-1- STATE OF CALIFORNIA

SUPPLEMENTAL INFORMATION FOR

RECOMMENDED LEAD NONATTAINMENT AREA

SOUTH COAST AIR BASIN PORTION OF LOS ANGELES COUNTY

EIGHT FACTOR ANALYSIS

INTRODUCTION

This document provides additional justification for recommending only the South Coast Air Basin portion of Los Angeles County be de signated as nonattainment for the 2008 lead national ambient air quality stan dard. Specifically, the following sections address the eight factors U.S. EPA recomme nds for evaluating lead area designations.

ANALYSIS

Jurisdictional Boundaries

As shown in Figure 1, Los Angeles County is divided between two air basins. The southern two-thirds of the County is located in the South Coast Air Basin (South Coast) and falls under the jurisdiction of t he South Coast Air Quality Management District (South Coast AQMD or District). The northern third of the County is located in the Mojave Desert Air Basin (M ojave Desert) and falls under the jurisdiction of the Mojave Desert Air Quality M anagement District. Pollutant concentrations are substantially higher in the Sout h Coast portion of the County because several significant lead-related stationary sources are located there, in the City of Commerce, the City of Industry, Santa F e Springs, and Vernon. As a result, the South Coast AQMD has implemented rigoro us, source-specific, emissions control requirements. The jurisdictional differences, along with the disparity among emissions sources and other factors , justify limiting the lead nonattainment area to the South Coast portion of Lo s Angeles County.-2- FIGURE 1
LOS ANGELES COUNTY

Air Quality Data

Mobile sources were once the major source of lead e missions in California, contributing over 90 percent of ambient lead concen trations. Since the 1970s, federal and State regulations have virtually elimin ated lead from gasoline sold in the State, except for very limited use in general a viation applications. Figure 2

shows the dramatic decrease in ambient lead concent rations since 1975. Values plotted in Figure 2 are representative of the South Coast, which generally has the highest lead concentrations in the State. Although lead from gasoline no longer poses an air quality problem, lead emissions from r emaining industrial sources, and potentially from general aviation airports, may still pose “hot spot” problems
at isolated South Coast locations. Such sources ar e not reflected in Figure 2.

Figure 3 compares maximum 24-hour measured lead con centrations in the South Coast portion of Los Angeles County with those in t he Mojave Desert portion. Although the 24-hour concentrations are not compara ble with the federal lead standard, they provide an indication of the differe nces in ambient concentrations. Data for the Mojave Desert portion of the County ar e available only through 1986, when lead sampling was discontinued at the La ncaster site because concentrations were very low. Data in Figure 3 rep resent neighborhood scale sites, and concentrations in the South Coast were, on average, four and a half times the level of concentrations in the Mojave Des ert. In terms of the current 0.15 micrograms per cubic meter (μg/m 3 ) federal standard, the highest three-month average concentration at Lancaster duri ng 1986 was 0.126 μg/m 3

,-3-

which is below the federal standard. In contrast, the highest three-month average for the South Coast portion of the County w as 0.443 μg/m 3 , a value that

exceeds the standard and is three and a half times the value for Lancaster. Based on data for 2005 through 2007, the most recen t complete three-year period for which data area available, design values for the continuing network of

FIGURE 2
MAXIMUM 30-DAY AVERAGE LEAD CONCENTRATIONS IN CALIF ORNIA

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0

1976 19 78 19 80 1982 1984 198

6 198 8

1 990 1992 1994 1996 19 98
2 000 2002 2004 20

06

Year30-Day Average Lead (ug/m3)

FIGURE 3
MAXIMUM 24-HOUR LEAD CONCENTRATIONS IN THE SOUTH CO AST AND

MOJAVE DESERT PORTIONS OF LOS ANGELES COUNTY

0 2 4 6 8 10 12 14 16

1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986

YearLead Concentration (ug/m3)

South Coast Mojave Desert-4-

neighborhood scale sites in the South Coast portion of the County are now all below the federal standard, ranging from less than 0.01 μg/m 3 to 0.03 μg/m 3

. Based on the continuing large differences in emissi ons, we expect the discrepancy in ambient concentrations in the South Coast and Mojave Desert portions of Los Angeles County still exists.

