Benzene Soluble Fraction Research Articles

The Influence of Retention of Volatile Substances in Pyrolysis Zone of Kaa-Khemsky and Mezhegeisky Coal Deposits on Component Composition of Coal Tar

Pyrolysis of Kaa-Khemsky and Mezhegeisky coals was investigated with an increase in temperature to 900 °С with a change in pressure in the reactor by increasing the retention time of volatile substances in the pyrolysis zone at 600 °С and 640 °С. Liquid products of coal pyrolysis were extracted by hexane and benzene. The composition of liquid extracts was studied by chemical analysis, GC-MS and IR-spectroscopy, the solid product of extraction-by elemental analysis and scanning electron microscopy. It was established, that coal nature and pyrolysis conditions affect significantly on the yield of liquid, solid and gaseous products. Also, the retention time of volatile substances in pyrolysis zone influences on the yield of solid product (increases from 60 %wt to 73 % wt) and on composition of hexane and benzene soluble tar fractions. This is also facilitated by an increase in pressure in the reactor as a result of the release of volatile substances from coal in the pyrolysis zone

Thermodynamic study of phase transition behavior between the isotropic phase and mesophase using benzene-soluble and benzene-insoluble as phase indicators

Preparing carbonaceous mesophase pitch precursor by thermal treatment of isotropic pitch is a feasible and effective method for fabricating various high-performance carbon materials including high-modulus carbon fiber, needle coke, graphite, etc. However, the industrial production of qualified mesophase with desirable properties needs to be further improved in many regions. Especially, during pitch preparation, the transformation from isotropic phase to mesophase is difficult to be controlled since it significantly depends on reaction conditions, raw material and preparation parameters. While the optimization of the production conditions of mesophase with special properties requires time-consuming and costly exploratory experiments due to the lack of the fundamental understanding in the transformation behavior from isotropic phase to mesophase. This paper elaborates a fundamental work seeking a more suitable and accurate thermodynamic model and a parameter estimation method to describe phase transition behavior using benzene-soluble (BS) and benzene-insoluble (BI) fractions of coal tar-based pitch as indicators of isotropic phase and mesophase, respectively. The combined equation of simplified statistical associating fluid theory with anisotropic pseudopotential (SSAFT-APP) is used to describe phase transition, and the related parameters of each equation are estimated based on average molecular weight and carbon aromaticity of BS and BI fractions, respectively. The mesophase content of various samples prepared by annealing the mixtures of BS and BI fractions under different mixing ratios are used to calibrate the computed data. The results show that BS fraction has a restraining effect on the formation of mesophase when BI fraction is lower than 60 wt%, while this effect becomes weak with a higher content of BI fraction. A phase diagram is proposed by substituting the estimated parameters in SSAFT-APP equation with experimental data. Mesophase is able to be generated when the adding amount of BI fraction is increased to 12 wt%, and 100% mesophase could be obtained when the ratio of BI fraction is higher than 94 wt%. This work is expected to shed light on the phase transition behavior between isotropic phase and mesophase during pitch preparation from coal tar. In addition, based on the thermodynamic study optimizing preparation conditions and a novel method for obtaining the products with an optimal proportion between isotropic phase and mesophase is proposed.

Molluscicidal activity of cardiac glycosides isolated from Adenium obesum.

Terrestrial mollusks are one of most important agricultural pests worldwide. Natural phytochemicals have an extended history as a source of pesticides. This study was planned to isolate molluscicidal active compounds from the stems of Adenium obesum. The benzene-soluble fraction of the hydroethanolic extract displayed the most potent molluscicidal activity against Monacha obstructa among different solvent fractions with a median lethal dose (LD50 ) of 4.91 µg g-1 body weight (bw). The bioactivity-guided chemical exploration of the benzene-soluble fraction led to the isolation of two known cardiac glycosides, cerberin and neriifolin which showed significant molluscicidal activity with LD50 values of 5.39 and 4.3µg g-1 bw, respectively. Isolation of the cardiac glycoside neriifolin from A. obesum and the molluscicidal activity of cerberin and neriifolin against terrestrial snails are reported for the first time. © 2019 Society of Chemical Industry.

