scholarly journals Pollution Characteristics of Atmospheric Carbonyls in Urban Linfen in Winter

Atmosphere ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 685
Author(s):  
Fanxiu Li ◽  
Hengyuan Wang ◽  
Xuezhong Wang ◽  
Zhigang Xue ◽  
Liqin Duan ◽  
...  
Keyword(s):  
Urban Area ◽  
Atmospheric Chemistry ◽  
Mass Concentration ◽  
High Performance ◽  
Exhaust Emissions ◽  
Photochemical Reactions ◽  
Vehicle Exhaust ◽  
Pollution Characteristics ◽  
The North ◽  
Mass Concentrations

Atmospheric carbonyls (aldehyde and ketone compounds) can be precursors for ozone and PM2.5, and they play an essential role in atmospheric chemistry. Linfen is a basin between mountains on the east and west, and there are many coking plants on the north and south sides of its urban area. The special topography and unfortunate industrial layout have frequently contributed to serious air pollution in Linfen. In order to investigate the pollution characteristics of atmospheric carbonyls in winter in urban Linfen, the carbonyl compounds were collected from the Municipal Committee site (MC) and the Yaowangtai site (YWT) from 16 to 25 January 2019, and their concentrations were analyzed by a high performance liquid chromatography-ultraviolet detector (HPLC-UV). The results show that formaldehyde, acetaldehyde, and acetone were the most abundant compounds, accounting for more than 70% of the total mass concentration of carbonyls in urban Linfen. Levels of these three carbonyls increased during the morning and evening traffic rush hours. The mass concentration of formaldehyde at both sites reached peak values at around noon (10:00–14:00). In addition, the mass concentrations of formaldehyde, acetaldehyde, and acetone were positively correlated with CO mass concentrations, whereas only formaldehyde and acetaldehyde were positively correlated with temperature. Therefore, atmospheric formaldehyde in urban Linfen’s winter mainly came from vehicle exhaust emissions and the secondary generation of photochemical reactions. Most of the acetaldehyde came from vehicle exhaust emissions, and photochemical reactions also partially contributed to it. For acetone, vehicle exhaust emissions were the main source. In addition, coking industry emissions from Northern Linfen′s Hongtong County may also have contributed to the atmospheric carbonyls in the urban area of Linfen. For the first time, this study found that formaldehyde showed different behavior to acetaldehyde and acetone; that is, the nighttime decrease in formaldehyde mass concentration was greater than that of acetaldehyde and acetone.

Measurement uncertainty and metrological traceability of whole blood cyclosporin A mass concentration results obtained by UHPLC-MS/MS

2018 ◽  
Vol 56 (9) ◽  
pp. 1458-1468 ◽  
Author(s):  
Raül Rigo-Bonnin ◽  
Pedro Alía ◽  
Francesca Canalias
Keyword(s):  
Measurement Uncertainty ◽  
Whole Blood ◽  
Mass Concentration ◽  
High Performance ◽  
Metrological Traceability ◽  
Top Down ◽  
Bottom Up ◽  
Clinical Laboratories ◽  
Liquid Chromatography Tandem Mass ◽  
Mass Concentrations

Abstract Background: Traceable and accurate results of cyclosporine A (CsA) mass concentrations in whole blood are required to ensure the monitoring of immunosuppressive therapy in transplant recipients. Metrological traceability and measurement uncertainty can allow ensuring reliability and comparability of these results over time and space. In this study, we provide a practical and detailed example of how the traceability and uncertainty of mass concentration of CsA results, obtained using an ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) procedure, can be described and estimated. Methods: Traceability was described mainly according to ISO 17511 and information obtained from certificates facilitated with the manufacturer’s calibrators. Uncertainty estimation was performed using the bottom-up and top-down approaches. For the bottom-up approach, the most relevant sources of uncertainty were identified and later used to estimate the standard, combined and expanded uncertainties. For the top-down approach, expanded uncertainty was estimated directly using intralab quality control data mainly. Results: Mass concentration of CsA results was traceable to the manufacturer’s product calibrators used to calibrate the UHPLC-MS/MS procedure. The expanded uncertainties estimated by the bottom-up and top-down approaches were 7.4% and 7.2%, respectively. Conclusions: After performing the bottom-up and top-down approaches, we observed that their results were quite similar. This fact would confirm that the top-down approach could be sufficient for estimating uncertainty of CsA mass concentrations in whole blood results in clinical laboratories. Finally, we hope that this study can help and motivate clinical laboratories to describe metrological traceability and to perform measurement uncertainty studies based on the simpler top-down approach.

