APPENDIX IV 

MATES III 

FINAL REPORT 

Measurements of Ambient Naphthalene and Other Polycyclic Aromatic 

Hydrocarbons 

Author

Jason Low 
MATES III Final Report

Appendix IV-1 

Appendix IV 

Measurements of Ambient Naphthalene and Other Polycyclic Aromatic 

Hydrocarbons

IV-1 Background 

Naphthalene is the most abundant PAH present in the atmosphere and exists primarily in the gas 

phase under ambient conditions. Major sources of naphthalene are shown in Figure IV-1. The 

total estimated inventory of naphthalene in the South Coast Air Basin (Basin) is 1,535 lbs./day 

for 2005 (see Chapter 3 of this report). 

Naphthalene was identified in 1990 as a Hazardous Air Pollutant (HAP) and classified by ARB 

in 1993 as a toxic air contaminant (TAC). The National Toxicology Program has recently listed 

naphthalene as a human carcinogen. Additionally, the California EPA Office of Environmental 

Health Hazard Assessment (OEHHA) has determined ambient naphthalene as a health risk and 

as a toxic air contaminant under California’s Air Toxics Program with a unit risk value of 3.4 x 

10-5 (μg/m3

)

-1

. 

Figure IV-1: Naphthalene Emission Inventory in the South Coast Basin 

Particle-bound PAHs are an important class in the complex mixture of chemical compounds 

observed in ultrafine particles. PAHs and the organic carbon component of ultrafine particles 

have been shown to be directly correlated to markers for oxidative stress (Li, et al. 2000; Li, et 

al. 2003; Cho, et al. 2003). Past monitoring in the Basin has shown that individual particle37%

25%

25%

13%

On Road Motor Vehicles

Off Road Mobile Sources

Consumer Products

Stationary and Other Area Sources
MATES III Final Report

Appendix IV-2 

bound PAHs are minor contributors to risk (SCAQMD, 2000), despite their high carcinogenicity, 

because of their low ambient air concentrations which have been decreasing over time (Figure 

IV-2). Also, some PAHs, such as benzo[g,h,i]pyrelene, have been suggested to be a tracer for 

light-duty vehicle exhaust (Miguel, et al. 2005). 

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

ng/m

3

BaP BGP IDP

Figure IV-2: CARB Trend Data from 1990 through 2003 for Benzo[a]Pyrene (BaP), 

Benzo[g,h,i]perylene (BGP), and Indeno[1,2,3-cd]pyrene (IDP) 

The MATES II cancer risk assessment showed that the particle-bound PAH contribution-tocancer risk was insignificant compared to other sources. However, the assessment did not 

include the semi-volatile or the volatile PAHs such as naphthalene (SCAQMD, 2000). Before 

1994, measurements (Table IV-1) showed ambient naphthalene ranging from 750 to 1,300 ng/m3

in the spring with concentrations reaching more than 4,000 ng/m3

 during high NOx or ozone 

events. In 1996 California Phase II reformulated gasoline (RFG) was introduced which 

decreased the amounts of alkenes, aromatics, sulfur compounds, and total volatility. 

Kirchshstetter, et al. (1999) showed that the concentrations of naphthalene and benzene in RFG 

sampled in Berkeley, California were reduced significantly. After implementation of RFG, 

significantly lower concentrations ranging from 200 to 575 ng/m3 were observed in the Los 

Angeles Basin as shown in the Southern California Children’s Health Study (CHS) from 2001 to 

2002 and subsequent studies by Reisen and Arey (2005). Recent measurements have shown that 

annual averages of naphthalene are at levels about 1,000 times higher than those of other PAHs 

(Eiguren-Fernandez, 2004). 
MATES III Final Report

Appendix IV-3 

Table IV-1 Previous measurements of ambient naphthalene in the South Coast Air Basin 

Period of 

Measurement Location

[Naphthalene]

ng/m3

(day)

[Naphthalene]

ng/m3(night)

