From sea to forest: measurements of atmospheric nanoparticle composition at two remote northern European locations

Description

This poster summarizes measurements of the composition of 10–30 nm diameter atmospheric nanoparticles from two remote locations in northern Europe during spring 2011. The measurements were performed using the Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS)¹, which was recently upgraded to a high-resolution, time-of-flight mass spectrometer, at Hyytiälä Forestry Station, Finland, (April 8–28) and Mace Head Research Facility, Ireland, (May 13–31)². Since new particle formation at Hyytiälä normally originates with clean arctic and marine air masses³, comparisons of the two sites may provide some insights into the formation and evolution of aerosols in the Boreal Region.

At the coastal site, several apparent open ocean nucleation events⁴ were observed. The TDCIMS-derived particle composition measurements and concurrent observations from a hygroscopicity tandem differential mobility analyzer (HTDMA) suggest that nascent particles during these events contain both significant organic and inorganic (chloride and sulfate) components. We hypothesize that these marine aerosol result from the growth of small sea salt-sulfate seeds by condensation of organic vapors. The atmospheric nanoparticles observed at Hyytiälä contained nitrate, sulfate, and highly oxygenated organic acids. Nitrate ions, which we hypothesize are derived from particulate organic nitrates that dissociate during analysis, were observed in all particles as small as 15 nm in diameter and displayed a diurnal concentration profile that peaked during the morning hours.

1. Smith, JN, KF Moore, PH McMurry, and FL Eisele. 2004. “Atmospheric measurements of sub-20 nm diameter particle chemical composition by thermal desorption chemical ionization mass spectrometry.” Aerosol Science and Technology 38 (2): 100–110.

2. Lawler, MJ, J Whitehead, C O'Dowd, C Monahan, and JN Smith. 2013. “Composition of 15–30 nm diameter particles in marine air.” Atmospheric Chemistry and Physics, in preparation.

3. Nilsson, ED, J Paatero, and M Boy. 2001. “Effects of air masses and synoptic weather on aerosol formation in the continental boundary layer.” Tellus, Series B, Chemical and Physical Meteorology 53(4): 462–478.

4. O'Dowd, C., C Monahan, and M Dall'Osto. 2010. “On the occurrence of open ocean particle production and growth events.” Geophysical Research Letters 37(19): doi:10.1029/2010GL044679.