Pig sector hits back at 'misleading' ammonia map claims

The pig sector has hit back at claims linking large-scale farming to ammonia pollution, following the release of a contentious new emissions map by campaign groups.

Compassion in World Farming (CIWF) and Sustain say their interactive ‘Ammonia Map’ reveals that areas with the highest emissions align with regions dominated by intensive pig and poultry units, raising “major concerns about air quality, the wider public health impact of industrial farming and damage to nearby ecosystems”.

The National Pig Association (NPA), however, has challenged both the conclusions and the data behind the findings.

Chief executive Lizzie Wilson said the sector “has a responsibility to ensure its impact on air quality is as limited as possible”, but questioned how the map had been compiled, arguing it “doesn’t appear to directly correspond with the type of production the report claims”.

She stressed that pig production operates under strict environmental controls, describing it as “one of the most highly regulated sectors within agriculture”, and noted it accounts for just 8% of total UK ammonia emissions.

Concerns have also been raised about the methodology used to produce the map. The Guardian reported that calculations were based on permitted stocking levels and standard emission factors for different livestock types, including pigs, broiler chickens and laying hens.

Wilson pointed instead to more recent evidence based on measured output rather than modelling. Trials led by AHDB, and accepted by the Environment Agency, show emissions have fallen by an average of 50% over the past decade across a range of housing systems.

Citing Defra data, she said “the fall in emissions from livestock other than cattle, especially from the pig and poultry sectors, is the main driver in the gradual fall of overall ammonia emissions since 1990”, adding that tighter rules introduced under the Pollution Prevention and Control Act 1999 have played a key role.

Campaigners, however, maintain that intensive farming remains a significant environmental and public health concern, particularly in areas where large units are concentrated.

Wilson also pointed to the UK’s reliance on imports, noting the country is “only approximately 60% self-sufficient in pigmeat”, with much of the shortfall made up by imports from countries with lower welfare and environmental standards.

She said domestic producers have improved efficiency, producing more pork from a shrinking national sow herd while reducing their overall environmental footprint.

The row highlights a broader tension between environmental concerns and food production, as the UK balances efforts to cut agricultural emissions with maintaining domestic output and avoiding greater reliance on imports.