Fossil Fuel Combustion Products Research Articles

Plasma and Superconductivity for the Sustainable Development of Energy and the Environment

The main aim of this review is to present the current state of the research and applications of superconductivity and plasma technologies in the field of energy and environmental protection. An additional goal is to attract the attention of specialists, university students and readers interested in the state of energy and the natural environment and in how to protect them and ensure their sustainable development. Modern energy systems and the natural environment do not develop in a sustainable manner, thus providing future generations with access to energy that is generated from renewable sources and that does not degrade the natural environment. Most of the energy technologies used today are based on non-renewable sources. Power contained in fuel is irretrievably lost, and the quality of the energy is lowered. It is accompanied by the emissions of fossil fuel combustion products into the atmosphere, which pollutes the natural environment. Environmental problems, such as the production of gaseous and solid pollutants and their emission into the atmosphere, climate change, ozone depletion and acid rains, are discussed. For the problem of air pollution, the effects of combustion products in the form of carbon oxides, sulfur and nitrogen compounds are analyzed. The plasma and superconductivity phenomena, as well as their most important parameters, properties and classifications, are reviewed. In the case of atmospheric pressure plasma generation, basic information about technological gas composition, pressure, discharge type, electromagnetic field specification, electrode geometry, voltage supply systems, etc., are presented. For the phenomenon of superconductivity, attention is mainly paid to the interdependencies between Tc, magnetic flux density Bc and current density Jc parameters. Plasma technologies and superconductivity can offer innovative and energy-saving solutions for power engineering and environmental problems through decreasing the effects of energy production, conversion and distribution for the environment and by reductions in power losses and counteracting energy quality degradation. This paper presents an overview of the application of technologies using plasma and superconductivity phenomena in power engineering and in environmental protection processes. This review of plasma technologies, related to reductions in greenhouse gas emissions and the transformation and valorization of industrial waste for applications in energy and environmental engineering, is carried out. In particular, the most plasma-based approaches for carbon oxides, sulfur and nitrogen compounds removal are discussed. The most common plasma reactors used in fuel reforming technologies, such as dielectric barrier discharge, microwave discharge and gliding-arc discharge, are described. The advantages of solid waste treatment using plasma arc techniques are introduced. Applications of superconductors for energy generation, conversion and transmission can be divided into two main groups with respect to the conducted current (DC and AC) and into three groups with respect to the employed property (zero resistivity, ideal magnetism/flux trapping and quench transition). Among the superconductivity applications of electrical machines, devices for improving energy quality and storage and high field generation are described. An example that combines the phenomena of hot plasma and superconductivity is thermonuclear fusion. It is a hope for solving the world’s energy problems and for creating a virtually inexhaustible, sustainable and waste-free source of energy for many future generations.

Primary- and secondary-sphere effects of amine substituent position on rhenium bipyridine electrocatalysts for CO2 reduction

It is well-established that electrocatalysts with biologically inspired moieties provide advantageous qualities for the efficient transformation of fossil fuel combustion products, such as carbon dioxide, into value-added products. Herein, we present a family of Re(bpy)(CO)3Cl electrocatalysts with pendant NH2 groups in the 4,4′-, 5,5′-, and 6,6′-positions of the bipyridine backbone with the objective of determining the effects of combined primary- and secondary-sphere interactions on the reduction of CO2 to CO. Cyclic voltammetry studies under CO2 indicate that the catalytic onset potential is more positive for 6,6′-NH2-Re, indicating that proximity of the available pendant protons to the metal center is beneficial during catalysis. Controlled potential electrolysis studies demonstrate that, similar to 6,6′-NH2-Re, 4,4′-NH2-Re displays a dependence of Faradaic efficiency (FE) on catalytic potential, reaching a maximum FECO of 91% at −2.40 V. This FE is greater than that observed for 6,6′-NH2-Re but occurs at a more negative potential. Density functional theory (DFT) calculations were performed to compare the HOMO-LUMO gap of these complexes, and the following trend of 4,4′-NH2-Re > 6,6′-NH2-Re > 5,5′-NH2-Re was determined. Mulliken electron population analysis indicates a greater degree of electron density on the metal center for 6,6′-NH2-Re compared to its related congeners, in agreement with the electrolysis studies which illustrate a more favorable CO2 reduction for 6,6′-NH2-Re. Ultimately, it is important that the various catalytic parameters are properly balanced to provide the greatest overall catalytic activity.

