Primary biogenic aerosol particles (PBAP) are used by organisms including fungi, pollinating plants, bacteria and viruses as a means to propagate their genetic material, either by transport of organisms themselves or their reproductive components. Many studies have suggested PBAP might be important for initiation of cloud formation and subsequent precipitation evolution by acting as cloud condensation nuclei (CCN) or possibly as ice nuclei (IN). This link is inferred from laboratory studies (e.g. Diehl et al, 2001) demonstrating the high activation efficiency of PBAP at warm temperatures, coupled with observations that biological particles are ubiquitous in the atmosphere. Despite more than two hundred years of research (e.g. Ehrenberg, 1830) information on the abundance, composition and more importantly the sources and heterogeneity of PBAP on global scales is still lacking.
We present new observations of PBAP below and above the canopy of a South-East Asian tropical rain forest in Sabah, Malaysia, using the WIBS-3: a novel real-time aerosol spectrometer (Kaye et al., 2005). The observations were validated using Environmental Scanning Electron Microscope (ESEM) analysis of bioaerosol that were collected onto Nucleopore filters in the same locations.