Long-term declining in carbon monoxide (CO) at a rural site of Beijing during 2006–2018 implies the improved combustion efficiency and effective emission control

2020 ◽  
Author(s):  
Yingruo Li ◽  
Zhiqiang Ma ◽  
Tingting Han ◽  
Weijun Quan ◽  
Junxia Wang ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Emission Control ◽  
Combustion Efficiency ◽  
Rural Site

scholarly journals Regional variability in black carbon and carbon monoxide ratio from long-term observations over East Asia: assessment of representativeness for black carbon (BC) and carbon monoxide (CO) emission inventories

2020 ◽  
Vol 20 (1) ◽  
pp. 83-98 ◽  
Author(s):  
Yongjoo Choi ◽  
Yugo Kanaya ◽  
Seung-Myung Park ◽  
Atsushi Matsuki ◽  
Yasuhiro Sadanaga ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
South Korea ◽  
East Asia ◽  
Black Carbon ◽  
North Korea ◽  
Northeast China ◽  
Emission Inventory ◽  
East China ◽  
Co Emission

Abstract. The black carbon (BC) and carbon monoxide (CO) emission ratios were estimated and compiled from long-term, harmonized observations of the ΔBC∕ΔCO ratios under conditions unaffected by wet deposition at four sites in East Asia, including two sites in South Korea (Baengnyeong and Gosan) and two sites in Japan (Noto and Fukuoka). Extended spatio-temporal coverage enabled estimation of the full seasonality and elucidation of the emission ratio in North Korea for the first time. The estimated ratios were used to validate the Regional Emission inventory in ASia (REAS) version 2.1 based on six study domains (“East China”, “North China”, “Northeast China”, South Korea, North Korea, and Japan). We found that the ΔBC∕ΔCO ratios from four sites converged into a narrow range (6.2–7.9 ng m−3 ppb−1), suggesting consistency in the results from independent observations and similarity in source profiles over the regions. The BC∕CO ratios from the REAS emission inventory (7.7 ng m−3 ppb−1 for East China – 23.2 ng m−3 ppb−1 for South Korea) were overestimated by factors of 1.1 for East China to 3.0 for South Korea, whereas the ratio for North Korea (3.7 ng m−3 ppb−1 from REAS) was underestimated by a factor of 2.0, most likely due to inaccurate emissions from the road transportation sector. Seasonal variation in the BC∕CO ratio from REAS was found to be the highest in winter (China and North Korea) or summer (South Korea and Japan), whereas the measured ΔBC∕ΔCO ratio was the highest in spring in all source regions, indicating the need for further characterization of the seasonality when creating a bottom-up emission inventory. At levels of administrative districts, overestimation in Seoul, the southwestern regions of South Korea, and Northeast China was noticeable, and underestimation was mainly observed in the western regions in North Korea, including Pyongyang. These diagnoses are useful for identifying regions where revisions in the inventory are necessary, providing guidance for the refinement of BC and CO emission rate estimates over East Asia.

On the Respective Roles of Nitric Oxide and Carbon Monoxide in Long-Term Potentiation in the Hippocampus

1999 ◽  
Vol 6 (1) ◽  
pp. 63-76 ◽  
Author(s):  
Min Zhuo ◽  
Jarmo T. Laitinen ◽  
Xiao-Ching Li ◽  
Robert D. Hawkins
Keyword(s):  
Nitric Oxide ◽  
Carbon Monoxide ◽  
Heme Oxygenase ◽  
Guanylyl Cyclase ◽  
Hippocampal Slices ◽  
Long Term Potentiation ◽  
No Synthase ◽  
Term Potentiation ◽  
Stimulation Of

Perfusion of hippocampal slices with an inhibitor nitric oxide (NO) synthase blocked induction of long-term potentiation (LTP) produced by a one-train tetanus and significantly reduced LTP by a two-train tetanus, but only slightly reduced LTP by a four-train tetanus. Inhibitors of heme oxygenase, the synthetic enzyme for carbon monoxide (CO), significantly reduced LTP by either a two-train or four-train tetanus. These results suggest that NO and CO are both involved in LTP but may play somewhat different roles. One possibility is that NO serves a phasic, signaling role, whereas CO provides tonic, background stimulation. Another possibility is that NO and CO are phasically activated under somewhat different circumstances, perhaps involving different receptors and second messengers. Because NO is known to be activated by stimulation of NMDA receptors during tetanus, we investigated the possibility that CO might be activated by stimulation of metabotropic glutamate receptors (mGluRs). Consistent with this idea, long-lasting potentiation by the mGluR agonist tACPD was blocked by inhibitors of heme oxygenase but not NO synthase. Potentiation by tACPD was also blocked by inhibitors of soluble guanylyl cyclase (a target of both NO and CO) or cGMP-dependent protein kinase, and guanylyl cyclase was activated by tACPD in hippocampal slices. However, biochemical assays indicate that whereas heme oxygenase is constitutively active in hippocampus, it does not appear to be stimulated by either tetanus or tACPD. These results are most consistent with the possibility that constitutive (tonic) rather than stimulated (phasic) heme oxygenase activity is necessary for potentiation by tetanus or tACPD, and suggest that mGluR activation stimulates guanylyl cyclase phasically through some other pathway.

