• Primary emission sources make significant contributions to the atmospheric organic compounds and six groups (including n-alkanes, PAHs, levoglucosan, branched-alkanes, n-alkenes and alkyl-benzenes) account for 66% of total identified organic compound mass. (birmingham.ac.uk)
  • In addition, polycyclic aromatic hydrocarbons (PAHs), and oxygenated PAHs (OPAHs) were abundant amongst the atmospheric organic compounds on both haze and non-haze days. (birmingham.ac.uk)
  • Occurrence of polycyclic aromatic hydrocarbons (PAHs) in freshwater may aggravate the water crisis currently being experienced in the Western Cape Province of South Africa. (scielo.org.za)
  • Among the list of prioritised emerging micro-contaminants that have been identified to degrade water quality is the polycyclic aromatic hydrocarbons (PAHs) group (Christensen and Arora, 2007). (scielo.org.za)
  • The concentrations of different PAH fractions and the sum total of PAHs detected in different aquatic environment varies. (scielo.org.za)
  • varied concentrations of PAHs have also been measured elsewhere in the world (Zhang et al. (scielo.org.za)
  • Sediment cores from Lake Superior were collected, dated, and analyzed for a suite of hydrophobic organic contaminants (HOCs) including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and n-alkanes. (umn.edu)
  • In particular, the model predicts a greater abundance of lower molecular weight PAHs in near-shore areas with higher total suspended material concentrations than in open waters. (umn.edu)
  • This phenomenon could explain the greater abundance of lower molecular weight PAHs observed in near-shore areas in other systems including the Black Sea and Lake Michigan. (umn.edu)
  • These samples were subjected to accelerated solvent extraction with a mixture of dichloromethane and acetone and separated into functional group fractions for analyses by GC/MS. Over 180 organic compounds belonging to three major fractions (n-alkanes, polycyclic aromatic hydrocarbons - PAHs, and polar organic compounds - POCs) were identified and quantified. (nottingham.edu.cn)
  • Polycyclic Aromatic hydrocarbons (PAHs) are one of the most concerning chemicals in the marine environment. (researchsquare.com)
  • PAHs are toxic, bioactive and carcinogenic, mutagenic and ubiquitous environmental compounds composed of 2-7 fused aromatic rings derived from pyrogenic, petrogenic and biogenic sources(Ke et al. (researchsquare.com)
  • Several significant positive associations were detected between OTUs and mid-to high-molecular weight PAHs. (duke.edu)
  • Ocean stratification plays a crucial role in many biogeochemical processes of dissolved matter, but our understanding of its impact on widespread organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), remains limited. (researchgate.net)
  • RM 6.5W contained higher concentrations of polycyclic aromatic hydrocarbons (PAHs), but diagnostic ratios of both extracts indicated similar PAH sourcing and composition. (pnnl.gov)
  • Polycyclic aromatic hydrocarbons (PAHs) are pyrolysis by-products and major environmental pollutants. (ac.ir)
  • The results demonstrated that the PAHs are present in significant concentrations in char product (54-1184 mg kg -1 ). (ac.ir)
  • In this case, 'taint' was due to the presence of the aromatic polycyclic aromatic hydrocarbons (PAHs) compounds (Yender, Michel, & Lord, 2002). (joe.org)
  • Low molecular weight PAHs, such as nalpthalene, in crude oils are highly odiferous and very noxious. (joe.org)
  • PAH incorporation in to the environment takes place from multiple resources (e.g. essential oil spills imperfect combustion procedures etc.) and a proven way to look for the origins of PAHs is certainly by analysing their molecular fingerprint. (biotech-angels.com)
  • The PAHs in Garden soil certified research materials which includes 16 PAHs at concentrations of 100 ppb Asaraldehyde to at least one 1 ppm was extracted from Analysis Technologies Company (SQC017 Laramie WY). (biotech-angels.com)
  • They therefore are linked with the metabolic activa- creases approximately logarith- occur predominantly in solid form, tion of PAHs, as well as their deposi- mically with increasing molecular bound to particulates in pol uted air, tion and disposition. (who.int)
  • A polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings. (wikipedia.org)
  • The simplest representative is naphthalene, having two aromatic rings, and the three-ring compounds anthracene and phenanthrene. (wikipedia.org)
  • C6) at a molecular level on non-haze and haze days, we determined more than 300 organic compounds in the PM2.5 from an urban area of Beijing in November-December 2016 using two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-TOFMS). (birmingham.ac.uk)