Influence of Intermolecular Hydrogen Bonding Interactions on the Electrocatalytic Reduction of CO2 to CO by 6,6′‐Amine Substituted Rhenium Bipyridine Complexes

AbstractThe introduction of biologically inspired motifs into electrocatalysts is an attractive strategy for efficiently transforming harmful fossil fuel combustion products such as carbon dioxide into useful chemical fuels. Herein, we present a series of Re(bpy)(CO)3Cl electrocatalysts with pendant primary, secondary, and tertiary amines with the aim of determining the effect of available pendant protons on the reduction of CO2 to CO. Cyclic voltammetry studies indicate that the availability of pendant protons leads to intermolecular hydrogen bonding interactions, altering the electrochemical behavior of the complexes. Further, controlled potential electrolysis studies show a clear trend in the catalytic activity of these complexes based on the availability of pendant protons. For the NMe2‐substituted complex with no pendant protons, the Faradaic efficiency (FE) remains quite stable with changing potential (41–65 % FECO), but for the NH2‐substituted complex with maximum available pendant protons, the FECO increases with more negative potentials, peaking at 83 % FECO. Together with the formation of H2 by the NH2‐substituted Re(bpy)(CO)3Cl complex, this suggests a change in electrocatalytic behavior due to the intermolecular hydrogen bonding interactions that occur with additional pendant protons.

Greenhouse gas sources and mitigation strategies from a geosciences perspective

Certain gases that are capable of trapping heat in the Earth’s atmosphere are known as “greenhouse gas” and are important for helping to regulate temperature. Major greenhouse gases include carbon dioxide, methane, water vapor, chlorofluorocarbons, and nitrous oxide. Burning fossil fuels produces carbon dioxide as a combustion product and atmospheric concentrations have increased dramatically over the past two centuries. The heat trapped by this additional greenhouse gas is changing climates, melting ice sheets and glaciers in polar regions, raising sea levels, and affecting ocean currents. Climate change can be mitigated by preventing the emission of additional fossil fuel combustion products to the atmosphere and reducing existing greenhouse gas levels back to pre-industrial revolution concentrations. This requires switching energy production to sustainable, non-fossil sources and applying carbon capture, use, and storage technology on the fossil fuel combustion that remains. The implementation of direct air capture technology to reduce existing carbon dioxide levels in the atmosphere can further remediate climate impacts. Captured carbon dioxide can be stored in plant tissues, soils, deep underground in geological repositories, or as solid materials like concrete or carbonates to keep it from reentering the atmosphere. Although non-carbon energy sources have recently become more cost-competitive with fossil energy, technological advancements and government policies are still needed to overcome the inherent economic advantages of fossil fuels. A global strategy must be developed to convince people that the higher cost of clean, sustainable energy is a price worth paying to replace fossil fuels and prevent a major environmental calamity. Cited as: Soeder, D. J. Greenhouse gas sources and mitigation strategies from a geosciences perspective. Advances in Geo-Energy Research, 2021, 5(3): 274-285, doi: 10.46690/ager.2021.03.04

Air Pollution, Oxidative Stress, and Diabetes: a Life Course Epidemiologic Perspective.

Ambient air pollution is strongly linked to cardiovascular and respiratory diseases. We summarize available published evidence regarding similar associations with diabetes across the life course. We performed a life-course survey of the recent literature, including prenatal, gestational, childhood/adolescence, and adult exposures to air pollution. Oxidative stress is identified as a key factor in both metabolic dysfunction and the effects of air pollution exposure, especially from fossil fuel combustion products, providing a plausible mechanism for air pollution-diabetes associations. The global burden of diabetes attributed to air pollution exposure is substantial, with a recent estimate that ambient fine particulate matter (PM2.5) exposure contributes to more than 200,000 deaths from diabetes annually. There is a growing body of literature linking air pollution exposure during childhood and adulthood with diabetes etiology and related cardiometabolic biomarkers. A small number of studies found that exposure to air pollution during pregnancy is associated with elevated gestational diabetes risk among mothers. Studies examining prenatal air pollution exposure and diabetes risk among the offspring, as well as potential transgenerational effects of air pollution exposure, are very limited thus far. This review provides insight into how air pollutants affect diabetes and other metabolic dysfunction-related diseases across the different life stages.

