Effectiveness and diurnal variations of vegetative environmental buffers (VEBs) for mitigating NH3 and PM emissions from poultry houses

Authors: YANG, ZIJIANG - University Of Maryland; YAO, QI - University Of Maryland; Hapeman, Cathleen; LI, HONG - University Of Delaware; Buser, Michael; Alfieri, Joseph; MCCONNELL, LAURA - University Of Maryland; Downey, Peter; TORRENTS, ALBA - University Of Maryland

Submitted to: Environmental Pollution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/5/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary: Poultry in the U.S. is typically grown in long houses containing up to 50,000 birds per house. The houses are equipped with large side wall fans to maintain the temperature and prevent the buildup of ammonia and particulates in house atmosphere. However, ammonia and particulate matter are also air pollutants and have raised concerns due to their potential negative impacts on human health and the environment. Producers and scientists have been developing a vegetative environmental buffer (VEB) which consists of trees and/or grasses planted that can remove these pollutants from the exhaust air from the poultry houses. Initial studies showed that VEBs could remove pollutants from the exhaust stream, but the effectiveness varies over a variety of conditions including daytime versus nighttime. Sampling results showed that ground-level concentrations beyond the VEB decreased by at least 75% of the original concentrations from the exhaust tunnel fan just outside the poultry house. Furthermore, the buffer decreased the concentration more during the daytime than the nighttime which is most likely due to the atmosphere being more active during the day because of the warming sunlight. These findings have been useful in developing more useful guidelines in constructing VEBs to remove exhaust pollutants effectively.

Technical Abstract: Air pollutants from poultry production, such as ammonia (NH3) and particulate matter (PM), have raised concerns due to their potential negative impacts on human health and the environment. Vegetative environmental buffers (VEBs), consisting of trees and/or grasses planted around poultry houses, have been investigated as a mitigation strategy for these emissions. Although previous research demonstrated that VEBs can reduce NH3 and PM emissions, these studies used a limited number of samplers and did not examine concentration profiles. Moreover, the differences between daytime and nighttime emissions have not been investigated. In this study, we characterized emission profiles from a commercial poultry house using an array with multiple sampling heights and explored the differences between daytime and nighttime NH3 and PM profiles. We conducted three sampling campaigns, each with ten sampling events (five daytime and five nighttime), at a VEB-equipped poultry production facility. NH3 and PM samples were collected downwind from the ventilation tunnel fans before, within, and after the VEB. Results showed that ground-level concentrations beyond the VEB decreased to 8.0% +/- 2.7% for NH3, 13% +/- 4% for TSP, 13% +/- 4% for PM10, and 2.4% +/- 2.8% for PM2.5 of the original concentrations from the exhaust tunnel fan, with greater reduction efficiency during daytime than nighttime. Furthermore, pollutant concentrations were positively intercorrelated. These findings will be valuable for developing more effective pollutant remediation strategies in poultry house emissions.