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4.
GC/MS Biomarker Signatures in Particle Emissions From Stationary
and Mobile Sources
Jean-Pierre
Charland, Tony MacPhee, Penny MacDonald and Gianni Caravaggio
Natural
Resources Canada, CANMET Energy Technology Centre - Ottawa,
1 Haanel Drive, Nepean, Ontario, K1A 1M1
Lisa
A. Graham
Environment
Canada, Emissions Research and Measurement Division 335 River
Road, Ottawa, Ontario, Canada, K1A 0H3
One
of the goals of the Canadian atmospheric fine particle research
program is to determine the sources of particles and their relative
contributions to atmospheric carbonaceous fine particles. The
data from this program will contribute to a database of particle
emission rates that will be used in computational atmospheric
models to help in determining the contribution of various transportation
sources to ambient fine particle levels in Canada.
Recent
work on quantifying the impact of vehicle emissions to ambient
air quality has been focused on using the unique chemical and
molecular composition of particle emissions to take advantage
of conserved tracers to link particles from source to ambient
atmosphere. The potential for using these tracers also known as
“biomarkers” to identify the various sources of carbonaceous
particles has been recognized. It is in this context that particle
matter (PM) samples (< 2.5µm) were collected from the
exhausts of in-use passenger cars and trucks at the BC AirCare
Research Facility in Burnaby, British Columbia. Lube oil samples
were also collected. In parallel, PM samples were also collected
from a typical home heating oil furnace tested with no. 2 and
no. 6 fuel oils. The analysis and chemical composition of these
samples is the focus of this work.
The
PM, lube and fuel oil samples were extracted and fractionated
using column chromatography to examine paraffins, biomarkers (hopanes
and steranes), PAH’s and polars in PM. All non-polar fractions
were analyzed by GC/MS for 70 biomarkers, i.e., 38 hopanes and
32 steranes. Chromatographic response factors were obtained for
8 pure hopanes and 6 pure steranes. The response factors of pure
R- and S-ab-homohopane were applied to other R,S-ab-homohopanes
(ab-homohopane, bis-, tris-, tetra- and pentakis-ab-homohopanes).
The extrapolated response factor used for the other hopanes was
obtained by averaging the response factors of 3 selected ab-hopanes.
For steranes, a linear regression correlating the response factors
of the pure steranes as a function of their carbon number was
calculated. This linear equation was used to extrapolate response
factors for the C20, C21, C22, C27, C28 and C29 steranes unavailable
as pure compounds.
Extracted
ion chromatograms typical of biomarkers from PM and lube oil fractions
demonstrate that the biomarkers analyzed in this work come mainly
from the lube oils. In addition, the results show clearly that,
for most vehicles used in this study, the biomarker chromatograms
from the PM and lube oil samples are nearly identical. Comparison
of GC/MS biomarker signatures of lube oil, diesel fuel, no. 2
and no. 6 fuel oils, and their PM will also be presented to show
that emission profiles of mobile and stationary sources are related.
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