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PULMONARY TOXICITY OF SIZE-CLASSIFIED COAL FLY ASH PARTICLES OF VARYING CARBON CONTENT
Citation:
Cho, S. H., J. YOO, H. JANG, W. P. LINAK, C. A. Miller, AND M. I. GILMOUR. PULMONARY TOXICITY OF SIZE-CLASSIFIED COAL FLY ASH PARTICLES OF VARYING CARBON CONTENT. Presented at American Thoracic Society 2008 International Conference, Toronto, ON, CANADA, May 16 - 21, 2008.
Impact/Purpose:
The purpose of the study is to investigate relative toxicity of coal fly ash in different size and chemical composition to find out physicochemical factors of particulate matter that induce pulmonary toxicity.
Description:
Epidemiological studies have shown that morbidity and mortality increase along with concentration of particulate matter (PM) in many different countries and regions despite great variations in the chemical makeup of the PM. In this study, Illinois bituminous coal with high sulfur and iron was burned to produce fly ash particles with no detectible carbon, and medium and high carbon content. Particles were then separated into coarse (>2.5µm), fine (0.5-2.5µm) and ultrafine (<0.5µm) fractions, and the samples analyzed for elemental composition. Pulmonary inflammation in mice was assessed at 4 or 18 h after oropharyngeal aspiration of 100µg of particles. In the medium and high carbon samples, iron was detected in various oxidation states while sulfur was in the reduced form. The ultrafine fractions of these samples had higher carbon, but a similar iron and sulfur chemistry profile to the fine and coarse fractions for each combustion condition. These ultrafine samples induced a higher degree of neutrophil influx and IL-6 release in the lung. For the carbon-free samples, inflammation was highest in the fine fraction, which was dominated by oxidized iron and alumino-silicates. We conclude that either carbon, or iron combined with alumino-silicates can cause pulmonary inflammation in different size fractions, and may provide an explanation for the relatively non-specific effects that different sizes of ambient PM appear to cause, regardless of geographic location and chemistry.