  • The identified organic compounds have been classified into groups, and quantitative methods were used to calculate their concentrations. (birmingham.ac.uk)
  • In addition, the concentrations of unidentified compounds were also estimated in the present study. (birmingham.ac.uk)
  • Moreover, they show that, in contrast to traditional belief, NSO compounds in oils and bitumens can form useful molecular tools to study questions in petroleum geochemistry, biogeochemistry, and palaeobiogeochemistry. (edu.au)
  • Organic sulfur compounds are used to identify sources and atmospheric processing of aerosol. (copernicus.org)
  • Although the mechanism of cardiovascular injury by PM is poorly understood, it has been shown that the particles are coated by a number of chemical compounds, including organic hydrocarbons (for example, polycyclic aromatic hydrocarbons and quinones), transition metals, sulfates and nitrates. (biomedcentral.com)
  • With its high temporal resolution and the high degree of conserved chemical composition information, CHARON PTR-TOFMS is thus the perfect analytical technique to identify and quantitatively follow atmospheric particulate tracer compounds like levoglucosan and polycyclic aromatic hydrocarbons. (ionicon.com)
  • In today's paper we demonstrated advantages of trapped ion mobility spectrometry coupled too mass spectrometry (TIMS-MS) coupled with theoretical calculations for fast identification (millisecond timescale) of polycyclic aromatic hydrocarbons (PAH) compounds from complex mixtures. (biotech-angels.com)
  • Although dermal contact may also contribute describe the time course of plasma concentrations using the data to workplace exposure for certain compounds, the current from the route comparison study. (cdc.gov)
  • Atmospheric pressure, laminar, premixed, fuel-rich flames of n-heptane/oxygen/argon and n-heptane/oxygenate/oxygen/argon were studied at an equivalence ratio of 1.97 to determine the effects of oxygenate concentration on species mole fractions. (iyte.edu.tr)
  • The oxygenate addition has increased the maximum flame temperatures and reduced the mole fractions of CO, low-molecular-weight hydrocarbons, aromatics, and polycyclic aromatic hydrocarbons. (iyte.edu.tr)
  • The reduction in mole fractions of aromatic and polycyclic aromatic hydrocarbon species by an increase in oxygenate concentration was more significant. (iyte.edu.tr)
  • Petroleum compositional changes, recorded mainly in the low-molecular-weight aromatic and phenol fractions, were tentatively attributed to abiotic oxidation processes. (edu.au)
  • The benzenoid hydrocarbons have been defined as condensed polycyclic unsaturated fully-conjugated hydrocarbons whose molecules are essentially planar with all rings six-membered. (wikipedia.org)
  • To follow up this discovery and related future exoplanet biosignature detections, it is important to spectroscopically detect the presence of phosphorus-bearing atmospheric molecules that could be involved in the chemical networks producing, destroying or reacting with phosphine. (frontiersin.org)
  • They can be present as primary biogenic molecules, rearranged biogenic molecules, or secondary functionalized hydrocarbons. (edu.au)
  • While the aerosol mass spectrometer provides high-time-resolution characterization of the overall extent of oxidation, the extensive fragmentation of molecules and specificity of the technique have posed challenges toward deeper understanding of molecular structures in aerosols. (copernicus.org)
  • Interior to this zone, many of the carbon-based molecules that are thought to be precursors to life, like polycyclic aromatic hydrocarbons, are destroyed. (bigthink.com)
  • He was a postdoctoral research associate of Prof. Dr John Paul Maier, FRS in Basel, Switzerland, where he researched highly unsaturated hydrocarbon molecules of astrophysical relevance. (edu.au)
  • Cass, GR 1998, Organic molecular tracers for particulate air pollution sources. (ac.ir)
  • Quantitatively detect sub-µm particulate organic matter in sub-ng m-³ mass concentrations in real-time with the new CHemical Analysis of aeRosol ON-line (CHARON) particle inlet coupled to your IONICON PTR-TOFMS instrument. (ionicon.com)
  • Fine particulate matter (PM 2.5 ) samples were collected between November 2020 and October 2021 at the Minzu University of China in Beijing and the n -alkyl nitrate concentrations in the PM 2.5 samples were determined to investigate n -alkyl nitrate pollution and formation mechanisms. (copernicus.org)
  • Temporal trends in and correlations between particulate-bound n -alkyl nitrate, ozone, PM 2.5 , and nitrogen dioxide concentrations were investigated to assess the relationships between particulate-bound n -alkyl nitrate concentrations and photochemical reactions and identify the n -alkyl nitrate formation mechanisms. (copernicus.org)
