Evaluation of the efficiency of volatile organic compounds extraction from eucalyptus viminalis (Eucalypti viminalis Labill) using subcritical extractants

Ozonolysis of <i>α</i>-phellandrene – Part 1: Gas- and particle-phase characterisation

“…Such conditions favour the formation of low-volatility compounds, with the highest SOA yields for monoterpenes found under low-NO x conditions (Presto et al, 2005;Ng et al, 2007;Capouet et al, 2008;Eddingsaas et al, 2012). Under these conditions, ozonolysis reactions remain important (Perraud et al, 2012;Zhao et al, 2015), which is conducive to autoxidation processes and therefore nascent SOA formation and growth due to enhanced propensity for intramolecular rearrangements (Ehn et al, 2014;Jokinen et al, 2015). SOA yields measured in experiment 11 are consistent, however, with the other ozonolysis experiments in this study (Fig.…”

“…Nitrate and PAN functionality is believed to significantly reduce the vapour pressure of constituents (Capouet and Müller, 2006;Pankow and Asher, 2008), with the result implying a small gas-phase concentration. Nevertheless, there exists evidence that organic nitrate contribution to SOA may be kinetically driven, rather than volatility driven (Perraud et al, 2012).…”

“…Nonetheless, the reduction in aerosol number concentration in the initial stages of experiment 11 does suggest that formation pathways of ELVOC species (i.e. oligomerisation, autoxidation) are suppressed by the inclusion of NO 2 (Perraud et al, 2012). Detailed modelling studies are required to establish the relative importance of α-phellandrene in different environments, although evidence suggests that it is likely a contributor to nucleation events and aerosol growth in regions where it is emitted.…”

“…1). One of the most reactive monoterpenes, α-phellandrene has been identified as a major constituent of extracts (Li et al, 1995;Brophy and Southwell, 2002;Pavlova et al, 2015;Maghsoodlou et al, 2015) and in emissions (He et al, 2000;Maleknia et al, 2009) from various Eucalypt species, the world's most widely planted hardwood tree (Myburg et al, 2014). During day-to-day activities and processes, Eucalypts, such as Eucalyptus microtheca, Eucalyptus viminalis and Eucalyptus dives, emit α-phellandrene into the atmosphere, with α-phellandrene likely contributing to the intense and frequent particle nucleation events observed over Eucalypt forests -a phenomenon already believed to be caused by monoterpene oxidation Lee et al, 2008;Ortega et al, 2009Ortega et al, , 2012.…”

Ozonolysis of α-phellandrene – Part 2: Compositional analysis of secondary organic aerosol highlights the role of stabilised Criegee intermediates

“…α-Phellandrene has been measured in 15 field studies in Brazil (Kesselmeier et al, 2000) and Japan (Ramasamy et al, 2016), although it has been noted that ambient detection is made difficult by its extremely high reactivity (Geron et al, 2000;Saxton et al, 2007). Believed then to be of particular importance is the abundance of α-phellandrene in extracts of numerous species of Eucalypts (Brophy and Southwell, 2002;Li et al, 1995;Maghsoodlou et al, 2015;Pavlova et al, 2015), with Maleknia et al (2009) and He et al (2000) having identified α-phellandrene in emissions of various Eucalypt species in the laboratory. Native to Australasia, the 20 remarkable adaptability, rapid growth rates and high quality wood of Eucalypts has led to plantation forestry in more than 100 countries spanning six continents (> 20 million ha), making Eucalypts the most widely planted hardwood forest trees in the world (Myburg et al, 2014).…”