### CHAPTER 1

INTRODUCTIONMATES III Final Report

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## Chapter 1. Introduction

1.1. Background The South Coast Air Basin (Basin), a highly urbaniz ed area, is home to about 16 million people who own and operate about 11 million motor vehicles and contains some of the highest concentrations of industrial and commercial operati ons in the country. It also has the poorest air quality in the U.S. In 1986, SCAQMD conducted the first MATES Study to determine the Basin-wide risks associated with major airborne car cinogens. At the time, the state of technology was such that only ten known air toxic c ompounds could be analyzed. In 1998, a second MATES Study (MATES II) represented one of th e most comprehensive air toxics measurement programs conducted in an urban environm ent. MATES II included a monitoring program of 40 known air toxic compounds, an updated emissions inventory of toxic air contaminants, and a modeling effort to characterize health risks from hazardous air pollutants.

Since these studies were conducted, several emissio ns control programs have been implemented at the national, state, and local levels; and toxic s emissions have been declining. However, at the community level, there is heightened awareness of t oxic air contaminant exposures. There are also environmental justice concerns that programs d esigned to reduce emissions may not be effective in reducing risks from toxic air contamin ants in certain areas, particularly in communities with lower income or multiple sources o f air toxics.

In September 2003, the SCAQMD Governing Board appro ved several enhancements to the District’s Environmental Justice Program. Initiati ve I-5 of these enhancements called for a oneyear sampling program for air toxics. Staff initia ted the MATES III Study in April 2004, to provide current data on air toxic levels and exposu res, address environmental justice issues, establish an updated baseline of toxic emissions, e xposures, and risk levels.

During the fall and winter of the study, there were unusual weather patterns that resulted in a near record rainfall in the Basin. To determine if these weather patterns affected the ambient levels of air toxics, the study was extended to two years through March, 2006. In this report the two years will be referred to as MATES III Year One (year 1) and MATES III Year Two (year 2).

1.2. Objective The objective of MATES III was to characterize the ambient air toxic concentrations and potential exposures in the Basin. This project inc luded two years of ambient monitoring for air toxics. The project developed an updated toxics em issions inventory and conducted air dispersion modeling to estimate ambient levels and the potential health risks of air toxics.

It is anticipated that the results of this study ad ditionally would serve to inform an update of the District’s Air Toxics Control Plan.

This study focuses on the carcinogenic risks from e xposures to air toxics. It does not include an analysis of noncancer mortality from exposure to pa rticulates. An analysis of mortality and other health effects from exposure to particulates was co nducted as part of the 2007 AQMP. The results of this effort can determine the spatia l concentration pattern of important hazardousMATES III Final Report

1-2 air pollutants in the Basin, assess the effectivene ss of current air toxic control measures, provide trend data of air toxic levels, and be used to upda te and develop appropriate control strategies for reducing exposures to toxics associated with signif icant public health risks.

There are three components to the study, as listed below:

• Air Toxics Monitoring and Analyses

• Emissions Inventory Enhancements

• Air Toxic Modeling and Risk Assessments

These components are further described in the chapt ers that follow.

1.3. Estimates of Risks A health risk assessment evaluates the potential he alth impacts from exposures to substances released from a facility or found in the air. Thes e assessments provide estimates of potential long-term cancer and noncancer health risks. The a ssessments do not collect information on specific individuals but are estimates of potential effects in a population at large.

Potential health risks were estimated using methodo logy consistent with the procedures recommended in the 2003 OEHHA “Air Toxics Hot Spots Program Guidance Manual for Preparation of Health Risk Assessments” (Guidance M anual). As discussed in the Guidance Manual, the risk assessment process generally consi sts of four parts, namely hazard identification, exposure assessment, dose response assessment, and risk characterization. The risk assessment steps, as applied in this study, ar e briefly summarized below.

Hazard Identification

Hazard identification involves determination of whe ther a hazard exists; and, if so, if the substance of concern is a potential human carcinoge n or is associated with other types of adverse health effects in humans. For this study, the list of air toxics in the OEHHA Guidelines was used in conjunction with information on ambient levels o f air toxics from previous studies, as well as input from the Technical Advisory Group, to determi ne which substances on which to focus for this assessment. This list is provided in Appendix I.

Exposure Assessment

The purpose of an exposure assessment is to estimat e the extent of public exposure for a substance. This can involve quantification of emis sions from a source, modeling of environmental transport and fate, and estimation of exposure levels over some period of time. In this study, annual averages of the air toxics of co ncern were estimated in two ways. For the fixed site monitoring station data, annual averages were calculated and used as an estimate of exposure. For the modeling analysis, emissions ove r the Basin were estimated and allocated to 2 kilometer geographic grids, and a regional dispersi on model was used to estimate the annual average concentrations in each grid space.MATES III Final Report

1-3 Dose Response Assessment

The dose response assessment characterizes the rela tionship between exposure to a substance and the incidence of an adverse health effect in an exp osed population. For estimating cancer risk, the dose-response is expressed in terms of a potenc y slope that is used to calculate the probability of cancer associated with a given exposure. These cancer potency factors are expressed as the 95 th statistical upper confidence limit of the slope of the dose response curve assuming a continuous lifetime exposure to a substance at a do se of one milligram per kilogram of body weight.

For effects other than cancer, dose-response data a re used to develop acute and chronic Reference Exposure Levels (RELs). The RELs are def ined as the concentrations at or below which no adverse noncancer health effects would be found in the general population. The acute RELs are designed to be protective for infrequent 1 hour exposures. The chronic RELs are designed to be protective for continuous exposure f or at least a significant fraction of a lifetime.

