| Diesel engines are a source of suspended ambient particulate matter, and some concerns have been raised about the health effects from the inhalation of these particles. Nitrated polycyclic aromatics adsorbed on some of these particles have been shown to have the potential to cause mutations in living cells. Typically, particulate matter is collected on teflon-coated glass fiber filters to quantify the amount of particulate matter generated by a Diesel engine. The collection procedures are open to question because of the possible generation of artifactual nitrated aromatics during the filtration process.;Pressure histories of the combustion event showed the consistency of the CVCB for the four oxidants, given equivalent masses of oxygen and fuel (50% isooctane and 50% tetradecane) were introduced into the CVCB for each oxidant. The NO(,x) increased as the flame temperature increased as long as there was nitrogen available in the oxidant to form NO(,x). The gas-phase and solid-phase emissions were consistent for each oxidant and accounted for the mass of fuel burned. There was a significant quantity of isooctane and tetradecane in the SOF of the particulate matter from the plug and the filter. Other paraffins and several PAH's including 1-nitropyrene were also identified in the SOF of the particulate matter.;The biological activity from the filter and plug samples showed no significant differences for three of the oxidants. This was consistent with the gas-chromatographic results in which little to no difference was found between the filter and the plug samples. The 1-nitropyrene in the samples was only partially responsible for the biological activity.;An experiment using a constant-volume combustion bomb (CVCB) was used with four oxidants (air, a N(,2) free oxidant (29% O(,2) 21% AR 50% CO(,2)), 50% O(,2)/50% N(,2) oxidant, and O(,2) (99.95% pure) oxidant) to address the concern over artifactual generation of nitrated-PAH on the filtration medium. Soot samples were collected both in situ in the CVCB and on teflon-coated glass fiber filters. Chemical comparisons of the collected samples were accomplished using chromatographic procedures. Biological comparison of the extracted material from the soot was accomplished using the Ames Salmonella test. |