Transformation of Petroleum Asphaltenes in Supercritical Alcohols Studied via FTIR and NMR Techniques

The aliphatic alcohols (methanol, ethanol, and 1- and 2-propanols) were used for the first time as a reaction media for the upgrading of crude oil asphaltenes. The process was realized in a batch reactor under supercritical conditions (at 350 °C). The three main fractions of the products (hexane- and benzene-soluble fractions, HSF and BSF, and insoluble residue, IR) were analyzed using attenuated total reflection Fourier tranform infrared (ATR-FTIR) and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy to characterize structural changes of the initial asphaltenes (IA). According to NMR data, the aliphatics are the main part of the hexane-soluble fraction (HSF) and benzene-soluble fraction (BSF). The alcohols were appeared to influence the content of both aliphatics and aromatics in the products. The content of aliphatics in the HSF increases in the line from “lighter” to “heavier” alcohols used but reduces in the BSF. However, the content of aromatics in the HSF increases from “heavier” to “lighter...

Evaluation of toxic potential of particulates emitted from Jatropha biodiesel fuelled engine

This study involved a comparative experimental characterization of trace metals and relative toxicity evaluation of particulates emitted by a medium-duty transportation diesel engine using diesel and 20% (v/v) Jatropha biodiesel blend (B20). The engine was operated at 1800 rpm and particulate samples were collected on a filter paper at five loads (0%, 25%, 50%, 75% and 100% rated load) at steady state using a partial flow dilution tunnel, for both diesel and B20. Samples were then analyzed for trace metals, particulate morphology, total organic carbon and benzene soluble organic fraction (BSOF), which is a marker of toxicity. Concentrations of crust elements (Al, Ca, Fe and Mg) in the particulates were relatively higher than that of anthropogenic elements (Cd, Cr, Cu, and Zn) for both test fuels. B20 emitted relatively lower trace metal concentrations in particulates compared to baseline mineral diesel and these concentrations decreased with increasing engine load. Concentrations of gaseous emissions namely CO and THC in biodiesel exhaust were relatively lower than mineral diesel however NOx was relatively higher. Scanning electron microscopy of the particulate samples collected on the filter papers was done along with EDAX analysis for comparison.

Toxic responses of different organs following occupational exposure to sub-threshold limit value levels of paving asphalt fumes

ABSTRACTThe main purpose of this study was to ascertain whether occupational exposure to asphalt fumes, under normal working conditions, is associated with any hepatotoxic, nephrotoxic, or hematotoxic response. This was a cross-sectional study in which 210 subjects (80 exposed and 130 reference subjects) were investigated. Using standard methods, atmospheric concentrations of total particulate and benzene-soluble fractions of asphalt fumes were measured. Additionally, urine and blood samples were taken from subjects for complete blood count, white blood cell differential test, urinalysis, and routine biochemical tests of kidney and liver function. Both groups were similar as far as their demographic variables and smoking habits were concerned. The levels of exposure to total particulate and benzene-soluble fractions were estimated to be 0.9 ± 0.2 and 0.32 ± 0.09 mg m−3, respectively (mean ± SD), both of which being lower than the existing threshold limit values. Statistically, significant associations between exposure to asphalt fumes and changes in most liver and kidney function tests and complete blood count parameters provided circumstantial evidence in favor of the notion that exposure to sub-threshold limit value levels of total particulate and benzene-soluble fractions is associated with early liver and kidney dysfunction as well as hematological disorders.

Airborne Exposures to Polycyclic Aromatic Compounds Among Workers in Asphalt Roofing Manufacturing Facilities