For this study, the dose-response estimates develop ed by OEHHA are used to estimate the potential for adverse health effects. It may be po inted out that these estimates sometimes differ from those developed by the U.S. EPA. For example, OEHHA has developed a cancer potency factor for diesel exhaust, whereas the U.S. EPA has elected not to do so. The U.S. EPA does state, however, that diesel exhaust is likely to be carcinogenic to humans and has adopted extensive regulations designed to reduce diesel exh aust exposure. While some of the potency estimates OEHHA has developed for other air toxics produce different estimates of risks then those that would be calculated using the U.S. EPA v alues, the risk from diesel exhaust calculated using OEHHA’s cancer potency factor is the dominant contributor to the estimated air toxics cancer risk in this study.

Risk Characterization

In this step, the estimated concentration of a subs tance is combined with the potency factors and RELs to determine the potential for health effects. In this study, the estimated or measured annual average levels for potential carcinogens wer e multiplied by the potency factor expressed as unit risks. The unit risk is the probability as sociated with a lifetime exposure to a level of one microgram per cubic meter of air of a given substan ce. The unit risk factors developed by OEHHA and used in this study are listed in Appendix I.

The potential cancer risk for a given substance is expressed as the incremental number of potential cancer cases that could be developed per million people, assuming that the population is exposed to the substance at a constant annual av erage concentration over a presumed 70-year lifetime. These risks are usually presented in cha nces per million. For example, if the cancer risks were estimated to be 100 per million, the pro bability of an individual developing cancer from a lifetime exposure would be one in a million. This would predict an additional 100 cases of cancer in a population of a million people over a 70-year lifetime period.

Perspectives of Risk

It may be useful to compare risks estimated from as sessments of environmental exposures to the overall rates of health effects in the general popu lation. For example, it is often estimated thatMATES III Final Report

1-4 the incidence of cancer over a lifetime in the U.S. population is about 1 in 4, to 1 in 3. This translates into a risk of about 300,000 in a millio n. It has been also estimated that the bulk of cancers from known risk factors are associated with lifestyle factors such as tobacco use, diet, and being overweight. One such study, the Harvard Report on Cancer Prevention, estimated that of cancers associated with known risk factors, abou t 30% were related to tobacco, about 30% were related to diet and obesity, and about 2% were associated with environmental pollution related exposures.

Source of Uncertainty

The estimates of health risks are based on the stat e of current knowledge, and the process has undergone extensive scientific and public review. However, there is uncertainty associated with the processes of risk assessment. This uncertainty stems from the lack of data in many areas necessitating the use of assumptions. The assumpti ons are consistent with current scientific knowledge, but are often designed to be conservativ e and on the side of health protection in order to avoid underestimation of public health ris ks.

As noted in the OEHHA guidelines, sources of uncert ainty, which may either overestimate or underestimate risk, include: (1) extrapolation of t oxicity data in animals to humans, (2) uncertainty in the estimation of emissions, (3) unc ertainty in the air dispersion models, and (4) uncertainty in the exposure estimates. Uncertainty may be defined as what is not known and may be reduced with further scientific studies. In add ition to uncertainty, there is a natural range or variability in the human population in such propert ies as height, weight, and susceptibility to chemical toxicants.

Thus, the risk estimates should not be interpreted as actual rates of disease in the exposed population, but rather as estimates of potential ri sk, based on current knowledge and a number of assumptions. However, a consistent approach to ris k assessment is useful to compare different sources and different substances to prioritize publ ic health concerns.

1.4. References The Air Toxics Hot Spots Program Guidance Manual fo r Preparation of Health Risk Assessments, Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, 2003.

Harvard Report on Cancer Prevention Volume 1: Cause s of Human Cancer Cancer Causes & Control, Volume 7 Supplement Novemb er 1996

### CHAPTER 2

AIR TOXICS MONITORING AND ANALYSESMATES III Final Report

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## Chapter 2. Air Toxics Monitoring and Analyses

2.1. Substances Monitored The chemical compounds (Table 2-1) to be monitored in MATES III include the toxics posing the most significant contributors to health risks a s found in previous studies in the Basin. Additional measurements include organic carbon, ele mental carbon, and total carbon, as well as Particulate Matter (PM), including PM 2.5 . Acrolein was initially considered to be included

. However, there was no suitable method available for routine analyses at the time the study began. Other compounds are also reported, since th ey are additionally captured in both the sampling and analytical protocols proposed.

Table 2-1 Substances Monitored in MATES III Benzene 1,3-Butadiene Carbon Tetrachloride Chloroform Dichlorobenzene Methylene Chloride

MTBE Perchloroethylene (Tetrachloroethylene) Dichloroethane Dibromoethane Ethyl Benzene Toluene Trichloroethylene Xylene Styrene Vinyl Chloride Acetaldehyde Formaldehyde Acetone Methyl ethyl ketone Arsenic Cadmium Hexavalent Chromium Copper Lead Manganese Nickel Selenium Zinc Elemental Carbon Organic Carbon Naphthalene PAHs PM 10 PM 2.5
Naphthalene and other polycyclic aromatic hydrocarb ons (PAHs), components of both mobile source and stationary source emissions, were measur ed. Recent reports have shown that annual averages of naphthalene are at levels hundreds to t housands of times higher than that of other PAHs. The National Toxicology Program has listed n aphthalene as a potential human carcinogen. Additionally, the California EPA’s Off ice of Environmental Health Hazard Assessment (OEHHA) recently evaluated the health ri sk of ambient naphthalene under California’s Air Toxics Program and developed a can cer potency factor. The International Agency for Research on Cancer considers naphthalene to be possibly carcinogenic to humans. Given the likely importance of naphthalene to publi c health, it is of value to obtain additional information on ambient levels and emissions of this compound.

