"वाष्पशील कार्बनिक यौगिक": अवतरणों में अंतर
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{{हिन्दी नहीं|1=अंग्रेजी|date=दिसम्बर 2015}}
'''वाष्पशील कार्बनिक यौगिक(Volatile organic compounds)''' या
'''वाष्पशील कार्बनिक यौगिक(Volatile organic compounds)''' या ('''VOCs''') वे कार्बनिक रसायन है जिनमे कमरे के समान्य ताप पर भी उच्च वाष्प दाब होता है। इनका उच्च वाष्प दाब, उनके कम क्वथनांक की वजह से अधिक अणुओं के ठोस या द्रव वाष्पीकृत या ऊर्ध्वपतित होकर यौगिक बनाने व आस पास की वायु में मिलने के कारण होता है। निम्न क्वथनांक के कारण इनमे उच्च वाष्प दाब होता है, अधिक अणुओ का जल या ठोस अवस्था से वाष्पीकरण या ऊर्ध्वपातन होता है तथा यौगिक बनकर वायुमंडल में मिश्रित हो जाता है। जैसे कि निम्न क्वथनांक के paint- 19 °C (–2 °F) से formaldehyde का वाष्पीकरण।▼
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VOCs, कई अलग अलग, और सर्वव्यापी हैं। इनमे दोनों मानव निर्मित और स्वाभाविक रूप से होने वाली रासायनिक यौगिक शामिल है। अधिकतर सुगंधिया VOCs है। VOCs पौधों के मध्य सम्प्रेषण में महत्वपूर्ण भूमिका निभाते हैं,<ref>{{cite web |url=http://content.yudu.com/Library/A1og25/PlantsADifferentPers/resources/73.htm |title=Plants: A Different Perspective |publisher=Content.yudu.com |date= |accessdate=2012-07-03 |archive-url=https://web.archive.org/web/20170217195618/http://content.yudu.com/Library/A1og25/PlantsADifferentPers/resources/73.htm |archive-date=17 फ़रवरी 2017 |url-status=live }}</ref> तथा पौधों से जीवो को संदेश भेजते हैं। कुछ VOCs मानव स्वास्थ्य के लिए खतरनाक होते हैं व वातावरण को हानी पहुंचाते हैं। [[Anthropogenic behaviour|Anthropogenic]] VOCs are regulated by law, especially indoors, where concentrations are the highest. Harmful VOCs typically are not acutely [[toxic]], but have compounding long-term health effects. Because the concentrations are usually low and the symptoms slow to develop, research into VOCs and their effects is difficult.
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===Indoor air===
{{Main|Indoor air quality}}
Since many people spend much of their time indoors, long-term exposure to VOCs in the indoor environment can contribute to [[sick building syndrome]].<ref name="Wang, S. 2007" /> In offices, VOC results from new furnishings, wall coverings, and office equipment such as photocopy machines, which can [[Outgassing|off-gas]] VOCs into the air.<ref name="test" /><ref>{{cite journal |doi=10.1016/S0360-1323(97)00055-3 |title=A review of the emission of VOCs from polymeric materials used in buildings |url=https://archive.org/details/sim_building-and-environment_1998-11_33_6/page/357 |year=1998 |last1=Yu |first1=Chuck |last2=Crump |first2=Derrick |journal=Building and Environment |volume=33 |issue=6 |pages=357–74}}</ref> Good ventilation and air-conditioning systems are helpful at reducing VOCs in the indoor environment.<ref name="test" /> Studies also show that relative [[leukemia]] and [[lymphoma]] can increase through prolonged exposure of VOCs in the indoor environment.<ref>{{cite journal |doi=10.1016/j.biopha.2007.10.006 |title=Lifestyle-related factors and environmental agents causing cancer: An overview |year=2007 |last1=Irigaray |first1=P. |last2=Newby |first2=J.A. |last3=Clapp |first3=R. |last4=Hardell |first4=L. |last5=Howard |first5=V. |last6=Montagnier |first6=L. |last7=Epstein |first7=S. |last8=Belpomme |first8=D. |journal=Biomedicine & Pharmacotherapy |volume=61 |issue=10 |pages=640–58 |pmid=18055160}}</ref>
In the United States, there are two standardized methods for measuring VOCs, one by the [[National Institute for Occupational Safety and Health]] (NIOSH) and another by [[Occupational Safety and Health Administration]] (OSHA). Each method uses a single component solvent; [[butanol]] and [[hexane]] cannot be sampled, however, on the same sample matrix using the NIOSH or OSHA method.<ref>{{Cite web |url=http://galsonlabs.com/services/referenceinfo/technical_bulletins.php?tb_id=42 |title=Who Says Alcohol and Benzene Don't Mix? |access-date=11 सितंबर 2015 |archive-url=https://web.archive.org/web/20080415162950/http://galsonlabs.com/services/referenceinfo/technical_bulletins.php?tb_id=42 |archive-date=15 अप्रैल 2008 |url-status=dead }}</ref>
