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Urban enhancement of PM 10 bioaerosol tracers relative to background locations in the Midwestern United States
Author(s) -
Rathnayake Chathurika M.,
Metwali Nervana,
Baker Zach,
Jayarathne Thilina,
Kostle Pamela A.,
Thorne Peter S.,
O'Shaughnessy Patrick T.,
Stone Elizabeth A.
Publication year - 2016
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2015jd024538
Subject(s) - indoor bioaerosol , bioaerosol , environmental science , particulates , environmental chemistry , seasonality , aerosol , atmospheric sciences , chemistry , biology , ecology , meteorology , geography , geology
Bioaerosols are well‐known immune‐active particles that exacerbate respiratory diseases. Human exposures to bioaerosols and their resultant health impacts depend on their ambient concentrations, seasonal and spatial variation, and copollutants, which are not yet widely characterized. In this study, chemical and biological tracers of bioaerosols were quantified in respirable particulate matter (PM 10 ) collected at three urban and three background sites in the Midwestern United States across four seasons in 2012. Endotoxins from Gram‐negative bacteria (and a few Gram‐positive bacteria), water‐soluble proteins, and tracers for fungal spores (fungal glucans, arabitol, and mannitol) were ubiquitous and showed significant seasonal variation and dependence on temperature. Fungal spores were elevated in spring and peaked in summer, following the seasonal growing cycle, while endotoxins peaked in autumn during the row crop harvesting season. Paired comparisons of bioaerosols in urban and background sites revealed significant urban enhancements in PM 10 , fungal glucans, endotoxins, and water‐soluble proteins relative to background locations, such that urban populations have a greater outdoor exposure to bioaerosols. These bioaerosols contribute, in part, to the urban excesses in PM 10 . Higher bioaerosol mass fractions in urban areas relative to background sites indicate that urban areas serve as a source of bioaerosols. Similar urban enhancements in water‐soluble calcium and its correlation with bioaerosol tracers point toward windblown soil as an important source of bioaerosols in urban areas.