Fluorescent biological aerosol particle size distributions and concentrations measured in different environments
J. ALEX HUFFMAN (1), Uli Pöschl (1)
(1) Max Planck Institute for Chemistry, Biogeochemistry Department
Abstract Number: 867
Preference: Poster Presentation
Last modified: August 10, 2010
Working Group: Biological Aerosol Detection and Sampling
Biogenic aerosols are ubiquitous in the Earth’s atmosphere, influencing atmospheric chemistry and physics, the biosphere, climate, and public health. They play an important role in the spread of biological organisms, can cause diseases, and may form nuclei which initiate water (CCN) and ice (IN) cloud formation.
The ultraviolet aerodynamic particle sizer (UV-APS) measures the concentration and aerodynamic diameter of particles in the size range of 1–20 micro-meter by light scattering and time-of-flight measurement, complemented by the measurement of fluorescence emission (420–575 nm) after excitation by a pulsed 355 nm laser. The instrument provides real-time detection of fluorescent biological aerosol particles (FBAP) as a lower-limit proxy of coarse-mode primary biological aerosol particles (PBAP) with relatively high time and size resolution. In certain circumstances the UV-APS may also provide information about the viability of bioaerosols.
The UV-APS was operated continuously in several different environments, including: semi-urban central Europe (Mainz, Germany), a boreal forest (Hyytiälä, Finland), and a tropical rainforest (Amazonia). Each study exhibited FBAP size distribution peaks and concentrations that varied significantly with time. Up to four particle modes were observed in certain locations, but a dominant average peak at ~3 um was surprisingly present in each study. This suggests that the number concentration of bioparticles may be dominated by fungal spores or agglomerated bacteria with aerodynamic diameters around 3 um. FBAP number concentrations were observed to be ~2–10x104 m-3, with mass concentration ~1 ug m-3 in each location. The relative number fraction of FBAPs within all super-micron particles sampled increased significantly from ~4% in central Europe to ~35% in Amazonia.
The authors gratefully acknowledge support by M.O. Andreae, M. Kulmala, P. Aalto, V. Hiltunen, J. Levula, R.M. Garland, and the AMAZE team.
Huffman, J.A., Treutlein, B., & Pöschl, U. (2010). Atmos. Chem. Phys., 10, 3215-3233.