PAHs were measured at three of the MATES III monito ring stations using EPA method TO-13A as a guideline. The West Long Beach and Central Los Angeles sites were selected because of their proximity to mobile emissions sources. Also, Lu, et al. (2005) incorporated ambient data from the Southern California Children’s Health Stud y and showed the highest naphthalene emissions rate in those regions. The Rubidoux site was selected as a receptor site and also for its particle-bound PAH measurement history as part of t he ARB toxics network.

Details of the methodology are given in Appendix IV

.MATES III Final Report

2-2 2.2. Siting of Monitoring Stations The MATES III project conducted air toxics monitori ng at ten locations over a two-year period. In addition to the ten fixed sites, the movable mon itoring platforms were deployed that focused on “microscale” studies at five locations for perio ds up to several months.

The combination of fixed and microscale sites was d one to ensure sufficient resolution to monitor representative concentrations of varying la nd use types and characterize spatial gradients in the Basin.

2.3. Ambient Sampling Schedule Sampling for MATES III followed a one-in-three day, 24-hour integrated-sampling schedule, which is double the schedule utilized during the MA TES II Study. In the microscale studies, a 24-hour integrated-sampling schedule was maintained for carbonyls, PM, and volatile organic compound (VOC) measurements, but in addition, three eight-hour integrated canister samples for VOCs were collected for higher temporal resolution over a single day. All data will be submitted to the U.S. EPA’s Air Quality System (AQS ) after review and validation.

2.4. Monitoring Sites

2.4.1. Fixed Sites The fixed monitoring sites are those used in the MA TES II Study, other than for the West Long Beach site. These sites were selected to measure n umerous air toxic compounds at different locations in the Basin in order to establish a base line of existing air toxic ambient concentrations, as well as risk level data, and to assist in the as sessment of modeling performance accuracy. The West Long Beach site for the MATES III Study is abo ut 2.5 miles east of the MATES II site, as the previous site was no longer available.

The locations for the ten fixed sites reflect key l ocations within the Basin and are geographically dispersed. Fixed site locations include areas vary ing in land-use types to obtain a good spatial representation of the Basin which includes expected areas of possible elevated toxics levels (e.g. industrial and commercial) and those areas that are not directly near source emissions (neighborhoods). The sites also reflect resource c onstraints and the leveraging of existing specialized equipment. In addition, using these si tes utilized in MATES I and MATES II allows for trend analysis. The sites used in MATES III ar e shown in Figure 2-1.

The ten sites were selected with the input from the MATES II Technical Review Group and the Environmental Justice Task Force, and locations are listed in Table 2-2. Five were selected to provide continuity with the ARB long-term trend sit es (Los Angeles, Burbank, Long Beach, Rubidoux and Inland Valley San Bernardino). The P ico Rivera site was selected because monitoring equipment was available from the EPA-spo nsored PAMS Program. Anaheim was chosen for geographic equity, such that at least on e site existed in each of the four counties. West Long Beach, Compton, and Huntington Park were sites selected to examine environmental justice concerns. Because the fixed site locations are based on EPA guidelines forMATES III Final Report

2-3 “neighborhood scale” monitoring, each of these site s may also be representative of adjacent communities.

Table 2-2 Mates II Fixed Site Locations Site Address Anaheim 1010 S. Harbor Blvd. Burbank 228 W. Palm Ave. Compton 720 N. Bullis Rd. Inland Valley San Bernardino 14360 Arrow Highway Huntington Park 6301 S. Santa Fe Ave. North Long Beach 3648 N. Long Beach Blvd. Central Los Angeles 1630 N. Main St. Pico Rivera 3713 B-San Gabriel River Parkway Rubidoux 5888 Mission Blvd. West Long Beach 1903 Santa Fe Ave.

At each site, sampling equipment included particula te samplers, canisters, and carbonyl samplers, as well as equipment to measure key meteo rological parameters.

Figure 2-1 Location of MATES III Monitoring Locati ons

2.4.2. Microscale Sites The purpose of the microscale sites is to monitor a ir contaminants on a neighborhood level at locations of concern within the Basin. This inform ation is used to determine if communities may F

o

Rubidoux

Wilmington Pico Rivera

Indio Sun Valley

San Bernardino

Industry

Fixed Sites Temporary Sites Compton Burbank

Anaheim

Inland Valley S.B.

Rubidoux

W. Long Beach N. Long Beach Pico Rivera Los Angeles

Huntington Park

Indio

Santa Ana Sun Valley

San Bernardino

Commerce

Fixed Sites Temporary SitesMATES III Final Report

2-4 be experiencing localized gradients of air toxics n ot otherwise determined by modeling as related to issues of environmental justice.

The microscale sites utilize the SCAQMD’s movable m onitoring platforms. As in MATES II, each microscale site will be paired with a nearby f ixed site for comparison to determine if toxic air emissions at these microscale sites statistical ly exceed a neighboring fixed site. Due to the limited number of mobile monitoring platforms, each microscale site study lasts only a few months. Other considerations for site selection in clude the following: (1) power availability; (2) security; (3) accessibility to SCAQMD staff; and (4 ) availability of the premises for a six-to tenweek period.