Ozone effects on plants in natural ecosystems.

Tropospheric ozone (O3 ) is an important stressor in natural ecosystems, with well-documented impacts on soils, biota and ecological processes. The effects of O3 on individual plants and processes scale up through the ecosystem through effects on carbon, nutrient and hydrologic dynamics. Ozone effects on individual species and their associated microflora and fauna cascade through the ecosystem to the landscape level. Systematic injury surveys demonstrate that foliar injury occurs on sensitive species throughout the globe. However, deleterious impacts on plant carbon, water and nutrient balance can also occur without visible injury. Because sensitivity to O3 may follow coarse physiognomic plant classes (in general, herbaceous crops are more sensitive than deciduous woody plants, grasses and conifers), the task still remains to use stomatal O3 uptake to assess class and species' sensitivity. Investigations of the radial growth of mature trees, in combination with data from many controlled studies with seedlings, suggest that ambient O3 reduces growth of mature trees in some locations. Models based on tree physiology and forest stand dynamics suggest that modest effects of O3 on growth may accumulate over time, other stresses (prolonged drought, excess nitrogen deposition) may exacerbate the direct effects of O3 on tree growth, and competitive interactions among species may be altered. Ozone exposure over decades may be altering the species composition of forests currently, and as fossil fuel combustion products generate more O3 than deteriorates in the atmosphere, into the future as well.

Pollution Characteristics and Health Risk Assessment of Polycyclic Aromatic Hydrocarbons in the Surface Soils of a Large Steel enterprise in the North of China

16 priority control polycyclic aromatic hydrocarbons (PAHs) were analyzed by GC-MS in 22 surface soil (0-20 cm) samples collected from a large steel enterprise in the north of China. The concentrations of Σ16PAHs ranged from 22.0 μg·kg-1 to 20062.0 μg·kg-1. 4 to 5 aromatic rings were the dominant, typically fluorene(Flu) and pyrene(Pyr). Compared with related domestic research, PAH pollution in the steel enterprise reached medium level, with fifty percent of the soil points were at moderate and severe pollution levels, mainly in the coking and pellet plant area. The concentrations of 10 PAHs in 20 soil samples exceeded the Dutch target reference values. Compared with soil screening value of Beijing contaminated industrial sites, only part of the sample points exceeded the standard, typically benzo[a]anthracene(BaA) and benzo[a]pyrene(BaP). The source apportionment showed that soil PAHs mainly originated from combustion products of coal and other fossil fuels with only a small portion contributed by oil combustion and spill. The health risk assessment showed that the carcinogenic risks of benzo[a]pyrene(BaP), benzo[a]anthracene(BaA), dibenz(a,h)anthracene(DBA), benzo[b]fluoranthene(BbF), indeno[1,2,3-cd]pyrene(InP) exceeded the threshold of 1×10-6 under residential land condition, the carcinogenic risks of benzo[a]pyrene(BaP), benzo[a]anthracene(BaA), dibenz(a,h)anthracene(DBA) also exceeded the threshold of 1×10-6 under industrial land condition. The carcinogenic risk value of benzo[a]pyrene(BaP) was the biggest among the 16 PAHs. The soil PAHs in the steel enterprise already caused harm to human health and the soil restoration project must be carried out.

Black carbon concentration and isotopic composition of surface sand from deserts and dune fields in Northern China