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The aromatic VOC compound [[benzene]], emitted from exhaled cigarette smoke is labeled as carcinogenic, and is ten times higher in smokers than in nonsmokers.<ref name="test">{{cite journal |doi=10.1503/cmaj.070359 |title=Quality of indoor residential air and health |year=2008 |last1=Dales |first1=R. |last2=Liu |first2=L. |last3=Wheeler |first3=A. J. |last4=Gilbert |first4=N. L. |journal=Canadian Medical Association Journal |volume=179 |issue=2 |pages=147–52 |pmid=18625986 |pmc=2443227}}</ref>
The United States Environmental Protection Agency (EPA) has found concentrations of VOCs in indoor air to be 2 to 5 times greater than in outdoor air and sometimes far greater. During certain activities indoor levels of VOCs may reach 1,000 times that of the outside air.<ref>{{Cite web |url=http://www.epa.gov/iaq/voc.html |title=An Introduction to Indoor Air Quality |access-date=11 सितंबर 2015 |archive-url=https://web.archive.org/web/20150909090046/http://www.epa.gov/iaq/voc.html |archive-date=9 सितंबर 2015 |url-status=live }}</ref> Studies have shown that individual VOC emissions by themselves are not that high in an indoor environment, but the indoor total VOC (TVOC) concentrations can be up to five times higher than the VOC outdoor levels.<ref>{{cite journal |doi=10.1016/S1352-2310(99)00272-1 |title=Indoor air quality and health |url=https://archive.org/details/sim_atmospheric-environment_1999-12_33_28/page/4535 |year=1999 |last1=Jones |first1=A.P. |journal=Atmospheric Environment |volume=33 |issue=28 |pages=4535–64}}</ref> New buildings especially, contribute to the highest level of VOC off-gassing in an indoor environment because of the abundant new materials generating VOC particles at the same time in such a short time period.<ref name="Wang, S. 2007">{{cite journal |doi=10.1016/j.envint.2007.02.011 |title=Volatile organic compounds in indoor environment and photocatalytic oxidation: State of the art |year=2007 |last1=Wang |first1=Shaobin |last2=Ang |first2=H.M. |last3=Tade |first3=Moses O. |journal=Environment International |volume=33 |issue=5 |pages=694–705 |pmid=17376530}}</ref> In addition to new buildings, we also use many consumer products that emit VOC compounds, therefore the total concentration of VOC levels is much greater within the indoor environment.<ref name="Wang, S. 2007"/>
VOC concentration in an indoor environment during winter is three to four times higher than the VOC concentrations during the summer.<ref>{{cite journal | last1 = Barro | first1 = R. | last2 = Regueiro | first2 = J. | last3 = Llompart | first3 = M. A. | last4 = Garcia-Jares | first4 = C. | title = Analysis of industrial contaminants in indoor air: Part 1. Volatile organic compounds, carbonyl compounds, polycyclic aromatic hydrocarbons and polychlorinated biphenyls | journal = Journal of Chromatography A | volume = 1216 | issue = 3 | pages = 540–566 | year = 2009 | pmid = 19019381 | pmc = | doi = 10.1016/j.chroma.2008.10.117 | displayauthors = 1 }}</ref> High indoor VOC levels are attributed to the low rates of air exchange between the indoor and outdoor environment as a result of tight-shut windows and the increasing use of humidifiers.<ref>{{cite journal |doi=10.1016/j.atmosenv.2003.11.003 |title=Seasonal cycle of indoor-VOCs: Comparison of apartments and cities |url=https://archive.org/details/sim_atmospheric-environment_2004-03_38_8/page/1181 |year=2004 |last1=Schlink |first1=U |last2=Rehwagen |first2=M |last3=Damm |first3=M |last4=Richter |first4=M |last5=Borte |first5=M |last6=Herbarth |first6=O |journal=Atmospheric Environment |volume=38 |issue=8 |pages=1181–90}}</ref>
=== Regulation of indoor VOC emissions ===
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===Formaldehyde===