  • The particulate-bound n -alkyl nitrate and ozone concentrations significantly negatively correlated despite gas-phase alkyl nitrate and ozone concentrations previously being found to positively correlate. (copernicus.org)
  • The particulate-bound n -alkyl nitrate concentrations followed the same trends as and significantly positively correlated with the PM 2.5 and nitrogen dioxide concentrations. (copernicus.org)
  • Particulate-bound n -alkyl nitrates are important components of PM 2.5 during haze events and strongly affect atmospheric visibility. (copernicus.org)
  • 3-D backward air mass trajectory analyses together with the carbon preference index (CPI), molecular diagnostic ratios and molecular markers were used to investigate the origin of organic species measured in this study. (nottingham.edu.cn)
  • Therefore, the PTR-MS technology we use allows for the detection of almost the full range of atmospheric organic carbon with one single instrument. (ionicon.com)
  • The n -alkyl nitrate homologue group concentrations increased as the carbon chain length increased, i.e, long-chain n -alkyl nitrates contributed more than short-chain n -alkyl nitrates to the total n -alkyl nitrate concentrations in PM 2.5 . (copernicus.org)
  • Based on these diagnostic tools, the increased abundance of atmospheric organic species during October could be attributed to the occurrence of regional smoke haze episodes due to biomass burning in Indonesia. (nottingham.edu.cn)
  • A heated quartz micro-probe coupled to an on-line gas chromatography/mass spectrometry has been used to establish the identities and absolute concentrations of stable major, minor, and trace species by the direct analysis of samples, withdrawn from the flames. (iyte.edu.tr)
  • 0.48 ppb, relative to a 0.04 ppb background), which are followed by a diversification of Acritarch species, suggests that combustion of 'early' terrestrial and marginallymarine biomass might have caused extensive smoke and atmospheric dimming, as well as subsequent photosynthetic stress. (edu.au)
  • To account for SOA formation from both diesel and gasoline sources, the parameterization has six lumped precursor species that resolve both volatility and molecular structure (aromatic versus aliphatic). (copernicus.org)
  • Finally, the proposed four-component mechanism was verified by comparing the calculated values of ignition delay and species concentrations with the experimental values. (vinca.rs)
  • 2020. Treatment of Polycyclic Aromatic Hydrocarbons in Oil Sands Process Affected Water with a Surface Flow Treatment Wetland . (sfu.ca)
  • Therefore, IVOCs in mobile-source emissions contribute almost as much SOA as traditional precursors such as single-ring aromatics. (copernicus.org)
  • Although the trapped noble gases in five DaG samples show ratios typical of solar or planetary gases, in all other DaG samples, they are dominated by atmospheric contamination, which increases with the degree of weathering. (arizona.edu)
  • There is a group of polymers such as polyolefines, cellulose, and others that undergo complete combustion in a medium that is poorer in oxygen than atmospheric air. (akjournals.com)
  • Our data show that seawater temperature, pH, and oxygen concentration, within the range of current and projected future values, had no significant effect on the dissolution of aerosol Fe. (bepress.com)
  • By definition, polycyclic aromatic hydrocarbons have multiple rings, precluding benzene from being considered a PAH. (wikipedia.org)
  • According to Clar's rule, the resonance structure of a PAH that has the largest number of disjoint aromatic pi sextets-i.e. benzene-like moieties-is the most important for the characterization of the properties of that PAH. (wikipedia.org)
  • Benzene-substructure resonance analysis for Clar's rule Phenanthrene Anthracene Chrysene For example, phenanthrene has two Clar structures: one with just one aromatic sextet (the middle ring), and the other with two (the first and third rings). (wikipedia.org)
  • benzene, which was due to their differences in hydrophobicity and molecular weight. (aaqr.org)
  • between 60% - 100% of the organic mass concentrations can be directly calculated without the need of any additional corrections. (ionicon.com)
  • These two acids showed strong linear relationships with maximum daily ozone concentrations throughout the entire sampling period. (nottingham.edu.cn)
  • 2023. Methods for Assessing the Bioaccumulation of Hydrocarbons and Related Substances in Terrestrial Organisms: A Critical Review . (sfu.ca)
  • 2023. The atmospheric fate of 1,2-Dibromo-1 4-(1,2-dibromoethyl)cyclohexane (TBECH): Spatial patterns, seasonal variability, and deposition to Canadian coastal regions . (sfu.ca)
