Farmers say they will tackle air pollution after figures revealed Suffolk is among the nation’s worst producers of toxic ammonia.
Data compiled by The Bureau of Investigative Journalism (TBIJ) shows Suffolk's pig and poultry farms produced 616,997kg of ammonia in 2017 - the fifth highest total of all UK counties.
The high levels reflect Suffolk's major role in intensive farming, which, nationally, is responsible for 88% of all ammonia pollution. Norfolk is the UK's third worst polluter.
But with growing focus the dangers of air pollution, which Public Health England (PHE) says is the "largest environmental risk to public health in the UK" costing an estimated £20billion each year, farmers are increasingly being asked to do more.
The Department for Environment Food and Rural Affairs (Defra) launched its Clean Air Strategy in January, which sets out what needs to be done to meet legally-binding international targets to cut air pollution.
Ammonia is among the five most damaging air pollutants, which together are responsible for as many as 36,000 annual deaths in the UK, according to PHE.
Whereas most pollutants arise from industrial processes, such as burning fossil fuels, ammonia mainly comes from farming - the storage of manures and slurries and the application of inorganic fertilisers.
Defra's strategy includes, for the first time, guidance on how farmers should tackle ammonia pollution, including a national code of good agricultural practice and requirements to invest in equipment to reduce emissions.
The National Farmers' Union (NFU) in East Anglia has welcomed the steps - and claims much has been achieved already.
"We take pride in our role as custodians of the countryside and this includes soil, air and water as well as landscape, biodiversity and food production," said the NFU's environment adviser Rob Wise. "Our industry has been working on cutting ammonia emissions long before the publication of this strategy, succeeding in cutting emissions by 10% over the last 30 years while food and fibre production has continued to increase over that period."
Mr Wise said farmers had been leading the way in cutting emissions by hosting workshops, developing a code of good practice and working with organisations including Defra and the Agriculture and Horticulture Development Board (AHDB).
"Achieving reductions is difficult so it will take long term commitment from farmers," he said. "But given it represents increased business efficiency as well as environmental enhancement; farmers will continue to be up for the challenge."
The figures collated by TBIJ, which were self-reported by farmers to the Environment Agency, show Suffolk's farms have achieved a 4.5% reduction in ammonia emissions between 2015-17, despite increases nationally.
Almost three quarters of the Suffolk farming businesses included in the list are poultry farms, some producing as many as 400,000 birds a year and including big names in the industry such as Hook 2 Sisters Limited, which operates across Suffolk, Norfolk and beyond. Also included are well known pig farming businesses such as Bacton Pigs.
The AHDB has held conferences warning East Anglia's pig farmers that the increased pressures facing their industry to meet stricter limits on emissions will require major changes to practices.
Environmentalists have welcomed the industry's efforts to cut emissions and said further improvements could be achieved by working together.
Green Party Suffolk county councillor Andrew Stringer said: "Ammonia is incredibly toxic but it's also naturally occurring, so it's all about striking a balance.
"We need food to eat but we also need air to breathe. As emissions move further up the political agenda, we've got to have these conversations, but we don't want it to become a battle ground between farmers and politicians."
Defra said while farming techniques had improved, more must be done to prevent further emissions damaging health and the environment.
"We are taking action to clean up our air through our ambitious Clean Air Strategy - tackling farm ammonia pollution for the first time by requiring and supporting farmers to invest in the infrastructure and equipment to reduce emissions," it said.
None of the businesses we contacted responded to requests for comment.
What is ammonia?
Ammonia is a pollutant released during the spreading of manures and slurries and the application of inorganic fertilisers.
Once released, it can lead to nitrogen enrichment and acidification of soil and water, as well as reacting with other greenhouse gases, such as sulphuric and nitric acid to form secondary pollutants.
These are associated with the main health impacts of ammonia, which can include chronic heart and breathing conditions.
According to Public Health England, agricultural emissions of ammonia have been linked with some of the worst recent pollution events.
They also contribute to emissions of nitrous oxide -a potent greenhouse gas.
Studies show reductions in ammonia emissions have helped mitigate other pollutants.
Since 2013, ammonia emissions have slightly increased, driven by the intensification of agricultural production.
How can farmers reduce ammonia emissions?
Farmers can reduce ammonia emissions by changing practices around livestock and fertiliser.
Defra's Code of Good Agricultural Practice includes recommendations on keeping fertiliser covered and in well maintained facilities, only spreading manure in the right conditions and devising plans for calculating when to apply manufactured fertiliser.
The code also advises farmers to consider using a professionally formulated diet for their livestock.
The Environment Agency said it required intensive farming operators to undertake "ammonia screening", looking at what needed to be done to protect nearby habitats, which can be adversely affected.
The EA is introducing new requirements, from 2021, meaning intensive farmers must cover slurry stores.
EA officers inspect intensive farms each year and will take enforcement action against those that do not meet conditions.
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