Development of a gas chromatography - mass spectrometry method for the determination of carbon disulfide in the atmosphere

[EN] Carbon disulfide (CS2), a relevant reduced sulfur compound in air, is well-known for its malodor and its significant effect on global atmospheric chemistry. Therefore, a reliable method for determining CS2 in atmospheric samples has been developed based on solid-phase sampling and gas chromatography-mass spectrometry (GC-MS). Two types of solid-phase sampling supports (Orbo-32 and SKC) and the elution with organic solvents - hexane and toluene - were evaluated for low-volume outdoor sampling. Recovery studies and the standard addition method were carried out to demonstrate the proper determination of CS2 in the absence of the influence of interferences such as ozone, hydrogen sulfide or water - important atmospheric pollutants. The proposed methodology was validated by performing experiments in a high-volume smog chamber and by comparison with two reference optical methods, Fourier Transform Infrared (FTIR) and Differential Optical Absorption Spectroscopy (DOAS) installed in these facilities. Satisfactory analytical parameters were reported: fast analysis, a correct repeatability of 6±1% and reproducibility of 14±3%, and low detection limits of 0.3-0.9pgm-3. Finally, the method was successfully applied to industrial samples near a pulp factory area, where a high correlation between industrial emissions and reported carbon disulfide concentrations were observed. © 2011 Elsevier B.V.The research leading to these results received funding from the Centro de Investigacion del Medio Ambiente (CIMA), Consejeria de Medio Ambiente, Gobierno de Cantabria. The Instituto Universitario CEAM-UMH is partly supported by Generalitat Valenciana, Fundacion Bancaja, and the projects GRACCIE (Consolider-Ingenio 2010) and FEEDBACKS (Prometeo - Generalitat Valenciana). We also acknowledged the European Community's Seventh Framework Program under the grant agreement no. 228335 (Eurochamp2), the Spanish Ministry of Science and Innovation, through INNPLANTA project: PCT-440000-2010-003 and the EUPHORE staff for their support in the chamber experiments. The authors also thank J.T.B. for his contribution.Borrás García, EM.; Ródenas, M.; Dieguez, J.; Pérez-García, M.; Lomba, R.; Lavin, J.; Tortajada-Genaro, LA. (2012). Development of a gas chromatography - mass spectrometry method for the determination of carbon disulfide in the atmosphere. Microchemical Journal. 101:37-42. https://doi.org/10.1016/j.microc.2011.10.002S374210

Characterization of major offensive odorants released from lake sediment

The amount of odorants effused from Lake Sihwa during the low tide period was estimated using sediment samples collected from various sites. A wide variety of odorants released from lake sediment were measured such as reduced sulfur compounds (RSCs), aldehydes, nitrogenous compounds, volatile organic compounds (VOCs), and volatile fatty acids (VFAs). A comparison of emission rates (mu g m(-2) min(-1)) showed large mean values from such species as NH3 (14,550), toluene (370), and DMS (106), while the lowest values were seen from VFAs and some VOCs. If their emission concentrations are converted into odor intensity (OI). the OI values were dominated by such odorants as NH3 (2.07), H2S (1.65), DMS (1.80), acetaldehyde (1.52), butyric acid (1.59), butyraldehyde (1.28), isovaleric acid (1.15), and valeric acid (0.78). The dilution to threshold (D/T) ratio derived on the basis of the air dilution sensory (ADS) test yielded a mean of 62 (range: 10-173); 19 out of 21 samples were seen to exceed the guideline D/T value of 15. The sum of odor intensities derived from individual odorants exhibited strong compatibilities with the D/T ratio (r(2) = 0.87; alpha = 0.003). The overall results of this study confirm that the sediment can play an important role in the malodor phenomenon in the area surrounding the Lake Sihwa. (C) 2010 Elsevier Ltd. All rights reserved.X111917sciescopu

Physical simulation of the EB-PVD coating process

The physical simulation (light box) of the Electron Beam-Physical Vapor Deposition (EB-PVD) coating process was improved and results of experiments recorded. The light box was first repaired and tested to ensure its functionality. It was then updated to allow for experiments with and without a shadow bar. Finally, data collected from experiments was compared to actual coating thickness measured in the EB-PVD coating chamber. All data corresponded accurately with coating thickness verifying a successful simulation

Spatial and temporal variations of volatile organic compounds using passive air samplers in the multi-industrial city of Ulsan, Korea

The source-receptor relationship of volatile organic compounds (VOCs) is an important environmental concern, particularly in large industrial cities; however, only a few studies have identified VOC sources using high spatial resolution data. In this study, 28 VOCs were monitored in Ulsan, the biggest multi-industrial city in Korea. Passive air samplers were seasonally deployed at eight urban and six industrial sites. The target compounds were detected at all sites. No significant seasonal variations of VOCs were observed probably due to the continuous emissions from major industrial facilities. Benzene, toluene, ethylbenzene, xylenes, and styrene accounted for 66-86% of the concentration of ??28 VOCs. The spatial distribution of the individual VOCs clearly indicated that petrochemical, automobile, non-ferrous, and shipbuilding industries were major VOC sources. Seasonal wind patterns were found to play a role in the spatial distribution of VOCs. Diagnostic ratios also confirmed that the industrial complexes were the dominant VOC sources. The results of principal component analysis and correlation analyses identified the influence of specific compounds from each industrial complex on individual sites. To the best of our knowledge, this is the first comprehensive report on the seasonal distribution of VOCs with high spatial resolution in a metropolitan industrial city in Korea

Perceived annoyance from environmental odors and association with atmospheric ammonia levels in non-urban residential communities: a cross-sectional study

<p>Abstract</p> <p>Objective</p> <p>Odor exposure is an environmental stressor that is responsible of many citizens complains about air pollution in non-urban areas. However, information about the exposure-response relation is scarce. One of the main challenges is to identify a measurable compound that can be related with odor annoyance responses. We investigated the association between regional and temporal variation of ammonia (NH₃) concentrations in five Danish non-urban regions and environmental odor annoyance as perceived by the local residents.</p> <p>Methods</p> <p>A cross-sectional study where NH₃ concentration was obtained from the national air quality monitoring program and from emission-dispersion modelling, and odor pollution perception from questionnaires. The exposure-response model was a sigmoid model. Linear regression analyses were used to estimate the model constants after equation transformations. The model was validated using leave-one-out cross validation (LOOCV) statistical method.</p> <p>Results</p> <p>About 45% of the respondents were annoyed by odor pollution at their residential areas. The perceived odor was characterized by all respondents as animal waste odor. The exposure-annoyance sigmoid model showed that the prevalence of odor annoyance was significantly associated with NH₃ concentrations (measured and estimated) at the local air quality monitoring stations (p < 0.01,R² = 0.99; and p < 0.05,R² = 0.93; respectively). Prediction errors were below 5.1% and 20% respectively. The seasonal pattern of odor perception was associated with the seasonal variation in NH₃ concentrations (p < 0.001, adjusted R² = 0.68).</p> <p>Conclusion</p> <p>The results suggest that atmospheric NH₃ levels at local air quality stations could be used as indicators of prevalence of odor annoyance in non-urban residential communities.</p