Autofluorescence Measurements of Primary Biological Aerosol Particles during Winter in Interior Alaska: The Influence of Biomass Burning
KAITLYN MCKINNEY, Saravanan Kanagaratnam, Anastasia Hewitt, Raghu Betha, Venky Shankar,
Texas Tech University Abstract Number: 359
Working Group: Bioaerosols
AbstractPrimary Biological Aerosol Particles (PBAPs) are significant contributors to climate change and can adversely impact human health, making it essential to understand their distribution, proliferation, and concentrations. While several methods exist to measure bioaerosols, autofluorescence methods have distinct advantages in high sensitivity and real-time monitoring. However, the major limitation of this measurement method is the interference from non-biological particles and anthropogenic emissions. To address this challenge, we developed an approach that involves using concurrent measurements of autofluorescence and chemical analysis of particle filter samples to quantify and isolate the interference of biomass-burning particles. This approach was applied to quantify the types, concentrations, and temporal distribution of bioaerosols during wintertime in the City of North Pole, Alaska. The results of this study show that fluorescent aerosol particles (FAPs) less than 0.75μm in diameter that are excited by wavelengths of either 370 nm or 280 nm and fluorescent emission wavelengths of 420 nm to 650 nm (Type-B and Type-C) are primarily biomass-burning particles. FAPs in this category make up 54% of the total FAPs. FAPs measured in these wavelengths have weak peak fluorescent intensities and are largely made of smaller particles. These findings fit a pattern of human activity in the local population. The concurrent measurement approach used in this study can be applied to other regions to understand the distribution and concentrations of bioaerosols further. Overall, this study provides valuable insights into the dynamics and variations of bioaerosols and demonstrates the importance of using accurate methods to measure them.