1986 (late winter, high 

NOx episode)1 Torrance 3,315 2,875 

1986 (summer, smog 

episode)2 Glendale 3,100 4,300 

1987 (spring)3 Reseda 750 1,300 

1993 (fall, smog episode)4 Los Angeles 6,000 

19955 Redlands 348 to 715 

2001 to 20026 Southern California 200 to 575 

2002 (summer)7 Los Angeles ~ 350 ~ 140 

2002 (summer)7 Riverside ~ 225 ~ 40 

2003 (winter)7 Los Angeles ~ 1,400 ~ 1,000 

2003 (winter)7 Riverside ~ 500 ~ 150 

1Arey, et al. 1987; 2Arey, et al. 1989; 3Atkinson, et al. 1994; 4

Fraser, 1998; 5Gupta, 1995; 

6Calvert, et al. 2002; Eiguren-Fernandez, et al. 2004; 7Reisen, 2003 

PAHs were measured at three of the MATES III monitoring 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 CHS 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 the ARB toxics network. Also, collocated samples were done 

once a month at the Rubidoux site. Table IV-2 provides a list of the 16 PAHs analyzed as part of 

MATES III. 

Table IV-2: List of PAHs Measured in the MATES III Study 

Acenaphthene Chrysene 

Acenaphthylene Dibenzo[a,h]anthracene 

Anthracene Fluoranthene 

Benzo[a]anthracene Fluorene 

Benzo[a]pyrene Indeno[1,2,3-cd]pyrene 

Benzo[b]fluoranthene Napthalene 

Benzo[g,h,i]perylene Phenanthrene 

Benzo[k]fluoranthene Pyrene 
MATES III Final Report

Appendix IV-4 

IV-2 Methodology 

IV-2-1 Sampling 

The sampling protocol was based on EPA TO-13A in which 24-hour integrated air samples were 

collected at eight cubic feet per minute (cfm) in a Tisch TE-1000 PUF (polyurethane foam) 

monitor. The particle phase sample was collected on a quartz fiber filter (102 mm) located 

upstream from a glass cartridge holding 20 grams of XAD-4 which collected the semi-volatile 

and vapor phase PAHs. XAD-4 was selected as the sampling media because it has more surface 

area than XAD-2, allowing for higher collection efficiency of the PAHs. A comparison was 

done with the PUF/XAD-4/PUF sandwich to ensure that results would not differ significantly 

from other sampling methodologies, and a breakthrough study was done to ensure that PAHs 

were not escaping through the XAD-4 cartridge. 

Since ambient PAH concentrations in the South Coast Basin have shown seasonal variation 

(Eiguren-Fernandez, 2004) with higher and more variable concentrations in the winter and lower 

concentrations in the spring and summer, the samples were collected every third day in the 

winter of 2004 and 2005 and every sixth day in the spring and summer of 2005. After collection, 

the samples were chilled and transported to Southwest Research Institute for extraction and 

analysis. 

IV-2-2 Sample Extraction 

As with sample collection, the extraction protocol was based on EPA TO-13A. The method was 

enhanced by using higher internal standard (IS) concentrations of the more volatile PAHs and 

lower concentrations of the particle-bound PAHs which are reflective of the ratios found in 

ambient air. This differs from TO-13A which just uses the same concentration for each 

compound in the IS. Prior to extraction, 25 μl of deuterated PAH IS mixture was added into 

each sample. The deuterated PAH IS mixture contained the following compounds: Naphthalened8 (1000 ng/μl), Acenaphthylene-d8 (300 ng/μl), 100 ng/μl each of Phenanthrene-d10 and 

Fluoranthene-d10, and 5.0 ng/μl each of Benzo[a]anthracene-d12, Chrysene-d12, 

Benzo[b]fluoranthene-d12, Benzo[a]pyrene-d12, Indeno[1,2,3-cd]pyrene-d12, 

Dibenz[a,h]anthracene-d14, and Benzo[g,h,i]perylene-d12. 

