Aerosol aromatic hydrocarbons

Wall Loss of Oxidation Products. It is known that some classes of hydrocarbons (the higher terpenes, for instance) are prolific aerosol formers when subjected to atmospheric oxidation. Other classes, aromatic hydrocarbons for instance, although they do not form large amounts of suspended aerosol, have been shown to lose (at least under some conditions) large amounts of oxidation products to the reaction vessel walls. The fate of these oxidation products in the open atmosphere remains open to question, as does the extent to which they continue to participate in gas-phase chemistry (187). 

The transformation of arenes in the troposphere has been discussed in detail (Arey 1998). Their destruction can be mediated by reaction with hydroxyl radicals, and from naphthalene a wide range of compounds is produced, including 1- and 2-naphthols, 2-formylcinnamaldehyde, phthalic anhydride, and with less certainty 1,4-naphthoquinone and 2,3-epoxynaphthoquinone. Both 1- and 2-nitronaphthalene were formed through the intervention of NO2 (Bunce et al. 1997). Attention has also been directed to the composition of secondary organic aerosols from the photooxidation of monocyclic aromatic hydrocarbons in the presence of NO (Eorstner et al. 1997) the main products from a range of alkylated aromatics were 2,5-furandione and the 3-methyl and 3-ethyl congeners. 

Forstner HJL, RC Flagan, JH Seinfeld (1997) Secondary organic aerosol from the photoxodation of aromatic hydrocarbons molecular composition. Environ Sci Technol 31 1345-1358. 

Chen, J., Quan, X., Yan, Y., Yang, F., Peijnenburg, W.J.G.M. (2001) Quantitative structure-property relationship studies on direct photolysis of selected polycyclic aromatic hydrocarbons in atmospheric aerosol. Chemosphere 42, 263-270. 

Dachs, J., Eisenreich, S.J. (2000) Adsorption onto aerosol soot carbon dominates gas-particle partitioning of polycyclic aromatic hydrocarbons. Environ. Sci. Technol. 34, 3690-3697. 

The NO + 03 chemiluminescent reaction [Reactions (1-3)] is utilized in two commercially available GC detectors, the TEA detector, manufactured by Thermal Electric Corporation (Saddle Brook, NJ), and two nitrogen-selective detectors, manufactured by Thermal Electric Corporation and Antek Instruments, respectively. The TEA detector provides a highly sensitive and selective means of analyzing samples for A-nitrosamines, many of which are known carcinogens. These compounds can be found in such diverse matrices as foods, cosmetics, tobacco products, and environmental samples of soil and water. The TEA detector can also be used to quantify nitroaromatics. This class of compounds includes many explosives and various reactive intermediates used in the chemical industry [121]. Several nitroaromatics are known carcinogens, and are found as environmental contaminants. They have been repeatedly identified in organic aerosol particles, formed from the reaction of polycyclic aromatic hydrocarbons with atmospheric nitric acid at the particle surface [122-124], The TEA detector is extremely selective, which aids analyses in complex matrices, but also severely limits the number of potential applications for the detector [125-127],... 

Strand, J.W. and A.W. Andren. 1980. Polyaromatic hydrocarbons in aerosols over Lake Michigan, fluxes to the Lake. Pages 127-137 in A. Bjorseth and A.J. Dennis (eds.). Polynuclear Aromatic Hydrocarbons Chemistry and Biological Effects. Battelle Press, Columbus, OH. 

Due to the fact that JP-8 contains hundreds of aliphatic and aromatic hydrocarbons, in addition to various performance additives, this complex mixture poses a serious challenge for risk assessment. Exposure assessment is complicated by the fact that JP-8 may be encountered as a vapor, aerosol, or liquid, and possibly as combustible products, and each physical state may contain different chemical entities. However, progress has been made in the identification of JP-8 components that may serve as reliable and predictable biomarkers of exposure, particularly for dermal exposures [12,35,81,82,83,84],... 

The first scientists to investigate the coastal atmospheric presence of APs were Van Ry and Dachs, in a study conducted in the Hudson river estuary. GC-MS analyses showed that atmospheric NP isomer mixtures have a similar composition to technical mixtures, with relatively high total concentrations in the range of 0.0002—0.069 xg m-3 in the gas phase, and 0.0001-0.051 p,gm-3 in the aerosol phase. These concentrations are higher than those of polycyclic aromatic hydrocarbons and up to two orders of magnitude higher than polychlorinated biphenyl concentrations in impacted urban-industrial areas [32]. 

Shihadeh A, Saleh R (2005) Polycyclic aromatic hydrocarbons, carbon monoxide, tar , and nicotine in the mainstream smoke aerosol of the narghile water pipe. Food Chem. Toxicol 43 655-661... 

Our knowledge of the chemical and physical processes that govern aerosol formation in the atmosphere is limited, and further research in the field is badly needed. Attention should be focused on laboratory studies of aerosol formation from aromatic hydrocarbons. The concentrations of aerosol precursors in the atmosphere should be determined more data on organic compounds in ambient aerosols are needed to estimate the relative importance of olefinic and aromatic hydrocarbons as aerosol precursors. 

Organic aerosols formed by gas-phase photochemical reactions of hydrocarbons, ozone, and nitrogen oxides have been identified recently in both urban and rural atmospheres. Aliphatic organic nitrates, such dicarboxylic acids as adipic and glutaric acids, carboxylic acids derived from aromatic hydrocarbons (benzoic and phenylacetic acids) and from terpenes emitted by vegetation, such as pinonic acid from a pinene, have been identified. The most important contribution in this held has been that of Schuetzle et al., who used computer-controlled... 