We studied exposure of 151 workers to polycyclic aromatic compounds and asphalt emissions during the manufacturing of asphalt roofing products—including 64 workers from 10 asphalt plants producing oxidized, straight-run, cutback, and wax- or polymer-modified asphalts, and 87 workers from 11 roofing plants producing asphalt shingles and granulated roll roofing. The facilities were located throughout the United States and used asphalt from many refiners and crude oils. This article helps fill a gap in exposure data for asphalt roofing manufacturing workers by using a fluorescence technique that targets biologically active 4–6 ring polycyclic aromatic compounds and is strongly correlated with carcinogenic activity in animal studies. Worker exposures to polycyclic aromatic compounds were compared between manufacturing plants, at different temperatures and using different raw materials, and to important external benchmarks. High levels of fine limestone particulate in the plant air during roofing manufacturing increased polycyclic aromatic compound exposure, resulting in the hypothesis that the particulate brought adsorbed polycyclic aromatic compounds to the worker breathing zone. Elevated asphalt temperatures increased exposures during the pouring of asphalt. Co-exposures in these workplaces which act as confounders for both the measurement of total organic matter and fluorescence were detected and their influence discussed. Exposures to polycyclic aromatic compounds in asphalt roofing manufacturing facilities were lower than or similar to those reported in hot-mix paving application studies, and much below those reported in studies of hot application of built-up roofing asphalt. These relatively low exposures in manufacturing are primarily attributed to air emission controls in the facilities, and the relatively moderate temperatures, compared to built-up roofing, used in these facilities for oxidized asphalt. The exposure to polycyclic aromatic compounds was a very small part of the overall worker exposure to asphalt fume, on average less than 0.07% of the benzene-soluble fraction. Measurements of benzene-soluble fraction were uniformly below the American Conference of Governmental Industrial Hygienists' Threshold Limit Value for asphalt fume.

Quantification of Total Particulate Matter and Benzene-Soluble Fraction Inhalation Exposures in Roofing Workers Performing Tear-off Activities

Asphalt shingle removal (tear-off) from roofs is a major job task for an estimated 174,000 roofers in the United States. However, a literature search showed that there are no published studies that characterize worker inhalation exposures to asphalt particulates during shingle tear-off. To begin to fill this gap, the present study of inhalation exposures of roofers performing asphalt shingle tear-off was undertaken. The airborne agents of interest were total particulate matter (TP) and organic particulates measured as the benzene-soluble fraction (BSF) of total particulate. The study's objectives were to measure the personal breathing zone (PBZ) exposures of roofing tear-off workers to BSF and TP; and to assess whether these PBZ exposures are different from ambient levels.Task-based PBZ samples (typical duration 1–5 hours) were collected during asphalt shingle tear-off from roofs near Houston, Texas and Denver, Colorado. Samples were analyzed for TP and BSF using National Institute of Occupational Safety and Health (NIOSH) Method 5042. As controls, area samples (typical duration 3–6 hours) were collected on the ground near the perimeter of the tear-off project Because of the presence of significant sources of inorganic particulates in the work environment, emphasis was placed on the BSF data. No BSF exposure higher than 0.25 mg/m3 was observed, and 69% of the PBZ samples were below the limit of detection (LOD). Due to unforeseen confounding, however, statistical comparisons of on-the-roof PBZ samples with on-the-ground area samples posed some special challenges. This confounding grew out of the interaction of three factors: statistical censoring from the left; the strong inverse correlation between LOD concentration and sampling duration; and variation in sampling durations between on-the-ground area samples and on-the-roof PBZ samples.A general linear model analysis of variance (GLM-ANOVA) was applied to help address the confounding. The results of this analysis indicate that personal sample BSF results were not statistically significantly different from the background/area samples.

Respiratory symptoms and lung functional impairments associated with occupational exposure to asphalt fumes.

