Sampling of vehicle emissions for chemical analysis and biological testing.

Abstract

Representative dilution tube sampling techniques for particulate and gas phase vehicle emissions are described using Teflon filter media and XAD-2 resin. More than 90% of the total gas (C8-C18) and particulate direct acting Ames assay mutagenicity (TA 98) was found in the particulate phase. The gas and particulate phase material was fractionated by HPLC into nonpolar, moderately polar and highly polar chemical fractions. The moderately polar chemical fraction of the particulates contained more than 50% of the direct acting Ames assay mutagenicity for the total extract. The concentration of oxygenated polynuclear aromatic hydrocarbons (oxy-PAH) and nitrated PAH (nitro-PAH) identified in the moderately polar particulate fractions are given. Nitro-PAH account for most of the direct-acting (TA 98) Ames assay mutagenicity in these moderately polar fractions. Reactions and kinetic expressions for chemical conversion of PAH are presented. Chemical conversion of PAH to nitro-PAH during dilution tube sampling of particulates on Teflon filters and gases on XAD-2 resin is a minor problem (representing 10-20%, on the average, of the 1-nitropyrene found in extracts) at short (46 min) sampling times, at low sampling temperatures (42 degrees C), and in diluted exhaust containing 3 ppm NO2. Particulate emissions collected from dilution tubes on filter media appear to be representative of what is emitted in the environment as based upon a comparison of highway and laboratory studies.

Photodegradation Mechanisms of 1-Nitropyrene, an Environmental Pollutant: The Effect of Organic Solvents, Water, Oxygen, Phenols, and Polycyclic Aromatics on the Destruction and Product Yields

“…Interestingly, the quantum yields of these hydroxynitropyrenes are similar in the alcohols, while in acetonitrile the yield of the 1-OH-2-NO 2 Py isomer is much higher (10 to 45 times in N 2 saturated solutions and 4 to 17 times in O 2 saturated solutions). Because 1-OH-2-NO 2 Py is found in ambient air but not in diesel particles 23 , while the other isomers have been detected only in diesel particles 12 , our results suggest that the photochemical formation of the 1-OH-2-NO 2 Py in air particles will be favorably formed under conditions in which 1-NO 2 Py is encountered in a polar aprotic environment under low humidity conditions.…”

“…8–11 In fact, more than 90% of the mutagenicity for the total exhaust emitted from a diesel engine was found in the particulate phase, and can be associated to nitro-PAHs. 12–13 …”

Relationship between redox activity and chemical speciation of size-fractionated particulate matter

“…There are numerous cites on the larger molecular weight PAHs for quinone formation, and therefore a particular PAH may lead to DTT activity that reflects a number of quinone isomers formed from the parent compound. Schuetzle et al [34] reported a wide range of organic compounds generated by vehicles, including PAH-quinones, PAH ketones, and carboxaldehydes, all of which may be transformed to quinones via atmospheric chemistry or biotransformation. Other compounds that have potential DTT activity include aromatic nitro-PAH groups that are formed via atmospheric chemistry [35].…”

“…Other compounds that have potential DTT activity include aromatic nitro-PAH groups that are formed via atmospheric chemistry [35]. Schuetzle et al [34] reported a number of nitro-PAHs from vehicle emissions. The emissions of nitro-PAHs from diesel vehicles have been described in a wide range of publications summarized by Arey [35].…”

Interactive effects of cerium oxide and diesel exhaust nanoparticles on inducing pulmonary fibrosis

“…Diesel exhaust particles (DEPs) are carbon-based particles containing various organic compounds, including polycyclic aromatic hydrocarbons and nitroaromatic compounds adsorbed onto the carbonaceous core (Schuetzle, 1983; Schuetzle et al, 1981). Diesel exhaust is a complex and variable mixture of gases, vapors, and particulates containing numerous chemicals.…”