Document Type


Date of Degree

Fall 2015

Degree Name

MS (Master of Science)

Degree In

Occupational and Environmental Health

First Advisor

Anthony, T Renée

First Committee Member

Rohlman, Diane S

Second Committee Member

Janssen, Brandi


Swine workers in concentrated animal feeding operations (CAFOs) are at risk of developing respiratory illnesses as a result of exposure to a combination of ammonia (NH3), carbon dioxide (CO2), and dust. The purpose of this study was to determine whether the use of a recirculating ventilation system with a filter-type air pollution control (APC) unit (Shaker Dust Collector, United Air Specialists Inc.), selected to control dust, would inadvertently increase NH3 and CO2 concentrations in a farrowing room.

During the 2013-14 winter season, NH3 and CO2 concentrations were measured at six fixed locations throughout the farrowing room test site. Direct reading instruments (NH3: VRAE, Rae Systems Inc.; CO2: ToxiRAE Pro, Rae Systems Inc.) were deployed for 24-hour periods throughout the season on 18 randomly selected days. Contaminant concentrations were measured and compared by ventilation status (APC ON: 11 days, APC OFF: 7 days).

Ammonia concentrations were above the literature recommended limit (7 ppm) on 13 of the 18 sample days (72%) and even exceeded the threshold limit value (TLV) of 25 ppm on one of the sample days. Carbon dioxide concentrations exceeded the literature recommended limit of 1540 ppm on all 18 sample days, and average concentrations were half of the TLV (2500 ppm). There was no statistically significant difference in NH3 (p > 0.23) or CO2 (p > 0.67) when concentrations were compared by APC status.

The results of this study indicate a recirculating ventilation system with filter dust control does not increase NH3 or CO2 concentrations spatially or temporally in the room during operation. Future work will investigate engineering control options to reduce CO2 concentrations in the farrowing room.

Public Abstract

Swine workers are at risk of developing health problems due to breathing in air contaminants in swine barns. Methods have been developed to reduce the amount of contaminants a worker breathes. The purpose of this study was to determine whether a system intended to reduce dust concentrations would inadvertently increase ammonia and carbon dioxide concentrations, two contaminants commonly found in swine production facilities.

Ammonia and carbon dioxide concentrations were measured over the course of 18 randomly selected days throughout the winter of 2013-14, with the dust control system in operation (11 days) or not (7 days). Gas measuring instruments were positioned at six fixed locations throughout the study site. Gas concentrations were measured when the dust control device was in operation and compared with gas concentrations when the device was turned off.

In the farrowing room of our test swine barn, ammonia and carbon dioxide concentrations were not increased when the dust control device was in operation. Future work will explore effective control options to reduce high carbon dioxide concentrations that were identified in this field study.




viii, 47 pages


Includes bibliographical references (pages 45-47).


Copyright 2015 Richard Gassman