  • The observed bimolecular rate constants along with the negative temperature dependences of k ( T ) allow us to conclude that the reactions of C 2 ( X 1 Σ g + ) with these unsaturated hydrocarbons in the temperature range 293- 573 K proceed via an addition mechanism. (pku.edu.cn)
  • This study uses diesel exhaust concentrations in the railroad work environment in conjunction with the USEPA's Integrated Risk Information System ("IRIS") risk assessment methodology to quantify the cancer risk posed to railroad workers due to occupational inhalation exposure to diesel exhaust. (springer.com)
  • OBJECTIVE: To evaluate the relative contribution of occupational vs. non-occupational secondhand tobacco smoke exposure to overall hair nicotine concentrations in non-smoking bar and restaurant employees. (who.int)
  • Employees used personal air nicotine samplers during working and non-working hours for a 24-h period to assess occupational vs. non-occupational secondhand tobacco smoke exposure and hair nicotine concentrations to assess overall secondhand tobacco smoke exposure. (who.int)
  • Hair nicotine concentration was not associated with personal air nicotine concentration during non-working hours (non-occupational exposure). (who.int)
  • Occupational exposure limits (OELs) are used by pharma- inhalation) and to compare the area under the plasma ceutical companies to provide guidance for acceptable levels of concentration versus time curve with similar data for the occupational exposure to the active pharmaceutical ingredients clinical route of exposure (e.g., po) on which the OEL is based. (cdc.gov)
  • An atmospheric pressure image ionization supply (APPI predicated on Asaraldehyde the Apollo II style Bruker Daltonics Inc. Asaraldehyde MA) utilizing a Kr light fixture with primary emission rings at 10.0 and 10.6 eV was useful for all analyses. (biotech-angels.com)
  • Parker DL, Rybak ME, Pfeiffer CM. Phytoestrogen biomonitoring: an extractionless LC-MS/MS method for measuring urinary isoflavones and lignans by use of atmospheric pressure photoionization (APPI) external icon . (cdc.gov)
  • Comparison with collocated measurements suggest polycyclic aromatic hydrocarbon concentrations in emissions estimated by conventional chromatography may be substantially under-estimated. (copernicus.org)
  • C 9 -C 16 n -alkyl nitrate standards were synthesized and the n -alkyl nitrate concentrations in PM 2.5 were determined by gas chromatography triple quadrupole mass spectrometry. (copernicus.org)
  • Mineva EM, Schleicher RL, Chaudhary-Webb, M, May KL, Botelho JC, Vesper HW, Pfeiffer CM. A candidate reference measurement procedure for quantifying serum concentrations of 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 using isotope-dilution liquid chromatography-tandem mass spectrometry external icon . (cdc.gov)
  • For 129I analysis of Knyahinya, a novel method to separate Te and analysis using ICP-MS was used, enabling the use of experimental elemental concentrations obtained from the same meteorite to calculate 129I production. (arizona.edu)
  • 2008. Seasonal increases in polycyclic aromatic hydrocarbons related to two-stroke engine use in a small Alaskan lake. (wwu.edu)
  • Oysters were exposed to various combination of the ambient temperature and pH currently measured in Persian Gulf (T = 24 ºC and pH = 8.1) and the expected ocean warming and acidification (T = 28 ºC and pH = 7.6), as well as proper PhE concentration (0.8 ng.l − 1 ) during 28 days. (researchsquare.com)
  • Devi, P & Saroha, AK 2015, Effect of pyrolysis temperature on polycyclic aromatic hydrocarbons toxicity and sorption behaviour of biochars prepared by pyrolysis of paper mill effluent treatment plant sludge. (ac.ir)
  • Bimolecular rate constants for the gas-phase reactions of C 2 ( X 1 Σ g + ) with unsaturated hydrocarbons C 2 H 4 and C 2 H 2 were measured over the temperature range 293-573 K by pulsed laser photolysis/laserinduced fluorescence (PLP-LIF). (pku.edu.cn)
  • Temperature Dependence of C 2 ( X 1 Σ g + ) in Reactions with Unsaturated Hydrocarbons[J]. Acta Phys. (pku.edu.cn)
  • Polycyclic aromatic hydrocarbons are discussed as possible starting materials for abiotic syntheses of materials required by the earliest forms of life. (wikipedia.org)
  • Besides a chemo-selective transfer, we observed a quick atmospheric aging of carbohydrates, possibly as a result of both biotic and abiotic processes. (copernicus.org)
  • The developed SRM has been used to estimate the contribution of vehicles and brick kilns to ambient PM concentrations, using a grid-based emission inventory that considers temporal variations in emissions. (researchgate.net)
  • Results of a few case studies have been reported in the paper to show the impact of emission redistribution on ambient concentration. (researchgate.net)
