The Experts below are selected from a list of 11541 Experts worldwide ranked by ideXlab platform
R.b. Schlesinger - One of the best experts on this subject based on the ideXlab platform.
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8.15 – Sulfur Oxides
Comprehensive Toxicology, 2010Co-Authors: R.b. SchlesingerAbstract:Sulfur Oxides comprise both gaseous and particulate chemical species. The significant Sulfur Oxides in terms of the potential for public health consequences are gaseous Sulfur dioxide (SO2), produced primarily from combustion sources, and the secondarily derived particulate acidic sulfates, Sulfuric acid and ammonium bisulfate. Short-term (24 h average) exposure to SO2 is associated with respiratory symptoms in asthmatic children, and an association between such exposure and emergency room visits or hospitalization for certain respiratory diseases, specifically asthma and especially in children and older adults. Effects with longer-term exposures are more equivocal. However, while ambient exposure to SO2 has been associated with increased mortality and morbidity, it is often unclear whether the SO2 was the causal factor or was a surrogate exposure index for other pollutants in the Sulfur oxide gas/particle complex, such as acid sulfates. The exact role of acidity versus SO2 in pollutant-associated health effects is not resolved. Extensive controlled studies with sulfate particles have shown that there are no significant biological responses at ambient concentrations, although exposures above ambient have shown effects on respiratory tract defense mechanisms. Furthermore, epidemiological studies are inconsistent in their outcomes related to sulfates.
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Toxicology of Sulfur Oxides
Air Pollution and Health, 1999Co-Authors: R.b. SchlesingerAbstract:Publisher Summary This chapter describes the effect of Sulfur dioxide (SO 2 ) on health. The toxicologically significant Sulfur Oxides are the gaseous SO 2 , produced primarily from combustion sources, and Sulfuric acid and ammonium bisulfate, the secondarily derived particulate strongly acidic sulfates. Controlled clinical studies strongly suggest that asthmatics are more sensitive to SO 2 , responding with bronchoconstriction at much lower exposure levels than do normal individuals. Toxicologically, exposure to high levels of SO 2 are needed before there are significant changes in pulmonary defenses, but exposure to lower levels of acidic sulfates will alter mucociliary transport, alveolar clearance of particles, and airway reactivity, even in normal individuals. While the exact mechanisms underlying the toxicity of Sulfur Oxides are not known with certainty, the main response to SO 2, that is, bronchoconstriction, is because of contraction of airway smooth muscle via the parasympathetic reflex and/or following release of humoral mediators. This is probably due most directly to the bisulfite ion produced upon dissolution of SO 2 in airway fluids. On the other hand, the toxicity of acid sulfates is most likely because of the deposition of H + on airway surfaces, and it appears that a threshold exists for both the number of deposited acid particles as well as the mass concentration needed to produce any biological response.
S Zhuiykov - One of the best experts on this subject based on the ideXlab platform.
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Development of dual Sulfur Oxides and oxygen solid state sensor for “in situ” measurements
Fuel, 2000Co-Authors: S ZhuiykovAbstract:Abstract Dual SO x /O 2 “in situ” potentiometric sensor based on zirconia solid electrolyte and a composition of metal sulfates was investigated for simultaneous measurement of both oxygen and Sulfur oxide emissions in combustion gas. The BaSO 4 –K 2 SO 4 –SiO 2 -based electrochemical cell of the sensor exhibited excellent sensing characteristics for SO x measurement within a reasonably wide working temperature range of 650–1000°C and measuring SO x concentrations (18–10,000 ppm). Carbon dioxide, oxygen and nitrogen Oxides had no measurable effect on the SO x sensing properties of the sensor. Typical response times at 700°C were in the range of 45–80 s. The sensor also showed good correlation between the measuring SO x concentration and the output EMF in accordance with the Nernst equation. The installation of the probe based on dual SO x /O 2 sensor in control loops can provide a better and a more effective way towards fuel saving and efficiency.
Chem Int - One of the best experts on this subject based on the ideXlab platform.
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Control and treatment of Sulfur compounds specially Sulfur Oxides (SOx) emissions from the petroleum industry: A review
2019Co-Authors: Chem IntAbstract:Sulfur compounds such as Sulfur Oxides (SOx) are generated and emitted from operations in the petroleum industry which have negative effects on the environment. This study gives a critical and detailed introduction to the control and treatment of Sulfur compounds specially Sulfur Oxides (SOx) emissions from the petroleum industry. It begins with the sectors, main sources, and type of operations that generate SOx emissions; maximum effluent level of them from the petroleum industry; minimization, control, prevention and treatment techniques of these emissions from the petroleum industry. Among these techniques, Sulfur recovery unit (SRU) which most often consists of a Claus process for bulk Sulfur removal and subsequently a tail gas treatment unit (TGTU) for the remaining H2S removal (SCOT process, Beavon Sulfur removal (BSR) process, and Wellman-Lord process) and flue-gas deSulfurization (FGD) processes (once-through or regenerable) have been discussed in detail; and removal efficiencies and technical and economic aspects have been compared.
P O Wennberg - One of the best experts on this subject based on the ideXlab platform.
