Aldehydes volatile organic compounds

Volatile organic compounds (VOCs) include organic compounds with appreciable vapor pressure. They make up a major class of air pollutants.I his class includes not only pure hydrocarbons but also partially oxidized hydrocarbons (organic acids, aldehydes, ketones), as well as organics containing chlorine, sulfur, nitrogen, or other atoms in the molecule. 

Many volatile organic compounds (hydrocarbons, alcohols, aldehydes, acids, esters, ketones, amines, etc.) have been identified in marine systems [ 156,157]. These volatile materials may have an important role in the cycling of organic... 

TEVES has been used to treat soils contaminated with laboratory-generated organic wastes including alcohols, aldehydes, amines, ketones, benzene and substituted benzenes, ethers, phenols, polymers, and heterocyclic compounds. The largest volume of organic wastes treated were volatile organic compounds (VOCs) and various types of oils (hydraulic, transformer, heat transfer fluid, and motor oils). 

Puxbaum, H., Biogenic Emissions of Alcohols, Ester, Ether, and Higher Aldehydes, in Biogenic Volatile Organic Compounds in the Atmosphere (G. Helas, J. Slanina, and R. Steinbrecher, Eds.), pp. 79-99, SPB Academic Publishing, Amsterdam, 1997. 

The volatile organic compounds on the list of hazardous air pollutants under the CAAA have been classified into four main categories (/) pure hydrocarbons (qv), (2) halogenated hydrocarbons (see CHLOROCARBONSANDCHLOROHYDROCARBONs), (3) nitrogenated hydrocarbons (see Cyanides), and (4) oxygenated hydrocarbons (see Aldehydes Ethers Ketones). The compounds in these groups are characterized by the following oxidation reactions (26) ... 

The first representative reference values for indoor air in German households were derived from a study conducted by the old Federal Health Office into around 500 households in West Germany in 1985/86 (Krause, Chutsch and Henke, 1991). In 2007 updated reference values for individual volatile organic compounds (VOCs) and for aldehydes (Tables 9.3 and 9.4) were derived from long-term sampling in >550 households by means of diffusion samplers. Additionally a number of mostly regional studies have been made in schools (Heinzow et al., 1994), day-care centers (Schreiner, Wetzel and Kirchbach, 2001) and offices (Schlechter et al., 2004). 

There are 14 analytical methods developed by U.S. EPA for measuring common organic pollutants in air. These analytes include aldehydes and ketones, chlorinated pesticides, polynuclear aromatic hydrocarbons, and many volatile organic compounds. These methods may also be applied to analyze other similar substances. All these methods are numbered from TO-1 to TO-14 and based on GC, GC/MS, and HPLC analytical techniques. Method numbers, sampling and analytical techniques, and the types of pollutants are outlined in Table 1, while individual substances are listed in Table 2. 

Organic gases Hydrocarbons Aldehydes, ketones Other organics Benzene, butadiene, butene, ethylene, isooctane, methane Acetone, formaldehyde Acids, alcohols, chlorinated hydrocarbons, peroxyacyl nitrates, polynuclear aromatics There are two main groups of hydrocarbons of concern volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs). 

Liquids that are likely to cause problems following encapsulation are low molecular weight water-soluble and volatile organic compounds, such as some alcohols, acids, ketones, and esters water (above 5%) emulsions (whether oil in water or water in oil) liquids with extremes of pH and aldehydes. 

Molds while growing produce various chemicals as a result of their primary metabolic processes. These processes are needed to ensure the continuation of the mold s life cycle. The gaseous metabolic products are collectively referred to as microbial volatile organic compounds (mVOCs). Some mVOCs are primary solvents and are chemically identical to those originating from solvent-based building materials and cleaning supplies (e.g., alcohols, aldehydes, ketones, hexane, methylene chloride, benzene, and acetone). 

