Model-Measurement Consistency and Limits of Bioaerosol Abundance Over the Continental United States
Abstract. Due to low concentrations and chemical complexity, in-situ observations of bioaerosol are geographically and temporally sparse, and this limits the accuracy of current emissions inventories. In this study, we apply a new methodology, including corrections for misidentification of mineral dust, to measurements of single particles over four airborne sampling campaigns to derive vertical profiles of bioaerosol over the continental United States. The new methodology is based on single particle mass spectrometry (SPMS), and it can extend historic datasets to include measurements of bioaerosol, allows for comparison to other techniques, and generally agrees with a global aerosol model. In the locations sampled, bioaerosols were at least a factor of 10 less abundant than mineral dust. Below 2 km, bioaerosol concentrations were measured between 6x10 m' and 2x10 m' . Between 2 km and 8 km, bioaerosol concentrations were between 0 and 2x10 m' , and Above 8 km, bioaerosol concentrations were between 0 and 1x 10 m' . Between 30% and 80% of single bioaerosol particles detected were internally mixed with dust. A direct comparison of the SPMS methodology with a co-located WIBS fluorescence sensor on a mountaintop site showed agreement to within a factor of 3 over the common size range.