Since the sampling periods for the microscale sites are limited, annual averages for measured substances cannot be calculated. However, comparin g the levels from the microscale sites to those from the nearest fixed site during the timefr ame that the microscale site was operating can yield insights on potential community gradients.

Microscale sites were selected using the following criteria, in consultation with the MATES III Technical Advisory Group:

• Proximity to emissions source(s);

• Areas identified with environmental justice issues;

• Potential for neighborhood gradients;

• Elevated risks from MATES II modeling analysis;

• Community concerns; and

• Geographic equity.

Input on potential types of sites has come from sev eral sources, including the following:

• Community concerns from public outreach and Town Ha ll meetings;

• Public complaints;

• MATES II modeling data;

• Data from existing studies; and

• MATES Technical Advisory Group.

The locations of the microscale monitoring sites ar e shown in Figure 2-1 and are listed below.

• Commerce

• Indio

• San Bernardino

• Santa Ana

• Sun Valley

2.5. Monitoring and Laboratory Analysis For MATES III, meteorological equipment and samplin g equipment for canisters, PM 10 and PM 2.5 filters, and carbonyl cartridges from the existing air monitoring network were used to the extent possible. The SCAQMD laboratory provided th e analytical equipment and conducted the routine analysis. The analytical methods to measur e the ambient species are briefly describedMATES III Final Report

2-5 below and in Table 2-3. Detailed protocols are des cribed in Appendix III.

Table 2-3 Sampling and Analysis Methods for MATES III Ambient Species Sampling

Method Laboratory Analysis Volatile Organic Compounds (VOCs) Summa

Polished/ SilicaLined Canisters Gas chromatograph – Mass spectrometer (GC-MS) with

automated pre-concentration and cryo-focusing

Carbonyls DNPH

Cartridge Solvent recovery and subsequent analysis via high

performance liquid chromatography (HPLC) Hexavalent Chromium Cellulose Fiber

Filters Treatment with buffer solution to maintain proper p H for

unwanted conversions and then subsequent analysis v ia ion chromatograph(IC) Elemental and Organic Carbon (EC/OC) PM Filters Section of PM filter removed and analyze d on a laser corrected carbon analyzer

PM 10 High-Volume

Quartz Filters Mass determined by analytical balance; metals

determined Energy Dispersive X-Ray Fluorescence Spectrometry; ions extracted with water from filter and then subsequently analyzed on IC PM 2.5 MediumVolume Teflon Filters Mass determined by Micro-balance; metals determined

by Energy Dispersive X-Ray Fluorescence Spectrometr y, ions extracted with water from filter and then subsequently analyzed on IC

Volatile Organic Compounds (VOCs) are measured from air samples collected in either summa polished or silica-lined six-liter canisters using an automated canister sampler to fill at a constant rate over a 24-hour or eight-hour time per iod depending upon the site. The filled canisters are brought back to the laboratory for an alysis within 48 hours of the sample being collected. VOCs are identified and measured using gas chromatograph mass spectrometry (GCMS). The SCAQMD currently has two GC-MS instrument s that are based upon the U.S. EPA’s TO-14 and TO-15 methods. These instruments are equ ipped with automated canister preconcentrators attached to the GC to enable continuo us analysis.

Carbonyl Compounds are sampled by drawing a continuous amount of air through a DNPH (2,4-Dinitrophenylhedrazine) cartridge. The carbon yl compounds undergo derivatization with DNPH, and the derivatives are analyzed using High P erformance Liquid Chromatography (HPLC) in conjunction with U.S. EPA method TO-11.

Hexavalent Chromium (Chrome VI) is analyzed using ion chromatography (IC). Sample collection involves drawing air at a prescribed rat e for 24-hours through a cellulose fiber filter. The filter is treated with sodium bicarbonate to pr event conversion of Chrome VI to Chrome III. Chrome VI is extracted from the filter by sonicatio n and subsequently analyzed using IC.MATES III Final Report

2-6 Particulate Matter less than 10 microns ( PM 10 ) and less than 2.5 microns ( PM 2.5 ) are collected separately over a 24-hour period using size selecti ve inlet (SSI) samplers according to the method based on U.S. EPA’s Federal Reference Method 40CFR50. All PM 10 and PM 2.5 samples are collected upon quartz filters and are analyzed for total PM mass, metals, ions, organic carbon (OC) and elemental carbon (EC). Metal analysis for particulate samples are determined using Energy Dispersive X-Ray Fluorescence Spectrometry. Identification of ions within the PM samples is also done by IC. Carbon analysis is con ducted by taking a small circular disk from sampled PM 10 or PM 2.5 filters. The small circular disk is placed into a carbon analyzer which utilizes either a thermal optical reflectance or th ermal optical transmittance method (IMPROVE method) to measure the OC and EC content of the fil ter. As part of this effort, speciation air sampling system (SASS) samplers were deployed to ch aracterize specific PM species.

Diesel PM . For MATES II, diesel PM was estimated using ambi ent measurements of EC and using EC emissions inventories to determine the con tribution of diesel emissions to ambient PM levels. For MATES III, several methodologies to as sess the levels of diesel PM were explored. These methods include the following:

• Using ambient EC levels as in MATES II

• Using ambient EC and the ratio of PM 2.5, EC, and diesel PM emissions from the 2005 emissions inventory

• Using the EPA Chemical Mass Balance model (CMB) to apportion source emissions to PM 2.5

• Using Positive Matrix Factorization (PMF) to apport ion source emissions to PM 2.5
The results of these analyses are presented in the monitoring results section below.

