Research in the Stone group focuses on the advancement of methodology to study the chemical composition of particulate matter in the atmosphere, or aerosols.   Aerosols play an important role in regulating global climate by reflecting solar radiation and altering cloud formation and lifetime.  Elevated levels of particulate matter also negatively affect human health.  The chemistry of aerosols is complex and varies drastically across different regions of the world.  Our research targets the organic fraction of ambient aerosol, which constitutes an average of half of particulate mass and remains the most poorly understood component due to its chemical complexity, variety of sources, and ability to transform in the atmosphere.  We develop new methodology to study organic compounds and functional groups in aerosols and apply these techniques to different environmental settings.  Our research incorporates field-based and laboratory experiments and utilizes a variety of quantitative analytical tools, including gas and liquid chromatography and mass spectrometry.