scholarly journals Secondary organic aerosol formation during June 2010 in Central Europe: measurements and modelling studies with a mixed thermodynamic-kinetic approach

2014 ◽  
Vol 14 (8) ◽  
pp. 3831-3842 ◽  
Author(s):  
B. Langmann ◽  
K. Sellegri ◽  
E. Freney
Keyword(s):  
Organic Carbon ◽  
Size Distribution ◽  
Atmospheric Chemistry ◽  
Mass Concentration ◽  
Three Dimensional ◽  
Kinetic Approach ◽  
Aerosol Size Distribution ◽  
Aerosol Formation ◽  
Organic Vapour ◽  
Mass Concentrations

Abstract. Until recently secondary organic carbon aerosol (SOA) mass concentrations have been systematically underestimated by three-dimensional atmospheric-chemistry-aerosol models. With a newly proposed concept of aging of organic vapours, more realistic model results for organic carbon aerosol mass concentrations can be achieved. Applying a mixed thermodynamic-kinetic approach for SOA formation shifted the aerosol size distribution towards particles in the cloud condensation nuclei size range, thereby emphasising the importance of SOA formation schemes for modelling realistic cloud and precipitation formation. The additional importance of hetero-molecular nucleation between H2SO4 and organic vapours remains to be evaluated in three-dimensional atmospheric-chemistry-aerosol models. Here a case study is presented focusing on Puy-de-Dôme, France in June 2010. The measurements indicate a considerable increase in SOA mass concentration during the measurement campaign, which could be reproduced by modelling using a simplified thermodynamic-kinetic approach for SOA formation and increased biogenic volatile organic compound (VOC) precursor emissions. Comparison with a thermodynamic SOA formation approach shows a huge improvement in modelled SOA mass concentration with the thermodynamic-kinetic approach for SOA formation. SOA mass concentration increases by a factor of up to 6 accompanied by a slight improvement of modelled particle size distribution. Even though nucleation events at Puy-de-Dôme were rare during the chosen period of investigation, a weak event in the boundary layer could be reproduced by the model in a sensitivity study when nucleation of low-volatile secondary organic vapour is included. Differences in the model results with and without nucleation of organic vapour are visible in the lower free troposphere over several days. Taking into account the nucleation of organic vapour leads to an increase in accumulation mode particles due to coagulation and condensational growth of nucleation and Aitken mode particles.

scholarly journals Spatiotemporal distribution of light-absorbing carbon and its relationship to other atmospheric pollutants in Stockholm

2011 ◽  
Vol 11 (22) ◽  
pp. 11553-11567 ◽  
Author(s):  
P. Krecl ◽  
A. C. Targino ◽  
C. Johansson
Keyword(s):  
Exhaust Emissions ◽  
Atmospheric Pollutants ◽  
Spatiotemporal Variability ◽  
Rural Site ◽  
Strong Increase ◽  
Population Exposure ◽  
Emission Sources ◽  
Vehicle Exhaust ◽  
Urban Background ◽  
Urban Sites

