The hydroxyl radical (OH) is an important chemical species.  It is the primary oxidizing agent in the troposphere, reacting with many pollutants and consequently maintaining the purity of the air.  It also plays an important role in the formation of sulfuric acid (H₂SO₄), which is important to aerosol production.  It is this role that made concentrations of OH a measurement of interest to the Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H₂O, Organics and Nitrogen (BEACHON) Project, a study that aimed to improve earth system models by quantifying geophysical systems.  High reactivity, short lifespan, and low concentrations of OH make this molecule is particularly difficult to measure.  Chemical Ionization Mass Spectrometry (CIMS) is one reliable method of measuring OH concentrations and was used in this study.  The CIMS instrument measures OH by first converting it to sulfuric acid  by the addition of isotopically labeled sulfur dioxide (³⁴SO₂), allowing naturally occurring H₂SO₄ to also be measured.  Concentrations of both OH and H₂SO₄ were taken in Manitou Experimental Forest (MEF) in Manitou Springs, Colorado in summer 2008.  Decay rates of OH were also determined.  While OH concentrations and decay rates were unavailable at the conclusion of this research, concentrations of OH and H₂SO₄ as well as OH decay rates were measured in a similar study conducted in Morgan-Monroe Experimental Forest in May 2008