The XAD-4 glass cartridge and the matching filter were extracted together using 1-Liter Soxhlet 

extractor with dichloromethane (DCM) as the extracting solvent. The extraction lasted for eight 

hours with a siphoning rate of 3-4 siphons per hour. At the end of the extraction, the sample 

extracts were concentrated to about 20 ml by using a rotary evaporator under a gentle vacuum. 

With each batch of field samples, four lab QC samples were created and extracted alongside the 

field samples as follows: solvent blank, XAD-4 blank, lab control spike (LCS), and lab control 

spike duplicate (LCSD). The solvent blank had 350 ml of DCM only. The XAD-4 blank 

consisted of 20 grams of clean XAD-4. The LCS and LCSD each had 20 grams of clean XAD-4 

and one clean filter and each was spiked with 25 μl of target PAH mix with the concentration 

similar to that of the PAH IS. Prior to the extraction, each of the QC samples was spiked with 

the same amount of PAH IS mixture as described above. 
MATES III Final Report

Appendix IV-5 

IV-2-3 Sample Extract Cleanup for PAH Analysis 

One quarter of each sample extract was archived as reserve. The remaining extract was solvent 

exchanged into 0.5 ml of hexane. Six ml of hexane was then added to the extract. The extract 

was then vigorously partitioned with 2.0 ml of 25% sulfuric acid in water for 20 seconds. 

A disposable pipette (8 mm i.d. x 30 cm long) packed with 5” of activated silica gel was used for 

sample extract cleanup. The column was pre-cleaned first with 20 ml of distilled DCM and then 

with 5 ml of hexane. The hexane layer of the acid-washed sample extract was quantitatively 

transferred onto the silica gel column using hexane as a rinsing solvent. Ten ml of hexane (~3 

ml at a time) was used to elute the column and the collected eluent discarded. The PAH fraction 

was then eluted with 23 ml of DCM/pentane (60/40, ~3 ml at a time). 

The collected PAH fraction was mixed well and divided into two parts. The first portion of the 

cleaned-up extract was carefully blown down to a final volume of 1.0 ml in DCM using a gentle 

stream of charcoal-filtered nitrogen. This final extract was used for naphthalene through pyrene 

analysis plus two PAH surrogates. 

The second portion of the cleaned-up extract was carefully blown down to 100 μl in two stages. 

This final extract was used for benzo[a]anthracene through benzo[g,h,i]perylene analysis. 

IV-2-4 Sample PAH Analysis by GC/MS 

The GC/MS (gas chromatograph/mass spectrometer) used was an Agilent 6890N GC interfaced 

with an Agilent 5973N MSD (mass spectrometer detector). The column used was a DB-5ms 30 

m x 0.25 mm i.d. with 25 μm film thickness. The GC injector and GC/MS interface temperature 

were held at 290o C. The GC oven temperature program was as follows: 40oC held for 1.5 

minutes, 15o C/min to 220o C, then 8o C/min to 310o C and held for 3.5 minutes. The carrier gas 

was helium at a constant flow rate of 1.5 ml/min. 

The GC/MS was operated under EI/PI/SIM mode (electron impact/positive ion/selective ion 

monitoring). Only the characteristic ions such as molecular ions of PAH ISs, and molecular and 

major fragment ions of PAH targets were monitored. Acenaphthene-d10, pyrene-d10, and 

benzo[e]pyrene-d12 were used as recovery standards (RSs). These RSs were spiked into the 

final sample extracts just prior to GC/MS analysis and were used to quantify the recoveries of the 

11 PAH ISs. 

The GC/MS analysis was carried out in two stages: the first GC/MS analysis quantified for 

naphthalene through pyrene on diluted sample extract (1.0 ml); the second GC/MS analysis 

quantified for benzo[a]anthracene through benzo[g,h,i]perylene on a concentrated sample extract 

(0.1 ml). Also the lowest calibration point was 10 pg/μl instead of 100 pg/μl as listed in Table 4 

of TO-13A. 