Black carbon (BC) is a continuum of incomplete combustion products of vegetation and fossil fuels. It can be used as a proxy for wildfires and paleovegetation reconstruction. Nevertheless, BC can be transported by wind and water via atmospheric and fluvial transport. To research the characteristics of BC in deserts and dune fields that are directly connected with the Chinese Loess Plateau (CLP) in Northern China, and to evaluate the possibility that BC in deserts and dune fields occurs as exogenous BC in the CLP, we investigated surface sand from the Mu Us dune field, the Tengger Desert, and the Badain Jaran Desert, and analyzed the stable carbon concentration and carbon isotopes of organic carbon (SOC%, δ13CSOC) and BC (BC%, δ13CBC). The δ13CSOC, δ13CBC values ranged from −27.4‰ to −22.5‰, and −28.2‰ to −23.0‰, respectively, which mainly reflected δ13C changes in surface C3 grasses. A positive correlation was observed between δ13CBC and δ13CSOC, suggesting that local vegetation mainly controls δ13CBC. The difference between δ13CBC and δ13CSOC ranged from −0.2‰ to +3.5‰, and the difference is likely to be due to carbon isotope discrimination occurring during burning and SOC decomposition. The SOC% and BC% in these deserts and dune fields are very small (averaging 0.048% and 0.011%). The BC% of surface sand in these areas is about 5.5% of BC% in the CLP surface soils, and the Δ-δ13СBC value between surface sand in deserts and surface soils in CLP ranged from −0.3‰ to −6.3‰, so the change of δ13СBC in the CLP surface soils, deduced by exogenous BC from deserts, is less than 0.35‰. All these findings suggest that BC in deserts has a limited impact on BC in the CLP and is unlikely to affect interpretations of the BC record of wildfires and paleovegetation information in the CLP.

Diurnal variations of carbonaceous components, major ions, and stable carbon and nitrogen isotope ratios in suburban aerosols from northern vicinity of Beijing

Abstract We report diurnal variations of organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC) and major ions as well as stable carbon and nitrogen isotope ratios (δ 13 C and δ 15 N) in ambient aerosols at a suburban site (Mangshan), 40 km north of Beijing, China. We found that aerosol chemical compositions were largely controlled by the air mass transport from Beijing in daytime with southerly winds and by relatively fresh air mass in nighttime from the northern forest areas with northerly winds. Higher concentrations of aerosol mass and total carbon were obtained in daytime. Further, higher OC/EC ratios were recorded in daytime (4.0 ± 1.7) than nighttime (3.2 ± 0.7), suggesting that OC is formed by photochemical oxidation of gaseous precursors in daytime. Contributions of WSOC to OC were slightly higher in daytime (38%) than nighttime (34%), possibly due to secondary formation of WSOC in daytime. We also found higher concentrations of Ca 2+ in daytime, which was originated from the construction dust in Beijing area and transported to the sampling site. δ 13 C ranged from −25.3 to −21.2‰ (ave. −23.5 ± 0.9‰) in daytime and −29.0 to −21.4‰ (−24.0 ± 1.5‰) in nighttime, suggesting that Mangshan aerosols were more influenced by fossil fuel combustion products in daytime and by terrestrial C 3 plants in nighttime. This study suggests that daytime air mass delivery from megacity Beijing largely influence the air quality at the receptor site in the north together with photochemical processing of organic aerosols during the atmospheric transport, whereas the Mangshan site is covered with relatively clean air masses at night.

Spatial Variation in the Origin of Dissolved Organic Carbon in Snow on the Juneau Icefield, Southeast Alaska.

Dissolved organic carbon (DOC) plays a fundamental role in the biogeochemistry of glacier ecosystems. However, the specific sources of glacier DOC remain unresolved. To assess the origin and nature of glacier DOC, we collected snow from 10 locations along a transect across the Juneau Icefield, Alaska extending from the coast toward the interior. The Δ(14)C-DOC of snow varied from -743 to -420‰ showing progressive depletion across the Icefield as δ(18)O of water became more depleted (R(2) = 0.56). Older DOC corresponded to lower DOC concentrations in snow (R(2) = 0.31) and a decrease in percent humic-like fluorescence (R(2) = 0.36), indicating an overall decrease in modern DOC across the Icefield. Carbon isotopic signatures ((13)C and (14)C) combined with a three-source mixing model showed that DOC deposited in snow across the Icefield reflects fossil fuel combustion products (43-73%) and to a lesser extent marine (21-41%) and terrestrial sources (1-26%). Our finding that combustion aerosols are a large source of DOC to the glacier ecosystem during the early spring (April-May) together with the pronounced rates of glacier melting in the region suggests that the delivery of relic DOC to the ocean may be increasing and consequently impacting the biogeochemistry of glacial and proglacial ecosystems in unanticipated ways.

A survey of liquid chromatographic-mass spectrometric analysis of mercapturic acid biomarkers in occupational and environmental exposure monitoring.

