The effect of pulmonary particulate levels on chronic lung conditions in a nonexposed population was studied. Lung tissue from randomly selected autopsy cases was minced, dried at 100 degrees-C, and ashed at 450 degrees-C for 3 days. Ash was suspended in 2.4 normal hydrochloric-acid and filtered on 0.45 micron pore size silver filter. In an alternate procedure, tissue was digested in nitric-acid and filtered on Nucleopore 0.4 micron pore size filter. The particulate matter collected on filters was analyzed with an x- ray diffractometer, using a copper target tube, a graphite crystal monometer, a scintillation counter, and a count rate computer. Quartz (14808607) and talc (14807966) were detected in all 48 cases examined. Kaolinite was identified in all cases prepared by acid digestion, but not in those prepared by ashing. Most of the samples also gave a peak in the 10 angstrom region, suggesting the presence of phyllosilicate, possibly mica. The smoking history was 47.9 +/- 39.76 pack years, with a minimum of zero and maximum of 160 pack years. The mean value of dust was 2.4 +/- 1.8; mean value of quartz was 0.26 +/- 0.30 milligrams/gram dry tissue. The plots of total dust and total quartz versus age indicated a possible relationship between particulate matter and age, but other factors were also involved. The percent emphysema ranged from zero to 96 percent, with a mean of 19.0 +/- 29.6 percent. The regression analysis showed a correlation between smoking and emphysema. The value of the regression coefficient was 0.59 at probability less than 0.002.