Assessment of workers exposure to ammonia in animal facilities

Confined animal facilities are industrial facilities that are considered as major sources of airborne pollutants that have an impact on both the environment and human health. Regulatory agencies such as the Occupational Safety and Health Administration (OSHA) have set standards to limit personal exposures to hazards in industrial and manufacturing facilities. Some previous studies showed that workers at animal facilities (e.g. swine, poultry) may be exposed to high levels of gases that may affect their health in the long run. This research aimed to study the exposure of workers to ammonia (NH3) in three animal facilities which were poultry, swine, and equine located at Stephen F. Austin State University's Walter C. Todd Agricultural Research Center in Nacogdoches, TX. Using NH3 passive personal monitoring samplers (badge), two workers in each facility were outfitted a different badge daily for 10 working days starting from September 29th to October 10th of 2014. The badges were analyzed in the lab using NIOSH Analytical Method 6015 (Visible Absorption Spectrophotometry for Ammonia). All participants in the study were asked to fill out an activity form during their workshifts in order to apportion the worker's exposure among their microenvironment. Ammonia concentrations were also measured inside the chicken houses and the swine center in addition to measuring the concentrations in the outside surrounding environment of each facility. Results of the study showed that poultry workers exposure to NH3 was about 127 % higher than equine workers' exposure and 91 % higher than swine workers' exposure. Swine workers were exposed to higher levels of NH3 than equine workers by about 19% and the geometric mean concentrations of NH3 for the workers at the swine, poultry, and equine facilities over the 10 sampling days were approximately similar (P = 0.173). Due to performing different tasks, results also showed differences of NH3 exposure between workers at the same facility; worker 1 at the poultry facility was exposed to higher levels of NH3 than worker 2 and their average concentrations were significantly different (P = 0.0004). At the equine facility, both of the workers were exposed to different levels of NH3 (P = 0.0001), and for the swine workers, average concentrations were not significantly different (P = 0.0802). Regarding NH 3 concentrations in and outside the surrounding environments, results showed that the poultry facility reported higher concentration values than the other two facilities during the whole sampling period. Regarding the aerial measurements, NH3 concentrations were not the same for each facility during the whole 10 sampling days and concentrations varied significantly (P = 0.0213) and days also played a role on the concentrations of NH 3 and had proven that NH3 concentrations were not the same every day in each facility (P = 0.0004) and there was an interaction between the facility and days (P < 0.0066).