A five-point initial calibration (ICAL) curve was established using five PAH standard mixtures 

containing all PAH targets, PAH ISs, surrogates, and RSs. The PAH targets in the five-point 

curve were at five different levels namely 10, 30, 100, 300, and 1000 pg/μl. The relative 

response factors (RRFs) of the PAH targets were established using the five-point curve. The 

relative standard deviation (RSD) of the RRF of each PAH target had to be equal to or less than 

25% in order for the ICAL to be considered valid. The RRFs for the ISs relative to the RSs were 

also established for the five calibration standards in the same way. The ISs and RSs were at 750 

pg/μl for all calibration standards. 
MATES III Final Report

Appendix IV-6 

At the beginning of each sample analysis sequence, a continuing calibration (CC) PAH standard 

mixture at 300 pg/μl was analyzed. The RRF of each PAH target was established using this CC 

standard. The percent difference of the RRF of each PAH target in the CC compared with the 

mean RRF of the ICAL had to be equal to or less than 25%. This CC criterion had to be met 

before the sample analysis could proceed. The same calibration criterion applied to the ISs as 

well. 

IV-2-5 Analysis of Standard Reference Material (SRM) from the National Institute of 

Standards and Technology (NIST) 

The PAH SRM 1597 was diluted 160 folds and 320 folds in DCM. An aliquot of each of the 

diluted SRM was then spiked with the same PAH IS mix which had been spiked into the field 

and lab QC samples prior to their extraction. The two NIST PAH SRM solutions were then 

analyzed alongside the field and lab QC samples. 

The analytical concentrations of various PAHs in the diluted SRM solutions were then compared 

with that of the expected PAH concentrations based on the NIST certified values. A list of PAH 

concentration ratios, expected/found, was established for those PAHs which had a value in the 

SRM certificate of analysis. These ratios were used as correction factors to adjust the found 

PAH concentrations of the field ambient air samples. This is an improvement from TO-13A 

which just calls for stating the percent recovery of the particular component. 

IV-3 Results 

The monthly averages for naphthalene over the monitoring period for PAHs are shown in Figure 

IV-3. 

Table IV-3 summarizes the results of the PAH ambient monitoring for MATES III year 2. 

Consistent with other studies, the highest levels of naphthalene were measured during the fall 

and winter season. This is also consistent with measurements of other volatile organic 

compounds, such as benzene, that are higher during this time period. This is likely due to cooler 

temperatures and lower mixing height. 

The levels of the other PAHs measured were substantially lower than naphthalene. This is also 

consistent with previous measurements in the Basin. 
MATES III Final Report

Appendix IV-7 

Naphthalene

0

50

100

150

200

250

300

350

400

450

500

Dec

Jan

FebMar

Apr

Ma

Jun

Jul

Au

Sep

Oct

No

Dec

Jan

FebMar

2004 2005 2006

ng/m3

Central LA Rubidoux W. Long Beach

Figure IV-3 Monthly Average Levels of Naphthalene 
MATES III Final Report

Appendix IV-8 

Table IV-3 MATES III Year 2 Monitored PAH Levels (ng/m3) 

 Site 

 Central L.A. Rubidoux 

N. Long 

Beach 

 Acenaphthene Avg 7.61 4.65 8.49 

 SD 4.76 2.92 6.70 

 N 91 91 91 

 95% CI 0.98 0.60 1.38 

 Max 21.39 13.42 34.78 

 Min 0.85 0.80 1.46 

 

 Acenaphthylene Avg 5.08 4.40 5.23 

 SD 4.05 4.50 5.38 

 N 91 91 91 

 95% CI 0.83 0.92 1.10 

 Max 16.02 20.92 24.68 

 Min 0.51 0.29 0.56 

 

 Anthracene Avg 1.19 0.72 1.07 

 SD 3.07 1.62 2.53 

 N 91 91 91 

 95% CI 0.63 0.33 0.52 

 Max 21.64 10.67 22.34 

 Min 0.09 0.06 0.12 

 

