Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6337971 | Atmospheric Environment | 2015 | 9 Pages |
Abstract
where Ei is the emission rate (μg C gdwâ1 hâ1) and piâ is the vapor pressure (mm Hg) of the pure liquid terpene or terpenoid, respectively, and xori and γori are the mole fraction and activity coefficient (on a Raoult's law convention), respectively, of the terpene and terpenoid in the oleoresin. Activity coefficients are calculated with Hansen solubility parameters that account for dispersive, polar, and H-bonding interactions of the solutes with the oleoresin matrix. Estimates of piâ at 25 °C and molar enthalpies of vaporization are made with the SIMPOL.1 method and are used to estimate piâ at environmentally relevant temperatures. Estimated mixing ratios of terpenes and terpenols were comparatively higher above resin-acid- and monoterpene-rich oleoresins, respectively. The results indicated a greater affinity of terpenes and terpenols for the non-functionalized and carboxylic acid containing matrix through dispersive and H-bonding interactions, which are expressed in the emission algorithm by the activity coefficient. The correlation between measured emission rates of terpenes and terpenoids for Pinus strobus and emission rates predicted with the algorithm were very good (R = 0.95). Standard errors for the range and average of monoterpene emission rates were ±6 - ±86% and ±54%, respectively, and were similar in magnitude to reported standard deviations of monoterpene composition of foliar oils (±38 - ±51% and ±67%, respectively).
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Physical Sciences and Engineering
Earth and Planetary Sciences
Atmospheric Science
Authors
Rosa M. Flores, Paul V. Doskey,