Research Program Area: Health & Exposure
Ambient air samples were collected during 1986-1987 at seven sites throughout California impacted by different combustion emissions. The sites and the dominant combustion emissions were as follows: Glendora, vehicle emissions; Yuba City, agricultural burning; Concord, industrial emissions; Mammoth Lakes, wintertime residential wood burning; Oildale, oil production emissions; Reseda, chosen as a residential site; and Pt. Arguello, chosen as a background / rural site. At these sites, a total of 118 12-hour daytime and nighttime ambient air samples were collected onto Tenax-GC solid adsorbent, Teflon-impregnated glass fiber (TIGF) filters and TIGF filters backed up by polyurethane foam (PUF) plugs. In addition, ambient particles were collected on TIGF filters at San Nicolas Island during the 1987 summertime South Coast Air Quality Study. These ambient air samples were subjected to chemical analysis for 32 polycyclic aromatic hydrocarbons (PAH), nine nitroarenes and one sulfur heterocycle and to mutagenicity testing on strains TA98 (with and without Sg) and TA98NR and TA98 / 1,8-DNP6 (both without Sg) [the PUF plug and TIGF filter samples being composited into 24 and 25 samples, respectively, for the .chemical analysis]. Large differences were observed among the sites for PAH and nitroarene concentrations and mutagenicity, with Concord having the highest PAH and nitroarene concentrations and mutagen, densities, and Pt. Argue 110, the lowest. Among the PAH and PAH-derivatives monitored, 2-nitropyrene correlated the best with ambient mutagenicity (strain TA98, -S9). Since 2-nitropyrene is formed in the atmosphere from the gas-phase reaction of pyrene with the hydroxyl radical (in the presence of oxides of nitrogen), this suggests that the direct-acting mutagen densities of ambient particulate organic matter may be associated with atmospheric transformation products. The ambient concentrations of the PAH and PAH-derivatives measured during this program will provide one important element of the database required by the California Air Resources Board for its review of the PAH as a potential toxic air contaminant.
For questions regarding this research project, including available data and progress status, contact: Research Division staff at (916) 445-0753
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