Evidence continues to grow that interventions that reduce IAP exposures substantially reduce lung cancer mortality. In a retrospective cohort study of more than 42,000 farmers with an average follow-up of 16 years, the use of high-efficiency portable stoves was associated with 40% decrease in deaths from lung cancer in men and 60% in women when compared with traditional stoves (Hosgood et al. 2008). The authors speculate that this may have been the result of lower exposure to combustion by-products because it was no longer necessary to open the stove multiple times each day to add coal. A retrospective cohort study conducted in China (n = 21,232) reported a decrease in lung cancer mortality after chimneys were installed in homes with improper ventilation (Lee KM et al. 2010).
Estimate effects of household solid-fuel combustion on cancers other than lung cancer. Many carcinogens such as PAHs and metals are present in both tobacco smoke and smoke from solid-fuel combustion products (IARC 2004, 2010), which suggests that other cancers associated with tobacco smoking may also be associated with exposure to IAP. Studies cited by the IARC Working Group in 2006 were not sufficient to allow firm conclusions about effects on cancers other than lung cancer, and only one additional study of associations between IAP and other cancers has been published since (Sapkota et al. 2008).
Fuels And Combustion Sp Sharma Pdf 25
Recent lung cancer genomewide association studies, which have been performed primarily in smoking Caucasian males, have reported associations between variants in loci 15q25, 5p15, and 6p21 and lung cancer susceptibility (Amos et al. 2008; McKay et al. 2008; Wang et al. 2008). The first genomewide association study of lung cancer among nonsmoking females in Asia reported that a variant in the CLPTM1L-TERT locus of chromosome 5 was strongly associated with lung cancer (Hsiung et al. 2010). The magnitude of the association was somewhat stronger than a previous estimate based on a genomewide association study of lung cancer among Caucasians, most of whom were smokers (Landi et al. 2009). Ongoing genomewide association studies of lung cancer in Asian populations should be able to provide new insights into how genetic susceptibility modifies the impact of IAP on lung cancer. Gene environment interactions have been explored among populations exposed to smoky coal, and similar studies are needed in populations with exposures to IAP emissions from the combustion of other solid fuels including wood, dung, and crop residues.
Metals which might be specific to airport emissions, either by abundance or type, such as the heavy-metal vanadium [47], could be potential chemical fingerprints. Abegglen et al. applied single particle mass spectrometry to investigate metal content and sources in emissions from different jet engines at various combustion conditions, and Mo, Ca, Na, Fe, Cu, Ba, Cr, Al, Si, Mg, Co, Mn, V, Ni, Pb, Ti and Zr were found to be significant frequently occurring metals. Fuel, lubrication oil, grease and engine wear are potential sources, but several metals were allocated to multiple sources [48].
In the studies of He et al and Shirmohammadi et al, particles were collected at Los Angeles Airport (LAX) and central Los Angeles (LA) and among other analyses, allocated according to elements associated with different sources [49, 50]. S was considered as aviation-related and particle-bound Na was viewed as ocean-related, due to sea salt from the ocean near by LAX. Al, Ca, Ti and K were considered as trace elements for road dust from LAX and central LA. Mn, Fe, Cu, Zn, Ba, Pb, Ni, and Mg were associated with traffic emissions, including fuel and lubricating oil combustions and brake abrasions, engine and tire wear. In LAX particles, S accounted for the largest fraction (49.5%), followed by road dust elements (21.8%) and traffic-related elements (15.9%). In particles from central LA, elements from traffic, road dust, and aviation were represented equally (28.5, 31.5, and 33.4%, respectively) [49, 50]. In a study from Montreal-Pierre-Elliott-Trudeau International Airport, several metals were found to be abundant in the particle fraction, such as Fe, Zn, and Al, and the authors speculate, that airports in fact may be hotspots for nanoparticles containing emerging contaminants [37]. A recent study investigated the levels of 57 elements at five sampling sites within the vicinity of Eskisehir Hasan Polatkan Airport in Turkey, based on moss bag biomonitoring using Sphagnum sp. in combination with chemical analyses of lubrication oil and aviation gasoline fuel used by general aviation, piston-engine, and turboprop aircraft. Moss bag biomonitoring was a useful tool in identification of the elements that accumulated downwind of the airport emissions. Characterization of the metal contents in moss bags and oil and fuel were in agreement, showing that Pb, along with Cd, Cu, Mo, Cr, Ni, Fe, Si, Zn, Na, P, Ca, Mg, and Al were dominating elements in the general aviation aircraft emissions [51].
