Characterization of Polar Organic Compounds in the Organic Film on Indoor and Outdoor Glass Windows

Abstract

Organic films on an impervious surface (window glass) were sampled at paired indoor-outdoor sites in July 2000 and characterized for their paraffinic and polar organic compositions along an urban-rural transect. Four classes of polar compounds (C11-C31 aliphatic monocarboxylic, C6-C14 dicarboxylic, nine aromatic polycarboxylic, and five terpenoid acids) constituted between 81 and 95% (w/w) of the total organic fraction analyzed comprising n-alkanes (C10-C36), 46 PAH, 97 PCBs, and 18 OC pesticides. Concentrations of the polar compounds plus their precursors, n-alkanes, ranged from 8 to 124 microg m(-20 and were dominated by monocarboxylic acids (67-89%, w/w). On outdoor windows, n-alkanes, aromatic acids, and terpenoid acids decreased in concentration along the urban-rural transect. The carbon preference index values and the interpretations of individual compounds indicate that the main sources of n-alkanes were plant waxes followed by petrogenic sources; monocarboxylic and dicarboxylic acids were from plant waxes and animal fats. Results of principal component analysis showed closer correspondence between outdoor and indoor signatures than among locations. In outdoor films, these compounds are suggested to play an important role in mediating chemical fate in urban areas by air-film exchange and facilitating "wash-off" due to their surfactant-like properties. In indoor films, these compounds provide a medium for the accumulation of more toxic compounds.

Reactions at surfaces in the atmosphere: integration of experiments and theory as necessary (but not necessarily sufficient) for predicting the physical chemistry of aerosols

“…SAMs formed by reaction of trichloroalkylsilanes on SiO x surfaces, for example on the thin oxide layer on silicon, may be particularly relevant to reactions of organic compounds on dust and on building materials for which silicates can be major components. 208,[238][239][240][241][242][243][244] Another advantage is that silicon crystals are readily available which can be used to make real-time measurements of the oxidation of SAMs attached to their surface using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. In one study, 221 ozonolysis of terminal alkene SAMs with 3-and 8-carbon atoms was observed to give CQO groups as products as expected, at least a portion of which were in the form of carboxylic acids that could be converted to carboxylates by reaction with gaseous NH 3 .…”

Polycyclic aromatic hydrocarbons on indoor/outdoor glass window surfaces in Guangzhou and Hong Kong, south China

“…The few existing studies on this topic show that organic films can range from 11 to 1000 nm in thickness and that the proportion of organic matter ranges from approximately 5e20% (Diamond et al, 2000;Liu et al, 2003b;Wu et al, 2008). Due to the high proportion of organic content of the film, the concentrations of semi-volatile organic compounds (SVOCs) are high on the artificial surfaces of urban areas (Butt et al, 2004;Gingrich et al, 2001;Liu et al, 2003a). SVOCs can accumulate in organic films through the exchange and partitioning of gasphase chemicals with air and/or the direct deposition of particlephase compounds (Diamond et al, 2000;Law and Diamond, 1998;Liu et al, 2003b).…”

Thermal and photochemical oxidation of self-assembled monolayers on alumina particles exposed to nitrogen dioxide

“…[24][25][26][27] Consistent with the results of laboratory studies, increased HONO levels have been measured during dust storms. 28 Organic compounds are also known to be taken up on airborne dust particles 4,9,[29][30][31] and on building materials in the boundary layer, [32][33][34][35][36][37] and there is evidence that oxidation of organics occurs on these surfaces as well. 33,38,39 A number of the well-known surface-bound nitrogen oxides such as nitrite and nitrate ions photolyze in the actinic region 24 above 290 nm to form O À radical anions, which react with water to generate OH radicals.…”