Influence of Physical and Chemical Characteristics of Diesel Fuels and Exhaust Emissions on Biological Effects of Particle Extracts:  A Multivariate Statistical Analysis of Ten Diesel Fuels

Abstract

The emission of diesel exhaust particulates is associated with potentially severe biological effects, e.g., cancer. The aim of the present study was to apply multivariate statistical methods to identify factors that affect the biological potency of these exhausts. Ten diesel fuels were analyzed regarding physical and chemical characteristics. Particulate exhaust emissions were sampled after combustion of these fuels on two makes of heavy duty diesel engines. Particle extracts were chemically analyzed and tested for mutagenicity in the Ames test. Also, the potency of the extracts to competitively inhibit the binding of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to the Ah receptor was assessed. Relationships between fuel characteristics and biological effects of the extracts were studied, using partial least squares regression (PLS). The most influential chemical fuel parameters included the contents of sulfur, certain polycyclic aromatic compounds (PAC), and naphthenes. Density and flash point were positively correlated with genotoxic potency. Cetane number and upper distillation curve points were negatively correlated with both mutagenicity and Ah receptor affinity. Between 61% and 70% of the biological response data could be explained by the measured chemical and physical factors of the fuels. By PLS modeling of extract data versus the biological response data, 66% of the genotoxicity could be explained, by 41% of the chemical variation. The most important variables, associated with both mutagenicity and Ah receptor affinity, included 1-nitropyrene, particle bound nitrate, indeno[1,2,3-cd]pyrene, and emitted mass of particles. S9-requiring mutagenicity was highly correlated with certain PAC, whereas S9-independent mutagenicity was better correlated with nitrates and 1-nitropyrene. The emission of sulfates also showed a correlation both with the emission of particles and with the biological effects. The results indicate that fuels with biologically less hazardous potentials should have high cetane number and contain less PAC and sulfur. The results also indicate that engine factors affect the formation and emission of nitrated PAC.

Bioassay-directed fractionation and salmonella mutagenicity of automobile and forklift diesel exhaust particles.

“…As shown previously, the distribution of mutagenic activity of the EOM across chemical fractions can vary depending on the type of engine (Clark et al 1981;Sjogren et al 1996), type of fuel (Clark et al 1982;Crebelli et al 1995;Sjogren et al 1996;Westerholm et al 2001), the running conditions (Bechtold et al 1984;Courtois et al 1993), and the collection conditions (Claxton and Barnes 1981;Lies et al 1986). As demonstrated by extensive studies, much of the mutagenic activity of diesel exhaust is due to PAHs and nitroaromatics, especially nitropyrenes (Austin et al 1985;Claxton 1981Claxton , 1983Lies et al 1986;Nakagawa et al 1983;Rosenkranz 1996;Tokiwa and Ohnishi 1986).…”

Cancer Risk Assessment, Indicators, and Guidelines for Polycyclic Aromatic Hydrocarbons in the Ambient Air

“…It is well known that PAH emissions from vehicles depend on several factors such as fuel type (Egebäck and Bertilsson 1983;Lies 1989), fuel parameters (Sjögren et al 1996a), driving conditions (Rijkeboer and Zwalve 1990), ambient temperatures (Laurikko and Nylund 1993), exhaust after treatment devices (Egebäck and Bertilsson 1983), and engine adjustment (Rijkeboer and Zwalve 1990). PAH profiles from different vehicle concepts are presented in Table 5 and Figures 1-3.…”

Elemental carbon and PM(2.5 )levels in an urban community heavily impacted by truck traffic.

“…This organic fraction is a complex mixture containing toxicologically important compounds such as benzene, toluene, ethylbenzene, xylene, and polycyclic aromatic hydrocarbons (PAHs). Common PAHs include phenanthrenes, fluorenes, naphthalenes, fluoranthrenes, and pyrenes, many of which are known mutagens and carcinogens (19)(20)(21)(22). DEP surfaces also act as a site for the concentration of airborne allergens.…”