Graduation Date

Fall 12-19-2025

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Programs

Environmental Health, Occupational Health, and Toxicology

First Advisor

Matthew Nonnenmann

Second Advisor

Risto Rautiainen

Third Advisor

Cheryl Beseler

Fourth Advisor

Aaron Yoder

Abstract

Farming is a hazardous occupation. Exposures are multifactorial, variable, and shaped by overlapping tasks, environments, and social contexts. This dissertation aimed to illustrate the complexity of agricultural exposures and the barriers to protective practices through three complementary studies.

The first study examined co-exposures to solvents and noise as risk factors for hearing loss (HL) among 7,495 farmers and ranchers in a 7-state region. Results indicated nearly 60% of co-exposed participants reported hearing loss, with an adjusted odds ratio nearly six-fold (OR=6.03, [4.67-7.78]) for moderate/severe HL. This work highlights the importance of recognizing chemical exposures as a modality in HL in addition to noise.

The second study presented a case of a family-operated pullet barn in rural Nebraska. Ammonia and dust concentrations were measured temporally during one growth cycle spanning approximately 16.5 weeks. Results indicated concentrations increased substantially with bird age, reaching levels capable of inducing adverse respiratory effects. Motivation to perform this exposure assessment was via the primary operators’ uncertainty as to what personal protective equipment (PPE) to use and when. This work highlights opportunities for outreach and education that support the health and safety of producers, particularly those new to poultry farming.

The third study focused on PPE use, fit, training, preferences, and self-reported adverse health effects despite the use of PPE among women in agriculture. Results indicated women were active users of PPE, but deficits in training and fit were evident. Nearly 90% of women expressed interest in purchasing PPE designed specifically for women, underscoring unmet demand for appropriately fitted and affordable protection.

Taken together, these studies show that agricultural exposures are complex and constantly changing, while protective behaviors remain inconsistent and limited. Using Protection Motivation Theory, this dissertation develops a framework that interprets coping appraisal constructs to predict behaviors in complex agricultural settings. By connecting exposure science with behavioral theory, this work highlights the importance of prevention strategies that focus on workers and enhance motivation and ability for personal protection.

Comments

2025 Copyright, the authors

Available for download on Sunday, May 31, 2026

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