Abstract. Carbon-containing particles have deleterious effects on both Earth's climate and human health. In Europe, the main sources of light-absorbing carbon (LAC) emissions are the transport (67%) and residential (25%) sectors. Information on the spatiotemporal variability of LAC particles in urban areas is relevant for air quality management and to better diagnose the population exposure to these particles. This study reports on results of an intensive field campaign conducted at four sites (two kerbside stations, one urban background site and a rural station) in Stockholm, Sweden, during the spring 2006. Light-absorbing carbon mass (MLAC) concentrations were measured with custom-built Particle Soot Absorption Photometers (PSAP). The spatiotemporal variability of MLAC concentrations was explored by examining correlation coefficients (R), coefficients of divergence (COD), and diurnal patterns at all sites. Simultaneous measurements of NOx, PM10, PM2.5, and meteorological variables were also carried out at the same locations to help characterize the LAC emission sources. Hourly mean (± standard deviation) MLAC concentrations ranged from 0.36±0.50 at the rural site to 5.39±3.60 μg m−3 at the street canyon site. Concentrations of LAC between urban sites were poorly correlated even for daily averages (R<0.70), combined with highly heterogeneously distributed concentrations (COD>0.30) even at spatial scales of few kilometers. This high variability is connected to the distribution of emission sources and processes contributing to the LAC fraction at these sites. At urban sites, MLAC tracked NOx levels and traffic density well and mean MLAC/PM2.5 ratios were larger (26–38%) than at the background sites (4–10%). The results suggest that vehicle exhaust emissions are the main responsible for the high MLAC concentrations found at the urban locations whereas long-range transport (LRT) episodes of combustion-derived particles can generate a strong increase of levels at background sites. To decrease pollution levels at kerbside and urban background locations in Stockholm, we recommend abatement strategies that target reductions of vehicle exhaust emissions, which are the main contributors to MLAC and NOx concentrations.

Tumble Flow Measurements Using Three Different Methods and Its Effects on Fuel Economy and Emissions

2006 ◽  
Author(s):  
Myoungjin Kim ◽  
Sihun Lee ◽  
Wootae Kim
Keyword(s):  
Fuel Economy ◽  
High Performance ◽  
Gasoline Engine ◽  
Exhaust Emissions ◽  
Combustion Stability ◽  
Lean Burn ◽  
Flow Measurements ◽  
Part Load ◽  
Gasoline Engines ◽  
Dynamometer Test

In-cylinder flows such as tumble and swirl have an important role on the engine combustion efficiencies and emission formations. In particular, the tumble flow, which is dominant in-cylinder flow in current high performance gasoline engines, has an important effect on the fuel consumptions and exhaust emissions under part load conditions. Therefore, it is important to know the effect of the tumble ratio on the part load performance and optimize the tumble ratio of a gasoline engine for better fuel economy and exhaust emissions. First step in optimizing a tumble flow is to measure a tumble ratio accurately. In this research the tumble flow was measured, compared and correlated using three different measurement methods: steady flow rig, 2-Dimensional PIV, and 3-Dimensional PTV. Engine dynamometer test was performed to find out the effect of the tumble ratio on the part load performance. Dynamometer test results of high tumble ratio engine showed faster combustion speed, retarded MBT timing, higher exhaust emissions, and a better lean burn combustion stability. Lean limit of the baseline engine was expanded from A/F=18:1 to A/F=21:1 by increasing a tumble ratio using MTV.

scholarly journals Impact of freeway weaving segment design on light-duty vehicle exhaust emissions

2018 ◽  
Vol 68 (6) ◽  
pp. 564-575 ◽  
Author(s):  
Qing Li ◽  
Fengxiang Qiao ◽  
Lei Yu ◽  
Shuyan Chen ◽  
Tiezhu Li
Keyword(s):  
Exhaust Emissions ◽  
Vehicle Exhaust ◽  
Light Duty ◽  
Light Duty Vehicle

scholarly journals Intrusion, retention, and snowpack chemical effects from exhaust emissions at Concordia Station, Antarctica

2018 ◽  
Author(s):  
Detlev Helmig ◽  
Daniel Liptzin ◽  
Jacques Hueber ◽  
Joel Savarino
Keyword(s):  
Nitrogen Oxides ◽  
Atmospheric Chemistry ◽  
Power Grid ◽  
Photochemical Reactions ◽  
Particulate Emissions ◽  
Surface Sampling ◽  
Surface Exchange ◽  
Exhaust Plumes ◽  
Clean Air ◽  
Main Station

