Influence of Rainfall on Taxon-specific Bioaerosols around a Livestock Farm

NOHHYEON KWAK, Erin Cortus, Carol Cardona, Kristelle Mendoza, Tara Gaire, Noelle Noyes, Jiayu Li, University of Miami

     Abstract Number: 82
     Working Group: Bioaerosols

Abstract
Bioaerosols are known to be a crucial factor in the transmission of pathogenic diseases in high-density livestock farming. However, their impact has yet to be thoroughly investigated, and there needs to be more information on size-resolved bioaerosols. Moreover, rainfall represents a liquid-air interface activity that can serve as a potential source of bioaerosols, and its influence on aerosols or bioaerosols is complex. The concentrations of bioaerosols have unique characteristics during rain events. Large particles are washed out by combining rain droplets due to their substantial surface area. In contrast, some aerosols containing microorganisms undergo increased growth during rain, attributed to the agitation and high relative humidity conditions. Therefore, this study aims to address the knowledge gap by identifying the size-resolved bioaerosol information around livestock farms and evaluating the effects of rainfall on bioaerosol concentration and diversity.

This study was conducted beside a livestock barn, and a non-farming environment located 400 m away from the farm. A cascade impactor (Sioutas Impactor, SKC) collected bioaerosol samples with three different size cuts (>2.5, 2.5-1, and 1-0.25 um). The genetic diversity of bioaerosols was analyzed using 16S gene amplicon sequencing targeting the V4 region. Aerosol mass concentration was characterized using an optical particle counter (OPC, Grimm).

The results revealed the presence of marker species around the livestock farm, such as Staphylococcus, Pseudomonas, and Jeotgalicoccus. Bioaerosol concentrations were higher by the livestock farm compared to the non-farming environment. While rainfall decreased the aerosol mass concentration, the bioaerosol concentrations remained stable. During the rainfall, the number concentration of bioaerosols increased in particles smaller than 1 um, indicating a potential influence of rain on bioaerosols. This research will provide valuable information on the concentration and diversity of bioaerosols in the vicinity of livestock farms with size-resolved data. Detailed information on the taxon-specific bioaerosols will be presented.