Estimating terpene and terpenoid emissions from conifer oleoresin composition

• Published in: Atmospheric environment (1994) Vol. 113; pp. 32 - 40
• Main Authors: Flores, Rosa M., Doskey, Paul V.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2015
• Subjects: Biogenic volatile organic compound (BVOC) emissions; Conifer oleoresin; Pinus strobus; Terpenes; Terpenoids; Terpenes; Terpenoids; Conifer oleoresin; Biogenic volatile organic compound (BVOC) emissions
• ISSN: 1352-2310; 1873-2844
• DOI: 10.1016/j.atmosenv.2015.04.062

The following algorithm, which is based on the thermodynamics of nonelectrolyte partitioning, was developed to predict emission rates of terpenes and terpenoids from specific storage sites in conifers: Ei=xoriγoripi∘ where Ei is the emission rate (μg C gdw−1 h−1) and pi∘ 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 pi∘ at 25 °C and molar enthalpies of vaporization are made with the SIMPOL.1 method and are used to estimate pi∘ 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). •A new terpene and terpenoid emission algorithm for conifers was developed.•The algorithm is based on the thermodynamics of nonelectrolyte partitioning.•Emission rates are related to conifer oleoresin composition.•Activity coefficients account for solute–oleoresin interactions.•The emission algorithm is a promising approach for developing emission inventories.