Abstract
Abstract. The largest global source of secondary organic aerosol (SOA) in the atmosphere is derived from the oxidation of biogenic emissions. Plant stressors associated with a changing environment can alter both the quantity and composition of the compounds that are emitted. Alterations to the biogenic volatile organic compound (BVOC) profile could impact the characteristics of the SOA formed from those emissions. This study investigated the impacts of one global change stressor, increased herbivory, on the composition of SOA derived from real plant emissions. Herbivory was simulated via application of methyl jasmonate (MeJA), a proxy compound. Experiments were repeated under pre- and post-treatment conditions for six different coniferous plant types. Volatile organic compounds (VOCs) emitted from the plants were oxidized to form SOA via dark ozone-initiated chemistry. The SOA chemical composition was measured using a Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-AMS). The aerosol mass spectra of pre-treatment biogenic SOA from all plant types tended to be similar with correlations usually greater than or equal to 0.90. The presence of a stressor produced characteristic differences in the SOA mass spectra. Specifically, the following m/z were identified as a possible biogenic stress AMS marker with the corresponding HR ion(s) shown in parentheses: m/z 31 (CH3O+), m/z 58 (C2H2O2+, C3H6O+), m/z 29 (C2H5+), m/z 57 (C3H5O+), m/z 59 (C2H3O2+, C3H7O+), m/z 71 (C3H3O2+, C4H7O+), and m/z 83 (C5H7O+). The first aerosol mass spectrum of SOA generated from the oxidation of the plant stress hormone, MeJA, is also presented. Elemental analysis results demonstrated an O : C range of baseline biogenic SOA between 0.3 and 0.47. The O : C of standard MeJA SOA was 0.52. Results presented here could be used to help identify a biogenic plant stress marker in ambient data sets collected in forest environments.
Highlights
Organic material comprises 20–90 % of the mass in atmospheric particles smaller than 1 micrometer (Jimenez et al, 2009; Zhang et al, 2007)
This result, when combined with the diversity in pre-treatment monoterpenoid emission profiles from these trees presented in Faiola et al (2015), suggests that aerosol mass spectra of biogenic secondary organic aerosol (SOA) formed from ozone-initiated chemistry under baseline conditions all look very similar even with a different mix of monoterpenes used to generate the SOA
These results are consistent with findings presented by Kiendler-Scharr et al (2009) who found similar aerosol mass spectrometer (AMS) characteristics between biogenic SOA generated from the emissions of different types of plant species
Summary
Organic material comprises 20–90 % of the mass in atmospheric particles smaller than 1 micrometer (Jimenez et al, 2009; Zhang et al, 2007). Most of this small organic particulate material is secondary organic aerosol (SOA), and the major fraction of SOA globally is formed from the oxidation of biogenic volatile organic compounds (BVOCs) released by vegetation (Hallquist et al, 2009). BVOC emission rates and emission profiles (i.e., the types of compounds emitted) can change significantly when plants are exposed to biotic and abiotic stressors (Holopainen, 2004; Peñuelas and Staudt, 2010; Pinto et al, 2010). It follows that plant stress exposure associated with climate change could have significant impacts on SOA formation, and could lead to a climate feedback because atmospheric aerosols play an important role in the global radiation budget.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
