Title: Comparing inhaled ultrafine versus fine zinc oxide particles in healthy adults: a human inhalation study.

Authors: Beckett, William S; Chalupa, David F; Pauly-Brown, Andrea; Speers, Donna M; Stewart, Judith C; Frampton, Mark W; Utell, Mark J; Huang, Li-Shan; Cox, Christopher; Zareba, Wojciech; Oberdörster, Günter

Published In Am J Respir Crit Care Med, (2005 May 15)

Abstract: RATIONALE: Zinc oxide is a common, biologically active constituent of particulate air pollution as well as a workplace toxin. Ultrafine particles (< 0.1 microm diameter) are believed to be more potent than an equal mass of inhaled accumulation mode particles (0.1-1.0 microm 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 microg/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 microg/m3 for 2 hours is below the threshold for acute systemic effects as detected by these endpoints.

PubMed ID: 15735058

MeSH Terms: No MeSH terms associated with this publication