volatile organic compounds in the atmosphere

... and may be removed in rain remote fromtheir point of original emission Once deposited in rain, they may re-evaporateback into the atmosphere and begin the cycle all over again Ultimately thismaterial ... of the scientific aspects relating to volatile organic compounds in the atmosphere In the first article, Dick Derwent of the Meteorological Office provides a broadly-based introduction to the ... thoseorganic compounds which could induce cancer in the human population: thehuman genotoxic carcinogens.12 The term ‘air toxics’ is usually given to thoseorganic compounds that are present in the

Ngày tải lên: 13/05/2022, 15:57

... misleading the final biological interpretation Third, extremes of pH coupled to the temperature used in the SPME extraction (e.g 60 °C) may promote further reactions involving compounds in the urine ... concentration of compounds in the headspace of the urine samples by increasing the ionic strength of these samples, which result in a richer profile of VOCs detected by GC-MS [11] Although the addition ... of headspace‑SPME‑GC‑MS The stability of the headspace-SPME-GC-MS system used in this study was assessed with the use of a reference solution containing four compounds (Fig. 1) Most compounds showed a variance in intensity

Ngày tải lên: 29/05/2020, 13:33

... tested the hypothesis that the secretions from the VEG gland of Spodoptera exigua caterpillars contain elicitors that induce plant defenses by regulating the expression of genes involved in the ... monoterpenes were emitted in higher amounts by plants damaged by VEGI caterpillars, suggesting the involvement of the VEG in the induction of plant VOCs For instance, most GLVs including (E)-2-hexenal, ... on the ventral surface of the caterpillar thorax and reaches the injured plant surface [32,61] Furthermore, because the tip of the everted VEG can reach the mandibles during feeding [35], the

Ngày tải lên: 27/05/2020, 01:24

... Road The coordinates of these locations are provided in Table 1 Locations for monitoring ambient air quality stations are selected in keeping with the Guidelines for Planning the Sampling of Atmosphere ... trend where the concentrations of BTX were high during the beginning of the year, lowest during the middle of the year and high during the end of the year followed by a marked decrease again after ... monsoon The concentrations increase during winter months This trend is depicted in Figures 2, 3 and 4 In all the three cities the benzene concentrations show a slight increase during the month

Ngày tải lên: 13/01/2020, 05:26

... releasing the compounds com- pletely onto the first capillary column The purge & trap parame- ters are specified in detail in the supporting information (Table S2 in SI) The effluent of the first ... contamination following this treatment Although the baseline in the first dimension remained noisy, tar- get compounds, with the exception of CT, could be isolated from the interfering compounds ... chlorinated and petroleum hydrocarbons were introduced to the subsurface during the 1960s These formed a downgradient plume in the heterogeneous sandy aquifer, further diffusing into a thin underlying

Ngày tải lên: 25/12/2022, 02:13

... are listed in Table At the soil–atmosphere interface, hence, the dominating transport mechanism shifts from pure diffusion in the soil to eddy diffusion in the atmosphere Typically, the eddy diffusion ... profiles in the soil (solid lines) as well as the results of our sensitivity analysis (dashed lines) With increasing organic carbon content in the soil, i.e with increasing sorption to the solid ... areas indicate the location of the topsoil layer Only in the low organic carbon case the pollution penetrated the high organic topsoil after the start of the regulation period In particular, Cousins

Ngày tải lên: 02/11/2022, 14:39

... species in the environment, but also influencing ecosystem functioning due to the toxicity of most BVOCs for omnivorous her-bivores, forcing them to change their dietary habits In the atmosphere, ... break down the leaf structures that hold the volatiles, but is much lower than the boiling point of BVOCs This avoids decomposition of most of the compounds in the essential oil Since heating is ... allowing the solsol-vent to vaporize By means of a condenser, the solvent turns back into liquid and then drips back onto the foliage, performing the BVOC extraction The foliage is contained in

Ngày tải lên: 17/03/2023, 16:32

... related compounds in other areas in Vietnam, for instance, industrial parks, informal waste recycling areas, and waste dumping and open burning sites 3.4.3 Other industrial chemicals The contribution ... knowledge, there have been no studies on the screening analysis of organic pollutants in northern Vietnam In the present study, 942 organic compounds were comprehensively monitored in the air samples ... about the occurrence of these carci-nogenic pollutants in Vietnamese working environments is limited These preliminary data on the concentrations of PAHs and related compounds in the air of the

Ngày tải lên: 22/03/2023, 10:47

... naturally in crude oil and in the tolu tree. It is produced in the process of making gasoline and other fuels from crude oil. Toluene is also used in making paints, paint thinners, fingernail ... a cleaning fluid, in industry and dry cleaning businesses, and in the household. Carbon tetrachloride also was used in fire extinguishers and as a fumigant to kill insects in grain. These uses ... 1,4-dichlorobenzene mainly by breathing vapors from 1,4dichlorobenzene products used in the home 1,4-Dichlorobenzene can also get into the body from drinking water that contains it or from eating certain foods,

Ngày tải lên: 14/02/2014, 03:20

... are marked increases in the future demand of all organic products This augurs well for the growth of the organic industry in the Eastern Cape and in South Africa in general The findings of this ... analyze the resulting data There is evidence of growing interest in organic products in the province, with a sizeable proportion of respondents having consumed or considered consuming organics ... vendors (21%) being the least preferred (Figure 1) Only 2% of the respondents in the Transkei and 1% in the Ciskei bought their food from the farm gate This finding is consistent with information

