• NH 3 EF were quantified for North American and European poultry housing systems. • NH 3 EF from North American broiler production was 76% higher than that of European. • Publication period has a significant impact on NH 3 EF from poultry housing systems. • Further research on newer poultry production systems (aviary systems) required. Ammonia (NH 3 ) is a major environmental pollutant, responsible for approximately 50% of the PM 2.5 pollution in Europe, contributing to eutrophication and acidification. Approximately 15% and 30% of NH 3 is emitted from poultry production systems in Europe and North America, respectively. Therefore, it is important to understand the factors affecting NH 3 emission factor (NH 3 EF) from poultry production systems. In this study, we analysed the DATAMAN database to identify and quantify NH 3 EF for different poultry housing systems. The data was classified into four production systems, including broiler production and layer production in North America and Europe· NH 3 EF were calculated for these systems. Results showed that the NH 3 EF from Europe-based layer production system was lower (52.7%) than North America-based layer production system; the difference was statistically significant (p = 0.0483). Similarly, the NH 3 EF for broiler production systems in Europe was 43% lower than that for North American systems (p = 0.0084). The effect of litter management systems on NH 3 EF was not significant (p = 0.387). However, the NH 3 EF for European-based new litter system (where the litter is removed after every flock) was 40% lower than North American-based built-up litter system (where several flocks are reared on the same litter). In this study, the EF from studies published after 2010 was 54% lower than those from studies published before 2010 (p = 0.007), probably due to improved poultry production systems. Further emission research on newer, improved production systems is required to accurately calculate NH 3 EF which is highly needed to improve the emission inventorying of modern poultry houses.
Umar et al. (Fri,) studied this question.