AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Preliminary Evidence for Aqueous Oxidation of Organic Compounds in Indoor Air
SARA DUNCAN, Yong Lim, Jeffrey R. Kirkland, Barbara Turpin, Rutgers University
Abstract Number: 244 Working Group: Indoor Aerosols
Abstract Aqueous processing of organic compounds alters the composition of ambient outdoor organic aerosols and could affect budgets of some gases. Since 20-50% of homes in the United States are considered “damp,” with relative humidities over 80%, it is likely that aqueous chemistry also plays a role in indoor air chemistry. This aqueous chemistry may occur in water films (e.g., on walls and skin) and in wet particles. Gas phase concentrations of organic compounds are frequently higher indoors than outdoors, and oxidants such as hydroxyl radical and nitrate radical are also found in indoor environments. Thus, aqueous chemistry indoors may alter human exposure to indoor pollutants.
Samples were collected and composited inside a living room in a local home using a mist-chamber apparatus (collection volume of 25 milli-liters and flow rate of 30 liters per minute) that scrubs water-soluble compounds out of the air and into the aqueous phase. Oxidation experiments were then conducted with these aqueous samples to identify reactive species for further study. The first experiment was conducted with a mist-chamber sample containing 780 micro-molar dissolved organic carbon. Hydroxyl radicals were generated in 11 cuvettes (3 milli-liter) held equidistance from a 254 nm ultraviolet lamp by photolyzing 1 milli-molar hydrogen peroxide. Cuvettes were removed from the reactor at 0 - 150 minutes and analyzed by electrospray ionization mass spectrometry (ESI-MS) and ion chromatography (IC). Oxalate was produced (approximately 50 micro-molar). ESI+ revealed the masses of fifteen reactants with unit mass resolution. Additional experiments, control experiments and MS-MS will be used to further characterize these precursor compounds.