Airborne contaminants applications

The provision of ventilation is the engineering approach to the control of airborne contamination. Applications are widespread and need not really be concerned with reducing pollution, since the suppression of... 

Airflow Systems, Inc Resource for the collection and filtration of dust, smoke, mist, fumes and other airborne contaminants generated during industrial and commercial manufacturing and processing applications. http., llwww.air, flowsvstems. com... 

Contaminant concentrations Dispersal of airborne contaminants such as odors, fumes, smoke, VOCs, etc. transported by these airflows and transformed by a variety of processes including chemical and radiochemical transformation, adsorption, desorption to building materials, filtration, and deposition to surfaces evolution of contaminant concentrations in the individual zones air quality checks in terms of CO2 levels cross-contamination evaluation of zones air quality evaluations in relation to perception as well as health. Methods ate also applicable to smoke control design. 

Petty, J.D. Gale,R.W. Huckins, J.N. Cranor, W.L. A1 varez, D. A. Clark, R.C. 2000,Development and Application of Techniques for Sampling Bioavailable Airborne Contaminants-Tentatively Identified Compounds by Gas Chromatography/Mass Spectrometry. USGS Colirmbia Environmental Research Center Colirmbia, MO Unpublished report to U.S. EPA National Exposure Assessment Laboratory Las Vegas, NV. 

Petty, J.D. Huckins, J.N. Robertson, G.L. Cranor, W.L. Gale, R.W. Alvarez, D.A. Clark, R.C. 2002, The application of semipermeable membrane devices (SPMDs) as samplers of airborne contaminants in indoor air. Presented at die 53 Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy, March 16-22, 2002 New Orleans, LA. 

This technology is applicable to the treatment of industrial wastewater and contaminated groundwater. The same technology can also be used to effectively destroy airborne contaminants in the off-gases from industrial processes, air strippers, or soil vapor extraction operations. 

Cothern CR. 1987. Development of regulations for radionuclides in drinking water. In Graves B, ed. Radon in ground water, radon, radium and other radioactivity in ground water Hydrogeologic impact and application to indoor airborne contamination. Proc National Water Well Association conference, Somerset, NJ, April 7-9, 1987. Chelsea, MI Lewis Publishers, Inc. 1-11. 

Other than isotopes separation for uranium enrichment described in Chapter 2, inorganic membranes are commercially used for particulate filtration of air or other gases in clean room applications, airborne contaminant analysis and high-purity hydrogen production. In addition, some inorganic membranes are us in pH and ion selective electrodes. 

Ljungqvist, B. Reinmiiller, B. Hazard analyses of airborne contamination in clean rooms application of a method for limitation of risks. PDA J. Pharm. Sci. Technol. 1995, 49, 239-243. 

Depending on the airborne contaminants in the return-air system it may be acceptable to use recirculated air, provided that HEPA filters are installed in the supply air stream to remove contaminants and thus prevent cross-contamination. The HEPA filters for this application should have an EN1822 classification of H13. 

Application of a protective overcoat to seal off airborne contaminants was also a popular approach initially. Although many polymers, lipophilic and hydrophilic, have been evaluated as a topcoat, water-soluble poly[ (meth)acryhc acid] is most commonly employed, which can be cast from a water solution without interfacial mixing with the resist layer and can be removed during aqueous base development. However, it has been reported that a poly(acrylic acid) overcoat allows diffusion of water, which reportedly contaminates a chemical amplification resist [211]. Poly(cx-methylstyrene) has been recommended as a good barrier against both airborne base and water [211]. 

The removal of airborne contaminants is an area of promising applications for photocatalysis. The challenges to be faced involve the treatment of relatively large gas flows in devices with low pressure-drops, good photocatalyst irradiation and efficient reactant species-photocatalyst contacting (Dibble and Raupp, 1992). In the near future photocatalytic reactors, incorporating the use of solar energy, are also anticipated to be developed. 

It is expected that the smaller size of these nanofibres will lead to a higher pressure drop and the interception and inertial impaction efficiencies will increase faster, which can more than compensate for the pressure drop inaease. Nanowebs have been used in many air filtration applications. Airborne contamination in the personnel cabins of mining equipment is of concern to mining workers, and it has been reported that nanofibre filter media can considerably reduce cabin dust concentration as compared to the standard (cellulose) filter media. ... 

Activated charcoal is often used in filters to remove nonpolar airborne contaminants in ductless laboratory hoods. These are hoods that filter laboratory air but subsequently recycle the filtered air directly back into the lab. See Section 7.2.3. However, remember that if a chemical with a stronger binding energy comes in contact with the charcoal, the bound adsorbates would be released. This means that if you are working in a ductless hood with a charcoal filter, the chemical will be released into your laboratory and the potential opportunity for exposure would be significant. Currently, some new ductless hoods are being marketed for chemistry labs. If properly used and maintained, these may see application in some limited circumstances, but we believe that ducted chemical hoods as described in Sections 7.1.4 and 7.2.3 should be the standard in most chemistry labs. 

Level D is applicable to spills where there are no airborne contaminants of concern and where there is a minimum likelihood of harm by contact with the spilled material. Many organizations provide treated cotton coveralls or similar garb for working in such frequently occurring situations. 

Some substances have the designation Sk and this refers to the potential contribution to overall exposure of absorption through the skin. In this case airborne contamination alone will not indicate total exposure to the chemical and the Sk designation is intended to draw attention to the need to prevent percutaneous absorption. In the application of the assigned exposure limit it is assumed that additional exposure of the sl is prevented. 

Various polymers, and, therefore, coating types, react differently to changes in one or more of these weathering stresses. In order to predict the service life of a coating in a particular application, therefore, one must know not only the environment — average time of wemess, amounts of airborne contaminants, UV exposure, and so on — but also how these weathering stresses affect the particular polymer [2]. 

Presented by ACGIH and its Industrial Ventilation Committee, Fundamentals in Industrial Ventilation covers both basic and advanced industrial ventilation topics. Practical Applications of Useful Equations includes calculation and estimation approaches related to airborne contaminants, TLV and TWA, OA for dilution, etc., as well as a calculations lab. April 11-15,2011, Cindmiati, Ohio. ACGIH Professional Learning Center, wwwacgihcrg, (513) 742-2020. Circle 316... 

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