Aerosol contribution procedures

Aerosol Contribution Procedures (ACP) for quantitative determination of x-4. using CAM or PCAM equipment and three examples of plant experience. 

The objective of these Aerosol Contribution Procedures (ACP) is to determine humidifier solids residue contributions, x,t> to apparent workplace respirable dust levels so feasibility OT engi-neering control or exclusion strategies may be evaluated. By engineering control of x, meant that low solids water is used for humidification. This can be a very cost-effective means of control. Generally, x, is the component which should receive first attention when co5t-prioritiling the various components of multi constituent, respirable cotton dust. 

It follows that the aerosol contribution procedures are specific to air-conditioning parameters and that the x, component is to be excluded from the total dust level Xt undef a given set of conditions. It would obviously be improper to determine x, in the wintertime and use it for subtraction in summertime. 

Aerosol Contribution Procedure 2 (ACP-2). In some cases it is impractical for technical or cost reasons to supply low solids water for ACP-1. In other cases, it is useful to obtain a quick but rough estimate relative to the viability of provision of low solids water. 

Aerosol Contribution Procedure-Prediction (ACP-P). Although the following equations have in several cases, with one of them reported here, served as accurate predictors, the assumptions are... 

According to the Aerosol Contribution Procedures, the experimental data of column 10 follow ACP-1 and the predicted data of column 9 follow ACP-P. 

Hoffman et al. (1974) found the same procedure applicable to data obtained from measurements on board of ships in the central Atlantic Ocean. Table 7-15 includes mean (X)/(Na) ratios from their work. Shown in parentheses are the values derived from the slopes of regression lines. They are distinctly lower than the averaged data. Hoffman et al. (1974) measured also the abundance of iron in the aerosols. Since the samples were taken in a region partly affected by fallout from the Saharan dust plume, iron serves as a convenient indicator for the contribution of material from continental sources. Not surprisingly, the enrichment of the elements Mg, Ca, K, and Sr was well correlated with the iron content. The (X)/(Na) ratios approached those of sea water only when the Fe concentrations were very low. These results demonstrate that materials from both marine and crustal sources are present over the open ocean. In addition, they provide some verification for the existence of a tropospheric background aerosol having the continents as a source, and they confirm the absence of a significant fractionation of alkali and alkaline earth elements in the production of sea salt. 

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