Background: Controversy exists as to the potential of asphalt fumes to induce respiratory symptoms and lung functional impairments. Objective: To examine the respiratory effects, if any, of occupational inhalation exposure to asphalt fumes. Methods: In this cross-sectional study, 74 asphalt workers and 110 unexposed employees were investigated. The prevalence of respiratory symptoms among subjects was investigated by a standard questionnaire. Additionally, the parameters of pulmonary function were measured both, prior to exposure and at the end of work-shift. Furthermore, to assess the extent to which workers were exposed to asphalt fumes, total particulate and the benzene-soluble fraction were measured in different worksites. Results: The mean levels of exposure to total particulate and benzene-soluble fraction in asphalt fumes were estimated to be 0.9 (SD 0.2) and 0.3 (SD 0.1) mg/m3, respectively. Mean values of FEV1, both prior to the exposure (89.58% [SD 18.69%] predicted value) and at the end of shift (85.38% [SD 19.4%]), were significantly (p<0.05) smaller than those of the comparison subjects (93.88% [SD 13.93%]). Similarly, pre-shift (87.05 [SD 8.57]) and postexposure (89.95 [SD 6.85]) FEV1/FVC ratio were both significantly (p<0.01) lower than those of the unexposed employees (107.56 [SD 9.64]). Moreover, the prevalence of respiratory symptoms such as cough and wheezing in exposed employees were 41% and 42%, respectively. The corresponding values for comparison subjects were 10.0% and 3.6%, respectively (p<0.001). The pattern of changes in parameters of lung function in asphalt workers was consistent with that of chronic obstructive lung disease. Conclusion: Significant decrements in the parameters of pulmonary function as well as, a significant increase in the prevalence of respiratory symptoms in asphalt paving workers compared to their unexposed counterparts provided evidence in favor of a significant association between exposure to asphalt fumes and lung function impairments.

Particulate Characterization and Size Distribution in the Exhaust of a Gasoline Homogeneous Charge Compression Ignition Engine

Agglomeration, coagulation, surface condensation, adsorption and oxidation processes are a part of particulate evolution process and lead to significant changes in characteristics of particulate matter (PM), when they enter the atmosphere. PM formation can be significantly reduced by advanced combustion concepts such as homogeneous charge compression ignition (HCCI). In the present study, experiments were performed in a modified gasoline fuelled HCCI engine at varying intake air temperatures (T_i), exhaust gas recirculation (EGR) rates and relative air-fuel ratios (λ). For particulate characterization, a partial flow dilution tunnel was used to collect particulate samples on a filter paper. These particulate samples were analysed for benzene soluble organic fraction (BSOF), trace metals, and particulate morphology using scanning electron microscopy (SEM). Physical characterisation of particulates was done using engine exhaust particle sizer (EEPS), which measured the particle size-number distribution. In the experiments, higher PM was found for richer fuel-air mixtures and it further increased with application of EGR. Trace metals were found to be significantly lower for HCCI generated PM, which increased with increasing EGR. BSOF was negligible as compared to total PM which showed relatively lower toxicity of gasoline HCCI particulates. Total number of particles reduced with increasing λ, however particulate size-number distribution curve shifted away from accumulation mode, indicating that the particulate size decreased with increasing λ. Higher particle size-number distribution and particle size-mass distribution were observed for increasing T_i. Particulate surface area and volume also increased with increasing T_i and mixture strength.

An evaluation of the emission profile for two-wheelers at a traffic junction

Two-wheeler vehicles are an important mode of transportation in developing countries. However, the emissions from two-wheeler vehicles are significant. Urban two-wheeler vehicles with gasoline-fueled engines produce NOx and particulate matter emissions that affect urban air quality. During traffic light stops and programmed stops, for instance, pollutants are emitted and are dangerous to human health. In this experimental study, two-wheeler vehicles with different makes, technologies and engine capacities were tested for exhaust emissions including gravimetric and online measurements at different engine speeds and a no load condition at a simulated traffic junction. Gravimetric measurements were performed by collecting the particulate mass (at two engine speeds: 1500 and 2500rpm) from a diluted engine-out exhaust on quartz filter paper. Next, these collected particulates were used to determine the presence of metals, as well as the benzene soluble organic fraction (BSOF). The total particulate mass, BSOF and trace elements were slightly higher at a higher engine speed (2500rpm). Online measurements were performed by sampling the engine exhaust (at four engine speeds: 1500, 2000, 2500, and 3000rpm) and using online instruments to determine the particle number and size distribution, the particle-bound polyaromatic hydrocarbons (PAHs), the gaseous emissions and the smoke opacity. Engines with higher cubic capacity emitted a higher concentration of nano-particles. The particle-bound PAH concentration increased as the engine speed increased, but this concentration was notably low for the highest engine speed tested (3000rpm). The regulated gaseous emissions increased as the engine speed increased for all vehicles.

