Airborne observations of bioaerosol over the Southeast United States using a Wideband Integrated Bioaerosol Sensor

Abstract

Biological aerosols represent a diverse subset of particulate matter that is emitted directly to the atmosphere in the form of (but not limited to) bacteria, fungal spores, pollens, viruses, and plant debris. These particles can have local air quality implications, but potentially play a larger climate role by acting as efficient ice nucleating particles (INPs) and cloud condensation nuclei. We have deployed a Wideband Integrated Bioaerosol Sensor on the NASA DC-8 aircraft to (1) quantify boundary layer (BL) variability of fluorescent biological aerosol particle (FBAP) concentrations in the Southeast United States (SEUS), (2) link this variability explicitly to land cover heterogeneity in the region, and (3) examine the vertical profile of bioaerosols in the context of convective vertical redistribution. Flight-averaged FBAP concentrations ranged between 0.1 and 0.43 scm À3 (cm À3 at standard temperature and pressure) with relatively homogeneous concentrations throughout the region; croplands showed the highest concentrations in the BL (0.37 scm À3 ), and lowest concentrations were associated with evergreen forests (0.24 scm À3 ). Observed FBAP concentrations are in generally good agreement with model parameterized emission rates for bacteria, and discrepancies are likely the result of fungal spore contributions. Shallow convection in the region is shown to be a relatively efficient lofting mechanism as the vertical transport efficiency of FBAP is at least equal to black carbon aerosol, suggesting that ground-level FBAP survives transport into the free troposphere to be available for INP activation. Comparison of the fraction of coarse-mode particles that were biological (f FBAP ) suggested that the SEUS (f FBAP = 8.5%) was a much stronger source of bioaerosols than long-range transport during a Saharan Air Layer (SAL) dust event (f FBAP = 0.17%) or summertime marine emissions in the Gulf of Mexico (f FBAP = 0.73%).

Real-time detection of airborne fluorescent bioparticles in Antarctica

“…This instrument was designed to identify common bio-fluorophores and discriminate potentially harmful pathogenic bioaerosols from the background population. A full technical description of earlier and later versions of the instrument can be found in Kaye et al (2005), Foot et al (2008) and , while results from monitoring bioaerosols and analysis tools for identification of bioaerosols, mainly at remote sites, can be found in Crawford et al (2016Crawford et al ( , 2014, Gosselin et al (2016), Whitehead et al (2016), Ziemba et al (2016), Perring et al (2015), O'Connor et al (2015O'Connor et al ( , 2014, Robinson et al (2013), , and Gabey et al (2013Gabey et al ( , 2011Gabey et al ( , 2010. The instrument has an inlet flow of 2.35 L min −1 , the majority of which is filtered with a HEPA filter to remove all particles, such that the 0.23 L min −1 sample flow is sheathed in particle free air to constrain the aerosol into a controlled jet and to minimise contamination of the optics.…”

Improved identification of primary biological aerosol particles using single-particle mass spectrometry

“…Four of the recent studies reported in Table 1 used an aircraft to access altitudes higher than 4000 m (DeLeon- Rodriguez et al, 2013;Pósfai et al, 2003;Twohy et al, 2016;Ziemba et al, 2016). Two of these used the WIBS to report vertical profiles of fluorescent particles (Twohy et al, 2016;Ziemba et al, 2016). In the remaining two cases, aerosols were collected on filters and analyzed off-line.…”

Systematic characterization and fluorescence threshold strategies for the wideband integrated bioaerosol sensor (WIBS) using size-resolved biological and interfering particles

“…Both the WIBS and UV-APS, in various version updates, have been applied to many types of studies regarding outdoor aerosol characterization. For example, they have been important instruments: in the study of ice nuclei Mason et al, 2015;Twohy et al, 2016), toward the understanding of outdoor fungal spore concentrations (Gosselin et al, 2016;Saari et al, 2015a;O'Connor et al, 2015b), to investigate the concentration and properties of bioaerosols from long-range transport (Hallar et al, 2011), in tropical aerosol Whitehead et al, 2010Whitehead et al, , 2016Huffman et al, 2012;Valsan et al, 2016), in urban aerosol Saari et al, 2015b;Yu et al, 2016), from composting centers (O'Connor et al, 2015b), at high altitude Gabey et al, 2013;Perring et al, 2015;Ziemba et al, 2016), and in many other environments (Healy et al, 2014;Li et al, 2016;O'Connor et al, 2015a). The same instrumentation has been utilized for a number of studies involving the built, or indoor, environment as well (Wu et al, 2016).…”