2.5.1. Quality Assurance and Quality Control (QA/QC) The SCAQMD is committed to achieving the highest po ssible data quality level in the MATES III Program. To achieve this data quality level, t he SCAQMD has an implemented QA/QC Plan which follows U.S. EPA’s Quality Assurance Project Plan for the Air Toxics M onitoring Network (EPA-454/R-01-007). The SCAQMD objectives, proced ures, documentation, and data review techniques assure the MATES III Program will produce accurate and precise data. The technical procedures for QA/QC include annual syste m audits on all equipment in the laboratory and at the MATES III sampling sites. Quality contr ol procedures include proper record keeping, standard checks, and routine calibrations of the sa mpling and analytical equipment. These procedures include operating collocated samples gre ater than 10% of samples collected. For example, the SCAQMD is currently conducting a collo cated sampling of its Rubidioux station using multiple samplers.

2.6. Findings The findings are presented in terms of the concentr ations of air toxics and by the estimated cancer risks resulting from exposures to the averag e concentrations found. Data are presented by year of the study, and these time periods are refer red to as MATES III Year One (April ‘4 – March ’05) and MATES III Year Two (April ’05 – Marc h ’06). In the following charts, the data are presented as annual means, and the error bars d enote the 95% confidence interval of the

mean.MATES III Final Report

2-7 For the second year of the study, a complete data s et was not available for the Huntington Park and the Pico Rivera sites, and summary data is not included.

Summary results are presented below by site and are compared to levels found in the MATES II Study to assess trends in levels of air toxics in t he Basin. In general, concentrations of most toxics substantially decreased compared to levels m easured during MATES II.

In the charts below, the data is presented as the a nnual average by site and as the overall sites average. The error bars represent the 95% confiden ce interval of the average.

2.6.1. Volatile Compounds Figures 2-2 and 2-3 present levels for 1,3 butadien e and benzene, which are emitted predominantly from mobile sources. Both substances show a substantial reduction in annual levels compared to MATES II, with benzene lower by 50% and 1,3-butadiene down by 73%. As in the MATES II Study, Compton and Huntington Park sites had the highest average levels. These decreases are likely reflective of reduced em issions from vehicle turnover and use of reformulated gasoline.

Levels of the chlorinated solvents perchloroethylen e and methylene chloride are shown in Figures 2-4 and 2-5. Both of these substances also show decreases from the MATES II Study. The decreases reflect the reduced usage of these su bstances as industrial solvents and in dry cleaning. Perchloroethylene and methylene chloride were lower on average by 78% and 53%, respectively. For methylene chloride, the North Lo ng Beach site shows an increased level for year 1. This was due to high levels measured over three sampling days in February, 2005. No known sources are nearby. These levels may reflect an unusual use of this solvent over this time period.

Formaldehyde and acetaldehyde concentrations are sh own in Figures 2-6 and 2-7. There was about a 9% reduction in the average levels between the MATES II and MATES III studies. Formaldehyde is emitted from mobile sources and is also formed as a secondary pollutant through chemical reactions in the atmosphere.

2.6.2. Metals Levels of several metals are shown in Figures 2-8 t o 2-12.

Arsenic and cadmium levels are shown in Figures 2-8 and 2-9. Both metals show declines, but this may be more a result of lower reporting limits for MATES III compared to MATES II. Figures 2-10 and 2-11 show the levels of lead and n ickel. Lead concentrations were reduced compared to MATES II, and the values are well below the Ambient Air Quality Standard for lead of 1,500 ng/m 3 . Nickel concentrations were also lower, other tha n for the West Long Beach site. This may be a reflection of the increased sh ipping activity at the ports, as nickel is a component of bunker fuel used in ships.

Hexavalent chromium concentrations are shown in Fig ure 2-12. It should be noted that from previous studies, localized increases can occur nea r facilities using hexavalent chromium, suchMATES III Final Report

2-8 as metal platers or facilities using paints contain ing hexavalent chromium. The monitoring locations in this study, however, are focused on a regional look at air toxics levels. Emissions that could result in a localized area of increased exposure thus may not be picked up in the monitoring.

For comparison purposes, only the data from the SCA QMD lab analyses from MATES II are shown. This is because in MATES II half of the sam ples were analyzed by ARB and showed a lower overall average than did the SCAQMD analyzed samples. The ARB laboratory also reported higher method detection limits, which may be part of the reason for the differences. Some sites, such as Burbank and Huntington Park, sh ow declines in average levels, whereas others show little change. The Rubidoux site actua lly showed an increase in average levels. If Rubidoux is not included, the average hexavalent ch romium level is about 13% lower compared to MATES II.

Subsequent efforts by staff to determine the source of the hexavalent chromium near the Rubidoux site led to a cement plant in the area. T he results of the intensive monitoring and analyses are available from the District’s web site at http://www.aqmd.gov/RiversideCement/RiversideCement .html

. It is recognized that there can be a measurable val ue for hexavalent chromium in blank filters. To determine the extent of this, trip blanks were p eriodically taken at Rubidoux; and the average values are also shown in Figure 2-12. One can note that the blank values are about a third of the sites average values. When estimating risk from ex posure to hexavalent chromium, the average blank value is subtracted out from the sites averag e.

2.6.3. Elemental Carbon In the MATES II Study, elemental carbon (EC) was me asured in the PM 10 samples. In addition, the MATES III Study measured the levels of EC in th e PM 2.5 samples. The results are shown in Figures 2-13 and 2-14.

