Published ahead of print on February 25, 2005, doi:10.1164/rccm.200406-837OC
© 2005 American Thoracic Society doi: 10.1164/rccm.200406-837OC
Comparing Inhaled Ultrafine versus Fine Zinc Oxide Particles in Healthy AdultsA Human Inhalation StudyDepartments of Environmental Medicine, Medicine, and Biostatistics, University of Rochester School of Medicine and Dentistry, Rochester, New York; and Division of Epidemiology, Statistics, and Prevention, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland Correspondence and requests for reprints should be addressed to William S. Beckett, M.D., University of Rochester Medical Center, 601 Elmwood Avenue, Box EHSC, Rochester, NY 14642. E-mail: bill_beckett{at}urmc.rochester.edu Rationale: Zinc oxide is a common, biologically active constituent of particulate air pollution as well as a workplace toxin. Ultrafine particles (< 0.1 µm diameter) are believed to be more potent than an equal mass of inhaled accumulation mode particles (0.1–1.0 µm diameter). Objectives: We compared exposure–response relationships for respiratory, hematologic, and cardiovascular endpoints between ultrafine and accumulation mode zinc oxide particles. Methods: In a human inhalation study, 12 healthy adults inhaled 500 µg/m3 of ultrafine zinc oxide, the same mass of fine zinc oxide, and filtered air while at rest for 2 hours. Measurements and Main Results: Preexposure and follow-up studies of symptoms, leukocyte surface markers, hemostasis, and cardiac electrophysiology were conducted to 24 hours post-exposure. Induced sputum was sampled 24 hours after exposure. No differences were detected between any of the three exposure conditions at this level of exposure. Conclusions: Freshly generated zinc oxide in the fine or ultrafine fractions inhaled by healthy subjects at rest at a concentration of 500 µg/m3 for 2 hours is below the threshold for acute systemic effects as detected by these endpoints.
Key Words: air pollution • metal fume fever • particulate matter, ultrafine • zinc This article has been cited by other articles:
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