Characterisation and source attribution of the semi-volatile organic content of atmospheric particles and associated vapour phase in Birmingham, UK

2003 ◽  
Vol 37 (35) ◽  
pp. 4985-4991 ◽  
Author(s):  
Stuart Harrad ◽  
Suzanne Hassoun ◽  
Marı́a S Callén Romero ◽  
Roy M Harrison
2019 ◽  
Author(s):  
Shahrul Azman Zainal Abidin ◽  
Azlina Khairi ◽  
Lukman Abdul Karim ◽  
Azleen Azna Khairil Hing

2018 ◽  
Vol 63 (1) ◽  
pp. 170-178 ◽  
Author(s):  
László Kiss

In this article, the feasibility of the CuxS modified carbon microdisc electrode was examined by exposure to four different volatile organic compounds (2-propanol, acetic acid, ethyl acetate and n-butylamine) directly in their vapour phase using cyclic voltammetry and amperometry. The performance of the modified microdisc was compared with the bare carbon microdisc (30 μm in diameter) which was involved in a narrow-gap cell. By using both methods high current increase was observed for 2-propanol with the modified electrode and its sensitivity was sufficiently higher than with the bare electrode. The modified electrode showed lower current signals in case of acetic acid and n-butylamine. The latter formed a condensation layer at the interelectrode gap. Neither the bare nor the modified electrode was sensitive to ethyl acetate.


2018 ◽  
Vol 11 (7) ◽  
pp. 2825-2840 ◽  
Author(s):  
Tim Butler ◽  
Aurelia Lupascu ◽  
Jane Coates ◽  
Shuai Zhu

Abstract. A system for source attribution of tropospheric ozone produced from both NOx and volatile organic compound (VOC) precursors is described, along with its implementation in the Community Earth System Model (CESM) version 1.2.2 using CAM4. The user can specify an arbitrary number of tag identities for each NOx or VOC species in the model, and the tagging system rewrites the model chemical mechanism and source code to incorporate tagged tracers and reactions representing these tagged species, as well as ozone produced in the stratosphere. If the user supplies emission files for the corresponding tagged tracers, the model will produce tagged ozone tracers which represent the contribution of each of the tag identities to the modelled total tropospheric ozone. Our tagged tracers preserve Ox. The size of the tagged chemical mechanism scales linearly with the number of specified tag identities. Separate simulations are required for NOx and VOC tagging, which avoids the sharing of tag identities between NOx and VOC species. Results are presented and evaluated for both NOx and VOC source attribution. We show that northern hemispheric surface ozone is dominated year-round by anthropogenic emissions of NOx, but that the mix of corresponding VOC precursors changes over the course of the year; anthropogenic VOC emissions contribute significantly to surface ozone in winter–spring, while biogenic VOCs are more important in summer. The system described here can provide important diagnostic information about modelled ozone production, and could be used to construct source–receptor relationships for tropospheric ozone.


Author(s):  
O. L. Shaffer ◽  
F.H. Walker ◽  
M. S. El-Aasser

The examination of polymer material by transmission electron microscopy (TEM) often relies on staining in order to improve contrast or preferentially stain a polymer phase. Stains such as osmium tetroxide for unsaturated polymers and ruthenium tetroxide for unsaturated as well as certain saturated polymers have been used quite extensively. A new stain, 3-iodopropionic acid, has been found to be very useful to stain preferentially the amine rich domains in waterborne epoxy films.An epoxy dispersion (epoxy equivalent weight, EEW=625) and a polyamine adduct curing agent (AHEW=163) at a 1.5:1 stoichiometry was prepared. The volatile organic content (VOC) was 2.6 lb./gal., and the solvent blend was 90.6% propoxy ethanol and 9.4% Aromatic 150. The particles size of the starting dispersion was obtained by TEM and disk centrifuge and found to be approximately 500 nm. Films (approximately 1.2 mil dry film thickness[DFT]) were cast on a partially fluorinated polyethylene film, 0.5, 2, 4, and 8 hours after hand mixing and cured for two or more weeks at 25° C and 50% relative humidity.


RSC Advances ◽  
2017 ◽  
Vol 7 (35) ◽  
pp. 21796-21808 ◽  
Author(s):  
Mohamed S. Selim ◽  
Mohamed A. Shenashen ◽  
Ahmed Elmarakbi ◽  
Ashraf M. EL-Saeed ◽  
Mahmoud M. Selim ◽  
...  