  • However, in order to assess the impact of a particular pollution control strategy, it is important to predict pollutant concentration over the entire city in response to the control strategy. (researchgate.net)
  • The developed SRM could be easily utilized to predict ambient PM concentrations as new sources are added/ removed from the domain. (researchgate.net)
  • Peer-reviewed literature defines the ambient air concentrations of diesel exhaust for several railroad occupations as being above environmental background levels. (springer.com)
  • Table 3) significantly affected RFS of HCC patients following LT. Effects of miR-20a restoration on HCC cell proliferation and cell cycles in vitro Cell proliferation is a GSK2245840 concentration key determinant of tumor malignancy. (aktsignals.com)
  • CONCLUSIONS: Personal air nicotine concentration at working hours was the major determinant of hair nicotine concentrations in non-smoking employees from Santiago, Chile. (who.int)
  • Our CQC calculations significantly improve on existing RASCALL data by providing quantitative intensities, new data in the fingerprint region (crucial for molecular identification) and higher frequency regions (overtones, combination bands), and improved data for fundamental transitions based on the specific chemical environment. (frontiersin.org)
  • Once malathion is introduced into the environment, it is degraded by atmospheric photooxidation, hydrolysis, or biodegradation mediated by microorganisms found in most sediment, soils, and water. (cdc.gov)
  • These data are of interest for astronomy and astrochemistry (importantly identifying potential ambiguities in molecular assignments), improving RASCALL's underlying data, big data spectral analysis and future machine learning applications. (frontiersin.org)
  • Atmospheric HOC loads focused via a terrestrial pathway by the St. Louis River also contribute to higher HOC loads to the western arm. (umn.edu)
  • In particular, members belonging to the Ascomycota phylum were the most diverse at higher PAH concentrations suggesting this phylum may be promising biostimulation targets. (duke.edu)
  • summer and the mean concentrations being higher at night than in the day. (copernicus.org)
  • Currently, new pyrolysis technologies are being used to treat medical waste that can reduce the amount of landfilled waste, make it safe, and eventually convert it to a hydrocarbon fuel. (ac.ir)
  • Present-day PhE environmental concentrations, which combined with ocean warming and acidification, may lead to rigorous interruption of physiological functions can be extra threatened the ecological fitness of pearl oysters. (researchsquare.com)
  • His research focuses on developing molecular tools to support environmental monitoring. (sccwrp.org)
  • CHARON PTR-TOFMS is an on-line analytical technique that characterizes the molecular composition of sub-µm organic particles on a chemical composition level at a one-minute time-resolution. (ionicon.com)
  • It was hypothesized that household tumble driers could be atmospheric sources of these microfibers. (researchgate.net)
  • The revised model predicts all mobile sources (including on- and off-road gasoline, aircraft, and on- and off-road diesel) contribute ∼1 µg m −3 to the daily peak SOA concentration in Pasadena. (copernicus.org)
  • Professor Schmidt has been the recipient of a number of awards for his research including the Coblentz Award (2010) for contributions to the science of molecular spectroscopy. (edu.au)
  • A study by the American Cancer Society reported a 6% increase in cardiopulmonary deaths for every elevation of 10 μg/m 3 in PM concentration [ 8 ]. (biomedcentral.com)
  • SPE6 SPME7 LLE combined to HPLC and GC-MS8 and GCxGC-FID9) the introduction of even more accurate analytical separations (e.g. post-ionization gas-phase parting) for molecular framework assignment with reduced to no test preparation remains required. (biotech-angels.com)
  • The grid-based SRM has been developed using an established atmospheric dispersion model, considering weather parameters round the year. (researchgate.net)
  • Only few polymers, designed for special applications, can be accepted as inflammable or flame-retardant due to their chemical composition and molecular structure. (akjournals.com)
  • A polyaromatic hydrocarbon may have rings of various sizes, including some that are not aromatic. (wikipedia.org)
  • Therefore, in this molecule the outer rings have greater aromatic character whereas the central ring is less aromatic and therefore more reactive. (wikipedia.org)
  • Based on a selective depletion of volatile aromatics and invariant phenol concentrations the results exclude both evaporative and oil-water partitioning processes. (edu.au)
  • RESULTS: Median hair nicotine concentrations were 1.5 ng/mg, interquartile range (IQR) 0.7 to 5.2 ng/mg. (who.int)