Journal Article
Atmospheric Chemistry and Physics, vol. 19, iss. 22, pp. 13859-13870, 2019
Authors
Maria A. Zawadowicz, Karl D. Froyd, Anne E. Perring, Daniel M. Murphy, Dominick V. Spracklen, Colette L. Heald, Peter R. Buseck, Daniel J. Cziczo
Abstract
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); it can extend historic datasets to include
measurements of bioaerosol, it allows comparisons to other techniques, and it 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 6×103 and 2×104 m−3. Between 2 and 8 km, bioaerosol concentrations were between 0 and 2×104 m−3, and above 8 km, bioaerosol concentrations were between 0 and
1×103 m−3. 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 wideband integrated bioaerosol sensor (WIB) fluorescence
sensor on a mountaintop site showed agreement to within a factor of 3 over
the common size range.
