China
Africa
Explore chapters and articles related to this topic
Energy Use and Environmental Impact
Published in B K Bala, Energy Systems Modeling and Policy Analysis, 2022
Depending upon where it occurs, ozone (O3) plays two very different roles in the atmosphere. In the troposphere, where it is produced through the interaction of sunlight, NO, and volatile organic compounds (VOCs), ozone can be a major local and regional pollutant that can cause acute respiratory symptoms and damage to materials, crops and forests. Tropospheric ozone is also a greenhouse gas.
Chemical Monitoring of California's Public Drinking Water Sources: Public Exposures and Health Impacts
Published in Rhoda G.M. Wang, Water Contamination and Health, 2020
Sources are often treated at the wellhead or intake to decrease a contaminant's concentration to below its MCL. VOC are removed by aeration or granular activated carbon (GAC). Other organics and pesticides can be treated using GAC. Many contaminants, including nitrate and inorganics, can be treated using reverse osmosis. Inorganics can also be treated with ion exchange or precipitated, coagulated, and filtered. Treatment is often the most expensive option, but in many cases may be the only one available if an entire water basin is contaminated and no other water sources are at hand.
Plant Security
Published in Frank R. Spellman, Handbook of Water and Wastewater Treatment Plant Operations, 2020
Volatile organic compounds (VOCs) are a group of highly utilized chemicals that have widespread applications, including use as fuel components, as solvents, and as cleaning and liquefying agents in degreasers, polishes, and dry cleaning solutions. VOCs are also used in herbicides and insecticides for agricultural applications. Laboratory-based methods for analyzing VOCs are well established; however, analyzing VOCs in the lab is time consuming—obtaining a result may require several hours to several weeks depending on the specific method. Faster, commercially available methods for analyzing VOCs in the field include use of portable gas chromatographs (GC), mass spectrometer (MS), or gas chromatographs/mass spectrometers (GC/MS), all of which can be used to obtain VOC concentration results within minutes. These instruments can be useful in rapid confirmation of the presence of VOCs in an asset, or for monitoring an asset on a regular basis. In addition, portable VOC analyzers can analyze a wide range of VOCs, such as toxic industrial chemicals (TICs), chemical warfare agents (CWAs), drugs, explosives, and aromatic compounds. There are several easy-to-use, portable VOC analyzers currently on the market that are effective in evaluating VOC concentrations in the field. These instruments utilize gas chromatography, mass spectroscopy, or a combination of both methods, to provide near laboratory-quality analysis for VOCs.
A review on the heterogeneous oxidation of SO2 on solid atmospheric particles: Implications for sulfate formation in haze chemistry
Published in Critical Reviews in Environmental Science and Technology, 2023
Qingxin Ma, Chunyan Zhang, Chang Liu, Guangzhi He, Peng Zhang, Hao Li, Biwu Chu, Hong He
Volatile organic compounds (VOCs) are chemicals that have high vapor pressures and fairly low boiling points, which tend to vaporize from the liquid or solid state under normal atmospheric conditions. The heterogeneous reactions of VOCs were considered to be a significant sink for VOCs and have been used to explain the big gap between field and model studies (Shen et al., 2013). Meanwhile, the effect of reactive VOCs on the heterogeneous reaction of SO2 on mineral particles has also been studied. For example, Wu et al. (2013) found that SO2 can reduce the formation of formate in the heterogeneous reaction of HCOOH on a-Fe2O3, and HCOOH exhibited negative effects on the formation of sulfate. Similar results were observed in the heterogeneous uptake and adsorption of SO2 and acetaldehyde (CH3CHO) on hematite (Zhao et al., 2015). VOCs usually show a competitive effect with SO2 in heterogeneous reactions (Yang et al., 2020; Zhanzakova et al., 2019). Chu et al. (2019) found that coexisting C3H6 had little effect on sulfate formation in the heterogeneous reaction of SO2 on TiO2 but suppressed sulfate formation in the heterogeneous reaction of SO2 and NO2. More research on the effect of VOCs, especially organic oxidants, on the heterogeneous oxidation of SO2 on particles is needed.
Restricted substances for textiles
Published in Textile Progress, 2022
Arun Kumar Patra, Siva Rama Kumar Pariti
In the textile and footwear industry, VOCs find wide use in chemical preparations. Some of them are used in printing inks, coatings for fabric and leather, adhesives and synthetic leather. They are likely to be present as impurities in polystyrene based resins used in manufacture of plastic trims and products like buttons. Moreover, VOCs may also be used in dry-cleaning, finishing and degreasing operations (https://afirm-group.com/afirm-rsl/). Interesting studies have also been carried out on correlation of body odour with next-to-skin textiles with respect to adsorption and release of VOCs (Laing, 2019). Other than from textiles, sources of VOC emissions include chemical industries, petrochemicals, food processing, paint drying, transportation, petroleum refineries, automobile manufacturers, metal degreasing, electronic component plants and solvents. There are also indoor sources of the volatile pollutants like office supplies, printers, household products, insulating materials, wood stoves and leakages from piping (Kamal et al., 2016). In fact, their concentrations are higher indoors than they are outdoors. The type and nature of VOC is source dependent, examples being simple alkanes, halogenated hydrocarbons, aldehydes, alcohols, ketones, aromatics, olefins, ethers, esters, paraffins and sulphur-containing compounds (Khan & Ghoshal, 2000). Some common VOCs are listed below (Table 14).
Association between BTEX (benzene, toluene, ethylbenzene and xylene) concentration in ambient air with hematological and spirometric indices: a population-based study
Published in Human and Ecological Risk Assessment: An International Journal, 2022
Hosna Moradkhani, Mostafa Leili, Jalal Puralajal, Ashraf Mazaheri Tehrani, Ayat Hossein Panahi, Mohammd Taghi Samadi, Sara Beheshtifar
A chemical extraction method using carbon disulfide solvent was used to extract VOC from the samples. Then, the concentration of different VOC was performed using gas chromatography. The GC-FID device, made by Agilant Technologies, model GC-7890A, was used to detect and measure BTEX samples. The column used in the device was BP-5, with a length of 30 m and a diameter of 0.32 mm. The inner cover of the column is made of methyl polysiloxane with a thickness of 0.25, and its temperature range was between 40 and 325 °C. To inject the samples into GC, first the activated charcoal in the front and back of the absorber, which contains the BTEX, was transferred to separate vials. Next, 1 mL of carbon disulfide was added to each vial and was shaken for 30 min. Eventually, the samples were injected into the GC to detect and to measure of BTEX compounds. Meteorological parameters including wind speed, relative humidity and air temperature were recorded at the time of sampling to calculate the correct volume of air (Ishii et al., 2007; Masih et al., 2018).