Many building materials such as paints, adhesives, wall boards, and ceiling tiles slowly emit [[formaldehyde]], which irritates the mucous membranes and can make a person irritated and uncomfortable.<ref name="test">{{cite journal |doi=10.1016/j.jaci.2007.10.045 |title=The health effects of nonindustrial indoor air pollution |url=https://archive.org/details/sim_journal-of-allergy-and-clinical-immunology_2008-03_121_3/page/585 |year=2008 |last1=Bernstein |first1=Jonathan A. |last2=Alexis |first2=Neil |last3=Bacchus |first3=Hyacinth |last4=Bernstein |first4=I. Leonard |last5=Fritz |first5=Pat |last6=Horner |first6=Elliot |last7=Li |first7=Ning |last8=Mason |first8=Stephany |last9=Nel |first9=Andre |last10=Oullette |first10=John |last11=Reijula |first11=Kari |last12=Reponen |first12=Tina |last13=Seltzer |first13=James |last14=Smith |first14=Alisa |last15=Tarlo |first15=Susan M. |journal=Journal of Allergy and Clinical Immunology |volume=121 |issue=3 |pages=585–91 |pmid=18155285}}</ref> Formaldehyde emissions from wood are in the range of 0.02 – 0.04 ppm. Relative humidity within an indoor environment can also affect the emissions of formaldehyde. High relative humidity and high temperatures allow more vaporization of formaldehyde from wood-materials.<ref>{{cite journal |doi=10.1016/j.envint.2007.04.004 |title=The dichotomy of relative humidity on indoor air quality |year=2007 |last1=Wolkoff |first1=Peder |last2=Kjaergaard |first2=Søren K. |journal=Environment International |volume=33 |issue=6 |pages=850–7 |pmid=17499853}}</ref>
==Health risks==
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Direct injection [[mass spectrometry]] techniques are frequently utilized for the rapid detection and accurate quantification of VOCs.<ref>{{cite journal |doi=10.1016/j.trac.2011.04.005 |title=Direct-injection mass spectrometry adds the time dimension to (B)VOC analysis |year=2011 |last1=Biasioli |first1=Franco |last2=Yeretzian |first2=Chahan |last3=Märk |first3=Tilmann D. |last4=Dewulf |first4=Jeroen |last5=Van Langenhove |first5=Herman |journal=Trends in Analytical Chemistry |volume=30 |pages=1003-1017 |issue=7}}</ref> [[Proton-transfer-reaction mass spectrometry|PTR-MS]] is among the methods that have been used most extensively for the on-line analysis of biogenic and antropogenic VOCs.<ref>{{cite book |last1=Ellis |first1=Andrew M. |last2=Mayhew | first2=Christopher A. |date=2014 |title=Proton Transfer Reaction Mass Spectrometry - Principles and Applications |location=Chichester, West Sussex, UK |publisher=John Wiley & Sons Ltd |isbn=978-1-405-17668-2}}</ref> Recent PTR-MS instruments based on [[time-of-flight mass spectrometry]] have been reported to reach [[detection limit]]s of 20 pptv after 100 ms and 750 ppqv after 1 min measurement (signal integration) time. The [[Resolution (mass spectrometry)|mass resolution]] of these devices is between 7000 and 10,500 m/Δm, thus it is possible to separate most common isobaric VOCs and quantify them independently.<ref>{{cite journal |doi=10.1016/j.ijms.2014.05.004 |title=A Proton Transfer Reaction-Quadrupole inferface Time-Of-Flight Mass Spectrometer (PTR-QiTOF): High speed due to extreme sensitivity |year=2014 |last1=Sulzer |first1=Philipp |last2=Hartungen |first2=Eugen |last3=Hanel |first3=Gernot |last4=Feil |first4=Stefan |last5=Winkler |first5=Klaus |last6=Mutschlechner |first6=Paul |last7=Haidacher |first7=Stefan |last8=Schottkowsky |first8=Ralf |last9=Gunsch |first9=Daniel |last10=Seehauser |first10=Hans |last11=Striednig |first11=Marcus |last12=Jürschik |first12=Simone |last13=Breiev |first13=Kostiantyn |last14=Lanza |first14=Matteo |last15=Herbig |first15=Jens |last16=Märk |first16=Lukas |last17=Märk |first17=Tilmann D. |last18=Jordan |first18=Alfons |journal=International Journal of Mass Spectrometry |volume=368 |pages=1–5 }}</ref>
== इन्हें भी देखें ==
* [[Aroma compound]]
* [[Criteria air contaminants]]
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