In the PM 10 samples, EC showed a decrease (

∼ 38%) between MATES II and MATES III. One source of the reduction is the use of updated analy tical instruments. For MATES III, new instruments were used to analyze for carbon. When compared with the older instrument used in MATES II, the new instruments showed about 10% lowe r results, on average. Thus, about a 28% reduction remains after correcting for differen ce in the analytical instruments. This may be a reflection of reduced carbon emissions and meteor ological differences. The Huntington Park and West Long Beach sites showed the highest levels . West Long Beach and Compton did not have data for EC from MATES II, so a comparison ove r time at these sites cannot be made.

For the PM 2.5 samples, year 2 levels on average were somewhat hi gher than for year 1 for the sites with data for both years. This may reflect w eather differences and/or an increase in emissions during the second year of the study. Hun tington Park and West Long Beach showed the highest levels for year 1 where data were avail able for all sites.

2.6.4. Diesel PM In the MATES II Study, EC was used as a surrogate f or diesel particulate levels, as staffMATES III Final Report

2-9 determined that this was the best method available during the MATES II Study. For the present study, staff used the Chemical Mass Balance (CMB) s ource apportionment technique to estimate the contribution from diesel, as well as from other major source categories, to the measured particulate levels. The CMB model was used on the recommendation of the Technical Advisory Group.

To compare different methods to estimate diesel par ticulate levels, the method used in MATES II , which was based on the emissions ratios of die sel particulate and elemental carbon from a study conducted in the South Coast in the 1980’s an d a method based on the ratio of PM 2.5 emissions from the 2005 emissions inventory were al so calculated. For MATES II, the PM 2.5 elemental carbon levels were multiplied by 1.04 to estimate diesel particulate. The 2005 inventory finds a ratio of diesel particulate to el emental carbon emissions of 1.95. The emissions and ratio are shown in Table 2-4. Multiplying the PM 2.5 elemental carbon levels by 1.95 gives another estimate of diesel particulate.

Table 2-4 2005 Emissions of Diesel PM and EC, lbs. /day PM 2.5 Diesel PM PM 2.5 EC DPM/EC Ratio 55,983 28,761 1.95

The estimates using these methods compared to using the CMB model are shown in Table 2-5. The CMB model used several species of substances fr om emissions source profiles to estimate the contribution of these sources to ambient PM lev els. The details of this calculation are given in Appendix VII.

Table 2-5 gives the sites average estimates for die sel PM using the CMB model and compares the level with the methods based on emissions inven tory ratios. For the CMB model, the estimates were sensitive to the species profile use d for gasoline vehicles. Table 2-5 shows the range of values using two different gasoline profil es. The estimates used for the risk calculations were the midpoint of the range.

As shown in the table, both the CMB model and the P M 2.5 emissions ratio method give higher estimates than the MATES II method. Thus the MATES II Study method may underestimate the levels of diesel particulate.

Table 2-5 Estimates of Average Diesel PM, μ g/m3 Estimation Method MATES III

Year One MATES III

Year Two MATES II: PM 10 EC x 1.04 2.18 2.14

2005 Inventory: PM 2.5 EC x 1.95 3.37 3.70

CMB 2.87 – 3.13 3.52 – 3.84

2.6.5. Naphthalene and Other PAH Compounds Limited measurements of naphthalene and other PAHs (Polycyclic Aromatic Hydrocarbons) were taken at three sites. Summary data for naphth alene are shown in Figure 2-15, and the otherMATES III Final Report

2-10 PAHs measured are shown in Figure 2-16.

Naphthalene levels were on average much higher than that of other PAHs, in line with previous observations in the Basin. For the three sites, Ce ntral Los Angeles showed the highest average levels of naphthalene and Rubidoux the lowest. For the sum of the other PAHs, West Long Beach showed the highest levels.

2.7. Cancer Risk Estimates In the MATES II Study, cancer risks were estimated for exposure to the measured ambient levels of air toxics. The estimates assumed that a lifeti me exposure (70 years) occurs to these levels, consistent with guidance on risk assessment establi shed by OEHHA. We use the same methodology to estimate risks for the levels of tox ics measured during MATES III.

There are inherent uncertainties in risk assessment , as discussed in the Introduction of this report and in the OEHHA Air Toxics Hot Spots Program Risk Assessment Guidelines (August 2003) 1

. Despite these uncertainties, risk assessment remain s the most useful tool to estimate the potential health risks due to low level environmental exposur es. This tool is also useful as a yardstick to measure progress in attaining healthful air quality

. Figures 2-17 and 2-18 show the estimated cancer ris ks for the toxics measured by site summed by substance for each year of the MATES III Study. The second year includes the levels for naphthalene and other PAHs for which there are adop ted cancer potency values for the three sites where measurements were collected. The sites avera ge also includes the PAHs using the available three-site average. The PAHs are relativ ely small contributors to the overall average risk. The average level of naphthalene was 180 ng/ m 3 over the three sites. This equates to a 70- year risk of about six per million.

As shown in the charts, diesel particulate is the m ajor contributor to air toxics risk. The average risk over the two years is about 1,200 per million. This compares to about 1,400 per million in the MATES II Study. It should be noted that differ ent methods were used to estimate diesel particulate levels in the MATES III Study, so the r esults are not strictly comparable. Based on the discussion above, the MATES II Study method may have underestimated the levels of diesel particulate.

On average, diesel particulate contributes about 84 % of the total air toxics risk. This is a larger portion of risk compared to the MATES II estimate o f about 70%. In addition to the differences in methods for estimating diesel particulate, this may reflect a larger relative decrease in ambient levels of other toxic air contaminants compared to diesel exhaust.

