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Contributions from Broiler Chicken Farms to Worker Ammonia Exposure

Abstract No:

1703

Abstract Type:

Student Poster

Authors:

A Matthews¹, W Vizuete¹

Institutions:

¹University of North Carolina at Chapel Hill, Chapel Hill, NC

Presenter:

Avery Matthews
University of North Carolina at Chapel Hill

Faculty Advisor:

Dr. Will Vizuete, PhD
University of North Carolina at Chapel Hill

Description:

Concentrated Animal Feeding Operations (CAFOs) are the number one source of ammonia emissions in the Southeastern U.S. Inadequate estimates of emissions from various types of CAFOs leads to underestimates of worker and community exposures. In this study, the role of litter pile contributions to total emissions from broiler chicken farms was assessed. Using a modelling approach, this study assessed the relative contributions of litter pile emissions to resulting ammonia concentrations in Robeson County, NC. These missing emissions from national estimates were found to contribute significantly to resulting concentrations, increasing frequency of worker exposure to concentrations above short-term limits.

Situation/Problem:

Concentrated Animal Feeding Operations (CAFOs) are the largest contributors to ammonia emissions in the U.S.. North Carolina is the nation's fourth largest broiler chicken producer, with Robeson County producing 52.5 million in 2024, the fourth highest in the state. Unlike other counties in the top four, Robeson County is not a major swine producer, making it a strong case study for the impacts of broiler ammonia emissions in isolation from other CAFO types. Ammonia is a hazardous air pollutant that can cause irritation at moderate levels and respiratory damage with sufficient acute exposure. Worker and community exposures to ammonia emissions from broiler CAFOs are poorly understood due to missing emission information from the litter storage component of the litter lifecycle.

Methods:

Current emission estimates for broiler farms were expanded to include litter storage emissions based on the latest literature values. Satellite data was used to locate, size, and identify 122 broiler farms. House emissions were based on Live Animal Weight (LAW), relative humidity, and temperature. Using these inputs, EPA regulatory dispersion model AERMOD was used to predict exposure estimates in Robeson County, NC for workers and community members from 2016 to 2018. Potential worker exposure was assessed through analysis of on-site concentrations during worker-relevant hours.

Results / Conclusions:

The incorporation of litter pile emissions increased countywide maximum ammonia concentrations by 20% across all receptors within 500m of emission sources. For work hours from 2016 to 2018, estimated ammonia emissions from barns and litter piles resulted in ~900 exceedances of the NIOSH Short-Term Relative Exposure Limit, and 560 exceedances of the ACGIH Threshold Limit Value Short Term Exposure Limit. These model results indicate the need for an assessment of litter pile emissions to be included in future studies to more accurately reflect worker and community exposure. Furthermore, these exceedances demonstrate the need for ammonia exposure monitoring amongst chicken CAFO employees, especially within the Southeastern United States.

Core Competencies:

Exposure Assessment

Secondary Core Competencies:

Community Exposure

Work Environments, Occupations, and Industrial Processes

Keywords

Choose at least one (1), and up to five, (5) keywords from the following list. These selections will optimize your presentation's search results for attendees.

Exposure Assessment

Environmental protection and monitoring

Indoor air quality

Targeted Audience (IH/OH Practice Level)

Based on the information that will be presented during your proposed session, please indicate the targeted audience practice level: (select one)

Professional: Professional is a job title given to persons who have obtained a baccalaureate or graduate degree in IH/OH, public health, safety, environmental sciences, biology, chemistry, physics, or engineering or who have a degree in another area that meets the standards set forth in the next section, Knowledge and Skill Sets of IH/OH Practice Levels, and has had 4 or more years of practice. One significant way of demonstrating professional competence is to achieve certification by a 3rd party whose certification scheme is recognized by the International Occupational Hygiene Association (IOHA) such as the Board of Global EHS Credentialing (BGC).

Volunteer Groups

Was this session organized by an AIHA Technical Committee, Special Interest Group, Working Group, Advisory Group or other AIHA project Team?

Worker Exposure Data and/ or Results

Are worker exposure data and/or results of worker exposure data analysis presented?

Practical Application

How will this help advance the science of IH/OH?

This research is intended to highlight an area of inadequate worker exposure assessment. Through a modelling approach, the study identified areas and times of greatest concern to worker health, in order to guide future exposure assessment efforts. The study highlights potential worker groups of particular concern for ammonia exposure, and addresses a previous gap in understanding of potential exposure levels. Revision of emission estimates to include litter pile emissions would allow for more accurate modeling of worker and community exposure.