Measurements were taken of N-nitrosamine concentrations present in the animal chambers used during the NIOSH Diesel Exhaust/Coal Dust study. Monthly, and sometimes weekly, samples were taken. Samples were taken over 2 to 7 hours. The following nitrosamines were sought: N-nitrosodimethylamine (62759) (NDMA), N- nitrosodiethylamine (55185) (NDEA), N-nitrosodipropylamine (621647) (NDPA), N-nitrosodibutylamine (924163) (NDBA), N-nitrosopiperidine (100754) (NPIP), N-nitrosopyrrolidine (930552) (NPYR), N- nitrosomorpholine (59892) (NMOR), and N-nitrosodiphenylamine (86306) (NDPhA). Only NDMA, NDEA, and NDPA were detected above the detection limits of the system, 6.0 nanograms/cubic meter (ng/m3). Chambers containing either diesel exhaust or diesel exhaust plus coal dust most often contained NDMA, NDEA, or NDPA. Low levels of NDMA were occasionally found in chambers containing coal dust and clean air. Values obtained from the monthly samples collected during the earlier part of the study did not show any definite trend of variation. Precursors of nitrosamine formation were present in and prior to the exposure chambers, as indicated by the conversion of nitrosatable amines in samplers into the corresponding nitrosamine. The authors conclude that the observed nitrosamines appear to occur subsequent to diesel exhaust emission from the engine.
Division of Physical Sciences and Engineering, NIOSH, U.S. Department of Health and Human Services, Cincinnati, Ohio, 27 pages, 11 references