Abstract. Continuous measurements of reactive gases in the snowpack and above the snowpack surface were conducted at Concordia Station (Dome C), Antarctica, from December 2012–January 2014. Measured species included ozone, nitrogen oxides, gaseous elemental mercury, and formaldehyde, for study of photochemical reactions, surface exchange, and the seasonal cycles and atmospheric chemistry of these gases. The experiment was installed ~ 1 km from the main station infrastructure inside the station clean air sector and within the station electrical power grid boundary. Air was sampled continuously from three inlets on a 10 m meteorological tower, as well as from two above and four below the surface sampling inlets from within the snowpack. Despite being in the clean air sector, over the course of the 1.2-year study, we observed on the order of 15 occasions when exhaust plumes from the camp, most notably from the power generation system, were transported to the study site. Highly elevated levels of nitrogen oxides (up to 1000 x background) and lowered ozone (down to ~ 50 %), most likely from titration with nitric oxide, were measured in the exhaust plumes. Within 5–15 minutes from observing elevated pollutant levels above the snow, rapidly increasing and long-lasting concentration enhancements were measured in snowpack air. While pollution events typically lasted only a few minutes to an hour above the snow surface, elevated nitrogen oxides levels were observed in the snowpack lasting from a few days to one week. These observations add important new insight to the discussion of if and how snow-photochemical experiments within reach of the power grid of polar research sites are possibly compromised by the snowpack being chemically influenced (contaminated) by gaseous and particulate emissions from the research camp activities. This question is critical for evaluating if snowpack trace chemical measurements from within the camp boundaries are representative for the vast polar ice sheets.

scholarly journals Source Profiles for PM10-2.5 Resuspended Dust and Vehicle Exhaust Emissions in Central India

2018 ◽  
Vol 18 (7) ◽  
pp. 1660-1672 ◽  
Author(s):  
Shamsh Pervez ◽  
Shahina Bano ◽  
John G. Watson ◽  
Judith C. Chow ◽  
Jeevan Lal Matawle ◽  
...  
Keyword(s):  
Central India ◽  
Exhaust Emissions ◽  
Vehicle Exhaust ◽  
Source Profiles

scholarly journals Sensitivity of modeled atmospheric nitrogen species to variations in sea salt emissions in the North and Baltic Sea regions

2015 ◽  
Vol 15 (20) ◽  
pp. 29705-29745
Author(s):  
D. Neumann ◽  
V. Matthias ◽  
J. Bieser ◽  
A. Aulinger ◽  
M. Quante
Keyword(s):  
Baltic Sea ◽  
Atmospheric Chemistry ◽  
Surf Zone ◽  
Fine Particles ◽  
Measurement Data ◽  
Monitoring And Evaluation ◽  
Sea Salt ◽  
The North ◽  
A Minor ◽  
The Impact

Abstract. Coarse sea salt particles are emitted ubiquitously from the oceans' surfaces by wave breaking and bubble bursting processes. These particles impact atmospheric chemistry by affecting condensation of gas-phase species and nucleation of new fine particles, particularly in regions with high air pollution. In this study, atmospheric particle concentrations are modeled for the North and Baltic Sea regions, Northwestern Europe, using the Community Multiscale Air Quality (CMAQ) modeling system and evaluated against European Monitoring and Evaluation Programme (EMEP) measurement data. As model extension, sea salt emissions are scaled by water salinity because of low salinity in large parts of the Baltic Sea and in certain river estuaries. The resulting improvement in predicted sea salt concentrations is assessed. The contribution of surf zone emissions is separately considered. Additionally, the impact of sea salt particles on atmospheric nitrate, ammonium and sulfate concentrations is evaluated. The comparisons show that sea salt concentrations are commonly overestimated at coastal stations and partly underestimated when going inland. The introduced salinity scaling improves predicted Baltic Sea sea salt concentrations considerably. Dates of measured peak concentrations are appropriately reproduced by the model. The impact of surf zone emissions is negligible in both seas. Nevertheless, they might be relevant because surf zone emissions were cut at an upper threshold in this study. Deactivating sea salt leads to a minor increase of NH4+ and NO3- and a minor decrease of SO42- concentrations. However, the overall effect is very low and lower than the deviation from measurements. Size resolved measurements of Na+, NH4+, NO3-, and SO42- are needed for a more detailed analysis on the impact of sea salt particles.

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