Personal Breathing Zone Exposures among Hot-Mix Asphalt Paving Workers; Preliminary Analysis for Trends and Analysis of Work Practices That Resulted in the Highest Exposure Concentrations

An exposure assessment of hot-mix asphalt (HMA) paving workers was conducted to determine which of four exposure scenarios impacted worker exposure and dose. Goals of this report are to present the personal-breathing zone (PBZ) data, discuss the impact of substituting the releasing/cleaning agent, and discuss work practices that resulted in the highest exposure concentration for each analyte. One-hundred-seven PBZ samples were collected from HMA paving workers on days when diesel oil was used as a releasing/cleaning agent. An additional 36 PBZ samples were collected on days when B-100 (100% biodiesel, containing no petroleum-derived products) was used as a substitute releasing/cleaning agent. Twenty-four PBZ samples were collected from a reference group of concrete workers, who also worked in outdoor construction but had no exposure to asphalt emissions. Background and field blank samples were also collected daily. Total particulates and the benzene soluble fraction were determined gravimetrically. Total organic matter was determined using gas chromatography (GC) with flame ionization detection and provided qualitative information about other exposure sources contributing to worker exposure besides asphalt emissions. Thirty-three individual polycyclic aromatic compounds (PACs) were determined using GC with time-of-flight mass spectrometry; results were presented as either the concentration of an individual PAC or a summation of the individual PACs containing either 2- to 3-rings or 4- to 6-rings. Samples were also screened for PACs containing 4- to 6-rings using fluorescence spectroscopy. Arithmetic means, medians, and box plots of the PBZ data were used to evaluate trends in the data. Box plots illustrating the diesel oil results were more variable than the B-100. Also, the highest diesel oil results were much higher in concentration than the highest B-100 results. An analysis of the highest exposure results and field notes revealed a probable association between these exposures and the use of diesel oil, use of a diesel-powered screed, elevated HMA paving application temperatures, lubricating and working on broken-down equipment, and operation of a broom machine. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource: a file containing tables summarizing statistical data and individual analyte results.]

Characterization of exhaust particulates from diesel fueled homogenous charge compression ignition combustion engine

Engine exhaust particulates undergo different processes in the ambient environment such as agglomeration, coagulation, surface condensation, adsorption, and oxidation before evolving as mature particles. Conventional CI engines emit a significant mass/number of particulates due to heterogeneous combustion. However this problem can be resolved by using an advanced combustion technology named as Homogeneous Charge Compression Ignition (HCCI), which has potential to substantially reduce particulates and NOx simultaneously and deliver efficiencies comparable to conventional CI combustion. In the present study involving homogeneous mixture of diesel and air, an electrically heated diesel vaporizer was developed. Experiments were performed at different relative air-fuel ratios and EGR levels. Enrichment of the mixture increases the peak in-cylinder temperature, which was effectively controlled by EGR under leaner HCCI conditions. A partial flow dilution tunnel was used to collect particulate samples for trace metal content and Benzene Soluble Organic Fraction (BSOF), which is considered to be a marker of toxicity. This analysis showed that the trace metals detected were comparatively lower in HCCI particles. Trace metal concentration increased with application of EGR in the HCCI engine. BSOF content of the HCCI particulates increased when the mixture becomes leaner as well as with increasing EGR. Physical characterization of particulates was also carried out using engine exhaust particle sizer (EEPS), which measures the particle size-number distribution for the nano-particles in the exhaust. The particles collected on the filter paper were also analyzed for morphology using scanning electron microscopy (SEM).

Asphalt Fume Exposure Levels in North American Asphalt Production and Roofing Manufacturing Operations

