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CBS presents a special seminar with guest speaker, Tonny Oyana.


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Dr. Tonny J. Oyana began his education with a BS in biology and geography education from the University of Dar-es-Salaam, Tanzania followed by a M.Sc. in the fields of geographic information systems and (GIS)/environmental planning from the National University of Ireland, University College. He later obtained his PhD from the State University of New York at Buffalo.

"Dr. Oyana has more than 23 years of experience covering North and South America, Europe, Asia and Africa, and his expertise lies mainly in information science, geospatial data science, visual analytics and spatial analytical methods. Oyana has applied the depth of his knowledge in geography, data analytics, and algorithms to solve complex problems in environmental health and health disparities." (biosketch)

From the Lab to Field: A novel spatial phytosampling method for ambient air pollution

Stable, bioreactive, radicals known as environmentally persistent free radicals (EPFRs) have been found to exist on the surface of airborne PM2.5. These EPFRs have been found to form during many combustion processes, are present in vehicular exhaust, and persist in the environment for weeks and biological systems for up to 12 hours. To measure EPFRs in PM samples, high volume samplers are required and measurements are less representative of community exposure; therefore, we developed a novel spatial phytosampling methodology to study the spatial patterns of EPFR concentrations using plants. Leaf samples for laboratory PM analysis were collected from 188 randomly drawn sampling sites within a 500-meter buffer zone of pollution sources across a sampling grid measuring 32.9 km × 28.4 km in Memphis, Tennessee. PM was isolated from the intact leaves and size fractionated, and EPFRs on PM quantified by electron paramagnetic resonance spectroscopy. The radical concentration was found to positively correlate with the EPFR g-value, thus indicating cumulative content of oxygen centered radicals in PM with higher EPFR load. Our spatial phytosampling approach reveals spatial variations and potential "hotspots" risk due to EPFR exposure across Memphis and provides valuable insights for identifying exposure and demographic differences for health studies.