scholarly journals Assessment of Organic Compounds as Vehicular Emission Tracers in the Aburrá Valley Region of Colombia

2016 ◽  
Vol 07 (11) ◽  
pp. 1561-1570
Author(s):  
Enrique Posada ◽  
Miryam Gómez ◽  
Viviana Monsalve
Keyword(s):  
Organic Compounds ◽  
Vehicular Emission ◽  
Emission Tracers

scholarly journals Vehicular emission of volatile organic compounds (VOCs) from a tunnel study in Hong Kong

2009 ◽  
Vol 9 (3) ◽  
pp. 12645-12674 ◽  
Author(s):  
K. F. Ho ◽  
S. C. Lee ◽  
W. K. Ho ◽  
D. R. Blake ◽  
Y. Cheng ◽  
...  
Keyword(s):  
Hong Kong ◽  
Organic Compounds ◽  
Abundant Species ◽  
Average Concentration ◽  
Ozone Formation ◽  
Vehicular Emission ◽  
Key Species ◽  
Ozone Formation Potential ◽  
Volatile Organic ◽  
Maximum Increment

Abstract. Vehicle emissions of VOCs were determined in summer and winter of 2003 at the Shing Mun Tunnel, Hong Kong. One hundred and ten VOCs were quantified in this study. The average concentration of the total measured VOCs at the inlet and outlet of the tunnel were 81 250 pptv and 117 850 pptv, respectively. Among the 110 compounds analyzed, ethene, ethyne and toluene were the most abundant species in the tunnel. The total measured VOC emission factors ranged from 67 mg veh−1 km−1 to 148 mg veh−1 km−1, with an average of 115 mg veh−1 km−1. The five most abundant VOCs observed in the tunnel were, in decreasing order, ethene, toluene, n-butane, propane and i-pentane. These five most abundant species contributed over 38% of the total measured VOCs emitted. The high propane and n-butane emissions were found to be associated with LPG-fueled taxi. And fair correlations were observed between marker species (ethene, i-pentane, n-nonane, BTEX) with fractions of gasoline-fueled or diesel-fueled vehicles. Moreover, ethene, ethyne, and propene are the key species that were abundant in the tunnel but not in gasoline vapors or LPG. In order to evaluate the ozone formation potential emissions in Hong Kong, the maximum increment reactivity is calculated. It was found that about 568 mg of O3 is induced by per vehicle per kilometer traveled. Among them, ethene, propene and toluene contribute most to the ozone-formation reactivity.

scholarly journals Investigating the concentration levels, distribution patterns, source identification and health risk assessment of PAHs, n-alkanes, hopanes, and steranes in deposited dust of Mashhad, Iran

2021 ◽  
Author(s):  
Faezeh mahdad ◽  
Alireza Riyahi Bakhtiari ◽  
Mazaher Moeinaddini ◽  
Susanne Charlesworthc ◽  
Nima Emrani
Keyword(s):  
Organic Compounds ◽  
Source Identification ◽  
Traffic Congestion ◽  
Distribution Patterns ◽  
Urban Environments ◽  
Diagnostic Ratios ◽  
Wood Combustion ◽  
Vehicular Emission ◽  
Lifetime Cancer Risk ◽  
Air Conditioning Systems

Abstract Deposited dust (DD) in urban environments contains carcinogenic organic compounds. The Indoor air quality is greatly affected by heating, ventilation, and air conditioning systems (HVAC), and in the Middle East most of the buildings are equipped by HVAC on top of them. It is possible that the DD on the roof near this equipment would be transferred to an indoor area. For these reasons, 40 samples of the over the roof DD were prepared, and organic compounds (16PAH compounds, 20n-alkane homologs, 8hopanes, and 6steranes) of DD were extracted using Soxhlet and analyzed by GC-MS. Source identification of organic compounds conducted by ring classification, diagnostic ratios, and factor analysis (FA). The results showed that the average (±SD) of total PAHs, n-alkanes, hopanes and steranes in DD were 1356.00 (±291.45) ng kg−1dw, 3211.65 (±969.18), 146.37 (±79.45) and 469.76 (±188.25) µg.g_1dw, respectively. The highest concentration of organic compounds was in the city center, where traffic congestion is common. Diagnostic ratios of n-alkanes results showed the dominant source is vehicular emission. FA results indicated vehicular emission and biogenic sources. In agreement, the results of sterane and hopane profiles confirm these results. On the other hand, the PAHs diagnostic ratios results indicated petroleum combustion sources. In this regard, FA findings showed combustion from vehicular emission and natural gas and wood combustion were the main factors. Furthermore, the incremental lifetime cancer risk was calculated as 8.45× 10−12 for children and 9.80 × 10−7 for adults, and the imposed risk was negligible.

The Tempo and mode(S) of Prebiotic Evolution

1997 ◽  
Vol 161 ◽  
pp. 419-429 ◽  
Author(s):  
Antonio Lazcano
Keyword(s):  
Origin Of Life ◽  
Organic Compounds ◽  
Biological Evolution ◽  
Current Evidence ◽  
Early Diversification ◽  
Time Period ◽  
The Galaxy ◽  
History Of ◽  
Widespread Phenomenon ◽  
The Origin Of Life

AbstractDifferent current ideas on the origin of life are critically examined. Comparison of the now fashionable FeS/H2S pyrite-based autotrophic theory of the origin of life with the heterotrophic viewpoint suggest that the later is still the most fertile explanation for the emergence of life. However, the theory of chemical evolution and heterotrophic origins of life requires major updating, which should include the abandonment of the idea that the appearance of life was a slow process involving billions of years. Stability of organic compounds and the genetics of bacteria suggest that the origin and early diversification of life took place in a time period of the order of 10 million years. Current evidence suggest that the abiotic synthesis of organic compounds may be a widespread phenomenon in the Galaxy and may have a deterministic nature. However, the history of the biosphere does not exhibits any obvious trend towards greater complexity or «higher» forms of life. Therefore, the role of contingency in biological evolution should not be understimated in the discussions of the possibilities of life in the Universe.

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