ENVIRONMENTAL IMPACT OF LIVESTOCK ACTIVITIES IN THE PO VALLEY AND MITIGATION PATHWAYS EVALUATION

In Italy, livestock production is of great importance within the agricultural sector, driven by social, economic and cultural factors, with the Po Valley hosting approximately 80% of the national dairy and beef cattle, and pig populations. The link between animal production and the environment is increasingly recognized as a critical issue, requiring a thorough understanding of their interaction. This thesis aimed to evaluate different mitigation strategies to reduce on-farm emissions of greenhouse gases and air pollutants, specifically examining air treatment technologies in pig housing facilities and some waste management measures for the cattle sector. Focus was made on the two above environmental aspects due on the one hand to the strong relationship that these have with the sector under analysis and on the other to their relevance in the Italian and the broader European context. To provide a comprehensive understanding of these issues, the approach included (i) direct measurements during field campaigns on farms to assess emissions; (ii) life cycle assessment (LCA) methodology using primary production data collected through surveys, complemented by secondary data from literature and estimation models; and (iii) large-scale modeling based on regional/national statistics and general activity factors, to estimate the potential resulting from widespread adoption of mitigation practices. The relationship between livestock in Italy and air pollution, with a focus on ammonia emissions, was explored through three different studies. The first focused on the evaluation of the evolution of atmospheric concentrations of ammonia (NH3) in Northern Italy during the COVID-19 pandemic. Ground-based and satellite data were analyzed for the year 2020 and compared with data from previous years, and it was concluded that, unlike some other air pollutants, the anti-COVID-19 measures affecting human activities did not lead to a reduction in NH3 air concentrations, confirming its strong relationship with agriculture, whose activities were not significantly interrupted during the pandemic. The other two studies focused instead on the adoption of abatement strategies in pig farms to reduce ammonia and particulate emissions from housing facilities. This phase of the agricultural cycle is very influential on the total emissions of these pollutants, but mitigation technologies aimed at it are not widespread in the Italian context. LCA has been used to quantify the environmental impact of pig production in a "standard" production context and to compare it with the production when implementing two air treatment technologies aimed at reducing pollutant emissions: i) wet scrubber; ii) dry scrubber. Inventories have been made of the technical performances of farms in Italy and Spain. Operation of the two technologies have been obtained from experimental trials carried out during the Life- MEGA project. Both technologies tested showed their potential to reduce emissions in the pig housing phase, which had an impact on all the categories affected by air pollutant emissions, such as particulate matter formation, acidification and eutrophication. At the same time, different trade-offs were observed with impact categories related to energy and resource use. The dry scrubber was found to be the most favorable option when considering the balance with the trade-offs. The third study explored the effect that the large-scale implementation of air cleaning technologies (with a focus on wet acid scrubbers) for pig housing facilities could have in and endpoint perspective in the European Union. Emissions related to the housing stage of NH3, PM10, NMVOC and indirect N2O from large pig farms (>1000 heads of sows or fattening pigs) were first estimated in the actual situation (current scenario - CS), considering implementation rates and removal efficiencies of the different emission abatement techniques available. Subsequently, alternative scenarios were simulated with a growing implementation rate of the wet acid scrubber (35% and 65% of the concerned pig farms in all Member States). In conclusion, scrubber technologies are promising for mitigating the environmental impacts of pig production and the emission reduction achievable with increased implementation rates across the EU would have a largely positive endpoint effect on human health, and lead to significant alleviation of current environmental costs on society of air pollution related to intensive pig farming. Future research should focus on more issues related to these technologies, including optimizing cost-effectiveness, impact on animal welfare and production performance, on farm worker working conditions, and effluent management. Subsequently, two studies were developed focused on the analysis of potential strategies for reducing greenhouse gas emissions from cattle farming waste management, one on the dairy and one on the beef sector. For the dairy sector, a direct measurement approach was adopted, through a campaign that included an on-farm trial lasting several months, adopting slurry treatment through the commercial additive SOP Lagoon and specific technologies for on-site control of emitted gases from slurry storage tanks. Although the effectiveness of emission reduction varied throughout the trial, the results were positive, particularly for methane, as three months after the first applications of the additive, the treated storage tank showed statistically significant lower emissions than the untreated tank. As for the beef cattle sector, on the other hand, a case study was developed to analyze a beef cattle farm integrating on-farm renewable energy production technologies by combining life cycle assessment and emissions modeling. The implementation of anaerobic digestion system on farm is shown to considerably enhance the environmental and energy performance of beef production. This study, to the authors' knowledge, was the first to quantify the possible environmental benefit deriving from such integrated management of livestock and energy production on a beef farm. Overall, this work has provided valuable context-specific insights into the technologies evaluated, highlighting the benefits and limitations of their application. It goes without saying that none of them can fully address the environmental challenges of animal production if implemented in isolation, as integrated interventions are required. LCA was confirmed as a valuable tool for identifying areas for improvement within the value chain and for highlighting trade-offs, ensuring that improvements in one aspect of a product's life cycle do not inadvertently shift environmental burdens to another phase or impact category. However, due to some of its limitations discussed in the course of the work, it cannot stand alone in guiding decision making and environmental policy development. This again underlines the importance of a holistic approach to assessing the environmental impacts of livestock production, as a key challenge is to capture the complexity and variability of farming systems where local practices and conditions vary widely.