Hopanoids, a class of pentacyclic organic compounds with 27 to 35 carbon atoms in a naphthenic structure, are largely derived from the lipid fraction of once-living organisms (Peters et al., 2007) and are considered petroleum biomarker they are not present in gasoline and diesel fuel because they are in the higher boiling fraction of petroleum, although they are found in engine oil lubricant (Omar et al., 2006; Pakbin et al., 2009; Zakaria et al., 2001), and therefore are detected in auto exhaust aerosol emission, as well as in road dust (Bahry et al., 2009). A few studies suggested that hopane emission rates are not affected by alternative fuels such as biodiesel. However, recently, it was speculated that fuel type may affect the amount of lubricating released into exhaust through several mechanisms and that higher cetane number fuel may leads to reduced emission of hopanes. These discrepancies in emission rates may limit the use of hopanes as traffic-related tracers. A wide set of hopanoids were identified and quanitifed for the first time in particulated matter of less than 10 microns. In spite of the scarcity of studies, there is evidence that hopanes may pose risks to human health. Strong and statistically significant positive association were observed between hopanoid hydrocarbon and ischemis heart diseases, cardiac dysrhythmia and congestive heart failure. Hopanes were also associated with asthma disease (Sarnat et al., 2015). There is a significant association between exposure to hopane and shortness of breath in cohort of myocardial infraction survivals in Germany (McDonald et al., 2004). Hopanes were detected in the aerosol of road tunnels in Brazil. Hopanes may occur in the 17?, 21?(H) stereochemistry (??) as found in living organisms and fossil fuels, whereas the ?? or ?? configurations are observed in fossil fuels. The sterochemical configurations at the C-17 and C-21 positions of hopanes are frequently taken to evaluate the geological maturity of samples. Hopanes with 17?(H), 21?(H) configurations are considered immature, 17?(H),21?(H) are moderately mature and 17?(H),21?(H) are fully mature (Bi et al., 2008, Han et al., 2015). Different biomarker rations have been widely used to evaluate the organic matter thermal maturity and degree of preservation, whether for coal or for oil-related products. Homohopane index. The specification profiles of homohopane index obtained can provide inputs to chemical mass balance (CMB) receptor models. The database can also serve as a repository to categories emissions form flex fuel vehicle and to verify profiles derived from ambient measurements by multivariate receptor models. Further studies are needed to fully understand the mechnisms by which hopanes are exhausted from lubricating oils.
1.4.8 Symptoms in myocardial infarction survivors
There were reports of involvement of particular organic compounds (POC) as aerosol component responsible for hazardous health effect. The survey was carried out in Augsburg, Germany with 153 myocardial infarction (MI) survivors by recording occurrence of different symptoms. Studies have shown that organic compounds were detected with notable toxicity. Present study discuses about two groups of organic compounds in which hopanes form one of the majorly discussed group, identified in emissions of burning coal, fuel oil and vehicles. Also current epidemiological studies concluded the association of hopanes with biomarkers of systemic inflammation as well as lung toxicity. In the period of January 2003-December 2004 sufficient PM 2.5filter samples were collected with the help of low volume sampler. Samples were spiked with isotope -labeled internal standards for quantification followed by GC-MS. Considering the difference in the hopane fingerprint they were classified into two groups with two different sources respectively:
Group 1- traffic hopanes:Hopanes primarily emitted from burning of mineral oil and lubricating oil from tailpipes.
(18?(H)-22,29,30-trisnorhopane, 17?(H),21?(H)-30-norhopane, 17?(H),21?(H)-30-hopane, 22S-17?(H),21?(H)-homohopane.
Group2-coal combustion hopanes:Hopanes detected in high concentration from emissions of coal combustion
(17?(H)-22,29,30-trisnorhopane, (17?(H)-22,19,30-trisnorhopane, 17?(H),21?(H)-30-norhopane, 17?(H),21?(H)-hopane and 22R-17?(H),21?(H)-homohopane.
Biostatisticle analysis evaluates high correlation within the different hopanes and polycyclic aromatic hydrocarbons (PAH) which forms the second group of POC. One of the hypotheses of the study indicates decrease in myocardial perfusion along with decrease in exercise capacity in case of ischemic heart disease when exposed to PM containing hopanes. Determination of the effects of various organic species on biomarkers of inflammation reveals striking association of hopanes with proinflammatory cytokines IL-6 and soluble tumor necrosis factor-? receptor II. Finally the study summaries that hopanes and PAH are coupled with change in incidence of daily symptoms in MI survivors.