Approaches for designing advanced nanomaterials with hyperbranched architectures and lack of volatile organic content (VOC) have attracted considerable attention.


2017 ◽  
Vol 54 (11) ◽  
pp. 1567-1579 ◽  
Author(s):  
Haijian Xie ◽  
Qiao Wang ◽  
Huaxiang Yan ◽  
Yunmin Chen

An analytical model for the diffusion of one-dimensional vapour-phase volatile organic compounds (VOCs) through a four-layer landfill composite cover system consisting of a protective layer, drainage layer, geomembrane (GMB), and compacted clay liner (CCL) is developed. Effects of degree of water saturation (Sr), adsorption, and degradation on vapour-phase VOC diffusion in a cover system are then analyzed. The vapour-phase benzene concentration profile increases with increase of Sr in the drainage and protective layers. When Sr1 = Sr2 = 0.5 (where Sr1 and Sr2 are degree of water saturation of the protective and drainage layers, respectively), surface flux for the case with the degree of water saturation of the CCL layer Sr4 = 0.3 is 1.3 and 1560 times larger than that with Sr4 = 0.7 and = 0.9, respectively. The effect of adsorption of the VOCs in the CCL on performance of the cover system is more important than that in the drainage and protective layers. Surface flux and concentration of benzene tends to be zero when CCL is amended with 0.5% biochar due to an increase of the retardation factor. The effect of degradation rate on benzene concentration increases with increase of degree of water saturation. The influence of half-life of VOCs in the soil layer, t1/2, on vapour-phase VOC concentration can be neglected when Sr ≤ 0.3.


2019 ◽  
pp. 291-294
Author(s):  
Lennart Mårtensson ◽  
Lars Thörneby ◽  
Staffan Bergström ◽  
Diauddin Nammari ◽  
Lennart Mathiasson

Volatile organic compounds (VOC) are typically defined as those predominantly presentin the vapour phase in air at ambient temperature, They range in volatility from methaneto n-e 16 above and include all chemical groups - alcohols, ketones, aldehydes, esters,glycol ethers, halogens and hydrocarbons, Many of the voes are produced and emittedwhen organic matter decomposes from microbiological activity, A great number ofvolatile compounds been identified in the air in the vicinity of landfills, voes emittedfrom landfills pose as health concern and odour annoyance for the neighbourhood, Highconcentrations of voes have also been identified in the working environments at wastehandling facilities, Emissions of volatile organics from leachate, and how the treatmentsystem affects the fate of the voes have been reported, A variety of different samplingstrategies and sampling media can be used to address different monitoring requirements,including adsorption tubes and impingers with a suitable absorption solution, Finalanalysis of voes can be performed with a combination of thermodesorption ofadsorption tubes and Ge-MS, Model studies of the emission of voes from the watersurface, at the actual site in ponds or in the laboratory, can be performed in order tofacilitate budget calculations using a special designed hood, Results from analysis ofleachate before and after treatment procedures, using purge and trap methodology, showshow some identified voes such as for example benzene, toluene, xylen and trimethylbenzene are to some extent removed from the liquid,


Author(s):  
Kathryn Nother ◽  
Madeleine S. Ashley ◽  
Peter M. Clayton

Summary Activated carbons are effective adsorbents for many volatile organic compounds and are used in cigarette filters to remove selected smoke toxicants. Polymer-derived carbon is more effective in removing many vapour phase toxicants found in cigarette smoke than coconut-shell-derived carbon. We compared mouth-level exposure to “tar”, nicotine and five vapour phase constituents (1,3- butadiene, benzene, toluene, isoprene, acrylonitrile) in two groups of Romanian smokers of 4-mg or 8-mg International Organization for Standardization (ISO) “tar” bands. Test cigarettes with 4 and 8 mg ISO “tar” were manufactured for the study with two target levels of polymer-derived carbon (30 mg and 56 mg), along with control cigarettes containing a target level of 56 mg of coconut-shell-derived carbon in both “tar” bands. No significant differences were found between mouth-level exposure to “tar” or nicotine yields obtained from control and test products (p > 0.05) in either ISO “tar” band. Mouth-level exposure to each of the five vapour phase constituents was significantly lower from the test products with polymer-derived carbon (p < 0.0001) than from control cigarettes with coconut-shell-derived carbon, by an average of 25% with 30 mg polymer-derived carbon and around 50% with 56 mg. [Beitr. Tabakforsch. Int. 27 (2016) 40-53]


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