The concentrations and size distribution of metalworking fluid aerosols wer
e investigated in grinding operations in the bearing manufacturing industry
. Fifteen paired open- and closed-face cassette samples and five cascade im
pactor samples were obtained in each of three types of grinding machinery (
face, microcentric, and progressive). Aerosol mass concentration as measure
d by open-face filter sampling ranged from 0.34 to 2.43 mg/m(3). As measure
d by closed-face sampling the range was 0.14 to 2.01 mg/m(3). For each grin
ding process, open-face concentration was significantly higher than the clo
sed-face concentration (paired t-test, p <0.05). Mass median aerodynamic di
ameter (MMAD) ranged from 3.33 to 6.26 <mu>m. The percentage of mass greate
r than 9 mum ranged from 8.0 to 45.3. The MMAD and fraction greater than 9
Lm were significantly greater for the aerosol produced by the face grinder
compared with the other two processes. The results indicate that (1) closed
-face sampling results in a lower aerosol mass concentration, as compared w
ith open-face sampling, with the degree of difference being somewhat depend
ent on grinding process; and (2) the particle size distribution and concent
ration of metalworking fluid aerosols may vary with the type of grinding op
eration sampled.