Carbonyl emissions from gasoline and diesel motor vehicles.
Carbonyls from gasoline-powered light-duty vehicles (LDVs) and heavy-duty diesel-powered vehicles (HDDVs) operated on chassis dynamometers were measured by use of an annular denuder-quartz filter-polyurethane foam sampler with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine derivatization and chromatography-mass spectrometry analyses. Two internal standards were utilized based on carbonyl recovery: 4-fluorobenzaldehyde for < C8 carbonyls and 6-fluoro-4-chromanone for > or = C8 compounds. Gas- and particle-phase emissions for 39 aliphatic and 20 aromatic carbonyls ranged from 0.1 to 2000 microg/L of fuel for LDVs and from 1.8 to 27 000 microg/L of fuel for HDDVs. Gas-phase species accounted for 81-95% of the total carbonyls from LDVs and 86-88% from HDDVs. Particulate carbonyls emitted from a HDDV under realistic driving conditions were similar to concentrations measured in a diesel particulate matter (PM) standard reference material. Carbonyls accounted for 19% of particulate organic carbon (POC) emissions from low-emission LDVs and 37% of POC emissions from three-way catalyst-equipped LDVs. This identifies carbonyls as one of the largest classes of compounds in LDV PM emissions. The carbonyl fraction of HDDV POC was lower, 3.3-3.9% depending upon operational conditions. Partitioning analysis indicates the carbonyls had not achieved equilibrium between the gas and particle phases under the dilution factors of 126-584 used in the present study.
Jakober
Chris A
CA
Department of Environmental Toxicology, University of California, Davis, One Shields Avenue, Davis, California 95616, USA.
Robert
Michael A
MA
Riddle
Sarah G
SG
Destaillats
Hugo
H
Charles
M Judith
MJ
Green
Peter G
PG
Kleeman
Michael J
MJ
D001547:Benzaldehydes; D008401:Gas Chromatography-Mass Spectrometry; D006835:Hydrazones / Q000032:analysis; D009930:Organic Chemicals / Q000032:analysis*; D052638:Particulate Matter / Q000032:analysis*; D001335:Vehicle Emissions / Q000032:analysis*
D001547:Benzaldehydes; D006835:Hydrazones; D009930:Organic Chemicals; D052638:Particulate Matter; D001335:Vehicle Emissions; C516422:4-fluorobenzaldehyde