Gathering evidence to make sure emissions targets are proportionate

Zanita Markham is an environment and buildings officer at AHDB

We have just taken a major step towards ensuring accurate information is used to assess the environmental impact of pigs’ ammonia emissions.

The first stage of our trials, which measured ammonia emissions from three different pig production systems – dry sows on solid floors, fully slatted farrowing and fully slatted weaner systems – has ended.

Government targets for how far to reduce emissions are still based on pig-unit performance and emission factors from more than 20 years ago.

However, AHDB will shortly be providing the Environment Agency (EA) with the first set of trial results, which will support the agency with its interim position on updates to the national emission factors.

Emission factors are expressed as kilograms of ammonia per animal place per year and are used to assess the impact of ammonia emissions from permitted pig farms. Indicative trial data so far suggests that emission factors are generally lower than two decades ago.

The AHDB trials will be extended over the next 18 months to include: free farrowing solid-floor systems, weaners on solid floors, finishers on solid floors and finishers on fully slatted floors, as well as continuing to monitor the first three systems we looked at. Data will be collated after each quarter of monitoring.

We have developed a bespoke ammonia analyser to measure emissions while also recording the number of pigs, weights, feed intake, protein, diets, ventilation, external and internal temperature and relative humidity.

The EA will look at all new data from the next round of trials as it updates the national emission factors and ensures that producers comply with the EU’s new Best Available Techniques (BAT) conclusions. These conclusions were published on February 21, 2017, giving all permitted farms four years to become compliant with them. Our trials will finish at the end of 2020, ready for compliance by the deadline of February 2021.

Encouragingly, the EA is reviewing all permitted units and it believes that most farms will already be compliant. Its revised emission factors, based on our trials, will also help with this.

During our podcast with the EA earlier this year, it helped to clarify what producers will need to report about emissions and when. To listen, go to and browse ‘pork podcasts’.

Finally, BAT conclusions state that all slurry stores must be covered by the February 2021 deadline. So look at the options as soon as possible. Get in touch via [email protected].

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