Antarctic new particle formation from continental biogenic precursors

Over Antarctica, aerosol particles originate almost entirely from marine areas, with minor contribution from long-range transported dust or anthropogenic material. The Antarctic continent itself, unlike all other continental areas, has been thought to be practically free of aerosol sources. Here we present evidence of local aerosol production associated with melt-water ponds in continental Antarctica. We show that in air masses passing such ponds, new aerosol particles are efficiently formed and these particles grow up to sizes where they may act as cloud condensation nuclei (CCN). The precursor vapours responsible for aerosol formation and growth originate very likely from highly abundant cyanobacteria Nostoc commune (Vaucher) communities of local ponds. This is the first time freshwater vegetation has been identified as an aerosol precursor source. The influence of the new source on clouds and climate may increase in future Antarctica, and possibly elsewhere undergoing accelerating summer melting of semi-permanent snow cover

Emissions of biogenic volatile organic compounds from the boreal forest floor and understory: a study by solid-phase microextraction and portable gas chromatography-mass spectrometry

Vegetation introduces to the atmosphere a diversity of biogenic volatile organic compounds (BVOCs) which affect atmospheric chemistry, air quality and climate. Understory emissions might contribute significantly to the total BVOCs budget. In this work, either dynamic or static solid-phase microextraction (SPME) combined with portable gas chromatography-mass spectrometry were optimised and used for the in-situ measurement of the most abundant BVOCs at understory level. The study was performed in summer 2015 at the SMEAR II station in Hyytiälä, Finland. The most abundant BVOCs measured in soil chambers and ambient air were α-pinene and Δ3-carene, and their relative concentrations were similar in every chamber. These species constituted 80%–90% of the measured monoterpenes. Aliphatic aldehydes were also measured, and their amounts were lower in soil chambers than in ambient air. Air BVOC concentrations were markedly higher when the wind direction was from SE, which was associated with transportation from nearby sawmills

Characterization of organic compounds in 10- to 50-nm aerosol particles in boreal forest with laser desorption -ionization aerosol mass spectrometer and comparison with other techniques

The aim of this study was to characterize the organic composition of ambient ultrafine particles (< 50 nm) in a boreal forest environment and compare the analytical results obtained by different techniques with use a data analysis software. In the chromatographic techniques, particles were collected on a filter and analyzed off-line after sample preparation, whereas in the aerosol MS, particle analysis was performed directly from the particle source.Many compounds and chemical groups were identified with a laser aerosol mass spectrometer (laser AMS) and selected organic compounds, including acids, polyols, amines and aldehydes, from 50 nm filter samples were quantified. Interesting components found with the laser AMS included oxygenated and aliphatic hydrocarbons, aromatic compounds, amines, and black carbon. The amines found on laser AMS may be related to new particle formation events at particle sizes 10-25 nm. Correlations between the results obtained with different instruments were clarified, and the best correlations were found between laser AMS and 50-nm size filter samples. There were no correlations between the laser AMS data and meteorological data or on-line measured gas phase compounds. The black carbon found on laser AMS had moderate correlation for levoglucosan found on all-sized filter samples. Finally, the correlation analysis revealed that the information obtained from sub-50-nm size range particles and results for particles several times higher could not be directly compared. (C) 2011 Elsevier Ltd. All rights reserved