AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Seasonal and Spatial Variation of Bioaerosols in Midwestern United States
CHATHURIKA RATHANYAKE, Nervana Metwali, Zach Baker, Peter Thorne, Patrick O'Shaughnessy, Thilina Jayarathne, Pam Kostle, Elizabeth Stone, University of Iowa
Abstract Number: 602 Working Group: Bioaerosols
Abstract This study examines the temporal and spatial variation of bioaerosols using six sites in Iowa. Coarse particulate matter (PM$_(10)) samples were collected at three urban sites (Davenport, Waterloo and Council Bluffs) and three background sites (State parks of Lake Sugema, Backbone and Viking Lake) during January, April, July and October in 2012. Samples were analyzed for chemical and biological tracers of fungal spores, pollens, bacteria, and animal detritus. Fungal spore tracers (arabitol, mannitol and fungal glucans) were highest in July, elevated in April, October and lowest in January. Significant correlation was observed between mannitol and arabitol (p<0.001, r=0.8) and a moderate correlation observed for mannitol and fungal glucans (p<0.001, r=0.4) during spring summer and autumn, indicating similar sources. Fungal glucan levels were significantly higher at urban sites compared to background sites (p<0.001) as determined by a paired t-test. Bacterial endotoxins peaked in October (0.5 ± 0.3 EU m-3), averaged 0.3 and 0.2 EU m-3 at urban and rural sites, respectively, and had a significant urban excess (p=0.001). Monthly average total protein concentrations ranged 0.9 – 3.8 µg m-3 (measured against bovine serum albumin standards) peaked in July and also had an urban excess (p<0.001). Our spatial analysis revealed urban enhancements of bioaerosols in Iowa, which are expected to be related to increased human activities that create bioaerosols in urban areas. The observed seasonal variation of fungal spore tracers and proteins is attributed to the greater extent of vegetation during summer and autumn, while peak endotoxin levels are attributed to agricultural dusts released during the harvesting season.