Burning of olive tree branches: a major organic aerosol source in the Mediterranean

TitleBurning of olive tree branches: a major organic aerosol source in the Mediterranean
Publication TypeJournal Article
Year of Publication2013
AuthorsKostenidou E., Kaltsonoudis C., Tsiflikiotou M., Louvaris E., Russell LM, Pandis S.N
JournalAtmospheric Chemistry and Physics
Date Published2013/09
Type of ArticleArticle
ISBN Number1680-7316
Accession NumberWOS:000324400600017
Keywordschemical-characterization; combustion; emissions; fine-particle; fireplace; functional-groups; high-resolution; positive matrix factorization; reaction mass-spectrometry; savanna fires; source apportionment; wood combustion

Aerosol produced during the burning of olive tree branches was characterized with both direct source sampling (using a mobile smog chamber) and with ambient measurements during the burning season. The fresh particles were composed of 80% organic matter, 8-10% black carbon (BC), 5% potassium, 3-4% sulfate, 2-3% nitrate and 0.8% chloride. Almost half of the fresh olive tree branches burning organic aerosol (otBB-OA) consisted of alkane groups. Their mode diameter was close to 70 nm. The oxygen to carbon (O : C) ratio of the fresh otBB-OA was 0.29 +/- 0.04. The mass fraction of levoglucosan in PM1 was 0.034-0.043, relatively low in comparison with most fuel types. This may lead to an underestimation of the otBB-OA contribution if levoglucosan is being used as a wood burning tracer. Chemical aging was observed during smog chamber experiments, as f(44) and O: C ratio increased, due to reactions with OH radicals and O-3. The otBB-OA AMS mass spectrum differs from the other published biomass burning spectra, with a main difference at m/z 60, used as levoglucosan tracer. In addition to particles, volatile organic compounds (VOCs) such as methanol, acetonitrile, acrolein, benzene, toluene and xylenes are also emitted. Positive matrix factorization (PMF) was applied to the ambient organic aerosol data and 3 factors could be identified: OOA (oxygenated organic aerosol, 55%), HOA (hydrocarbon-like organic aerosol, 11.3%) and otBB-OA 33.7%. The fresh chamber otBB-OA AMS spectrum is close to the PMF otBB-OA spectrum and resembles the ambient mass spectrum during olive tree branches burning periods. We estimated an otBB-OA emission factor of 3.5 +/- 0.9 g kg(-1). Assuming that half of the olive tree branches pruned is burned in Greece, 2300 +/- 600 tons of otBB-OA are emitted every year. This activity is one of the most important fine aerosol sources during the winter months in Mediterranean countries.

Short TitleAtmos. Chem. Phys.
Integrated Research Themes: 
Student Publication: