Airborne contamination exposure limits

In recent years, the use of solvent-borne adhesives has been seriously restricted. Solvents are, in general, volatile, flammable and toxic. Further, solvent may react with other airborne contaminants contributing to smog formation and workplace exposure. These arguments have limited the use of solvent-bome adhesives by different national and European regulations. Although solvent recovery systems and afterburners can be effectively attached to ventilation equipment, many factories are switching to the use of water-borne rubber adhesives, hot melts or 100% solids reactive systems, often at the expense of product performance or labour efficiency. 

In exposures by inhalation of airborne materials, the dose is the concentration multiplied by the time (CT), and is roughly a constant for any given material and specified effect. The CT value can be used to provide a rough approximation of other combinations of concentration and time which would have about the same effect. Although this concept must be used very cautiously and cannot be applied at extreme conditions of either concentration or time, it is most important in setting limits for airborne contaminants and physical agents in respect to environmental exposures. The worker is exposed for various periods of time, day after day, to the... 

The TLVs for airborne contaminants are based on the premise that although all chemical substances are toxic at some concentration for some period of time, a concentration exists for all substances from which no toxicity may be expected no matter how often the exposure is repeated. A similar premise holds for substances producing irritation, discomfort and nuisance. In using these limits, items such as excursion factors, ceiling values, "skin" notations, mixtures of substances, and inert material should be considered. These factors are discussed below. 

Maximum Exposure Limit MEL) Maximum limits of concentration of airborne toxic contaminants, listed by the Health and Safety Executive which must not be exceeded. 

Occupational exposure limits for airborne contaminants are reviewed annually in the UK by the Health and Safety Executive. They are published as Guidance Note EH 40/ —. The two types of exposure limit are ... 

NRC (National Research Council). 1984b. Emergency and Continuous Exposure Limits for Selected Airborne Contaminants, Vol. 2. Washington, DC National Academy Press. 

Chapter 4 described methods for limiting the time of exposure to weapons of mass destruction that utilize no explosives (e.g., aerosol delivery) or use of conventional explosives (e.g., dirty bomb). The basic procedure is to leave the contaminated area as quickly as possible, enter a nearby building to shelter against airborne contamination, remove soiled articles of clothing, and wash all exposed body parts (including the mouth and hair) as soon as possible. In Chapter 4, the time factor is applied primarily to limit the chances of potential future health effects. In this section, the time factor is applied after a nuclear explosion to prevent serious bodily harm and death. 

Within the plants surveyed, styrene was the principal airborne contaminant of concern. Since these surveys were made in operating plants, there were other substances present however, styrene was the dominant vapor and the only one potentially of concern relative to accepted exposure limits (TLV s). 

Exposure Limits PELs and TLVs. Threshold limit values (TLVs) were developed in the 1940s, long before the existence of OSHA. The TLV is defined as the airborne concentration of a contaminant to which it is believed that most workers may be repeatedly exposed, day after day, without developing adverse health effects. Developed and maintained by the American Conference of Governmental Industrial Hygienists (ACGIH), these values have been determined based on industrial experience and animal and human studies. 

BGCAPP or PMACWA personnel. Plans for the disposal of secondary wastes generated at BGCAPP call for the waste to be (1) shipped offsite to an approved TSDF or (2) treated onsite and then shipped offsite. Whether onsite treatment of secondary waste is needed depends on whether the waste is agent-contaminated on noncontaminated on whether it meets airborne exposure limit guidance standards for offsite slupment, which will be set in the permit and on what may be required by the approved WAP. 

Tlie source document for the estimates given in this table reported quantities using the. Army s X system of classification rather than the currently preferred system based on airborne exposure limits. (AELs). A classification of IX indicates agent contamination to be >1 VSL. 

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