Inclusion of complete ion chemistry in the calculation of minor specie
s production during energetic particle deposition events leads to sign
ificant enhancement in the calculated nitric acid concentration during
precipitation. An ionization rate of 1.2 x 10(3) cm-3 s-1 imposed for
1 day increases HNO3 from 3 x 10(5) to 6 x 10(7) cm-3 at 50 km. With
an ionization rate of 600 cm-3 s-1, the maximum HNO3 is 3 x 10(7) cm-3
. Calculations which neglect negative ions predict that nitric acid wi
ll fall during precipitation events. The decay time for converting HNO
3 into odd nitrogen and hydrogen is more than 1 day for equinoctial pe
riods at 70-degrees latitude. Examination of nitric acid data should y
ield important information on the magnitude and frequency of charged p
article events.