High-performance liquid chromatography/mass spectrometry (HPLC/MS) is sensitive and specific for targeted quantitative analysis and is readily utilized for small molecules from biological matrices. This brief review describes recent selected HPLC/MS methods for the determination of urinary mercapturic acids (mercapturates) which are useful as biomarkers in characterizing human exposure to electrophilic industrial chemicals in occupational and environmental studies. Electrophilic compounds owing to their reactivity are used in chemical and industrial processes. They are present in industrial emissions, are combustion products of fossil fuels, and are components in tobacco smoke. Their presence in both the industrial and general environments are of concern for human and environmental health. Urinary mercapturates which are the products of metabolic detoxification of reactive chemicals provide a non-invasive tool to investigate human exposure to electrophilic toxicants. Selected recent mercapturate quantification methods are summarized and specific cases are presented. The biological formation of mercapturates is introduced and their use as biomarkers of metabolic processing of electrophilic compounds is discussed. Also, the use of liquid chromatography/tandem mass spectrometry in simultaneous determinations of the mercapturates of multiple parent compounds in a single determination is considered, as well as future trends and limitations in this area of research.

Comparing the heat of combustion of fossil fuels to the heat accumulated by their lifecycle greenhouse gases

We compare the heat released directly due to combustion of fossil fuels to the heat accumulated indirectly in the earth system due to the effect of greenhouse gases (GHGs) associated with the fuels. We differentiate between GHG emissions from the combustion products of fossil fuels and from the fuel cycle activities of extracting, processing, and transporting the fuels. We find that the direct release of heat from the combustion of fossil fuels is minor in relation to the indirect accumulation of heat due to radiative forcing. The quantity of indirect heat accumulated by GHGs continues to increase over time, as additional energy is accumulated in the earth system as long as the GHGs remain in the atmosphere. Fuel cycle emissions contribute significantly to total lifecycle GHG emissions and radiative forcing.

The evaporite–coal transition: Chemical, mineralogical and organic composition of the Late Triassic Abu Ruweis Formation, NW Jordan—Reference type of the “Arabian Keuper”

The Abu Ruweis Formation, NW Jordan, was studied with regard to its chemical (major, minor elements, REE, S-, O-, C isotopes, organic chemistry), mineralogical compositions (rock-forming minerals), coal petrography (maceral analyses) and palynology (age determination and palaecosystem) for the evaporite–coal facies transition which is very rarely found. The palynomorphs point to a Late Triassic/Carnian age of formation. Strong evaporation in the series is demonstrated by the presence of dolomite, gypsum and celestite. Mg, Ca, F, Cl, S, Sr and Ba reflect the variation of evaporation during basin subsidence. A detrital influx is characterized by the abundance of Si, Ti, Al, Fe, Mn Ce, Co, Cr, V, Y and the (Zr+Rb)/Sr ratio. Salinity variation may be characterized by the fractionation of LREE (La) and HREE (Lu). The element triplet Zn, Cu and Pb offers a clue to the redox regime and supports the idea of mineralogical-based proximity indicators: Zn (Eh≪0)⇒Cu (Eh≤0)⇒Pb (Eh≤0). Oxygen isotope composition (δ18O −8.3 to −0.9‰) of the carbonate fraction resulted in uniform isotope formation temperatures near 50°C. Temperature data obtained during coal petrography yielded maximum paleotemperatures of 100°C for the black shale and about 70°C for the remaining coal samples that are likely to reflect hot brine activity in some parts of the basin. The carbon isotopic composition (δ13C −12.4 to −3.9‰) of the carbonate fractions indicates a biogenic 12C-enriched CO2 source, which probably was admixed to marine pore water bicarbonate (with δ13C near 0‰) during early diagenesis. The S isotope composition (sulfide fraction −28.9 to −24.0‰) is typical of sulfides formed in the course of bacterial reduction with some sulfate (sulfate fraction +7.5 to +11.6‰) resulted from later re-oxidation of the sulfides. Phosphate distribution is a measure for the aridity while high-sulfur contents in the coal-bearing sediments point to brackish or alkaline waters. The results of the organic chemistry are interpreted in terms of a bloom of algae which were preserved during dysaerobic conditions in the course of early diagenesis. Sesqui- and diterpenoids are most probably derived from precursor molecules abundant in leaf resins of conifers. Phenanthrene and its methylated analogues derived from combustion products of fossil fuels generated by wild fires. Among the maceral types, textinites A and B represent xylem features of tree trunks and the crassi-cutinite upper leaf cuticles. The data allow for a definition of a special geological setting called the “Arabian Keuper Facies”. This facies type is characterized by an evaporite–coal transition which translates into a geodynamic setting positioned between the fully marine “Alpine Triassic Facies” of the Tethyan Ocean where submarine brines were responsible for the Alpine-type MVT Pb–Zn deposits and the epicontinental “Germanic Keuper Facies” that lacks both hydrothermal activity and major marine incursions.

