Chemical and Biological Properties of Diesel Exhaust Particles Collected during Selected Segments of a Simulated Driving Cycle

Chemical and Biological Properties of Diesel Exhaust Particles Collected during Selected Segments of a Simulated Driving Cycle. BECHTOLD, W. E., DUTCHER, J. S., MOKLER, B. V., LOPEZ, J. A., WOLF, I., LI, A. P., HENDERSON, T. R., AND MCCLELLAN, R. O. (1984). Fundam. Appl. Toxicol. 4, 370–377. Particle emissions, percentage of organic extractable materials, and mutagenicities of extracts from a diesel engine operating on a test stand have been determined for the full Federal Test Procedure driving cycle and several individual segments thereof. Particle samples were collected using a computer controlled high volume sampler. Extracts of the exhaust particles were screened for the potent mutagens nitropyrene/nitrofluoranthenes by mass spectrometry/mass spectrometry (MS/MS). Results indicate that a long acceleration from 0-55 mph produced approximately seven times more particles per second than the full cycle. Also, the 0-to 55-mph acceleration and a subsequent 55-mph cruise produced significantly higher amounts of mutagens than other segments or the full FTP cycle. A direct correlation of both NOx levels and temperature with mutagenicity was noted (r = 0.89 and r = 0.89). The specific activities of the extracts showed decreases or remained unchanged when assayed in TA-98 NR or TA-98 1,8 DNP6, nitroreductase deficient strains of TA-98. Three extracts were found to have high levels of nitropyrenes/nitrofluoranthenes, and two of the three had high specific activities in TA-98.