Environmental criteria have been established for many of these, but the utility and applicability of such criteria for indoor environments is controversial for at least four reasons. Eor example, the goals of the threshold limit values often do not include preventing irritation, a primary concern in indoor environments with requirements for close eye work at video display terminals. For most of the pollutant categories, the problem of interactions, commonly termed the multiple contaminants problem , remains inadequately defined. Even for agents that are thought to affect the same receptor, such as aldehydes, alcohols, and ketones, no prediction models are well established. Finally, the definition of representative compounds for measurement is unclear. That is, pollutants must be measurable, but complex mixtures vary in their composition. It is unclear whether the chronic residual odor annoyance from environmental tobacco smoke correlates better with nicotine, particulates, carbon monoxide, or other pollutants. The measure total volatile organic compounds is meanwhile... 

For ventilation systems a separate study named AIRLESS was performed [30,55]. Experiments were performed to investigate why, when and how the components of HVAC systems pollute or are the reason for pollution. Different combinations of temperature, relative humidity, airflow and pollution in passing air were investigated. Measurements of perceived air quality, particles, chemical compounds (such as very volatile organic compounds and aldehydes) and biological compounds were selected for each component. The most polluting components of HVAC systems were studied in the laboratory and in the field. The perceived air quality or odour intensity was in most cases measured with a trained sensory panel, according to the protocol developed for the AIRLESS project (Sect. 3.2). 

Abstract The possible utilization of room temperature ionic liquids (RTILs), instead of volatile organic compounds (VOCs), in the electrochemical procedures of organic synthesis has been discussed. The synthesis of p-lactams, the activation of carbon dioxide and its utilization as renewable carbon source and the carbon-carbon bond formation reactions via umpolung of aldehydes (benzoin condensation and Stetter reaction) and via Henry reaction have been selected as typical electrochani-cal methodologies. The results, related to procedures performed in RTILs, have been compared with those performed in VOCs. The double role of RTILs, as green solvents and parents of electrogenerated reactive intermediates or catalysts, has been emphasized. 

Chiarotto I, Feroci M, Orsini M, Feeney MMM, Inesi A (2010) Study on the reactivity of aldehydes in electrolysed ionic liquids. Benzoin condensation VOCs (volatile organic compounds) vs RTlLs (room temperature ionic liquids). Adv Synth Catal 352 3287-3292... 

Aldehydes are emitted directly into the atmosphere from a variety of natural and anthropogenic sources and are also formed in situ from the atmospheric degradation of volatile organic compounds (VOCs). The atmospheric fate of aldehydes is controlled by photolysis and reaction with hydroxyl (OH) or nitrate (NO3) radicals and, in the case of unsaturated compounds, reaction with ozone (Atkinson, 1994). The photolysis of aldehydes is of particular importance because it is a source of free radicals in the troposphere, and thus may significantly influence the oxidizing capacity of the lower atmosphere (Finlayson-Pitts and Pitts, 1986). 

This book provides standardized methods for measuring the major toxic organic contaminants found in air, inducting volatile organic compounds, aldehydes and ketones, phosgene, non-methane organic compounds, pofynudear aromatics hydrocarbons, and others. 

The various classes of volatile organic compounds have different distribution coefficients, which aid in their separation and identification. Two equilibrations transfer all alkanes and cycloalkanes into the gas phase, leaving aromatics in the water. Alcohols, acids, aldehydes, and ethers partition little to the gas phase and generally do not interfere in hydrocarbon analyses. If present in amounts that interfere, they can be identified as nonhydrocarbons by their distribution coefficients. They can be analyzed if desired by greatly increasing the gas-to-water ratio. 

D. Volatile organic compounds (VOCs), including low-molecular-weight alcohols, aldehydes, and ketones, are generated by molds, and are often responsible for the musty, disagreeable odor associated with indoor molds. A role for these VOCs in some building-related symptoms is possible. 

Committee on the Medical Effects of Air Pollutants (COMEAP) (1998) The quantification of the effects of air pollution on health in the United Kingdom. http //www.doh.gov.uk.htmlx Davis ME, Blicharz AP, Hart JE, Laden F, Garshick E, Smith TJ (2007a) Occupational exposure to volatile organic compounds and aldehydes in the U.S. trucking industry. Environ Sci... 

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