# Seasonal and Diurnal Ammonia Emissions from Swine-Finishing Barn with Ground Channel Ventilation

## TL;DR

A ground channel ventilation system helps reduce ammonia emissions in swine barns by stabilizing air temperature across seasons.

## Contribution

The study introduces a ground channel ventilation system that effectively balances barn temperature and ammonia emissions year-round.

## Key findings

- Ammonia emissions remained consistent across seasons with the ground channel system.
- The system improved air quality in cold seasons without affecting thermal comfort.
- Reduced ventilation in summer lowered ammonia emissions effectively.

## Abstract

Swine barns often experience extreme temperature fluctuations, making it challenging to maintain optimal conditions for both animal welfare and reducing environmental impact. In hot weather, increased ventilation, while necessary for cooling, can inadvertently lead to higher ammonia emissions. Conversely, reducing ventilation in cold weather to conserve heat can worsen indoor air quality. This study investigated the effects of a ground channel ventilation system on ammonia emissions from swine barns. This system utilizes an underground air passage to moderate incoming air temperature. By pre-tempering the air, the system enables higher ventilation rates even in cold weather, improving air quality without compromising barn temperature. Furthermore, it reduces the need to maximize ventilation for cooling during hot weather, thereby helping to lower ammonia emissions. The results demonstrated that this system helped stabilize ammonia emissions across seasons. In conclusion, controlling inlet air temperature offers a promising strategy for managing ammonia emissions and promoting a more sustainable swine production system.

This study evaluated the impact of a ground channel ventilation system on seasonal ammonia emissions in a swine-finishing barn over three distinct seasons: summer, late autumn, and winter. The ground channel system tempered inlet air, cooling it during summer and warming it during colder seasons, maintaining stable room temperatures despite external fluctuations. During summer, the ground channel reduced the incoming air temperature from 26.9 °C to 22.5 °C, contributing to steady barn temperatures (28.0 °C) and mitigating ammonia emissions, which reached 111.0 ± 23.6 g day−1 AU−1. In late autumn and winter, it warmed the inlet air from 4.7 °C and −0.7 °C to 8.1 °C and 6.8 °C, respectively, maintaining stable room temperatures (25.1 °C and 24.3 °C). Ammonia emissions remained consistent across seasons, with 125.0 ± 37.3 g day−1 AU−1 in late autumn and 107.1 ± 20.5 g day−1 AU−1 in winter. Thus, ammonia emissions showed no seasonal differences, highlighting the system’s effectiveness in balancing ventilation rates with emissions. During late autumn and winter, it improved air quality without compromising thermal comfort for the swine. In summer, the reduced ventilation demand lowered ammonia emissions, supporting the effective management of ammonia emissions year-round. Future research should investigate the system’s effects on other gases and slurry pit temperatures.