Review of Distribution Characteristics and Sources of Volatile Organic Compound in Atmosphere

2013 ◽  
Vol 726-731 ◽  
pp. 944-949
Author(s):  
Zhen Hua Xiong ◽  
Feng Qian ◽  
Xue Feng ◽  
Rong Rong Su ◽  
Yu Zeng

Volatile Organic Compounds (VOCs) have many sources, and they have effects on ecology and human health, which has aroused extensive attentions of many researchers. The Chinese and other countries studies in VOCs in atmosphere focused on detecting concentrations and compositions, sources apportionment, secondary pollutants transformation, health effects and other aspects. In the present paper, VOCs level in atmosphere, distribution characteristics and sources apportionment of VOCs in atmosphere were reviewed, the current studies results of VOCs in atmosphere were summarized.

The Analyst ◽  
2018 ◽  
Vol 143 (13) ◽  
pp. 3148-3155 ◽  
Author(s):  
Oluwasola Lawal ◽  
Hugo Knobel ◽  
Hans Weda ◽  
Lieuwe D. Bos ◽  
Tamara M. E. Nijsen ◽  
...  

Bacterial volatile organic compounds have the potential to be utilised as diagnostic biomarkers for infections.


2014 ◽  
Vol 11 (4) ◽  
pp. 445 ◽  
Author(s):  
Victor Vargas ◽  
Marie-Cecile Chalbot ◽  
Robert O'Brien ◽  
George Nikolich ◽  
David W. Dubois ◽  
...  

Environmental context Volatile organic compounds are precursors of ozone, a pollutant with adverse environmental effects. It is important to determine the associations between the various sources of volatile organic compounds and ozone levels because emission controls are based on sources. We estimated the contributions of specific sources of volatile organic compounds on ozone levels using both measurements and statistical models, and found that traffic is the largest source even in events when wildfire smoke is present. Abstract Here, we present the application of a tiered approach to apportion the contributions of volatile organic compound (VOC) sources on ozone (O3) concentrations. VOCs from acetylene to n-propylbenzene were measured at two sites at Boise, Idaho, using an online pneumatically focussed gas chromatography system. The mean 24-h concentrations of individual VOCs varied from 0.4ppbC (parts per billion carbon) for 1-butene to 23.2ppbC for m- and p-xylene. The VOC sources at the two monitoring sites were determined by positive matrix factorisation. They were attributed to: (i) liquefied petroleum and natural gas (LPG/NG) emissions; (ii) fugitive emissions of olefins from fuel and solvents; (iii) fugitive emissions of aromatic VOCs from area sources and (iv) vehicular emissions. Vehicle exhausts accounted for 36 to 45% of VOCs followed by LPG/NG and fugitive emissions of aromatic VOCs. Evaluation of photochemical changes showed that the four separate VOC sources were identified by PMF rather than different stages of photochemical processing of fresh emissions. The contributions of VOC sources on daily 8-h maximum O3 concentrations measured at seven locations in the metropolitan urban area were identified by regression analysis. The four VOC sources added, on average, 6.4 to 16.5 parts per billion by volume (ppbv) O3, whereas the unexplained (i.e. intercept) O3 was comparable to non-wildfire policy-relevant background O3 levels in the absence of all anthropogenic emissions of VOC precursors in North America for the region. Traffic was the most significant source influencing O3 levels contributing up to 32ppbv for days with O3 concentrations higher than 75ppbv.


Atmosphere ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1487
Author(s):  
Yannick Robin ◽  
Johannes Amann ◽  
Tobias Baur ◽  
Payman Goodarzi ◽  
Caroline Schultealbert ◽  
...  

With air quality being one target in the sustainable development goals set by the United Nations, accurate monitoring also of indoor air quality is more important than ever. Chemiresistive gas sensors are an inexpensive and promising solution for the monitoring of volatile organic compounds, which are of high concern indoors. To fully exploit the potential of these sensors, advanced operating modes, calibration, and data evaluation methods are required. This contribution outlines a systematic approach based on dynamic operation (temperature-cycled operation), randomized calibration (Latin hypercube sampling), and the use of advances in deep neural networks originally developed for natural language processing and computer vision, applying this approach to volatile organic compound measurements for indoor air quality monitoring. This paper discusses the pros and cons of deep neural networks for volatile organic compound monitoring in a laboratory environment by comparing the quantification accuracy of state-of-the-art data evaluation methods with a 10-layer deep convolutional neural network (TCOCNN). The overall performance of both methods was compared for complex gas mixtures with several volatile organic compounds, as well as interfering gases and changing ambient humidity in a comprehensive lab evaluation. Furthermore, both were tested under realistic conditions in the field with additional release tests of volatile organic compounds. The results obtained during field testing were compared with analytical measurements, namely the gold standard gas chromatography mass spectrometry analysis based on Tenax sampling, as well as two mobile systems, a gas chromatograph with photo-ionization detection for volatile organic compound monitoring and a gas chromatograph with a reducing compound photometer for the monitoring of hydrogen. The results showed that the TCOCNN outperforms state-of-the-art data evaluation methods, for example for critical pollutants such as formaldehyde, achieving an uncertainty of around 11 ppb even in complex mixtures, and offers a more robust volatile organic compound quantification in a laboratory environment, as well as in real ambient air for most targets.


