Field Comparison of Methods for Evaluation of Vapor/Particle Phase Distribution of Ammonia in Livestock Buildings. Stephen J. Reynolds,* Dayyu Y. Chao,** Peter S. Thorne,* Periyasami Subramanian,* Peter F. Waldron,* Mustafa Selim,* Paul S. Whitten,* and William J. Popendorf+
Ammonia is a significant respiratory hazard for workers in enclosed livestock buildings. It is hypothesized that ammonia originating from animal wastes is present in both vapor phase and adsorbed onto dust (particulate phase), and that this physical distribution is an important determinant of deposition in the human respiratory system. The goals of this project were: (1) to evaluate the vapor/particle phase distribution of ammonia in enclosed livestock buildings using annular denuders and impingers with prefilters; and (2) to compare the annular denuders air sampling method to traditional active and passive ammonia sampling methods. Ammonia was sampled and analyzed using six methods: annular denuder systems with ion chromatographic (IC) analysis; impingers with pre-filter and IC analysis; impingers without pre-filters with IC analysis; long-term colorimetric tubes; direct reading colorimetric detector tubes; and passive dosimeters. Field studies were conducted in six enclosed swine and poultry buildings during the summer season. Analysis of variance confirmed by individual t-tests indicated that passive dosimeters and long-term colorimetric tubes consistently yielded higher ammonia values than the denuder and impinger methods. Denuder systems were less precise (pooled CV = 0.41) than impingers without pre-filters (pooled CV = 0.16), but more precise than impingers with pre-filters (pooled CV = 0.47). The results of this study indicate that a measurable proportion of ammonia in enclosed livestock buildings is indeed associated with particles, and that annular denuder systems have potential to be used in this environment for evaluation of phase distributions of ammonia. However, the precision and overall collection efficiency of the specific annular denuder evaluated was poor compared to the traditional impinger method, and further work is needed to develop a more suitable denuder system for the relatively higher concentrations of gases and particulates encountered in agriculture environments.
Support for this research was provided through the University of Iowa Environmental Health Sciences Research Center, NIH Grant No. P30 ES05605-01 and the Center for Agricultural Disease and Injury Research Education and Prevention, NIH Grant No. CDC/NIOSH U07/CCU 706145.
*University of Iowa, Dept. of Preventive Medicine and Environmental Health, Institute of Rural and Environmental Health, Iowa City, IA 52242-5000. For corresponding author (Stephen J. Reynolds): telephone (319) 335-4212, fax (319) 335-4225, e-mail stephen_reynolds@uiowa.edu.
**Researcher, National Institute of Preventive Medicine, FETP, Department of Health, Executive Yuan, Taipei, Taiwan, ROC.
+Professor, Department of Biology, Utah State University, Logan, Utah.
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