A evaluation of biogenic components of indoor and outdoor particulate matter and indoor settled dust in homes in Baltimore, Maryland

Particulate matter (PM) exposure has been widely associated with the increase in morbidity and mortality from cardiovascular and respiratory diseases. PM is a complex mixture containing organic and inorganic carbon, metals, and crustal materials. Biogenic material derived from living organisms is an important component of organic carbon.;Sources of outdoor and indoor PMs are vary. Outdoor PM is generated from vehicle emission, coal and fuel burning, industrial furnaces, and natural process. Indoor PM is from outdoor PM penetration and the additional indoor sources include cooking and human activities such as vacuuming, dusting, and sweeping. Much of the health effects and PM characterization literature has focused on exposures to ambient PM with less research on unique characteristics of indoor PM.;The indoor environment is important exposure source since people spend nearly 80% of their time indoors. Biogenic components are thought to be more prevalent in indoor air. Biogenic compounds are important because they are biologically active and may induce or exacerbate respiratory diseases.;The overall objective of this research is to characterize and compare the biogenic components in indoor and outdoor PM and in indoor settled dust. Biogenic components assessed include total protein, allergens (house dust mite, mouse, cockroach, cat, and dog allergens), ergosterol (a chemical marker of fungal biomass), and endotoxin (a pro-inflammatory agent of gram-negative bacteria). Air and dust samples were collected from ten homes in Baltimore during May--July 2007.;Micro BCA(TM) assay was used for total protein analysis. The Enzyme-Linked Immunosorbent Assay was used for allergen analysis. Ergosterol was analyzed using GC-MS-MS. Limulus Amebocyte Lysate and recombinant Factor C assays were used for endotoxin analyses.;Our findings suggest that biogenic components are generally greater in indoor PM than outdoor. Biogenic components are greater in PM10 than PM2.5. Biogenic components in indoor PM and settled dust are poorly to moderately correlated. Total protein contributes a significant fraction of PM and indoor settled dust mass.;These data support the hypothesis that biogenic materials may be important risk factor for PM toxicity. Research should be conducted to evaluate whether indoor biogenic components are associated with cardiac and respiratory health effects.