PAH profiles

Frenklach, M. and Warnatz, J., Detailed modeling of PAH profiles in a sooting low-pressure acetylene flame. Combust. Sci. Tech., 51,265,1987. 

Because of the very low concentrations, the detection and quantification of POCs in the water of alpine lakes and streams is very challenging [38] and is therefore rarely attempted. Nevertheless, studies of POCs in lakes in Europe show HCH concentrations in water that rival those of the highest measured in inland waters [46]. Mountain lakes close to populated areas showed PAH profiles which favored the lighter PAHs, including some transformation products, whereas a more remote lake contained relatively higher concentrations of heavier PAHs, a hallmark of LRT because the lighter PAHs are generally the more labile [47]. The concentration of POCs in water and sediments of alpine lakes is dynamically controlled by the rates of input and loss. In order to understand the contamination of the alpine aquatic biota, it is important to understand the processes that deliver POCs to the lakes and that lead to their loss from the lakes (Pig. 2). Two alpine lakes in particular have... 

Once the polycyclics are released from the combustion system, presumably adsorbed on soot or fly ash, they are then exposed to potential atmospheric degredation. A simple way in which to note the relative degradation susceptibility of the various PAH is to compare the GCMS data of the PAH coming from a combustion system (see Figure 1) with the PAH profile of atmospheric particulates... 

On the other hand, comparison of the average PAH profiles in the sediments (Fig. 10) with snow deposition [62] and atmospheric PAH gas and particulate phases distribution [34] shows a good agreement between the PAH composition in the sediments and in the atmospheric particulate phase (r2 = 0.94 p < 0.01) and snow deposition (r2 = 0.92 p < 0.01). 

Fig. 10 PAH profiles in environmental compartments from the High Tatras (a) air gas phase [34] (b) air particulate phase [34] (c) snow deposition [62] (d) sediment [66], FL fluorene, PFIE...

Severson et al. (3616) determined the pyrolytic conditions that gave the PAH profiles of tobacco pyrolysates that they claimed could be correlated with [CSC] PAH profiles. Examination of their data indicates that this claim is not valid. Severson et al. conducted two major experiments. They examined ... 

Severson et al. (1979) describe the pyrolytic conditions that yielded [PAH] profiles of tobacco pyrolyzates that could be correlated with [cigarette smoke condensate] profiles.. 

Concentrations of total PAHs in bivalves from the Caribbean and Central and South America ranged from 28.4 ng/g to 13,800 ng/g dry weight [31]. As expected, the highest concentrations were observed near ports or urban centers. Only three PAH profiles, one each from Chile, Brazil, and Argentina, are shown in the report. The latter is conspicuous by relatively low concentrations of naphthalene and alkyl naphthalenes, indicating primarily a combustion source. 

A morphological approach has been used to differentiate between coal and oil SCP types in North American studies (e.g. Kothari Wahlen, 1984), including PIRLA (Charles et al., 1990). However, in this latter study, fuel-type determinations were difficult in many cases (D. Charles, pers. commun.) and although it was still possible to produce individual profiles of coal and oil, these were found to contain more variation than some metal and PAH profiles (Charles et al., 1990) and this may be as a result of these difficulties. 

CARCINOGENIC IMPACT FROM AUTOMOBILE EXHAUST CONDENSATE AND THE DEPENDENCE OF THE PAH-PROFILE ON VARIOUS PARAMETERS... 

A first attempt to an estimation of the contribution of benzo(a)pyrene of the total biological activity of condensates is recording their PAH-profiles. Typical profiles from OTTO- and DIESEL-engines after Europates t cycles are given in figures 5 and 6 ... 

Figure 5 PAH-profile of automobile exhaust from OTTO-engine car (25 m glass-capillary column CPsil5)...

X) Content of PAH present already in the gasoline ISeveral times repeated tests with PAH-free and analo-gous but PAH-containing gasoline did not give any evidence for a relevant influence on the PAH mass concentration or the PAH profile of the exhaust. MEYER et al. (11) did not find differences in the mass concentrations... 

E) PAH concentration in lubricating oil t In lubricating oil a considerable accumulation of PAH occurs with increasing time of operation. Under the described operation conditions a PAH-profile is formed in used oil which is similar to the PAH-profile of gasoline (13) ... 

Figure 11. PAH-profiles of air samples in various areas of Essen (Northrhine-Westphalia)...

In some cases the emission source can be readily recognized from the PAH-profile which may be seen from the tunnel-profile which resembles the automobile exhaust PAH-profile (fig 12) ... 

Figure 12 Comparison of the PAH-profiles of (a) air in a automobile tunnel and (b) emissions of a passenger car on a chassis dynamometer, simulating city-traffic (ECE-reglement 15) ...

III) A predominant contribution of automobile exhaust to the air pollution in certain areas may be recognized from the similarities of the PAH-profiles ... 

IV) DIESEL and OTTO exhausts differ significantly in their PAH-profiles. Hence, the balance of effect may look different in both cases. An investigation on the balance of effect of DIESEL exhaust fractions using carcinogen-specific test models seem to be highly desirable and has still to be performed. 

The air-fuel ratio has a significant influence on PAH emissions. With leaner mixtures the mass of PAH in the exhaust gas drops noticably. The PAH profile changes to the extent that the share of carcenogenic components of total PAH are lower, whereas especially the share of Pyren increases. The absolute levels of the PAH emissions have no effect on the PAH profile for equal air-fuel ratios. 

These measures lead to a reduction of the emission levels as well as a shift in the PAH profile, whereby the emission of carcinogenic components are reduced by a greater margin than the non-carcinogenic components. 

The equivalent air-fuel-ratio also influences the PAH profile. The profile describes the mass relationship of the different PAH components. The portion of carcinogenic components of Epah drops with increasing X. In Fig. 3 the reduction of "Chrysene (consisting of Chrysene + Benzo(a)anthracene + Cyclopenta(cd)pyrene + Triphenylene) is illustrated for mixture leaning. Benzo(a)pyrene also drops from 3 % at X = 0,9 to approx. 2 % at X = 1,1. The non-carcinogenic component Pyrene is mainly the component which proportionally increases with increasing X. 

In the effort to reduce emissions as well as fuel consumption, the development of modern production engines has followed these guidelines. This has resulted not only in a considerable reduction in PAH pollution through spark ignition engines but also has shifted the PAH profile towards the non-carcinogenic components. ... 

PAH profiles measured in flames indicate a rapid formation of PAH, followed by destruction, with in several systems a subsequent increase of PAH concentration in the exhaust. 

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