Date of Award

Winter 2012

Project Type


Program or Major


Degree Name

Master of Science

First Advisor

Howard R Mayne


Multiphase processing of reactive halogens impact important, interrelated chemical processes in Earth's troposphere. During the Nitrogen, Aerosol Composition, and Halogens on a Tall Tower (NACHTT) campaign at the National Oceanic and Atmospheric Administration Boulder Atmospheric Observatory tower, Erie, CO, USA in winter 2011, soluble trace gases, the ionic composition of size-resolved aerosols, and the associated meteorological conditions were measured. Aerosol pH was inferred from the multiphase coupling of HNO3, NH3 , and HCl. pHs calculated from the measured phase partitioning and thermodynamic properties of HNO3 and NH3 were similar both in terms of absolute values as well as overall trends across the sampled size fractions while pHs inferred from the HCl couple were consistently higher. Aerosols were acidic across all size fractions and throughout the duration of the campaign. Total Cl was greater than ClNO2 in sampled air parcels suggesting that Cl availability was not the limiting factor in ClNO2 production.