Conflicting results have been reported for aromatic compounds. Aerosol formation has been reported from benzene, toluene, and other alkylbenzenes by several investigators, whereas no aerosol formation was observed in other studies. This merits further investigation, in view of the large fraction of aromatic hydrocarbons present in polluted atmospheres. 

From all available evidence, the hydroxyl radical plays a major role in the photooxidation and aerosol formation processes for aromatic hydrocarbons. However, much research remains to be done to improve our knowledge in this field. 

Nothing is known about the threshold concentration for aromatic hydrocarbons. No vapor-pressure data on the polyfunctional products are available. However, a possible threshold concentration of several parts per million seems indicated by data of Kopczynski (mesitylene aerosol at 25 ppm, no aerosol at lower concentration), O Brien et al. (mesitylene aerosol at 10 ppm, no aerosol at 2 ppm), Schwartz... 

Pierce, R. C., and M. Katz. Dependency of polynuclear aromatic hydrocarbon content on size distribution of atmospheric aerosols. Environ. Sci. Technol. 9 347-353,... 

Laboratory (smog-chamber) studies of aerosol formation from aromatic hydrocarbons gas-phase reaction mechanism, physical processes controlling gas-to-aerosol conversion, kinetic data on aerosol formation... 

Identification of organic components of ambient aerosob, to permit estimation of the relative importance of olefinic and aromatic hydrocarbons as aerosol precursors,... 

Sicre MA, Marty JG, Saliot A, Aparicio X, Grimalt J, Albaiges J, Aliphatic and aromatic hydrocarbons in different sized aerosols over the Mediterranean Sea Occurrence and origin, Atmos Environ 21 2247—2259, 1987. 

Although the ultimate source of much of particulate organic matter (POM) in the urban aerosol appears to be fossil fuel a specific knowledge of the amounts and classes of organic compounds contributed by various types of sources is lacking. Estimates of source contributions have been based on emission inventories which have been largely directed toward polycyclic aromatic hydrocarbons and/or benzo(a)pyrene. There has been very little work on the development of mathematical and statistical models for POM source identification and allocation (1). In view... 

Daisey, J. M., M. A. Leyko and T. J. Kneip. Source identification and allocation of PAH compounds in the New York City aerosol Methods and applications. In Polynuclear Aromatic Hydrocarbons. P. W. Jones and P. Leber, eds. Ann Arbor Science Publishers, Inc., Ann Arbor, Michigan. 201-215 (1979). 

The yields of secondary organic aerosols from a series of aromatic hydrocarbon-NOx oxidations have been measured by Odum et al. (1997a, 1997b). They showed that the total secondary organic aerosol formed from a mixture of aromatic hydrocarbons can be approximated as the sum of the individual contributions. Based on their experiments, the yield of secondary organic aerosols expressed as the total organic particle mass concentrations formed, AM, (in fxg m 3), divided by the mass concentration of aromatic precursor reacted, A (aromatic), is given by... 

FIGURE 9.53 Yield (Y) of secondary organic aerosol as a function of the amount of aerosol generated, AM , during the VOC-NO. oxidations in air of some aromatic hydrocarbons (adapted from Odum et al., 1997b). 

Forstner, H. J. L., R. C. Flagan, and J. H. Seinfeld, Secondary Organic Aerosol from the Photooxidation of Aromatic Hydrocarbons Molecular Composition, Environ. Sci. Technol., 31, 1345-1358 (1997b). 

Izunii, K and T. Fukuyama, Photochemical Aerosol Formation from Aromatic Hydrocarbons in the Presence of NO, Atmos. Environ., 24A, 1433-1441 (1990). 

In a similar study, Allen and co-workers (1996) determined the particle size distribution for 15 PAHs with molecular weights ranging from 178 (e.g., phenan-threne) to 300 (coronene) and associated with urban aerosols in Boston, Massachusetts. As for BaP in the winter (Venkataraman and Friedlander, 1994b), PAHs with MW >228 were primarily present in the fine aerosol fraction (Dp < 2 /Am). A study of 6-ring, MW 302 PAH at the same site showed bimodal distributions, with most of the mass in the 0.3- to 1.0-/zm particle size size range a smaller fraction was in the ultrafine mode particles (0.09-0.14 /xm) (Allen et al., 1998). For PAHs with MW 178—202, the compounds were approximately evenly distributed between the fine and coarse (D > 2 /am) fractions. Polycyclic aromatic hydrocarbons in size-segregated aerosols col-... 

Allen, J. O., N. M. Dookeran, K. A. Smith, A. F. Sarofim, K. Taghizadeh, A. L. Lafieur, Measurement of Polycyclic Aromatic Hydrocarbons Associated with Size-Segregated Atmospheric Aerosols in Massachusetts, Environ. Sci. Technol., 30, 1023-1031 (1996). 

Chen, S.-J., S.-H. Liao, W.-J. Jian, S.-C. Chiu, and G.-C. Fang, Particle-Bound Composition of Polycyclic Aromatic Hydrocarbons and Aerosol Carbons in the Ambient Air, J. Environ. Sci. Health, A32, 585-604 (1997). 

C. L. Crespi, Human Cell Mutagenicity of Oxygenated, Nitrated, and Unsubstituted Polycyclic Aromatic Hydrocarbons Associated with Urban Aerosols, Mutat. Res., 371, 123-157 (1996). 

Feilberg, A., and T. Nielsen, Effect of Aerosol Chemical Composition on the Photodegradation of Nitro-Polycyclic Aromatic Hydrocarbons, submitted to Environ. Sci. Technol. (1999b). 

---