Carcinogenic substances are evaluated and listed by the International Agency of Research in Cancer (IARC) under WHO according to accumulated scientific findings in cellular, animal and human studies. Group 1 entails substances with sufficient evidence of carcinogenicity in humans and group 2 includes substances that IARC has classified as probably (2A) or possibly (2B) carcinogenic to humans [82]. As almost all current aviation fuel/jet fuels are extracted from the middle distillates of crude oil (kerosene fraction), which is between the fractions for gasoline and diesel [5] (whose combustion emissions are classified as group 2B and group 1 carcinogens, respectively [69]), there is cause for concern in terms of the potential carcinogenicity of exposure to jet fuel combustion products.
Although a range of kerosene-based aircraft fuel types are in use, they are overall similar in chemical composition [24, 29]. Kerosene lies between the distillated crude oil fractions of gasoline (gasoline combustion exhaust, IARC group 2b) and diesel (diesel combustion exhaust, IARC group 1) and the carcinogenic potential of jet fuel combustion products could be anticipated given the reported similarities to diesel exhaust particles. We highlight two important reported characteristics of airport particles:
The energy required to run any conventional powerplant generally comes from converting the calorific value of a fossil-based fuel into a propulsive force. Petrol, diesel, compressed natural gas, and high-grade kerosene are fundamental fossil-based fuels, being extensively used in automobiles, trains, ships, and aircraft powerplants (Abas et al. 2015; Martins et al. 2019). As per the monthly oil market report (MOMR) of April 2021, published by the Organization of the Petroleum Exporting Countries (OPEC), the global oil demand in 2021 is expected to rise to an average of 96.5 million barrels per day (mb/d) in contrast to an average of 90.5 mb/d in 2020. One key factor in this projected upsurge in the global oil demand is the unavoidable industrial and anthropogenic rebound of the globally imposed COVID-19 lockdown measures in the year 2020. The report concluded that the average global consumption of gasoline and diesel over the first quarter of the year 2021 was around 24.0 and 26.3 mb/d, which is forecasted to increase to 25.6 mb/d and 26.6 mb/d in the 2nd quarter of the year 2021, respectively. Researchers have predicted that by the year 2030, world oil consumption will increase to 118 mb/d and, given this rate, the global crude oil reserves will deplete by the year 2060 (OPEC 2021).
Categories of biofuels. The first-generation biofuels pose a threat to food availability due to their edible feedstocks, while the production of second- and third-generation biofuels is more preferred due to their inedible feedstocks
The inherent requirements of farming land, irrigation, and fertilizers impose certain constraints on harvesting large quantities of feedstocks to produce first- or second-generation biofuels. These problems are mitigated by third-generation biofuels that rely on algal species, providing unmatched amount and diversity to produce biofuels (Patle et al. 2021). It is acknowledged that algae can thrive even under adverse growth conditions and provide various products (Rashid et al. 2014; Mofijur et al. 2019). Figure 3 represents the different products derived from first-, second-, and third-generation feedstocks (Rashid et al. 2014; Bhuiya et al. 2016; Saladini et al. 2016; Bhatia et al. 2017; Mofijur et al. 2019).
Various biofuel derivatives from different feedstocks. More number of biofuel variants can be obtained from third-generation feedstocks. The simplicity of harvesting algae and extracting algal oils makes biofuels of the third generation compared to the two former generations
When pure Ni0.5Zn0.5Fe2O4 and Ni0.5Zn0.5Fe2O4 nanoferrites doped with 0.4 mol of Cu2+ ions are used for methyl transesterification of soybean oil, a conversion rate of around 13% and 50% can be obtained, respectively. The particle size of 23 nm and 62 nm for Ni0.5Zn0.5Fe2O4 and Cu0.4Ni0.1Zn0.5Fe2O4 nanoferrite particles can deliver a surface area of 48.89 m2/g and 18.06 m2/g, respectively. The inclusion of Cu2+ ions in the composition increases biodiesel production by 26% due to its higher catalytic activity. The reaction duration also decreases, along with increased stability and combustion flame temperature because of Cu2+ ions in the catalyst composition (Dantas et al. 2014). The transesterification of soybean oil using methanol and Ni0.5Zn0.5Fe2O4 nanoferrite catalysts doped with Cu2+ ions in the range of 01 and 0.4 mol. The reaction can be carried out with 4% catalyst loading by weight with an alcohol/oil molar ratio of 20:1, at 160 C for 2 h. The addition of 0.4 mol of Cu2+ ions in the catalyst composition delivers a conversion rate of around 50.25%. This conversion rate can be credited to the higher surface area of 23.49 m2/g and a particle size of 47.64 nm (Dantas et al. 2013). 2ff7e9595c
Comments