1 California Environmental Protection Agency Office of Environmental Health Hazard Assessment, Air Toxi cs Hot Spots Program Risk Assessment Guidelines. The Air Toxics Hot Spots Program Guidance Manual for Prepar ation of Health Risk Assessments. August 2003.MATES III Final Report

2-11 1,3 Butadiene

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

Anaheim Burbank Central LA Compton Inland Valley S.B. Huntington

Park North Long

Beach Pico Rivera Rubidoux West Long Beach Sites

Average p p b MATES II MATES III Year 1 MATES III Year 2

Figure 2-2 Average Concentrations of 1,3-Butadiene

Benzene

0.0 0.5 1.0 1.5 2.0 2.5

Anaheim Burbank Central LA Compton Inland Valley S.B. Huntington

Park North Long

Beach Pico Rivera Rubidoux West Long Beach Sites

Average p p b MATES II MATES III Year 1 MATES III Year 2

Figure 2-3 Average Concentrations of BenzeneMATES III Final Report

2-12 Perchloroethylene

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70

Anaheim Burbank Central LA Compton Inland Valley S.B. Huntington

Park North Long

Beach Pico Rivera Rubidoux West Long Beach Sites

Average p p b MATES II MATES III Year 1 MATES III Year 2

Figure 2-4 Average Concentrations of Perchloroethy lene

Methylene Chloride

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

Anaheim Burbank Central LA Compton Inland Valley S.B. Huntington

Park North Long

Beach Pico Rivera Rubidoux West. Long Beach Sites

Average p p b MATES II MATES III Year 1 MATES III Year 2

*Extremely higher concentrations measured for three samples over a 15-day period.

Figure 2-5 Average Concentrations of Methylene Chl orideMATES III Final Report

2-13 Formaldehyde

0.0 1.0 2.0 3.0 4.0 5.0 6.0

Anaheim Burbank Central LA Compton Inland Valley S.B. Huntington

Park North Long

Beach Pico Rivera Rubidoux West Long Beach Sites

Average p p b MATES II MATES III Year 1 MATES III Year 2

Figure 2-6 Average Concentrations of Formaldehyde

Acetaldehyde

0.0 0.5 1.0 1.5 2.0 2.5 3.0

Anaheim Burbank Central LA Compton Inland Valley S.B. Huntington

Park North Long

Beach Pico Rivera Rubidoux West Long Beach Sites

Average p p b MATES II MATES III Year 1 MATES III Year 2

Figure 2-7 Average Concentrations of AcetaldehydeMATES III Final Report

2-14 Arsenic

0.0 0.5 1.0 1.5 2.0 2.5

Anaheim Burbank Central LA Compton Inland Valley S.B. Huntington

Park North Long

Beach Pico Rivera Rubidoux West Long Beach Average ng/m3 MATES II MATES III Year 1 MATES III Year 2

Figure 2-8 Average Concentrations of Arsenic in To tal Suspended Particulate (TSP)

Cadmium

0 5 10 15 20 25 30 35

Anaheim Burbank Central LA Compton Inland Valley S.B. Huntington

Park North Long

Beach Pico Rivera Rubidoux West Long Beach Average ng/m3 MATES II MATES III Year 1 MATES III Year 2

Figure 2-9 Average Concentrations of Cadmium in To tal Suspended Particulate (TSP)MATES III Final Report

2-15 Lead

0 10 20 30 40 50 60 70 80

Anaheim Burbank Central LA Compton Inland Valley S.B. Huntington

Park North Long

Beach Pico Rivera Rubidoux West Long Beach Average ng/m3 MATES II MATES III Year 1 MATES III Year 2

Figure 2-10 Average Concentrations of Lead in Tota l Suspended Particulate (TSP)

Nickel

0 5 10 15 20 25

Anaheim Burbank Central LA Compton Inland Valley S.B. Huntington

Park North Long

Beach Pico Rivera Rubidoux West Long Beach Average ng/m3 MATES II MATES III Year 1 MATES III Year 2

Figure 2-11 Average Concentrations of Nickel in To tal Suspended Particulate (TSP)MATES III Final Report

2-16 Hexavalent Chromium

0.0 0.1 0.2 0.3 0.4 0.5 0.6

Anaheim Burbank Central LA Compton Inland Valley S.B. Huntington

Park North Long

Beach Pico Rivera Rubidoux West Long Beach Average Rubidoux Filter Blank ng/m3 MATES II AQMD Lab data MATES III Year 1 MATES III Year 2

Figure 2-12 Average Concentrations of Hexavalent C hromium in Total Suspended Particulate (TSP)

Elemental Carbon - PM10

0.0 1.0 2.0 3.0 4.0 5.0 6.0

Anaheim Burbank Central LA Compton Inland Valley S.B. Huntington

Park North Long

Beach Pico Rivera Rubidoux West Long Beach Sites

Average ug/m3 MATES II MATES III Year 1 MATES III Year 2

Figure 2-13 Average Concentrations of PM 10 Elemental Carbon (EC)MATES III Final Report

2-17 EC PM2.5

0.0 0.5 1.0 1.5 2.0 2.5 3.0

Anaheim Burbank Central LA Compton Inland Valley S.B. Huntington

Park North Long

Beach Pico Rivera Rubidoux West Long Beach Sites

Average ug/m3 MATES III Year 1 MATES III Year 2

Figure 2-14 Average Concentrations of PM 2.5 Elemental Carbon (EC)

