4-Nitrophenol, 1-nitropyrene, and 9-nitroanthracene emissions in exhaust particles from diesel vehicles with different exhaust gas treatments. (June 2015)

• Record Type: Journal Article
• Authors: Inomata, Satoshi; Fushimi, Akihiro; Sato, Kei; Fujitani, Yuji; Yamada, Hiroyuki
• Is Part Of: Atmospheric environment. Volume 110(2015)
• Page Start: 93
• Page End: 102
• Publication Date: 2015-06
• Subjects: Diesel exhaust particles (DEPs) -- Nitro-PAH -- Nitrophenol -- TD-GC/MS -- LC/MS; 1NP 1-nitropyrene -- 9NA 9-nitroanthracene -- DEP diesel exhaust particle -- DOC diesel oxidation catalyst -- DPF diesel particulate filter -- DPNR diesel PM-NOx reduction -- EC elemental carbon -- EF emission factor -- HC hydrocarbon -- LC/MS liquid chromatography/mass spectrometry -- LNT lean NOx trap -- NOx nitrogen oxides -- NSR NOx storage reduction -- OC organic carbon -- PAH polycyclic aromatic hydrocarbon -- PM particulate matter -- PNMC 3-methyl-4-nitrophenol -- PNOC 2-methyl-4-nitrophenol -- PNP 4-nitrophenol -- SCR selective catalytic reduction -- TC total carbon -- TD-GC/MS thermal desorption gas chromatography/mass spectrometry -- vehicle-DOC diesel truck with an oxidation catalyst -- vehicle-DPNR diesel truck with a PM–NOx reduction system -- vehicle-GASOLINE compact gasoline passenger car with a three-way catalyst -- vehicle-SCR diesel truck with a urea-selective catalytic reduction system -- VOC volatile organic compound; Air -- Pollution -- Periodicals; Air -- Pollution -- Meteorological aspects -- Periodicals; 551.51
• DOI: 10.1016/j.atmosenv.2015.03.043
• Languages: English
• ISSNs: 1352-2310

Abstract

Abstract: The dependence of nitro-organic compound emissions in automotive exhaust particles on the type of aftertreatment used was investigated. Three diesel vehicles with different aftertreatment systems (an oxidation catalyst, vehicle-DOC; a particulate matter and NO x reduction system, vehicle-DPNR; and a urea-based selective catalytic reduction system, vehicle-SCR) and a gasoline car with a three-way catalyst were tested. Nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) and nitrophenols in the particles emitted were analyzed by thermal desorption gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry. The secondary production of nitro-organic compounds on the filters used to collect particles and the adsorption of gaseous nitro-organic compounds by the filters were evaluated. Emissions of 1-nitropyrene, 9-nitroanthracene, and 4-nitrophenol in the diesel exhaust particles were then quantified. The NO x reduction process in vehicle-DPNR appeared to remove nitro-hydrocarbons efficiently but not to remove nitro-oxygenated hydrocarbons efficiently. The nitro-PAH emission factors were lower for vehicle-DOC when it was not fitted with a catalyst than when it was fitted with a catalyst. The 4-nitrophenol emission factors were also lower for vehicle-DOC with a catalyst than vehicle-DOC without a catalyst, suggesting that the oxidation catalyst was a source of both nitro-PAHs and 4-nitrophenol. The time-resolved aerosol mass spectrometry data suggested that nitro-organic compounds are mainly produced when an engine is working under load. The presence of 4-nitrophenol in the particles was not confirmed statistically because of interference from gaseous 4-nitrophenol. Systematic errors in the estimated amounts of gaseous 1-nitropyrene and 9-nitroanthracene adsorbed onto the filters and the estimated amounts of volatile nitro-organic compounds that evaporated during sampling and during post-sampling conditioning could not be excluded. An analytical method in which all gaseous compounds are absorbed before particles are collected, and in which the volatile compounds are derivatized, would improve the precision and the accuracy of the data. Highlights: 4-Nitrophenol probably dominates nitro-organics in diesel emission particles. The DPNR system decreased emissions of nitro-PAHs but probably not 4-nitrophenol. Nitro-PAH and 4-nitrophenol emissions were suppressed by the urea-SCR system. Oxidation catalysts are sources of nitro-PAHs and possibly 4-nitrophenol. Nitro-organic compounds are mainly produced by engines under load.