Cover Picture: Mol. Nutr. Food Res. 9'2011

AbstractThis special issue of Molecular Nutrition & Food Research is dedicated to acrolein (2‐propenal), a constituent of many foods that has poorly understood long‐term effects on human health. Acrolein is primarily formed from carbohydrates, lipids and certain amino acids in foods by heat treatment. Besides intake of acrolein via the diet, humans are exposed to acrolein through inhalation of vapors emitted from heated cooking oils, cigarette smoke, and inhalation of combustion products of fossil fuels. Finally, acrolein is formed endogenously as a product of polyamine metabolism and oxidative stressThese and other aspects are covered in this special issue by nine reviews and three research articles.

Acrolein

This special issue of Molecular Nutrition and Food Research is dedicated to acrolein (2-propenal), a constituent of many foods that has poorly understood long-term effects on human health. It is therefore not a surprise that the number of publications on acrolein has steadily increased from 61 publications per year in 2000 to 197 in 2010 (source: http://gopubmed.org/). Acrolein is primarily formed from carbohydrates, lipids and certain amino acids in foods by heat treatment. Besides intake of acrolein via the diet, humans are exposed to acrolein through inhalation of vapors emitted from heated cooking oils, cigarette smoke and inhalation of combustion products of fossil fuels. Finally, acrolein is formed endogenously as a product of polyamine metabolism and oxidative stress. The adverse effects of acrolein on human health originate from its capability to form Michael-type adducts with cysteine, lysine and histidine residues in proteins and with amine groups in DNA bases. These and other aspects are covered in this special issue by nine reviews and three research articles. Abraham et al. (this issue) provide an overview of the metabolism of acrolein, its toxicity and carcinogenicity and its occurrence in various foods and beverages. They conclude that exposure to acrolein via the diet probably does not pose immediate health risks, but, at the same time, point out that a risk assessment is difficult to make due to technical difficulties with measuring acrolein levels in foods. An accurate risk assessment is further complicated by lack of knowledge regarding the immediate and especially the long-term consequences of acrolein's ability to interfere with many metabolic pathways and (redox-sensitive) signaling networks. The contributions by Bein and Leikauf, Conklin et al., Fabisiak et al. and by Myers et al. provide a wealth of new information with respect to the effects of acrolein on gene regulation. Other contributions emphasize the chemical diversity of the cellular damage exerted by acrolein and the molecular consequences of acrolein exposure in cultured cells, laboratory animals and humans. Knowing how and to what extent acrolein modifies DNA and proteins is necessary for elucidating the mechanisms by which acrolein causes cellular dysfunction. The mechanisms of acrolein-related toxicity that affect the nervous system (spinal cord trauma), the brain and the lung are discussed in this issue by experts in the field. Also discussed are strategies aimed at mitigating the deleterious effects of acrolein by using acrolein scavengers such as flavonoids and other (dietary) phytochemicals, vitamins, neutraceuticals and pharmaceuticals. Progress in understanding acrolein's impact on health would not have been possible without the advent of new analytical technologies. Recent analytical breakthroughs include the development of acrolein-specific immunochemical techniques and microarray technologies for assessing acrolein toxicity. Substantial progress has been achieved in assessing acrolein exposure at the molecular level in vivo. Modern mass spectrometry-based techniques enable the analysis of acrolein-mediated DNA damage (reviewed by Chen in this issue) and the analysis of acrolein adducts in mitochondrial proteomes (Wu et al.). This special issue on acrolein offers an overview of the astounding progress that has been made in unraveling the multifaceted effects of acrolein on biological systems and human health. Despite the advances made in understanding the biological consequences of acute acrolein exposure, many questions remain unanswered regarding the health impact of chronic acrolein exposure via the diet and the environment. We agree with the contributors of this issue that further progress in this area requires the development of methods for reliable quantification of acrolein in foods and beverages as well as methods for probing the interaction of acrolein with its biological environment. We are grateful to the Editor-in-Chief for providing us the opportunity to invite distinguished authors to contribute to this issue, to the reviewers for their invaluable comments and to the Editorial Office for tireless support in smoothing the path towards completion of this special issue. Jan Frederik Stevens Oregon State University Claudia S. Maier Oregon State University