This study extends by 8 years (1998–2005) a previous survey of asphalt fume exposures within North American asphalt processing and roofing product manufacturing workers. It focuses on characterizing personal, full-shift samples and seeks to address several limitations of the previous survey. Five major roofing manufacturers with established occupational health programs submitted workplace asphalt fume sampling results to a central repository for review and analysis. A certified industrial hygienist-led quality assurance team oversaw the data collection, consolidation, and analysis efforts. The analysis dataset consisted of 1261 personal exposure samples analyzed for total particulate (TP) and benzene soluble fraction (BSF) using existing NIOSH methods. For BSF, the survey's arithmetic (0.25 mg/m3, SD = 0.62) and geometric (0.12 mg/m3, GSD = 2.88) means indicate that the industry has sustained the control levels achieved in the late 1980s, early 1990s. Similar results were found for TP. The survey-wide summary statistics are consistent with other post-1990 multi-company exposure studies. Although these findings indicate that currently available controls are capable of achieving substantial (95%) compliance with the current threshold limit value in asphalt processing and inorganic shingle and roll plants, they also show that the majority of plants are not achieving this level of exposure control, and that exposures are significantly higher in plants making other product lines, particularly organic felt products. The current retrospective survey of existing company exposure data, like its predecessor, has several important limitations. These include lack of data on smaller manufacturers and on several commercially important product lines; insufficient information on the prevalence and effectiveness of engineering controls; no standard criteria by which to define and assess exposures in non-routine operations; and a paucity of exposure data collected as part of a random sampling strategy. To improve efforts to characterize exposures and potential health risks in roofing plants, a prospective program is currently being developed and piloted with the aim of building a more complete, higher-quality database based on a common industrial hygiene protocol.

Composition and comparative toxicity of particulate matter emitted from a diesel and biodiesel fuelled CRDI engine

Abstract There is a global concern about adverse health effects of particulate matter (PM) originating from diesel engine exhaust. In the current study, parametric investigations were carried out using a CRDI (Common Rail Direct Injection) diesel engine operated at different loads at two different engine speeds (1800 and 2400 rpm), employing diesel and 20% biodiesel blends (B20) produced from Karanja oil. A partial flow dilution tunnel was employed to collect and measure the mass of the primary particulates from diesel and biodiesel blend collected on a 47 mm quartz substrate. The collected PM (particulate matter) was subjected to chemical analyses in order to assess the amount of Benzene Soluble Organic Fraction (BSOF) and trace metals using Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES). For both diesel and biodiesel, BSOF results showed decreasing levels with increasing engine load. B20 showed higher BSOF as compared to those measured with diesel. The concentration of different trace metals analyzed also showed decreasing trends with increasing engine loads. In addition, real-time measurements for Organic Carbon (OC), Elemental Carbon (EC) and total particle-bound Polycyclic Aromatic Hydrocarbons (PAHs) were carried out on the primary engine exhaust coming out of the partial flow dilution tunnel. Analysis of OC/EC data suggested that the ratio of OC to EC decreases with corresponding increase in engine load for both fuels. A peak in PAH concentration was observed at 60% engine load at 1800 rpm and 20% engine load at 2400 rpm engine speeds almost identical for both kinds of fuels. Comparison of chemical components of PM emitted from this CRDI engine provides new insight in terms of PM toxicity for B20 vis-a-vis diesel.

Emissions from diesel versus biodiesel fuel used in a CRDI SUV engine: PM mass and chemical composition

The diesel tailpipe emissions typically undergo substantial physical and chemical transformations while traveling through the tailpipe, which tend to modify the original characteristics of the diesel exhaust. Most of the health-related attention for diesel exhaust has focused on the carcinogenic potential of inhaled exhaust components, particularly the highly respirable diesel particulate matter (DPM). In the current study, parametric investigations were made using a modern automotive common rail direct injection (CRDI) sports utility vehicle (SUV) diesel engine operated at different loads at constant engine speed (2400 rpm), employing diesel and 20% biodiesel blends (B20) produced from karanja oil. A partial flow dilution tunnel was employed to measure the mass of the primary particulates from diesel and biodiesel blend on a 47-mm quartz substrate. This was followed by chemical analysis of the particulates collected on the substrate for benzene-soluble organic fraction (BSOF) (marker of toxicity). BSOF results showed decrease in its level with increasing engine load for both diesel and biodiesel. In addition, real-time measurements for organic carbon/elemental carbon (OC/EC), and polycyclic aromatic hydrocarbons (PAHs) (marker of toxicity) were carried out on the diluted primary exhaust coming out of the partial flow dilution tunnel. PAH concentrations were found to be the maximum at 20% rated engine load for both the fuels. The collected particulates from diesel and biodiesel-blend exhaust were also analyzed for concentration of trace metals (marker of toxicity), which revealed some interesting results.

