Performance Evaluation of Bioaerosol Samplers in an Environmentally Controlled Chamber

MARINA NIETO-CABALLERO, Kevin Barry, Emily Kraus, Kristin Rugh, Mark Hernandez, Sonia Kreidenweis, Colorado State University

     Abstract Number: 211
     Working Group: Bioaerosols

Abstract
Accurate characterization of bioaerosols is critical for understanding their roles in human health and atmospheric processes. However, current bioaerosol samplers vary widely in collection efficiency and may introduce biases due to microbial stress, cell damage, or loss of nucleic acid integrity. As part of the NSF-funded BROADN project (Colorado State University), this study aims to improve and standardize bioaerosol sampling methodologies by systematically evaluating the performance of five widely used samplers—two filter-based (SASS 3100 and polycarbonate filters) and three liquid-based (Coriolis-μ, BioSpot-VIVAS, and SKC-BioSampler)—under environmentally controlled chamber conditions.

Experiments were conducted in a 10 m³ chamber at the University of Colorado Boulder, under two relative humidity regimes (25% and 80%) to mimic dry and humid environments. Microbial suspensions of Pseudomonas syringae (gram-negative) and Lysinibacillus parviboronicapiens (gram-positive) were nebulized using the SLAG nebulizer, selected for its low biological impact. Bioaerosols were sampled in parallel using the five samplers to ensure consistent exposure. Post-collection analyses included traditional culturing, quantitative PCR (qPCR), SYTO-9/PI fluorescence microscopy for live/dead cell visualization, and ice nucleating particle (INP) assays to evaluate activity relevant to atmospheric processes.

Preliminary results indicate that liquid-based samplers outperformed filter-based methods for maintaining viability and genomic integrity of gram-negative bacteria, particularly under high humidity conditions. Differences in sampler performance were also observed in INP activity preservation and membrane integrity assessments. These findings highlight the importance of sampler selection based on experimental goals—whether assessing microbial viability, diversity, or atmospheric functionality.

This study contributes critical data toward the standardization of bioaerosol sampling protocols and offers practical guidance for researchers selecting methods for diverse indoor and outdoor applications in aerobiology, public health, and atmospheric science.