Article
Variations in speciated emissions from spark-ignition and compression-ignition motor vehicles in California's south coast air basin
Journal of the Air & Waste Management Association
(2007)
Abstract
The U.S. Department of Energy Gasoline/Diesel PM Split
Study examined the sources of uncertainties in using an
organic compound-based chemical mass balance receptor
model to quantify the contributions of spark-ignition (SI)
and compression-ignition (CI) engine exhaust to ambient
fine particulate matter (PM2.5). This paper presents the
chemical composition profiles of SI and CI engine exhaust
from the vehicle-testing portion of the study. Chemical
analysis of source samples consisted of gravimetric mass,
elements, ions, organic carbon (OC), and elemental carbon
(EC) by the Interagency Monitoring of Protected Visual
Environments (IMPROVE) and Speciation Trends
Network (STN) thermal/optical methods, polycyclic aromatic
hydrocarbons (PAHs), hopanes, steranes, alkanes,
and polar organic compounds. More than half of the mass
of carbonaceous particles emitted by heavy-duty diesel
trucks was EC (IMPROVE) and emissions from SI vehicles
contained predominantly OC. Although total carbon
(TC) by the IMPROVE and STN protocols agreed well for
all of the samples, the STN/IMPROVE ratios for EC from SI
exhaust decreased with decreasing sample loading. SI vehicles,
whether low or high emitters, emitted greater
amounts of high-molecular-weight particulate PAHs (benzo[
ghi]perylene, indeno[1,2,3-cd]pyrene, and coronene)
than did CI vehicles. Diesel emissions contained higher
abundances of two- to four-ring semivolatile PAHs. Diacids
were emitted by CI vehicles but are also prevalent in
secondary organic aerosols, so they cannot be considered
unique tracers. Hopanes and steranes were present in
lubricating oil with similar composition for both gasoline
and diesel vehicles and were negligible in gasoline or
diesel fuels. CI vehicles emitted greater total amounts of
hopanes and steranes on a mass per mile basis, but abundances
were comparable to SI exhaust normalized to TC
emissions within measurement uncertainty. The combustion-
produced high-molecular-weight PAHs were found
in used gasoline motor oil but not in fresh oil and are
negligible in used diesel engine oil. The contributions of
lubrication oils to abundances of these PAHs in the exhaust
were large in some cases and were variable with the
age and consumption rate of the oil. These factors contributed
to the observed variations in their abundances to
total carbon or PM2.5 among the SI composition profiles.
Disciplines
Publication Date
June, 2007
DOI
10.3155/1047-3289.57.6.705
Publisher Statement
Copyright 2007 Air & Waste Management Association. Publisher's version of record: https://dx.doi.org/10.3155/1047-3289.57.6.705
Citation Information
L. Mazzoleni, Eric M. Fujita, Barbara Zielinska, David B Campbell, et al.. "Variations in speciated emissions from spark-ignition and compression-ignition motor vehicles in California's south coast air basin" Journal of the Air & Waste Management Association Vol. 57 Iss. 6 (2007) p. 705 - 720 ISSN: 1047-3289 Available at: http://works.bepress.com/l-mazzoleni/2/