Composition, Toxicity, and Mutagenicity of Particulate and Semivolatile Emissions from Heavy-Duty Compressed Natural Gas-Powered Vehicles

Abstract

Particulate matter (PM) and vapor-phase semivolatile organic compounds (SVOC) were collected from three buses fueled by compressed natural gas. The bus engines included a well-functioning, conventional engine; a "high emitter" engine; and a new technology engine with an oxidation catalyst. Chemical analysis of the emissions showed differences among these samples, with the high emitter sample containing markers of engine oil constituents. PM + SVOC samples were also collected for mutagenicity and toxicity testing. Extraction efficiencies from the collection media were lower than for similarly collected samples from gasoline or diesel vehicles. Responses to the recovered samples were compared on the basis of exhaust volume, to incorporate the emission rates into the potency factors. Mutagenicity was assessed by Salmonella reverse mutation assay. Mutagenicity was greatest for the high emitter sample and lowest for the new technology sample. Metabolic activation reduced mutagenicity in strain TA100, but not TA98. Toxicity, including inflammation, cytotoxicity, and parenchymal changes, was assessed 24 h after intratracheal instillation into rat lungs. Lung responses were generally mild, with little difference between the responses to equivalent volumes of emissions from the normal emitter and the new technology, but greater responses for the high emitter. These emission sample potencies are further compared on the basis of recovered mass with previously reported samples from normal and high-emitter gasoline and diesel vehicles. While mutagenic potencies for the CNG emission samples were similar to the range observed in the gasoline and diesel emission samples, lung toxicity potency factors were generally lower than those for the gasoline and diesel samples.

Detoxification Potential of Pseudomonas fluorescens SM1 Strain for Remediation of Major Toxicants in Indian Water Bodies

“…The use of the strains TA98 and TA100 in detecting the mutagens among organic and inorganic pollutants has been established by several workers (Lopez et al 2000;Harrington et al 1983;Meier 1988;Le Curieux et al 1995;Aleem and Malik 2003;Seagrave et al 2005). As is evident from the results, a remarkable decrease in the genotoxic potential of the sample was obtained after it was passed through the immobilized cells of P. fluorescens SM1 strain (Table 6).…”

Measurements and Analysis of Polycyclic Aromatic Hydrocarbons near a Major Interstate

“…Epidemiologic research over the last 30 years has shown increases in adverse cardiovascular and respiratory outcomes in relation to mass concentrations of particulate matter (PM) ≤2.5 μm or ≤10 μm in aerodynamic diameter (PM2.5 and PM10, respectively). A number of research papers [1][2][3][4][5] have been published that examine the exposure and risk of Polycyclic Aromatic Hydrocarbons (PAHs) and their association with PM2.5, PM10 and ultrafine particles (UFPs). Many PAHs are known carcinogens [6][7][8].…”

“…A number of research papers [1][2][3][4][5] have been published that examine the exposure and risk of Polycyclic Aromatic Hydrocarbons (PAHs) and their association with PM 2.5 , PM 10 and ultrafine particles (UFPs). Many PAHs are known carcinogens [6][7][8].…”

Methods for Genotoxicity Testing of Environmental Pollutants

“…The Salmonella/microsome assay has been used to detect mutagens in samples of cigarette smoke (Roemer et al 2004), diesel exhaust (Seagrave et al 2005), surface waters (Siddiqui and Ahmad 2003;Tabrez and Ahmad 2009;Valente-Campos et al 2009), sewage sludge (Perez et al 2003), and soils (Xiao et al 2006;Brinkmann and Eisentraeger 2008). This bioassay has also been used to identify and characterize various mutagens such as heterocyclic amines in cooked foods (Shishu and Kaur 2003;Sugimura et al 2004).…”