-5- .-, ,. ( ,... .7 . . ..,- Light scattering instruments capable of sizing and counting particles in In the first mode, the diameter range 0.3 ~m to 10 um were used in two modes. Climet Instruments Co.) wasoperated so that a particle analyzer (Piodel CI-201, Particles in air entering in situ particle-size number-densities were determined. fie~w volume at a rate of 0.43 m3 h-l (0.25 cfm) are counted individually by the resulting pulses -