Hydrofluoric acid and anhydrous ammonia spills evaporation/air dispersion modeling and exposure assessment.

摘要

This report provides an assessment of the air dispersion and human exposure to toxic airborne chemical concentrations resulting from potential spill scenarios involving a volatile liquid--hydrofluoric acid (HF) and a liquified gas--anhydrous ammonia (NH3). The HF spill was evaluated both as a ground-level area source and a stack release from within a building. The NH3 spill was only evaluated as a ground-level area source. Critical receptors for exposure assessment were located downwind at 100 m, the nearest public highway, and the nearest site boundary. In addition, worker exposure inside a building after an indoor spill of HF was evaluated. The evaporation computer code SPILLS was used to determine time-variable emission (evaporation) rates for input into the air dispersion model INPUFF. First order kinetic models were used to evaluate the buildup and decay of the indoor HF spill using both steady state and SPILLS time-variable emission rates. Air concentrations were plotted as a function of time to determine the time intervals that receptor concentrations exceeded the TLV, IDLH, and 10,000*TLV levels. 7 refs., 12 figs., 5 tabs.