Shropshire Farming Talk: The ammonia emissions trial that will save the pig sector millions
A couple of months ago we said to expect big news on a project has been seven years in the making. Well, it’s official: British pig farmers have collectively saved an estimated £15.3 million in potential environmental mitigation costs, thanks to significant progress in reducing ammonia emissions.
This achievement is particularly gratifying because it stems from a multi-year ammonia-monitoring trial I was privileged to lead.
The results have directly influenced the Environment Agency’s (EA) updated ammonia emission factors (EFs), providing a clearer and fairer reflection of modern farming practices.
This journey began with international air pollution agreements requiring the UK farming industry to reduce ammonia emissions by 16 per cent by 2030 compared with 2005 levels.
However, the EA’s initial standard EFs were based on outdated research over 20 years old, sparking concerns about their relevance.
The pork sector, accounting for 8 per cent of the UK’s agricultural ammonia emissions, faced potentially unnecessary costs to comply with these targets.
A quarter of a million pounds of levy funds were allocated to develop a more accurate set of EFs, which have since shown that many farms are already compliant.
Ammonia, primarily released from slurries and fertilisers, reacts with other compounds to form particulate matter that can harm human health and sensitive habitats.
Agriculture is responsible for 88 per cent of the UK’s total ammonia emissions. Permitted pig farms, operating under Environmental Permitting Regulations (EPR), must meet Best Available Technique (BAT) Associated Emission Levels (AELs) to minimise this impact.
Our study, built on the preliminary work of a former colleague, provided updated data on ammonia emissions across various pig housing systems. It showed that emissions from modern systems are generally much lower than previous estimates, in some cases halved. For example, the EF for finishers on straw is now 1.88 kg of ammonia per animal place per year, down from the outdated figure of 2.97 kg. This means many farms can avoid costly upgrades previously thought necessary to meet BAT AELs.
Key findings include significant reductions in ammonia emissions across most systems and these reductions reflect improved efficiencies in feed, housing, and slurry management.
However, two systems—fully slatted floors for pigs over 30 kg, and dry sows—remain non-compliant. Adjustments such as altering feed protein content or redesigning housing and slurry systems could close this gap. Alternatively, site-specific emission factors can be used during permitting.
The updated EFs have been published on GOV.UK, streamlining environmental assessments for planning and permitting. This will help Natural England, Defra, and the EA more accurately model and regulate ammonia emissions. Importantly, it demonstrates the sector’s proactive approach in reducing emissions, which benefits policy development and bolsters public confidence in the industry.
This project highlights the value of using levy funds to support evidence-based solutions, ensuring the pig sector’s sustainability while avoiding unnecessary costs. Continued innovation and investment in building design and management will further enhance this progress, cementing our role as responsible stewards of the environment.
by Zanita Markham Projects & Engagement Relationship Manager, AHDB
