group Members Monitoring and Laboratory Analysis Protocols Measurements of Ambient Naphthalene and Other PAHs PM 2.5 Particulate Bound Organic Compound Analysis Summary of Fixed Monitoring Site Data PM 2.5 Source Apportionment Methodology 2005 Emissions by Major Source Category Regional Modeling Analyses Weekday/Weekend PM 2.5 Speciation Project viii

15 CHAPTER 6 FINDINGS AND DISCUSSION

16 MATES III Final Report Chapter 6. Findings and Discussion The MATES III Study incorporates several updates and improved methodologies compared to previous air toxics studies in the Basin to measure and model ambient levels of air toxics and their associated risks. Key elements and findings are listed below Improvements to Ambient Monitoring Samples were taken at ten fixed sites, once every three days. This compares to once every six days in previous studies. Sampling occurred for two full years at eight sites, and one full year at all ten sites. An updated method was used to estimate the contribution of diesel exhaust to ambient particulates Improvements to Air Toxics Modeling An updated modeling platform, CAMx, was used to model levels of air toxics throughout the Basin using the 2005 emissions inventory. This is the same model as used in the 2007 Air Quality Management Plan (AQMP). An updated meteorology model for the year 2005 was used. Updated emissions inventories based on the 2007 AQMP were used. An improved assignment of on-road truck emissions using the Caltrans/SCAG Truck Model was used. The CAMx platform was also applied to the MATES II time frame, using a back-cast of the MATES III air toxics emissions inventory to give more of an apples to apples comparison of modeled air toxics risks Key Findings During the study period, the overall Basin cancer risk from air toxics based on the annual average levels calculated from the ten monitoring sites data was approximately 1,200 per million. Diesel exhaust was the key driver for air toxics risk, accounting for over 80% of the total air toxics risk. Of the pollutants measured, only formaldehyde was above the current chronic exposure levels developed by OEHHA. However, OEHHA has proposed revised limits. If the proposed limits are approved, all average levels of air toxics would be below established Reference Exposure Levels. Ambient levels of most substances measured were lower over the period of the MATES III Study compared to that of the MATES II Study, which was conducted in , reflecting the success of various control strategies to reduce exposure to air toxics. Benzene and 1,3-butadiene average levels, pollutants mainly from vehicles, were down 6-1

17 MATES III Final Report 50% and 73%, respectively. Stationary source-related pollutants, such as methylene chloride (a solvent used in paint remover) and perchloroethylene (an industrial solvent used in dry cleaning) also showed declines of 53% and 78%, respectively. Levels of elemental carbon in the PM 10 particulate fraction were about 38% lower than those found in MATES II. About a 10% reduction was traced to a difference in analytical instrumentation used in MATES III. The net 28% reduction in ambient levels may reflect decreased emissions combined with annual meteorological differences. Estimated air toxics cancer risks for the second year of the study were somewhat higher than the first year. It should be noted that the first year of the study had higher rainfall than the second year, which is expected to affect particulate measurements. This mainly reflects a higher estimate for diesel particulate levels in the second year. The Rubidoux station showed higher levels of hexavalent chromium in the ambient measurements compared to MATES II, and higher levels than found at the other monitoring locations. Additional follow up studies by District staff identified a nearby cement facility as the source. A report on the additional intensive monitoring results can be found on the District s web site at Modeling analysis shows the highest risks from air toxics surrounding the port areas, with the highest grid cell risk about 3,700 per million, followed by the area south of Central Los Angeles where there is a major transportation corridor, with grid cell modeled risks ranging from about 1,400 to 1,900 per million. Modeling analysis also showed pronounced exposures along freeways and near intermodal facilities. While the model estimates of air toxics risk showed an overall Basin-wide reduction, some areas showed an increase in air toxics risk. This was shown to be the case near the ports, in the eastern portions of the Basin and in northern Los Angeles County. Most of the monitored pollutants at the microscale sites did not show increased levels compared to the nearest fixed sites. The exception was the Santa Ana microscale site, which showed elevations of several pollutants related to vehicle emissions. Risk estimates in this study do not include mortality from particulate exposure. This was done in the 2007 AQMP Discussion and Policy Implications Although there are uncertainties in the ambient estimates, diesel particulate continues to be the dominant toxic air pollutant based on cancer risk. This finding holds up regardless of methodology used. The study findings therefore clearly call for a step-up in reducing diesel emissions as early as practicable and as aggressively as feasible. Goods movement is a significant source of diesel emissions. With the projected future growth in goods movement, diesel emissions may increase. The interplay between (a) the increase in goods movement and (b) projected emission reduction strategies will be 6-2

18 MATES III Final Report crucial in determining whether diesel exposures are reduced in the future. There are several uncertainties in estimating air toxics risks. These include uncertainties in the cancer potencies of the substances, in the estimates of population exposure, and uncertainty in estimating the level of diesel particulate. There is at present no direct measurement method for ambient levels of diesel particulate. For this study, staff used the Chemical Mass Balance (CMB) approach to estimate diesel particulate levels. The CMB method is considered to be the best available method based on current scientific knowledge and was recommended by the Technical Advisory Group as well. Using the CMB model takes advantage of the specific profile of chemical species in different emissions sources and results in a more robust statistical correlation of source contributions to ambient particulate matter levels. The CMB method gave higher estimates of diesel particulate than did the method used in MATES II. Thus, the methods used in MATES II may have underestimated risk from diesel particulate. Since diesel emissions will likely continue to be the dominant source of cancer risk from air toxics for the future, improvement in the methodology to estimate ambient levels of diesel particulates would help reduce uncertainty in risk estimates and better characterize future changes in risk. Since the timeframe of the MATES III study, there have been numerous regulations and initiatives to reduce diesel exhaust emissions by national, state, and regional authorities. Staff expects that any future air toxics study will be able to assess the effectiveness of these endeavors. Although the estimated Basin-wide risks declined from the MATES II period, areas near the ports, and inland in the eastern and northern portions of the District, actually showed increases in estimated air toxics risk. These are likely due to increases in emissions related to the additional cargo container traffic and goods movement that occurred between MATES II and MATES III time periods. 6-3