Inhalable Particulate Levels in Northern Idaho from the Initial Eruptions of Mount St. Helens

Crystalline silica in Mount St. Helens ash

“…St. Helens Ash Frequency (cm ') Laser power, 190 mW at sample; time constant, 1 s; scan rate, 1 cm _1 s-1; slits, 3 cm-1; full-scale, 20 K counts; zero suppress, 19.7 X 100 focused entirely on evaluating human exposure levels via the collection of continuous, meaningful inhalabie particulate data using dichotomous virtual impactor samplers (1,2). We assumed that the crystalline silica content in the inhalabie portion of the volcanic ash would be quickly and conclusively determined by laboratories with greater instrumental capabilities than our facilities at the University of Idaho.…”