Adaptive Carbon Monoxide Kinetics for Exhaust Aftertreatment Modeling

2009 ◽  
Author(s):  
Christopher Depcik ◽  
Sudarshan Loya ◽  
Anand Srinivasan
Keyword(s):  
Carbon Monoxide ◽  
Co Oxidation ◽  
Oxidation Mechanism ◽  
Kinetic Mechanism ◽  
Combustion Efficiency ◽  
Platinum Group Metals ◽  
Catalyst Loading ◽  
Low Temperature Combustion ◽  
Inlet Conditions ◽  
Ci Engines

Future emission standards are driving the need for advanced control of both Spark (SI) and Compression Ignition (CI) engines. However, even with the implementation of cooled Exhaust Gas Recirculation and Low Temperature Combustion (LTC), it is unlikely that in-cylinder combustion strategies alone will reduce emissions to levels below the proposed standards. As a result, researchers are developing complex catalytic aftertreatment systems to meet these tailpipe regulations for both conventional and alternative combustion regimes. Simulating these exhaust systems requires fast and accurate models suitable for significant changes in inlet conditions. Most aftertreatment devices contain Platinum Group Metals because of their widely documented beneficial catalysis properties; examples include Diesel Oxidation Catalysts, Three-Way Catalysts and Lean NOx Traps. There are kinetic mechanisms available for each of these devices, but often they do not extrapolate well to other formulations. For example, Carbon Monoxide (CO) levels entering a catalyst are significantly different between an SI and CI engine. In addition, modifying engine control to utilize LTC operation can result in an increase in CO levels due to lower combustion efficiency. This adversely affects the conversion capabilities of a catalytic device through increased levels of CO inhibition. Finally, catalyst loading and metal dispersion differences between devices often prohibit a direct extension of kinetic constants. As a result, mechanisms often need recalibration for correct modeling capabilities. In order to begin creating a more predictive kinetic mechanism, this paper simulates CO oxidation as a function of different inlet concentration levels and metal loadings. While aftertreatment devices contain many reactions, modeling of one fundamental reaction is a first step to determine the feasibility of adaptive kinetics. In addition, research into the history of the CO oxidation mechanism over platinum illustrates a more accurate rate expression to utilize in deference to current modeling activities. The authors calibrate this expression to experimental data taking into account significant changes in inlet conditions, metal loading and dispersion values. Model fidelity is determined through the simulation of additional data not part of the initial calibration efforts. In addition, the paper discusses strengths and weaknesses of the model along with how other researchers can help foster adaptive kinetic development.

Long term trends of methane, non methane hydrocarbons, and carbon monoxide in urban atmosphere

2015 ◽  
Vol 518-519 ◽  
pp. 595-604
Author(s):  
Ezaz Ahmed ◽  
Ki-Hyun Kim ◽  
Eui-Chan Jeon ◽  
Richard J.C. Brown
Keyword(s):  
Carbon Monoxide ◽  
Urban Atmosphere ◽  
Long Term Trends

scholarly journals Quantitative Recovery of 14C-labeled Carbon Monoxide (14CO) From Viable Heme-labeled Red Blood Cells in the Rat

Blood ◽  
1972 ◽  
Vol 40 (2) ◽  
pp. 257-260 ◽  
Author(s):  
Stephen A. Landaw
Keyword(s):  
Carbon Monoxide ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Quantitative Recovery

Abstract Long-term recovery of 14C-labeled carbon monoxide (14CO) from labeled, transfused red blood cells (RBC) was studied in buffalo rats. Donor RBC (labeled with 14C-2-glycine) were transfused into host rats, and the 14CO formed from degradation of labeled hemoglobin heme was collected over the next 110+ days. The heme-equivalent 14CO recovery in 13 animals averaged 102.1 ± 2.1% (mean ± SE) of activity in hemoglobin heme of donor RBC. This confirms that heme of circulating RBC destroyed by random hemolysis and senescence is quantitatively converted to CO.

A Simple Combustion Efficiency Indicator for Automobile Engines

1973 ◽  
Vol 6 (10) ◽  
pp. 399-400 ◽  
Author(s):  
M. S. Bolton ◽  
D. S. Taylor
Keyword(s):  
Carbon Monoxide ◽  
Internal Combustion Engines ◽  
Fuel Mixture ◽  
Internal Combustion ◽  
Combustion Efficiency ◽  
Exhaust Emission ◽  
Combustion Engines ◽  
Widespread Application ◽  
Mixture Ratio ◽  
Automobile Engines

A cheap device which can indicate carbon monoxide levels in exhaust emission of internal combustion engines, and hence could be used for adjusting the engine's operating air: fuel mixture ratio, would have widespread application in garages, etc. The instrument described here is sensitive to both unburnt hydrocarbons and carbon monoxide but measures the carbon monoxide to an accuracy well within the tuning capability of most carburation systems.

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