 Benz(a)Anthracene Avg 0.10 0.12 0.14 

 SD 0.08 0.12 0.13 

 N 91 91 91 

 95% CI 0.02 0.03 0.03 

 Max 0.34 0.46 0.65 

 Min 0.01 0.01 0.01 

 

 Benzo(a)pyrene Avg 0.12 0.14 0.18 

 SD 0.10 0.15 0.17 

 N 91 91 91 

 95% CI 0.02 0.03 0.04 

 Max 0.51 0.62 0.82 

 Min 0.01 0.02 0.02 

 

 Benzo(b+j+k)Fluoranthene Avg 0.34 0.40 0.39 

 SD 0.26 0.37 0.37 

 N 91 91 91 

 95% CI 0.05 0.08 0.08 

 Max 1.03 1.38 1.59 

 Min 0.04 0.03 0.03 

 
MATES III Final Report

Appendix IV-9 

Table IV-3 MATES III Year 2 Monitored PAH Levels (ng/m3

) 

 Site 

 Substance Central L.A. Rubidoux 

N. Long 

Beach 

 Benzo(ghi)perylene Avg 0.35 0.33 0.40 

 SD 0.24 0.31 0.36 

 N 91 91 91 

 95% CI 0.05 0.06 0.07 

 Max 1.04 1.33 1.85 

 Min 0.04 0.04 0.04 

 

 Chrysene Avg 0.32 0.35 0.43 

 SD 0.19 0.29 0.31 

 N 91 91 91 

 95% CI 0.04 0.06 0.06 

 Max 0.89 1.15 1.51 

 Min 0.08 0.03 0.05 

 

 Dibenz(a,h)anthracene Avg 0.03 0.04 0.06 

 SD 0.02 0.05 0.06 

 N 91 91 91 

 95% CI 0.01 0.01 0.01 

 Max 0.13 0.44 0.53 

 Min 0.00 0.00 0.00 

 

 Fluoranthene Avg 2.12 1.37 1.90 

 SD 0.86 0.64 1.07 

 N 91 91 91 

 95% CI 0.18 0.13 0.22 

 Max 4.37 3.09 4.84 

 Min 0.48 0.33 0.54 

 

 Indeno(1,2,3-cd)pyrene Avg 0.17 0.18 0.18 

 SD 0.12 0.16 0.17 

 N 91 91 91 

 95% CI 0.02 0.03 0.03 

 Max 0.53 0.60 0.70 

 Min 0.02 0.02 0.01 

 

 Naphthalene Avg 201.29 154.91 183.78 

 SD 110.52 110.68 150.79 

 N 91 91 91 

 95% CI 22.71 22.74 30.98 

 Max 447.60 533.56 726.14 

 Min 35.29 24.30 29.95 
MATES III Final Report

Appendix IV-10 

Table IV-3 MATES III Year 2 Monitored PAH Levels (ng/m3

) 

 Site 

 Substance Central L.A. Rubidoux 

N. Long 

Beach 

 Phenanthrene Avg 14.35 8.96 13.65 

 SD 6.52 4.39 8.40 

 N 91 91 91 

 95% CI 1.34 0.90 1.73 

 Max 34.54 20.99 37.59 

 Min 2.62 2.24 3.47 

 

 Pyrene Avg 1.67 1.19 1.68 

 SD 0.73 0.70 1.01 

 N 91 91 91 

 95% CI 0.15 0.14 0.21 

 Max 3.41 3.56 5.09 

 Min 0.42 0.25 0.39 

 
MATES III Final Report

Appendix IV-11 

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Arey, J., Atkinson, R., Zielinska, B., McElroy, P.A., Environ. Sci. Tech., 23, 3, 321-327, 

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Atksinson, R., Arey, J., Environ. Health Perspectives, 102 (Suppl. 4), 117-126, 1994. 

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SCAQMD, Multiple Air Toxics Exposure Study (MATES II) Final Report, March 2000.