scholarly journals Disjunct eddy covariance measurements of oxygenated volatile organic compounds fluxes from an alfalfa field before and after cutting

2002 ◽  
Vol 107 (D8) ◽  
Author(s):  
C. Warneke
Keyword(s):  
Volatile Organic Compounds ◽  
Eddy Covariance ◽  
Organic Compounds ◽  
Alfalfa Field ◽  
Oxygenated Volatile Organic Compounds ◽  
Volatile Organic ◽  
Before And After ◽  
Eddy Covariance Measurements

scholarly journals Species and characteristics of volatile organic compounds emitted from an auto-repair painting workshop

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Y. Song ◽  
H. Chun
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Large Scale ◽  
Butyl Acetate ◽  
Small Scale ◽  
Indoor Environments ◽  
Voc Emissions ◽  
Volatile Organic ◽  
Before And After ◽  
Adsorption Systems

AbstractVolatile organic compounds (VOCs) are secondary pollutant precursors having adverse impacts on the environment and human health. Although VOC emissions, their sources, and impacts have been investigated, the focus has been on large-scale industrial sources or indoor environments; studies on relatively small-scale enterprises (e.g., auto-repair workshops) are lacking. Here, we performed field VOC measurements for an auto-repair painting facility in Korea and analyzed the characteristics of VOCs emitted from the main painting workshop (top coat). The total VOC concentration was 5069–8058 ppb, and 24–35 species were detected. The VOCs were mainly identified as butyl acetate, toluene, ethylbenzene, and xylene compounds. VOC characteristics differed depending on the paint type. Butyl acetate had the highest concentration in both water- and oil-based paints; however, its concentration and proportion were higher in the former (3256 ppb, 65.5%) than in the latter (2449 ppb, 31.1%). Comparing VOC concentration before and after passing through adsorption systems, concentrations of most VOCs were lower at the outlets than the inlets of the adsorption systems, but were found to be high at the outlets in some workshops. These results provide a theoretical basis for developing effective VOC control systems and managing VOC emissions from auto-repair painting workshops.

scholarly journals Characteristics of marine shipping emissions at berth: profiles for particulate matter and volatile organic compounds

2018 ◽  
Vol 18 (13) ◽  
pp. 9527-9545 ◽  
Author(s):  
Qian Xiao ◽  
Mei Li ◽  
Huan Liu ◽  
Mingliang Fu ◽  
Fanyuan Deng ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Mass Spectrometer ◽  
Elemental Carbon ◽  
Atmospheric Stability ◽  
Diesel Oil ◽  
Human Populations ◽  
Volatile Organic ◽  
Before And After ◽  
The Impact

Abstract. Emissions from ships at berth play an important role regarding the exposure of high density human populations to atmospheric pollutants in port areas; however, these emissions are not well understood. In this study, volatile organic compounds (VOCs) and particle emissions from 20 container ships at berth were sampled and analyzed during the “fuel switch” period at Jingtang Port in Hebei Province, China. VOCs and particles were analyzed using a gas chromatography-mass spectrometer (GC-MS) and a single particle aerosol mass spectrometer (SPAMS), respectively. VOC analysis showed that alkanes and aromatics, especially benzene, toluene and heavier compounds e.g., n-heptane, n-octane and n-nonane, dominated the total identified species. Secondary organic aerosol (SOA) yields and ozone (O3) forming potential were 0.017 ± 0.007 g SOA g−1 VOCs and 2.63 ± 0.37 g O3 g−1 VOCs, respectively. Both positive and negative ion mass spectra from individual ships were derived and the intensity of specific ions were quantified. Results showed that elemental carbon (35.74 %), elemental carbon–organic carbon mixtures (33.95 %) and Na-rich particles (21.12 %) were major classes, comprising 90.7 % of the particles observed. Particles from ship auxiliary engines were in the 0.2 to 2.5 µm size range, with a peak occurring at around 0.4 µm. The issue of using vanadium (V) as tracer element was examined, and it was found that V was not a proper tracer of ship emissions when using low sulfur content diesel oil. The average percentage of sulfate particles observed in shipping emissions before and after switching to marine diesel oil remained unchanged at 24 %. Under certain wind conditions, when berths were upwind of emission sources, the ratios before and after 1 January were 35 and 27 % respectively. The impact of atmospheric stability was discussed based on PM2.5 and primary pollutant (carbon monoxide) concentration. With a background of frequent haze episodes and complex mechanisms of particulate accumulation and secondary formation, the impact of atmospheric stability is believed to have been weak on the sulfate contribution from shipping emissions. The results from this study provide robust support for port area air quality assessment and source apportionment.

scholarly journals Seasonal and Spatial Variation of Volatile Organic Compounds in Ambient Air of Almaty City, Kazakhstan

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1592
Author(s):  
Olga P. Ibragimova ◽  
Anara Omarova ◽  
Bauyrzhan Bukenov ◽  
Aray Zhakupbekova ◽  
Nassiba Baimatova
Keyword(s):  
Air Pollution ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Power Plants ◽  
Ambient Air ◽  
Spatial Variations ◽  
Primary Sources ◽  
Volatile Organic ◽  
Seasonal And Spatial Variations ◽  
Before And After