Analysis of emission data from global commercial aviation: 2004 and 2006

Abstract. The global commercial aircraft fleet in 2006 flew 31.26 million flights, burned 188.20 million metric tons of fuel, and covered 38.68 billion kilometers. This activity emitted substantial amounts of fossil-fuel combustion products within the upper troposphere and lower stratosphere that affect atmospheric composition and climate. The emissions products, such as carbon monoxide, carbon dioxide, oxides of nitrogen, sulfur compounds, and particulate matter, are not emitted uniformly over the Earth, so understanding the temporal and spatial distributions is important for modeling aviation's climate impacts. Global commercial aircraft emission data for 2004 and 2006, provided by the Volpe National Transportation Systems Center, were computed using the Federal Aviation Administration's Aviation Environmental Design Tool (AEDT). Continuous improvement in methodologies, including changes in AEDT's horizontal track methodologies, and an increase in availability of data make some differences between the 2004 and 2006 inventories incomparable. Furthermore, the 2004 inventory contained a significant over-count due to an imperfect data merge and daylight savings error. As a result, the 2006 emissions inventory is considered more representative of actual flight activity. Here, we analyze both 2004 and 2006 emissions, focusing on the latter, and provide corrected totals for 2004. Analysis of 2006 flight data shows that 92.5% of fuel was burned in the Northern Hemisphere, 69.0% between 30N and 60N latitudes, and 74.6% was burned above 7 km. This activity led to 162.25 Tg of carbon from CO2 emitted globally in 2006, more than half over three regions: the United States (25.5%), Europe (14.6), and East Asia (11.1). Despite receiving less than one percent of global emissions, the Arctic receives a uniformly dispersed concentration of emissions with 95.2% released at altitude where they have longer residence time than surface emissions. Finally, 85.2% of all flights by number in 2006 were short-haul missions, yet those flights were responsible for only 39.7% of total carbon from CO2. The following is a summary of these data which illustrates the global and regional aviation emissions footprints for 2004 and 2006, and provides temporal and spatial distribution statistics.

Organic Molecular Compositions and Size Distributions of Chinese Summer and Autumn Aerosols from Nanjing: Characteristic Haze Event Caused by Wheat Straw Burning

Size-segregated aerosol samples were collected in urban Nanjing, China during summer and autumn of 2007 including a period of hazy days during June 1-5. Organic aerosols in the haze event were characterized by elevated concentrations of levoglucosan, high molecular weight (HMW) n-alkanes, and HMW fatty acids due to the emissions from field burning of wheat straw. In contrast, organic aerosols on nonhazy days were characterized by a predominance of fossil fuel combustion products. Levoglucosan (4030 n g m(-3)), n-alkanes (1520 ng m(-3)), fatty acids (2629 ng m(-3)), and PAHs (57 ng m(-3)) in the haze samples were 3-40 times more abundant than those in nonevent samples. Approximately 30-90% ofthe organics during the haze period can be attributed to wheat straw burning. Concentrations of particulate material (PM) mass, n-alkanes, and low molecular weight (LMW) PAHs showed a unimodal size distribution, peaking at 0.7-1.1 microm during the hazy days, and a bimodal distribution, peaking at 0.7-1.1 microm and 4.7-5.8 microm during nonhazy days. The geometric mean diameters (GMDs) of organic aerosols are larger in the fine mode (<2.1 microm) during the hazy days, suggesting aerosols emitted from the wheat straw burning are larger than those from fossil fuel combustion, and fine particle coagulation and organic compound repartitioning were enhanced.

