Sesquiterpene ozonolysis: Origin of atmospheric new particle formation from biogenic hydrocarbons

Abstract

Atmospheric new aerosol particle formation observed in remote areas (e.g., in Finland, Portugal and in the U.S.). is generally attributed to low‐volatile oxidation products of monoterpenes (C10H16), which are emitted by the vegetation. In this article we show that this atmospheric new particle formation is not caused by monoterpene products, but most likely initiated by very low‐volatile substances produced during sesquiterpene (C15H24)‐ozone reactions. For this purpose, the nucleation times of the most abundant monoterpene reactions have been calculated and discussed exemplarily for the Finnish site Hyytiälä, at which nucleation events have been observed. In addition, the important negative influence of water vapor on the nucleation threshold of the β‐caryophyllene‐ozone reaction has been studied in detail at different dew points in the laboratory. Therein, the saturation vapor pressure of the nucleating compounds was estimated to be less than 1.2 · 10−10 hPa, which is recommended for atmospheric homogeneous nucleation of non‐volatile organics.

Role of the reaction of stabilized Criegee intermediates with peroxy radicals in particle formation and growth in air

“…Accurate mass measurements performed on selected m/z values were again in excellent agreement with the predicted elemental compositions of oligomers for each series, as reported in Table 2. As chlorine has two stable isotopes, 35 Cl and 37 Cl, OLI-C was detected as a series of doublet peaks with intensity ratios equal to that of the two isotopes, i.e., 3 : 1.…”

“…19,36 In ozonolysis experiments where SCI were scavenged using small acids or water, particle nucleation was shown to be suppressed, suggesting that the oligomers formed from SCI were potentially the nucleating precursors. 19,20,37 In an a-pinene/O 3 system, the formation of 10-20 nm particles was well correlated with gas phase oxidation products of high molecular weight (MW) (430-560 Da), whereas particles larger than 20 nm were correlated with those having lower MW (140-380 Da). 31 In a similar system, the gas phase formation of high MW ester dimers was shown to be correlated with new particle formation in the presence of inorganic seed particles.…”

Flux estimates and OH reaction potential of reactive biogenic volatile organic compounds (BVOCs) from a mixed northern hardwood forest

“…Many compounds emitted by forest vegetation, such as reactive MT and sesquiterpenes (SQT), are reactive with oxidants and contribute to aerosol nucleation and growth (Bonn and Moortgat, 2003;Lee et al, 2006). These processes can occur within the canopy rendering many commonly used abovecanopy flux measurements infeasible.…”

Regionalizing global climate models

“…This figure is available in colour online at wileyonlinelibrary.com/journal/joc aerosol (SOA) (Tsigaridis and Kanakidou, 2007;Heald et al, 2008). A number of controlled chamber experiments have demonstrated considerable aerosol yield from monoterpenes and sesquiterpenes (Hoffmann et al, 1997;Bonn and Moortgat, 2003;Lee et al, 2006) and isoprene is also an aerosol source (Claeys et al, 2004). SOA are estimated to increase substantially in response to enhanced future BVOC emissions, responding to warmer temperature.…”