(5) Analysis of samples. Once air samples have been requested on
charcoal tubes, filters, and so forth, the sample media is sent to USAEHA for analysis. The
sampling form with instructions is at Appendix I. This information applies to each type of
i. This description of sampling techniques and strategies has of necessity been
general and relatively brief. For detailed guidance on specific sampling procedures, see
USAEHA Technical Guide (TG) 141. Technical Guide 141 can be obtained by sending
a DA Form 17 to the Commander, USAEHA, Aberdeen Proving Grounds, and Maryland
a. General. In deciding upon a sampling strategy, it is important to remember
that the sampling period must be statistically significant, that is, it must provide a sample
of the exposure, which is truly representative of the exposure in time and space. The
purpose of the evaluation will be the major consideration in determining how long the
sampling period must be in order to be statistically significant. The purpose of the
evaluation, as well as the general nature of the suspected contaminant (for example,
probable concentration, gaseous, or particulate), will influence the choice of sampling
technique and/or equipment, which will fall into one of the following categories.
b. Gases and Vapors.
(1) In the case of soluble contaminants, absorption devices may also collect
samples. These devices concentrate the contaminant by dissolving it in some medium;
bubblers and impinges (see Figure 2-3) are examples of such devices. They are used in
conjunction with some form of pump or suction device, which captures the air-gas
mixture and brings it into the absorption device where it is impinged on a receptive
liquid. In using such a device, it is necessary to know the rate at which the air-gas
mixture was collected (flow rate) and the duration of the sampling period, in order to
determine the volume of air from which the contaminant was extracted.