Air pollution is one of the primary sources of risk to human health in the world. In this study, seasonal and spatial variations of multiple volatile organic compounds (VOCs) were measured at six sampling sites in Almaty, Kazakhstan. The seasonal and spatial variations of 19 VOCs were evaluated in 2020, including the periods before and after COVID-19 lockdown. The concentrations of 9 out of 19 VOCs had been changed significantly (p < 0.01) during 2020. The maximum concentrations of total VOCs (TVOCs) were observed on 15, 17, and 19 January and ranged from 233 to 420 µg m−3. The spatial distribution of TVOCs concentrations in the air during sampling seasons correlated with the elevation and increased from southern to northern part of Almaty, where Combined Heat and Power Plants are located. The sources of air pollution by VOCs were studied by correlations analysis and BTEX ratios. The ranges of toluene to benzene ratio and benzene, toluene, and ethylbenzene demonstrated two primary sources of BTEX in 2020: traffic emissions and biomass/biofuel/coal burning. Most of m-, p-xylenes to ethylbenzene ratios in this study were lower than 3 in all sampling periods, evidencing the presence of aged air masses at studied sampling sites from remote sources.

scholarly journals Mapping Asian anthropogenic emissions of non-methane volatile organic compounds to multiple chemical mechanisms

2013 ◽  
Vol 13 (12) ◽  
pp. 32649-32701 ◽  
Author(s):  
M. Li ◽  
Q. Zhang ◽  
D. G. Streets ◽  
K. B. He ◽  
Y. F. Cheng ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Individual Species ◽  
Chemical Mechanisms ◽  
Mixing Ratios ◽  
Wide Range ◽  
Oxygenated Volatile Organic Compounds ◽  
Volatile Organic ◽  
Species Mapping ◽  
Multiple Chemical

Abstract. An accurate speciation mapping of non-methane volatile organic compounds (NMVOC) emissions has an important impact on the performance of chemical transport models (CTMs) in simulating ozone mixing ratios and secondary organic aerosols. In this work, we developed an improved speciation framework to generate model-ready anthropogenic Asian NMVOC emissions for various gas-phase chemical mechanisms commonly used in CTMs by using an explicit assignment approach and updated NMVOC profiles, based on the total NMVOC emissions in the INTEX-B Asian inventory for the year 2006. NMVOC profiles were selected and aggregated from a wide range of new measurements and the SPECIATE database. To reduce potential uncertainty from individual measurements, composite profiles were developed by grouping and averaging source profiles from the same category. The fractions of oxygenated volatile organic compounds (OVOC) were corrected during the compositing process for those profiles which used improper sampling and analyzing methods. Emissions of individual species were then lumped into species in different chemical mechanisms used in CTMs by applying mechanism-dependent species mapping tables, which overcomes the weakness of inaccurate mapping in previous studies. Gridded emissions for eight chemical mechanisms are developed at 30 min × 30 min resolution using various spatial proxies and are provided through the website: http://mic.greenresource.cn/intex-b2006. Emission estimates for individual NMVOC species differ between one and three orders of magnitude for some species when different sets of profiles are used, indicating that source profile is the most important source of uncertainties of individual species emissions. However, those differences are diminished in lumped species as a result of the lumping in the chemical mechanisms.

scholarly journals Using collision-induced dissociation to constrain sensitivity of ammonia chemical ionization mass spectrometry (NH<sub>4</sub><sup>+</sup> CIMS) to oxygenated volatile organic compounds

2019 ◽  
Vol 12 (3) ◽  
pp. 1861-1870 ◽  
Author(s):  
Alexander Zaytsev ◽  
Martin Breitenlechner ◽  
Abigail R. Koss ◽  
Christopher Y. Lim ◽  
James C. Rowe ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Mass Spectrometer ◽  
Chemical Ionization ◽  
Chemical Ionization Mass Spectrometry ◽  
Collision Induced Dissociation ◽  
Ionization Mass ◽  
Oxygenated Volatile Organic Compounds ◽  
Volatile Organic

Abstract. Chemical ionization mass spectrometry (CIMS) instruments routinely detect hundreds of oxidized organic compounds in the atmosphere. A major limitation of these instruments is the uncertainty in their sensitivity to many of the detected ions. We describe the development of a new high-resolution time-of-flight chemical ionization mass spectrometer that operates in one of two ionization modes: using either ammonium ion ligand-switching reactions such as for NH4+ CIMS or proton transfer reactions such as for proton-transfer-reaction mass spectrometer (PTR-MS). Switching between the modes can be done within 2 min. The NH4+ CIMS mode of the new instrument has sensitivities of up to 67 000 dcps ppbv−1 (duty-cycle-corrected ion counts per second per part per billion by volume) and detection limits between 1 and 60 pptv at 2σ for a 1 s integration time for numerous oxygenated volatile organic compounds. We present a mass spectrometric voltage scanning procedure based on collision-induced dissociation that allows us to determine the stability of ammonium-organic ions detected by the NH4+ CIMS instrument. Using this procedure, we can effectively constrain the sensitivity of the ammonia chemical ionization mass spectrometer to a wide range of detected oxidized volatile organic compounds for which no calibration standards exist. We demonstrate the application of this procedure by quantifying the composition of secondary organic aerosols in a series of laboratory experiments.

Calcium-Deficient and Stoichiometric Hydroxyapatites Promoted by Cobalt for the Catalytic Removal of Oxygenated Volatile Organic Compounds

2010 ◽  
Vol 135 (3-4) ◽  
pp. 197-206 ◽  
Author(s):  
Belaïd Aellach ◽  
Aziz Ezzamarty ◽  
Jacques Leglise ◽  
Carole Lamonier ◽  
Jean-François Lamonier
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Oxygenated Volatile Organic Compounds ◽  
Volatile Organic ◽  
Catalytic Removal
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