Although concentrations at all of the South Coast n eighborhood scale sites meet the standard, concentrations measured near lead-rel ated stationary sources do not. To address this hot spot problem, the South C oast AQMD established a network of source-specific lead sampling sites in t he early 1990s and has expanded the network over the years. A number of t hese source-oriented sites were established as part of the District’s Rule 142 0 -- Emissions Standard for Lead. The samplers are located at or beyond the pr operty line of lead-related facilities, and they comply with U.S. EPA siting an d operating criteria. Lead samples are generally collected on a 1-in-6 day sch edule, although samples are collected more frequently at sites with the highest concentrations.

Design values for the affected facilities are summa rized in Table 1. Based on these data, the design value for the South Coast po rtion of Los Angeles County is 2.49 μg/m 3 , which exceeds the 0.15 μg/m 3 federal lead standard. Although the design value is much higher than the 2008 federal l ead standard, values for the District’s other source-oriented sites surrounding the Exide facility are lower, with maximum 3-month averages ranging from 0.03 μg/m 3 to 0.55 μg/m 3 . Although one of these values also exceeds the standard, both values are significantly lower than the high concentration. In addition, co ncentrations at these other sites decrease with distance from the Exide facility, con firming the rapid drop in lead

concentrations with distance from a source. This r elationship provides additional support for limiting the size of the nonattainment area.

TABLE 1
LEAD DESIGN VALUES FOR

SOUTH COAST SOURCE-ORIENTED MONITORS

Facility

Name City Monitor 3-Month

Period Lead

Design

Value*

Exide Technologies City of

Commerce LA Paper Box,

61 st Street Jan-Mar

2006 0.14

μg/m 3 * Quemetco,

Inc. City of Industry Closet World,

500 S. 7

th Street Jan-Mar

2006 0.09

μg/m 3
Trojan Battery Co. Santa Fe Springs Uddeholm,9331 Santa Fe Springs Road May-Jul

2007 0.18

μg/m 3

Exide Technologies Vernon Rehrig-Pacific Street Jan-Mar

2008 2.49

μg/m 3

* * Data available for LA Paper Box monitor from Jan uary 2006 through May 2006 only. Data available fo r Closet World monitor from January through December 2006 and Octo ber through December 2008. Data available for Rehr ig-Pacific Street monitor from mid-November 2007 through mid-J uly 2009.-5-

Emissions Data and Level of Emissions Control

As shown in Table 2, there are significant differen ces between lead emissions in the South Coast and Mojave Desert portions of Los A ngeles County. In combination, sources in the South Coast portion of the County emit nearly three times more lead than sources in the Mojave De sert portion of the County. When looking only at stationary sources, emissions in the Mojave Desert portion of the County are less than 1 percent of the South Coast value. In addition, the Air Resources Board’s emissions inventory indicates there are no stationary sources or general aviation airports located in the Mojave Desert portion that come close to meeting the 0.5 ton per year threshol d of concern established by U.S. EPA. While the Exide facility and several gen eral aviation airports in the South Coast portion of the County exceed the 0.5 to n per year threshold U.S. EPA is currently considering (only Exide Techn ologies and Van Nuys Airport exceed 1 ton/year), the closest one is more than 20 miles from the South CoastMojave Desert air basin boundary. Given the rapid drop in lead concentration with distance, the South Coast facilities do not ha ve any measurable impact on concentrations in the Mojave Desert portion of the County.

TABLE 2
LEAD EMISSIONS IN THE SOUTH COAST AND MOJAVE DESERT

PORTIONS OF LOS ANGELES COUNTY

Emissions Category Los Angeles County

South Coast Portion (tons / day ) Los Angeles County Mojave Desert Portion (tons / day) Stationary 4.45 0.03

Area-wide 13.63 6.59

On-Road Mobile 0.20 0.01

Other Mobile 0.09 0.34

TOTAL 18.37 6.97

In September 1992, the South Coast District adopted Rule 1420, which is specifically aimed at reducing lead emissions from non-vehicular sources. Rule 1420 (Emissions Standard for Lead) applies to all facilities that use or process materials containing lead, including primar y or secondary lead smelters, foundries, lead-acid battery manufacturers or recyc lers, as well as facilities that produce lead-oxide, brass, and bronze. The Rule ha s been, and will continue to be, very effective in dealing with high, facility-r elated lead concentrations, and

forms the basis of the District’s lead attainment s trategy. This type of rule is not warranted in the Mojave Desert portion of the Count y because of the lack of lead sources and measurable impact.-6-

