Articles | Volume 12, issue 22
https://doi.org/10.5194/acp-12-10771-2012
https://doi.org/10.5194/acp-12-10771-2012
Research article
 | 
16 Nov 2012
Research article |  | 16 Nov 2012

Long-term volatility measurements of submicron atmospheric aerosol in Hyytiälä, Finland

S. A. K. Häkkinen, M. Äijälä, K. Lehtipalo, H. Junninen, J. Backman, A. Virkkula, T. Nieminen, M. Vestenius, H. Hakola, M. Ehn, D. R. Worsnop, M. Kulmala, T. Petäjä, and I. Riipinen

Abstract. The volatility of submicron atmospheric aerosol particles was investigated at a boreal forest site in Hyytiälä, Finland from January 2008 to May 2010. These long-term observations allowed for studying the seasonal behavior of aerosol evaporation with a special focus on compounds that remained in the aerosol phase at 280 °C. The temperature-response of evaporation was also studied by heating the aerosol sample step-wise to six temperatures ranging from 80 °C to 280 °C. The mass fraction remaining after heating (MFR) was determined from the measured particle number size distributions before and after heating assuming a constant particle density (1.6 g cm−3). On average 19% of the total aerosol mass remained in the particulate phase at 280 °C. The particles evaporated less at low ambient temperatures during winter as compared with the warmer months. Black carbon (BC) fraction of aerosol mass correlated positively with the MFR at 280 °C, but could not explain it completely: most of the time a notable fraction of this non-volatile residual was something other than BC. Using additional information on ambient meteorological conditions and results from an Aerodyne aerosol mass spectrometer (AMS), the chemical composition of MFR at 280 °C and its seasonal behavior was further examined. Correlation analysis with ambient temperature and mass fractions of polycyclic aromatic hydrocarbons (PAHs) indicated that MFR at 280 °C is probably affected by anthropogenic emissions. On the other hand, results from the AMS analysis suggested that there may be very low-volatile organics, possibly organonitrates, in the non-volatile (at 280 °C) fraction of aerosol mass.

Download
Altmetrics
Final-revised paper
Preprint