(VCCEP) Tier 1 Pilot Submission for BENZENE - Tera

Refueling NFs ranged from 1.3 for the study conducted in Cincinnati to 5.4 for the study
conducted in Los Angeles. The refueling NFs were used to calculate normalized refueling
exposure concentrations as follows:
where;
Benzene VCCEP Submission
March 2006
CH
CN
=
NF
CN = Refueling air concentration of benzene normalized to 2003 (mg/m 3 )
CH = Historical air concentration of benzene from the studies (mg/m 3 )
NF = Normalization factor (unitless)
The air concentrations for the various studies normalized to 2003 fuel and fleet properties are
summarized in Table 7.33.
Table 7.33: Normalized Benzene Air Concentrations During Refueling (mg/m 3 )
Study Concentration for
the Year of Data
Collection
(Historical Fleet and
Benzene Content)
133
Study Estimate Normalized to
Year 2003 Fleet and Benzene
Content a
Study City
Year of Data
Collection
Mean Maximum Mean Maximum
Smith,
1999
Toronto 1999
1.1 4.1 0.27 1.01
API, 1993 Cincinnati 1990 0.49 2.5 0.38 1.95
Phoenix 1.725 8.4 0.42 2.03
Los Angeles 0.965 3.9 0.18 0.72
Backer, et.
al., 1997
Fairbanks
(RG)
1995 1.21 2.36 0.87 1.70
Fairbanks
(E10)
0.83 2.70 0.60 1.9
Average 1.0 4.0 0.45 1.6
a
Estimated using Mobile 6.2 refueling emissions for study year fleet and benzene content versus year 2003 fleet and
benzene content.
The Northeast States for Coordinated Air Use Management (NESCAUM) reviewed nine pre-
1989 refueling studies and determined mean and high-end exposure concentrations for
benzene and other VOCs (NESCAUM, 1989). Data were reviewed and weighted, yielding
mean and high-end benzene exposure estimates of 2.9 and 13.4 mg/m 3 . A comparison of the
NESCAUM mean to the exposure concentrations shown on Table 7.33 demonstrates that the
refueling exposure concentrations of benzene have decreased over the years. Thus, refueling
exposure concentrations are expected to continue to decline as RFG continues to be phased in.
Benzene intakes were estimated for male and female adults and a teenager 16 to