Population Density, Degree of Urbanization, and Exp ected Growth

Similar to air quality and emissions, there are vas t differences between the population and degree of urbanization in the two po rtions of Los Angeles County. Based on estimates for 2010, the highly urbanized S outh Coast portion of the County has a population of more than 10 million, co mpared with a population of 328,000 in the Mojave Desert portion. This means t hat nearly 97 percent of the County population lives in the South Coast portion, compared with only 3 percent in the Mojave Desert portion of the County. In ter ms of urbanization, the South Coast portion of Los Angeles County is part of the largest metropolitan area in California. In contrast, the Lancaster-Palmdale ar ea is the only urbanized area in the Mojave Desert portion of the County. In terms of size, the South Coast portion of Los Angeles County is a little more than one and a half times larger than the Mojave Desert portion (2538 square miles v ersus 1522 square miles). However, the population density is 3,992 people per square mile, compared with only 216 people per square mile in the Mojave Deser t portion.

Over the last decade, the South Coast and Mojave De sert portions of Los Angeles County have realized similar growth rat es, with population in both areas showing a seven percent increase from 2000 to 2005 and a two percent increase from 2005 to 2010. These trends are expec ted to continue, thereby maintaining the significant differences in populati on between the two sub-county

areas.

Geography and Meteorology

Meteorological conditions in the South Coast and Mo jave Desert portions of Los Angeles County are substantially different. Th e South Coast portion is bounded by the Pacific Ocean, which makes for a mor e temperate climate with cooler temperatures and a diurnal pattern of on-sho re / off-shore air flow. Temperatures generally average in the 70s during th e summertime and the 50s during the wintertime. Average annual precipitatio n is about 15 inches per year. In contrast to the coastal area, the Mojave Desert portion of Los Angeles County is a high desert area with average temperatures in the 80s during summer and the 40s during the winter. This desert portion of the County receives half as much rainfall, averaging about 7 inches per year.

The South Coast portion of Los Angeles, where the m ajor lead emissions sources are located, is surrounded by mountains whi ch act as barriers to airflow between the South Coast and Mojave Desert (refer to Figure 1). Although there are a limited number of gaps in these mountains whe re transport has been documented, transport of lead emissions from the So uth Coast into the Mojave Desert is highly unlikely, given the weight of lead particles and the rapid

decrease in concentration with distance from a sour ce. As a result, emissions sources in the South Coast are not expected to have an impact on lead concentrations in the Mojave Desert portion of the County.-7-

SUMMARY AND RECOMMENDATION

The South Coast and Mojave Desert portions of Los A ngeles County are two distinct areas. The highly urbanized South Coast p ortion is primarily a coastal area with a high population density and a concentra tion of several lead-related processing facilities that have the potential to vi olate the federal lead standard. In contrast, the Mojave Desert portion of the Count y is a sparsely populated high desert area that lacks any notable lead emissions s ources.

Because of these differences, the lead air quality problem in the South Coast portion of the County is much more significant than in the Mojave Desert portion. Even so, lead concentrations exceeding the federal standard are found only near the lead-related facilities that are generally loca ted in the coastal plain area of the

South Coast. Lead measurements show these concentr ations decrease rapidly with distance from the source, and transport of lea d particles or pollutants from the South Coast to the Mojave Desert is not expecte d to occur. The two areas are separated by mountains, and although there are some documented transport routes, the heavy weight of lead particles and the quick decrease in

concentration with distance from the source make an y measurable transport impact extremely unlikely.

In terms of air quality regulation, the two County portions fall under the jurisdiction of two separate air pollution control districts. The primary strategy for dealing with the high concentrations in the South C oast portion of Los Angeles County is the South Coast District’s Rule 1420, whi ch has been effective in reducing source-specific emissions and resulting hi gh concentrations. This strategy will continue to address violations of the federal lead standard. Rule 1420 has no application in the Mojave Desert p ortion of the County because

there are no sources.

Based on the previous analyses, the Air Resources B oard recommends that
U.S. EPA limit the extent of the federal lead nonat tainment area to the portion of Los Angeles County located in the South Coast Air B asin.