Ngày tải lên: 14/02/2014, 03:20

... increasing concentration of Se in the culturing media The selenomethionine made up 30–40% of the total Se in biomass In both the wild type and Se-resistant strains, the activity of thioredoxin reductase, ... which are involved in maintaining the cell redox potential [15] Most of the selenoproteins are found as animal proteins They have not been found in yeast and land plants Sur-prisingly, they have ... accumulation [33] In Chlorella zofingiensis the accumulation of boiling-stable proteins and the increased activities of the antioxidant enzymes suggested that these compounds were involved in the mechanisms

Ngày tải lên: 12/08/2014, 03:20

... Trang 1CÁC CÔNG NGHỆ XỬ LÝ H2S VÀ VOC (VOLATILE ORGANIC COMPOUNDS) TRONG KHÍ THẢI Giảng viên : Ts Phạm Xuân Núi Nhóm thực hiện : 1.Nguyễn Hữu ... được tạo thành xâm nhập hệ tuần hoàn tác động đến các vùng cảm giác – mạch, vùng sinh phản xạ của các thần kinh động mạch cảnh - Thường xuyên tiếp xúc với H2S ở nồng độ dưới mức gây độc cấp tính ... trở lại chu trình để kết hợp với CO2 và H2O có trong khí thải tạo thành amin cacbonat và phản ứng trên tiếp tục xảy ra theo sơ đồ hệ thống xử lí khí H2S bằng amoni cacbonat Trang 9 Sơ đồ hệ thống

Ngày tải lên: 12/04/2015, 14:24

... products, and plastics, as well as in the synthesis of other organic compounds VOCs also are used in the dry cleaning of clothing, in refrigeration units, and in the degreasing of equipment and home septic ... restricts the downward movement of water and contaminants to the underlying confined part of the Edwards aquifer, resulting in a smaller VOC occurrence in the confined area than in the unconfined ... understanding the quality of drinking-water supplies including the monitoring of river intakes and production wells of large CWSs, as well as the continued sampling of domestic wells In addition,...

Ngày tải lên: 14/03/2014, 19:20

... identified as a single point in Fig Point (∼17:00) is an interception of the plume at a lower altitude upon return into the MCMA The higher mixing ratios of MTBE at the beginning and the end of the flights ... evolution of volatile organic compounds (lower panel) shows the averaged mixing ratios for the top 20 VOCs obtained on the C130 during the over-flights and the pie chart to the right of the bar chart ... further reduction of the boundary layer height in the morning together with some contribution from traffic and industry during the early morning before the boundary layer has expanded During the...

Ngày tải lên: 28/03/2014, 20:20

... noise in mfc Although it is difficult to determine the exact starting and ending points of the noise interval, the selected noise range should be sufficiently long to reflect the noise information ... are presented in Figures 10-14 The plot showing emitter locations was produced by superimposing the wind directional plot (blue area) onto the map where the corresponding emitters in the observed ... corresponds to the wind direction plot for this source The red × at the center of the blue area is the sampling site of the reasons why isoprene and M87 occur in the same source The KD value of...

Ngày tải lên: 22/03/2014, 14:20

... 19% The total explained variance of the model was therefore 66.5% In order to test the discriminant power of the exhaled VOC pattern, a multinomial logistic regression was made using the coding ... identifying biomarkers of early lung cancer probably require the use of a panel rather than single substances [17] The main finding of our study was that none of selected VOCs alone distinguished the ... [20]; furthermore, it allowed us to measure most of the substances of interest proposed in the literature Another reason for the difference in VOC identification may be the different clinical characteristics...

Ngày tải lên: 12/08/2014, 18:21

... weight of the reactive organic compounds contained in aerosol coating products, for the purpose of determining compliance with the Aerosol Coatings Regulation 5.1 The testing begins when the Executive ... to determine the boiling point for a compound or for a mixture If the boiling point exceeds 216oC, the compound or mixture is an LVP-VOC If the boiling point is less than 216oC, then the weight ... portion of the product sample is analyzed to determine the reactive organic compounds in the sample, including the presence of any prohibited compounds This analysis is conducted by performing the following...

Ngày tải lên: 14/03/2014, 20:20

... and Lindvall, T., 1993 Volatile organic compounds in ventilating air in buildings at different sampling points in the building and their relationship with the prevalence of occupant symptoms Indoor ... of volatile compounds (VOC) and formaldehyde in the Swedish housing stock In: Indoor Air '93, Proceedings of the 6th Interantional Conference on Indoor Air Quality and Climate, Helsinki, Finland, ... Cometto-Muniz and Cain (1995) An evaluation of the usefulness of these refined indices of VOC exposure is beyond the scope set out for the working group, and is therefore not included in the present...

Ngày tải lên: 28/03/2014, 19:20

... in 2004, an 11% increase due to the growing popularity of regional markets, the on 2003 increase of green conscience including The formation of The organic food production is stepping up in the ... concern, beginning with the first step of organic product getting The achievement of the organic product under the Obtaining organic products is possible, if the green form a reference model is the result ... recent amendment to the organic The NOP has raised the profile of organic products and legislation has allowed some in the second largest in the they are becoming highly visible in mainstream retailers...

Ngày tải lên: 14/02/2014, 08:20

... confirms the hypothesis that the silk is indeed present in two states, soluble and insoluble, the latter being in some way protected from dissolution in water The peculiarity of the WSM led to the ... characterize these proteins are presently in progress Above all these distinctions, the global amino acid composition showed clearly that the proteins extracted by the two methods are not the same On the ... extract and study organic compounds of the biomineral nacre, by bypassing the demineralization step We think that it may present a new perception of how the different fractions of the organic matrix...

Ngày tải lên: 21/02/2014, 01:21