The electron impact mass spectra of di- and trinitrofluoranthenes.

The fragmentation pathways of a series of 18 dinitrofluoranthenes (DNF) and four trinitrofluoranthenes have been studied under electron impact conditions. In general, multiple losses of NO2, NO and CO from the molecular ion were observed. Quinonoid ions were observed in the spectra of DNF containing conjugated nitro groups. In addition, some unique fragmentation pathways were detected in the ortho-substituted 1,2- and 2,3-DNF and in the peri-substituted 3,4-DNF.

Ubiquitous occurrence of 2-nitrofluoranthene and 2-nitropyrene in air.

Several nitrated polycyclic aromatic hydrocarbons (nitro-PAH) are direct-acting mutagens and/or carcinogens, and are important constituents of combustion emissions and ambient air. These nitro-PAH are emitted from various combustion sources including gasoline and diesel engine exhaust, aluminium smelting effluent, coal fly ash, wood smoke, and cigarette smoke condensates. Of these, diesel engine exhaust is the best characterized, more than 50 nitrated polycyclic aromatic compounds having been identified by Paputa-Peck et al., including 1-nitropyrene (1-NP) as the single most abundant nitro-PAH. However, nitro-PAH may also be formed during source-receptor transport by atmospheric reactions of adsorbed or gas-phase PAH with oxides of nitrogen, nitric acid and other atmospherically important species such as the OH radical. Evidence for the atmospheric formation of nitro-PAH has come only recently, from observations that 2-nitropyrene (2-NP) and 2-nitrofluoranthene (2-NF) neither of which has been reported to be emitted from combustion sources, are among the major nitro-PAH present in ambient air. We present here data from several locations which demonstrate that these two atmospherically formed nitro-PAH are ubiquitous in tropospheric ambient air.

Analysis of chlorinated styrenes in environmental samples using negative ion chemical ionization mass spectrometry.

A method for the separation and identification of chlorinated styrene isomers with fully chlorinated aromatic nuclei in environmental samples is presented. Gas chromatography combined with negative ion chemical ionization mass spectrometry is used. The method has been applied to a combined fish liver and filét extract. All the possible chlorostyrenes with fully chlorinated aromatic nuclei were detected in the sample.

Thermal oxidation of polycyclic aromatic hydrocarbons adsorbed on alumina.

The reevaporation of polycyclic aromatic hydrocarbons (PAH) from secondary alumina (alumina used in a fluidized bed for pot gas cleaning) used in the production of aluminum in aluminum reduction plants has been studied. The secondary alumina contains around 100 ppm of PAH when introduced to the pots. The results of this study indicate that only a minor part of the adsorbed PAH is reevaporated at the pot temperature of 300-400 degrees C and that the use of secondary alumina has little effect on the PAH concentration in the workplace atmosphere of the aluminum reduction plants.

Mutagenicity of polycyclic aromatic compounds (PAC) identified in source emissions and ambient air.

Several polycyclic aromatic compounds (PAC) including nitrated and oxygenated derivatives of polycyclic aromatic hydrocarbons (PAH) were tested for mutagenic activity in the Salmonella/microsome assay. Among the compounds tested the isomer mix of nitro-1-hydroxypyrenes showed the highest direct mutagenic response in both the Salmonella strain TA98 and TA100 (1251 revertants/micrograms and 463 revertants/micrograms, respectively). The direct-acting mutagenicity of the nitro-1-hydroxypyrene isomer mix was dependent upon reduction of the nitro function as evidenced by the decrease in activity observed with the nitroreductase-deficient and arylhydroxylamine esterifying-deficient tester strains. The oxygenated derivatives of PAH containing aldehyde or keto groups showed weak or no mutagenic responses. In most cases addition of S9 was essential for any mutagenic activity and the strain TA100 was more sensitive than the strain TA98. Within this group, 7H-dibenzo[c,g]fluoren-7-one showed the highest mutagenic effect; 7 and 22 revertants/micrograms using the strains TA98 and TA100, respectively.

Short-term bioassays of fractionated emission samples from wood combustion.

Extracts of an emission sample from wood burning, consisting of particles and volatiles, have been fractionated on an HPLC silica gel column into five fractions of increasing polarity. Nonfractionated samples and the individual fractions have been tested in three different short-term bioassays: the Ames Salmonella assay, the sister chromatid exchange (SCE) induction-test in Chinese hamster ovary cells (CHO), and the cell transformation test on Syrian hamster embryo (SHE) cells. Most of the total activity was found in the volatile part of the sample with all three bioassays, whereas the particle extract had the highest activity per unit mass extracted. The second most polar fraction contained most of the mass and was also highly active in all assays. The most polar fraction was very potent in the Salmonella assay, but showed only a weak response in the eukaryotic bioassays. Storage of the samples for several months at 0 degrees C revealed that the bacterial mutagens present in the most polar fraction were labile; the mutagenicity was almost totally lost after 1 year's storage.

Contribution of wood combustion to indoor air pollution as measured by mutagenicity in Salmonella and polycyclic aromatic hydrocarbon concentration.

Samples of airborne particles have been collected in the same room when the room was heated by electricity and when heating was done by woodburning. These samples were compared with respect to mutagenic activity and concentration of polycyclic aromatic hydrocarbons (PAH). The effects of the various heating conditions were examined in the presence and absence of tobacco smoking. Whereas wood heating in an "airtight" stove was found to cause only minor changes in the concentration of PAH and no measurable increase of mutagenic activity of the indoor air, both these parameters increased considerably when wood was burned in an open fireplace, yielding PAH concentrations comparable to those of ambient urban air. Relatively high concentrations of moderately polar polycyclic aromatic hydrocarbon derivatives were also found in the indoor air when wood was burned in an open fireplace. Woodburning in the closed stove did, however, result in increased concentrations of mutagenic compounds and PAH on particles sampled in the vicinity of the house. The effects of wood burning in an open fireplace on the mutagenic activity of indoor air could still be considered moderate when compared to those resulting from tobacco smoking in the room. The extracts of particles collected when moderate smoking occurred were several times more mutagenic than samples from urban air collected close to streets with heavy traffic when measured in the Salmonella assay with strain TA98 with metabolic activation.

Mutagenicity testing of high performance liquid chromatography fractions from wood stove emission samples using a modified Salmonella assay requiring smaller sample volumes.

Organic extracts of emissions from wood combustion have been fractionated by high performance liquid chromatography (HPLC) into 25-28 fractions. Each fraction was tested for mutagenic activity in a modified Ames Salmonella/microsome bioassay requiring one-third of the test volumes needed for the ususal test. Direct mutagenic activity was noted predominantly in the most polar fractions, whereas indirect mutagenic activity was associated with the fractions containing polycyclic aromatic hydrocarbons (PAH) and with polar fractions probably consisting of aza-arenes and aromatic amines.

The fate of airborne polycyclic organic matter.

Biological tests have shown that a significant part of the mutagenicity of organic extracts of collected airborne particulate matter is not due to polycyclic aromatic hydrocarbons (PAH). It is possible that part of these unknown compounds are transformation products of PAH. This survey focuses on the reaction of PAH in the atmosphere with other copollutants, such as nitrogen oxides, sulfur oxides, ozone and free radicals and their reaction products. Photochemically induced reactions of PAH are also included. The reactivity of particle-associated PAH is discussed in relation to the chemical composition and the physical properties of the carrier. Recommendations for future work are given.