Characterization and quantification of air emissions from dairies

Abstract

Animal agriculture is a significant and growing source of atmospheric pollutants. The primary pollutants of interest are ammonia (NH3), ammonium particulates (NH4+), carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4), volatile organic compounds (VOC), odor, and hydrogen sulfide (H2S). These species are of interest due to their negative impacts on the environment, air quality, and human health. A reduction of pollutants with best management practices is vital to the sustainability of livestock production. In order to mitigate pollutants from livestock operations, accurate quantification and characterization of the seasonality, spatial variability, and behavior of each species is necessary. The objective of this dissertation was to quantify, characterize, and offer mitigation solutions for air emissions from livestock operations with a focus on dairies and feedlots. First, a comprehensive literature review was conducted on the impacts, emissions values, and measurement techniques of each pollutant. Second, a review of best management practices was compiled to offer solutions to reduce emissions from dairy and feedlot operations. Third, we created a unique measurement system that was able to characterize the vertical and horizontal variability of emissions plumes from dairies using helium balloons and sampling equipment attached to the balloon tether lines. We validated the system with laboratory and field trials and found it to work well under field conditions. Lastly, we used this novel system to quantify and characterize emissions of NH3, NH4+, nitric acid, CO2, N2O, and CH4, from two dairy operations in Colorado. We found that emissions were different from the two operations, and there was strong seasonal, vertical, and horizontal plume variability within each dairy. These results can be used to better characterize emissions from dairy operations and allow researchers, producers, and regulators to better understand and mitigate harmful air emissions, while maintaining agriculture in Colorado.