5.1 The health of workers in many industries is at risk through exposure by inhalation to toxic metals. Industrial hygienists and other public health professionals need to determine the effectiveness of measures taken to control workers' exposures, and this is generally achieved by making workplace air measurements. Exposure to some metal-containing particles has been demonstrated to cause dermatitis, skin ulcers, eye problems, chemical pneumonitis, and other physical disorders (1).3

(A) High concentrations of silicon in the sample can cause an interference for many of the elements in this table and may cause aspiration problems. No matter what elements are being measured, if large amounts of silica are extracted from the samples, the samples should be allowed to stand for several hours and centrifuged or filtered to remove the silica.(B) Samples are periodically analyzed by the method of additions to check for chemical interferences. If interferences are encountered, determinations must be made by the standard additions method or, if the interferent is identified, it may be added to the standards.(C) Some compounds of these elements will not be dissolved by the procedure described here. When determining these elements, one should verify that the types of compounds suspected in the sample will dissolve using this procedure (see 12.2).(D) Ionization interferences are controlled by bringing all solutions to 1000 ppm cesium (samples and standards).(E) 1000-ppm solution of lanthanum as a releasing agent is added to all samples and standards.(F) In the presence of very large calcium concentrations (greater than 0.1 %) a molecular absorption from CaOH may be observed. This interference may be overcome by using background corrections when analyzing for barium.

5.2 FAAS is capable of quantitatively determining most metals in air samples at the levels required by federal, state, and local occupational health and air pollution regulations. The analysis results can be used for the assessment of workplace exposures to metals in workplace air.