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multi scale modeling study of the source contributions to near surface ozone and Sulfur Oxides levels over california during the arctas carb period
Atmospheric Chemistry and Physics, 2010Co-Authors: Min Huang, Gregory R Carmichael, B Adhikary, S Kulkarni, Yafang Cheng, Chao Wei, Youhua Tang, A Dallura, P O WennbergAbstract:Chronic high surface ozone (O_3) levels and the increasing Sulfur Oxides (SO_x = SO_2 + SO_4) ambient concentrations over South Coast (SC) and other areas of California (CA) are affected by both local emissions and long-range transport. In this paper, multi-scale tracer, full-chemistry and adjoint simulations using the STEM atmospheric chemistry model are conducted to assess the contribution of local emission sourcesto SC O_3 and to evaluate the impacts of transported Sulfur and local emissions on the SC Sulfur budgetduring the ARCTAS-CARB experiment period in 2008. Sensitivity simulations quantify contributions of biogenic and fire emissions to SC O_3 levels. California biogenic and fire emissions contribute 3–4 ppb to near-surface O_3 over SC, with larger contributions to other regions in CA. During a long-range transport event from Asia starting from 22 June, high SO_x levels (up to ~0.7 ppb of SO_2 and ~1.3 ppb of SO_4) is observed above ~6 km, but they did not affect CA surface air quality. The elevated SO_x observed at 1–4 km is estimated to enhance surface SO_x over SC by ~0.25 ppb (upper limit) on ~24 June. The near-surface SO_x levels over SC during the flight week are attributed mostly to local emissions. Two anthropogenic SO_x emission inventories (EIs) from the California Air Resources Board (CARB) and the US Environmental Protection Agency (EPA) are compared and applied in 60 km and 12 km chemical transport simulations, and the results are compared withobservations. The CARB EI shows improvements over the National Emission Inventory (NEI) by EPA, but generally underestimates surface SC SO_x by about a factor of two. Adjoint sensitivity analysis indicated that SO_2 levels at 00:00 UTC (17:00 local time) at six SC surface sites were influenced by previous day maritime emissions over the ocean, the terrestrial emissions over nearby urban areas, and by transported SO_2 from the north through both terrestrial and maritime areas. Overall maritime emissions contribute 10–70% of SO2 and 20–60% fine SO_4 on-shore and over the most terrestrial areas, with contributions decreasing with in-land distance from the coast. Maritime emissions also modify the photochemical environment, shifting O_3 production over coastal SC to more VOC-limited conditions. These suggest an important role for shipping emission controls in reducing fine particle and O_3 concentrations in SC.
B Adhikary - One of the best experts on this subject based on the ideXlab platform.
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multi scale modeling study of the source contributions to near surface ozone and Sulfur Oxides levels over california during the arctas carb period
Atmospheric Chemistry and Physics, 2010Co-Authors: Min Huang, Gregory R Carmichael, B Adhikary, S Kulkarni, Yafang Cheng, Chao Wei, Youhua Tang, A Dallura, P O WennbergAbstract:Chronic high surface ozone (O_3) levels and the increasing Sulfur Oxides (SO_x = SO_2 + SO_4) ambient concentrations over South Coast (SC) and other areas of California (CA) are affected by both local emissions and long-range transport. In this paper, multi-scale tracer, full-chemistry and adjoint simulations using the STEM atmospheric chemistry model are conducted to assess the contribution of local emission sourcesto SC O_3 and to evaluate the impacts of transported Sulfur and local emissions on the SC Sulfur budgetduring the ARCTAS-CARB experiment period in 2008. Sensitivity simulations quantify contributions of biogenic and fire emissions to SC O_3 levels. California biogenic and fire emissions contribute 3–4 ppb to near-surface O_3 over SC, with larger contributions to other regions in CA. During a long-range transport event from Asia starting from 22 June, high SO_x levels (up to ~0.7 ppb of SO_2 and ~1.3 ppb of SO_4) is observed above ~6 km, but they did not affect CA surface air quality. The elevated SO_x observed at 1–4 km is estimated to enhance surface SO_x over SC by ~0.25 ppb (upper limit) on ~24 June. The near-surface SO_x levels over SC during the flight week are attributed mostly to local emissions. Two anthropogenic SO_x emission inventories (EIs) from the California Air Resources Board (CARB) and the US Environmental Protection Agency (EPA) are compared and applied in 60 km and 12 km chemical transport simulations, and the results are compared withobservations. The CARB EI shows improvements over the National Emission Inventory (NEI) by EPA, but generally underestimates surface SC SO_x by about a factor of two. Adjoint sensitivity analysis indicated that SO_2 levels at 00:00 UTC (17:00 local time) at six SC surface sites were influenced by previous day maritime emissions over the ocean, the terrestrial emissions over nearby urban areas, and by transported SO_2 from the north through both terrestrial and maritime areas. Overall maritime emissions contribute 10–70% of SO2 and 20–60% fine SO_4 on-shore and over the most terrestrial areas, with contributions decreasing with in-land distance from the coast. Maritime emissions also modify the photochemical environment, shifting O_3 production over coastal SC to more VOC-limited conditions. These suggest an important role for shipping emission controls in reducing fine particle and O_3 concentrations in SC.