Figure 2-15 Average Monitored Naphthalene Concentr ations for MATES III Year 2 Naphthalene

0 50 100 150 200 250

Central LA Rubidoux West Long Beach Sites Avg ng/m3MATES III Final Report

2-18 PAHs - MATES Year 2

0 5 10 15 20 25 30 35 40 45 50

Central LA Rubidoux W. Long Beach Sites Avg ng/m3

Benz(a)Anthracene Benzo(a)pyrene Indeno(1,2,3-cd)pyrene Benzo(ghi)perylene Dibenz(a,h)anthracene Chrysene Benzo(b+j+k)Fluoranthene

Anthracene Pyrene
Fluoranthene Acenaphthylene Acenaphthene
Fluorene
Phenanthrene

Figure 2-16 Average Concentration of PAHs for MATE S III Year 2MATES III Final Report

2-19 Air Toxics Risk - MATES Year 1

0 200 400 600 800 1000 1200 1400 1600

Anaheim Burban

k Central L A

C om p ton

Inl a n d V a ll e y S .B.

Hu n t i n g ton Park North Lo n g B e a ch Pico Rivera Rubi

d o ux West L o ng B e ac h

S i t e s A ve r a g e Risk per Million

Chloroethene (Vinyl Chloride) Trichloroethylene, 1,1,2- (TCE)
Lead Chloroform Methylene Chloride
NickelDichlorobenzene, pEthylbenzene Perchloroethylene
Arsenic
Cadmium Acetaldehyde
Cr+6
Carbon Tetrachloride Formaldehyde Butadiene, 1,3-
Benzene
Diesel PM

Figure 2-17 Estimated 70-Year Risk from MATES III Year 1 Monitoring Data

Air Toxics Risk - MATES Year 2

0 200 400 600 800 1000 1200 1400 1600

A n a hei m
B u r b a n k Central L

A

C o mp to n Inland Valley

S .B. North Long Beach Rubidoux

West L o ng B e ac h Sites Average Risk per Million Chrysene Benz(a)Anthracene Dichloro ethane, 1,2- (EDC) Indeno(123-cd)pyrene Dibromo ethane,1,2- (EDB) Chloroethene (Vinyl Chloride) Benzo(b+j+k)fluoranthene Dibenz(ah)anthracene Trichloroethylene, 1,1,2- (TCE) Benzo(a)pyrene
Lead Chloroform Methylene Chloride
NickelDichlorobenzene, pEthylbenzene Perchloroethylene
Arsenic Naphthalene Cadmium Acetaldehyde Cr+6
Carbon Tetrachloride Formaldehyde Butadiene, 1,3-
Benzene
Diesel PM

Figure 2-18 Estimated 70-Year Risk from MATES III Year 2 Monitoring DataMATES III Final Report

2-20 2.8. Other Data Sources

Measurements of PM 2.5 mass and limited analyses of some PM 2.5 components are available for several other sources and studies. For example, ch arts and averages of PM 2.5 mass and EC were provided to staff by the ports in comments to the J anuary 2008 draft MATES III report. While useful for geographic comparisons, these data are o f limited use for comparing to the MATES III data, as the time periods of sample collection were different, and the sampling periods did not completely overlap the MATES III study period.

In visually comparing the port monitoring data with the MATES III data on a daily basis during the times of sampling overlap, there was a concorda nce in the reported values. Although the different monitoring sites showed different values, as might be expected, the correlation of the values appeared to be high.

In terms of source apportionment, these data are al so limited in that organic components and other species needed for the source apportionment m ethods are not available.

In terms of comparable data, the EPA Speciation Tre nds Network (STN) provides data from two of the MATES III monitoring sites, namely Central L os Angeles and Rubidoux. The PM 2.5 sampling methods are equivalent, as the MATES III s ampling protocol is based on the method used by EPA. Comparisons of the daily values and a verages from data taken over the MATES III monitoring period from these locations are show n in the charts below. The MATES III samples give similar results as the collocated EPA samplers.

       Apr-04May-04Jun-04Jul-04Aug-04Sep-04Oct-04Nov-04Dec-04Jan-05Feb-05Mar-05Apr-05May-05Jun-05Jul-05Aug-05Sep-05Oct-05Nov-05Dec-05Jan-06Feb-06Mar-06ug/m3 PM2.5 Mass - Central LA MATES III EPA Speciation Trend Network (STN)

   
 	 
   

Figure 2-19 PM 2.5 Mass from MATES III and EPA Collocated Samplers at Los AngelesMATES III Final Report

2-21 0 20 40 60 80 100 120Apr-04May-04Jun-04Jul-04Aug-04Sep-04Oct-04Nov-04Dec-04Jan-05Feb-05Mar-05Apr-05May-05Jun-05Jul-05Aug-05Sep-05Oct-05Nov-05Dec-05Jan-06Feb-06Mar-06ug/m3 PM2.5 Mass - Rubidoux
MATES III EPA Speciation Trends Network (STN)

    
  
     

Figure 2-20 PM 2.5 Mass from MATES III and EPA Collocated Samplers at Rubidoux

Commenters on the draft report also provided annual average PM 2.5 mass comparisons from the ambient monitoring data available from the ARB air quality database. These measurements, however, use a different sampler (also referred to as RASS or FRM samplers) that has a different design and higher flow rates than the samplers used in MATES III and the EPA STN network (also referred to as SASS samplers). It is known t hat the speciation samplers (SASS) give somewhat higher mass values than the samplers (FRM) used in the network designed to assess compliance with ambient air quality standards.