1994 ◽  
Vol 77 (3) ◽  
pp. 735-737
Author(s):  
Alan D Hewitt

Abstract This paper describes a vapor fortification method for preparing quality assurance/quality control soils for volatile organic compound analysis. Treatment of soils with volatile organic compounds occurs in a closed container in a manner somewhat analogous to the way the vadose zone often becomes contaminated. One advantage of this method for preparing soils for quality assurance/quality control purposes is that the efficiency of various extraction methods can be reliably compared. Furthermore, by substantially reducing the error due to sample inhomogeneity, the error associated with the determinative step can also be properly evaluated.


1993 ◽  
Vol 5 (4) ◽  
pp. 361-366 ◽  
Author(s):  
N. J. Roberts ◽  
H. R. Burton ◽  
G. A. Pitson

Five volatile organic compounds were identified throughout 1991 in the hypolimnion of Organic Lake. These were dimethylsulphide (DMS), dimethyldisulphide (DM2S), dimethyltrisulphide (DM3S), dimethyltetrasulphide (DM4S) and phenol. The concentration of these compounds increased with lake depth. The concentration of DMS and DM2S was higher in the sediment than in the water column. Carbon disulphide occurred only in the sediment. DMS was the only volatile organic compound detected in the epilimnion of the lake, where its concentration increased from winter onwards. The source of DMS was not dimethylsulphoniopropionate (DMSP). This was determined by hydroxylation of the sample with NaOH. There was no change in the concentration of DMS but the concentration of DM2S increased dramatically while the concentrations of DM3S and DM4S decreased concomitantly. This has important implications in the estimation of DMS derived from DMSP by hydroxylation when organic polysulphides are also present. The stability of the hypolimnion of Organic Lake was reflected by the lack of change in temperature, density, redox potential and the relatively constant concentration of volatile organic compounds throughout the year. Potential sources of the volatile organic compounds are discussed in relation to the isolated nature of the lake.


2016 ◽  
Vol 26 (2) ◽  
pp. 166-184 ◽  
Author(s):  
Wei Ye ◽  
Doyun Won ◽  
Xu Zhang

Volatile organic compounds emissions from building materials can be a major pollution source in low-occupant-density spaces. Composite-style indoor air quality references, which reflect the combined effects of multiple volatile organic compounds, can be used to determine ventilation rate requirements based on building material emissions. The lowest concentration of interest concept was adopted to implement the idea. Twenty-eight building materials selected from the National Research Council of Canada database were subjected to emission modelling, resulting in 101 volatile organic compounds as a starting volatile organic compound pool. A method was proposed to generate a volatile organic compound priority list that determines ventilation rate requirements while considering ozone-initiated reactions. Three priority lists were obtained based on three lowest concentration of interest schemes, i.e., AFSSET, AgBB and EU-LCI, with each consisting of 17–21 volatile organic compounds that were most likely to attribute to large ventilation rate requirements. Also, analyses of selected volatile organic compounds showed that the changes in the composition of the priority lists due to ozone-initiated reactions could be ignored at a typical indoor ozone concentration level. The application of priority lists was discussed for source control and air cleaning device testing. This paper provides a method to prioritize the chemicals based on ventilation rate requirements with a goal of developing volatile organic compound control strategies at building design stage.


Author(s):  
Muyue Han ◽  
Jing Zhao ◽  
Lin Li

Abstract The integration of additive manufacturing technologies with stimuli-responsive shape memory materials allows the dynamic self-adaptation of fabricated parts upon exposure to external stimulations. The additional dimension of time inspires the concept of four-dimensional printing technology. However, the emerging feedstock materials and the employment of external stimuli in 4D printing are also associated with new workplace hazards and occupational health concerns. Current evaluation studies on additive manufacturing are mainly focused on the safety and health effects that originated from the part production phase and cannot be directly applied in 4D printing processes. In this study, the emissions of volatile organic compounds from stereolithography-based 4D printing process with thermo-responsive materials are targeted as the potential safety concern. Real-time total volatile organic compound monitoring is conducted during various production phases to align the emission sources with critical operating activities, including both operator interventions and machine operations. Comparative experiments are performed to evaluate the effectiveness of proposed emission control strategies. In particular, alterations in operation procedures such as stirring speed in material mixing and post-printing stimulation method can contribute positively to air emission control during manual operations. In addition, the installation of activated carbon fiber filters inside the machine build chamber can lead to a significant reduction of air emissions during part fabrication with an overall total volatile organic compound concentration reduction of 58.91%.


Chemosensors ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 104
Author(s):  
Hung-Yang Kuo ◽  
Wei-Riu Cheng ◽  
Tzu-Heng Wu ◽  
Horn-Jiunn Sheen ◽  
Chih-Chia Wang ◽  
...  

This paper presents the synthesis and evaluation of a carbon molecular sieve membrane (CMSM) grown inside a MEMS-fabricated μ-preconcentrator for sampling highly volatile organic compounds. An array of µ-pillars measuring 100 µm in diameter and 250 µm in height were fabricated inside a microfluidic channel to increase the attaching surface for the CMSM. The surface area of the CMSM was measured as high as 899 m2/g. A GC peak amplification factor >2 × 104 was demonstrated with gaseous ethyl acetate. Up to 1.4 L of gaseous ethanol at the 100 ppb level could be concentrated without exceeding the capacity of this microchip device. Sharp desorption chromatographic peaks (<3.5 s) were obtained while using this device directly as a GC injector. Less volatile compounds such as gaseous toluene, m-xylene, and mesitylene appeared to be adsorbed strongly on CMSM, showing a memory effect. Sampling parameters such as sample volatilities, sampling capacities, and compound residual issues were empirically determined and discussed.


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