1989 Volume 24 Issue 3 Pages 214-226
The concentrations of airborne asbestos in environments at an urban commercial area were measured utilizing phase contrast microscopy (PCM) and transmission electron microscopy (TEM) equiped with EDX.
Results of the concentrations of asbestos fibers by PCM and TEM were compared. The concentrations of asbestos fibers by TEM were the average 5.15 (171) and showed a highly seasonal variance.
The relationship between the concentrations of asbestos fibers by PCM and those by TEM were not found to be correlated, but the relationship between the concentrations of asbestos fibers by PCM and those of both asbestos and nonasbestos mineral fibers with length of 5μm or more than were found to be significantly correlated.
The chrysotile fibers and tremolite fibers for the types of asbestos fibers observed were constituted each average about 50%. The results suggest that the source of tremolite fibers might be caused by concomitant mineral fi bers in talc dusts from rubber industrial plants adjacent to this area.
The aspect ratio (width to length) of asbestos fibers with length of 5μm less than and those with length of 5μm or more than was 20:1, 27:1, respectively. In frequency distribution of asbestos fibers with length of 5μm less than, 38.5% of those was smaller particles that had length of 1μm less than with width of 0.4μm less than.
The mass concentrations of asbestos fibers was a highly variable because each of asbestos fibers showed the changes in the types and the shapes.
The concentrations of all mineral fibers as asbestos and nonasbestos fibers was about 120 times greater than the concentrations of asbestos fibers and also 97% of all mineral fibers was smaller particles that had length of 5μm less than. The frequency distribution of all mineral fibers was highly in the particles that were shorter in length and finer in width.