Photochemical and Other Sources of Organic Compounds in the Canadian High Arctic Aerosol Pollution during Winter−Spring

Total suspended particles collected at Alert in the Canadian high Arctic (February-June) were analyzed for solvent extractable organic compounds using gas chromatography-mass spectrometry to better understand the sources and source apportionment of aerosol pollution that can affect the Arctic climate. More than 100 organic species were detected in the aerosols and were grouped into different compound classes based on the functional groups. Polyacids were found to be the most abundant compound class, followed by phthalates, aromatic acids, fatty acids, fatty alcohols, sugars/sugar alcohols, and n-alkanes, while polycyclic aromatic hydrocarbons, sterols, and lignin and resin acids were minor. Concentrations of total quantified organics seemed slightly higher in darkwinter aerosols (13.2-16.6 ng m(-3), average 14.5 ng m(-3)) than those after polar sunrise (6.70-17.7 ng m(-3), average 11.8 ng m(-3)). During dark winter, fossil fuel combustion products (30-51%), secondary oxidation products, as well as higher plant emissions were found as major contributors to the Arctic aerosols. However, after polar sunrise on 5 March, secondary oxidation products (5-53%) and plasticizer-derived phthalates became the dominant compound classes, followed by fossil fuel combustion and microbial/marine sources. Biomass burning emissions were found to contribute only 0.4-6% of the total identified organics, although they maximized in dark winter. This study demonstrates that long-range atmospheric transport, changes in the solar irradiance, and ambient temperature can significantly control the chemical composition of organic aerosols in the Arctic region.

Structure of chemical elements deposited with atmospheric precipitation in the north of the European territory of Russia derived with multivariate analysis methods

Data on deposition density of Ag, Al, As, B, Ba, Bi, Br, Ca, Cd, Co, Cr, Cs, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, S, Sb, Si, Sn, Sr, Th, Tl, U, V, Zn, Cl−, NO 3 − , and SO4 4 2− in atmospheric precipitation were derived at 11 observation stations in the northern part of the European territory of Russia (ETR). Three sets (factors) of chemical indices that are mutually independent and determine the precipitation chemical content over that territory were revealed by using the hierarchical factor analysis of deposited density of chemical ingredients studied. These are two first-order factors: one is presented with the elements of a “marine” origin; the second is associated with biogenic elements. The second-order factor is formed by the ingredients characteristic of the combustion products of different fossil fuels. The structure and space-time distribution of factors are considered. The discriminant and cluster analyses allowed to classify the observation stations considered by the atmospheric precipitation chemistry and to show that Amderma, Vorkuta, Arkhangelsk, and Kargopol stations mostly differ from each other.

Comparison of polycyclic aromatic hydrocarbon levels in placental tissues of Indian women with full- and preterm deliveries

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants formed from combustion products of fossil fuels, cigarette smoking and in grilled/smoked foods. They are reported to alter trophoblast proliferation in placenta, in addition to disturbing its endocrine functions, which may be able to increase the risk of preterm delivery in pregnant women. The present study was planned to assess possible involvement of PAHs exposure of pregnant women (measured as placental PAHs concentrations) with preterm delivery cases among women of Lucknow city (India). We performed a case-control study and a total of 60 mothers (n=31 full term and n=29 preterm deliveries) were recruited at a local nursing home of Lucknow, for the period of August 2005-February 2006. Subsequent to parturition, placental tissues from each participant were immediately collected and kept at -20 degrees C until PAHs analyses. Placental tissue PAHs concentrations were determined by HPLC, using a fluorescence detector. Mean+/-SD placental level (61.91+/-12.43ppb) of benzo(b)fluoranthene, a carcinogenic PAH, was found significantly elevated (p<0.05) among women with preterm delivery when compared with the level (23.84+/-7.01) in women having full-term deliveries. In the same way, non-carcinogenic fluoranthene level (325.91+/-45.14ppb) was also detected to be higher in the preterm delivery group compared to 208.6+/-21.93ppb level from the full-term delivery group of women. Additionally naphthalene, acenaphthylene, phenanthrene, anthracene, benzo(a)pyrene and dibenzo(a,h)anthracene levels in placental tissue were also found to be higher in the preterm delivery group of women but the difference did not reach statistically significant levels. This foremost study from India with modest samples size and limited statistical power does not show a substantial involvement of PAHs with preterm delivery, but higher concentrations of placental PAHs detected among preterm delivery group of women could show some possible association with these environmental toxicants. Further study with large sample size, controlled for confounders and great statistical power, is reasonable to elucidate the association of PAHs exposure with preterm delivery of women in India.