Side-by-Side Comparison of Field Monitoring Methods for Hot Bitumen Emission Exposures: The German IFA Method 6305, U.S. NIOSH Method 5042, and the Total Organic Matter Method

Field studies were conducted at paving and roofing sites to compare the German Institute for Occupational Safety and Health of the German Social Accident Insurance (IFA) Fourier transform infrared spectroscopy method 6305 with the National Institute for Occupational Science and Health (NIOSH) benzene soluble fraction method 5042 plus total organic matter. Sampling using both methods was performed in multiple bitumen-related workplace environments. To provide comparable data all samplings were performed in parallel, and the analytical data were related to the same representative bitumen condensate standard. An outline of the differences between the sampling and analytical methods is provided along with comparative data obtained from these site investigations. A total of 55 bitumen paving sampler pairs were reported and statistical comparisons made using the 35 pairs of detectable data. First, the German inhalable aerosol data and the NIOSH benzene soluble fraction (BSF) method showed a correlation coefficient of R2= 0.88 (y(BSF)= 0.60 ×(aerosol)). Second, the aerosol data compared with total particulate matter (TPM) show a R2 of 0.83 (y(TPM)= 1.01 ×(aerosol)). Finally, total organic matter (TOM) and “aerosol + vapor” data yielded a R2 of 0.78 (y(TOM)= 0.44 ×(aerosol+vapor)). Twenty-nine pairs of roofing data were also collected; 37% were below the limit of detection. When comparing the TOM data with the aerosol + vapor data, using the 13 of 29 pairs where both samplers showed detectable results, the relationship was y(TOM)= 0.74 ×(aerosol+vapor) (R2= 0.91). The slopes within these equations provide predictive factors between these sampling and analysis methods; intended for use with large sets of data, they are not applicable to single point measurements.

Is potroom asthma due more to sulphur dioxide than fluoride? An inception cohort study in the Australian aluminium industry

ObjectivesAlthough an asthma-like syndrome has been recognised in aluminium smelter workers for over 70 years, the causal agent has been difficult to identify.MethodsAn inception cohort study was conducted at two...

Toxic Potential Evaluation of Particulate Matter Emitted from a Constant Speed Compression Ignition Engine: A Comparison between Straight Vegetable Oil and Mineral Diesel

This study was primarily focused on analyzing particulate matter coming out of engine exhaust from diesel and straight vegetable oils (SVO) for the following parameters: (1) Benzene soluble organic fraction (BSOF), (2) Metal traces, and (3) Particulate surface morphology. Hence, the exhaust from a small compression ignition (CI) engine emitted under varying engine load conditions at constant engine speed was extensively analyzed for its chemical constituents and PM morphology. Two fuels, namely mineral diesel and straight vegetable oil, were tested with this engine and the engine emissions were compared in order to assess their relative toxic potential. One of the major findings of this study suggested that by preheating, viscosity of vegetable oil can be lowered to the level of mineral diesel, and vegetable oil gives better particulate emission results than mineral diesel in terms of lower toxic metal emissions as well as less soot formation.

FTIR and Mass Spectral Analyses of an Upgraded Bio-oil

Bio-oil prepared from flash pyrolysis of rice stalk around 500°C was upgraded by filtration and catalytic esterification. Both raw and upgraded bio-oils were observed with an optical microscope. The upgraded bio-oil was extracted with benzene, carbon disulfide, hexane, and carbon tetrachloride, respectively, and the soluble fractions were analyzed with FTIR and GC/MS. In addition, ion trap mass spectrometer was used for analysis of the benzene-soluble fraction. The results show that the upgrading substantially improved the dispersity of organic droplets in the bio-oil and completely removed char particles from the bio-oil, but heavy species are still the main components in the upgraded bio-oil; the soluble fractions contain aliphatic, benzene-ring-containing, ester, and bonded hydroxyl moieties, and methoxy-containing species are the most abundant GC/MS-detectable compounds.