Revealed: factory farm pollution is costing the UK £130m a year

• We have calculated that air pollution from industrial-scale farms is causing tens of millions of pounds’ worth of damage to the environment and public heath

• Much of this pollution is driven by farms’ ammonia emissions. And our calculations don’t include ammonia from cattle farms – the most polluting sector

• Ammonia and the airborne particles it forms can enter the bloodstream and cause or compound asthma, lung conditions, heart disease and other chronic illnesses

At the edge of a large wooded area of countryside in the south of England are six vast chicken sheds, each ugly structure accompanied by its own cone-shaped feed silo. In the foreground lies a fenced-off lagoon containing waste water from the farm. The hum of traffic from a nearby dual carriageway provides a suitably industrial backdrop.

What’s less visible, however, is the toxic gas quietly emanating from the facility day and night. This farm, which supplies a large poultry breeding company, is one of hundreds across England that feature in a major government database of industrial pollutants.

Records show that in 2024 it emitted more than 5,000kg of ammonia, a gas that can damage both the environment and public health.

Air pollution is a chronic problem in the UK, driven in part by industrial farms – and we have been working to put a price on the issue. Now, along with our colleagues at DeSmog, we can reveal that air pollution from factory farms cost England and Wales over £130m in 2024.

Every pig and poultry farm that both emits more than 1,000kg of ammonia a year and houses more than 40,000 chickens, 2,000 fattening pigs or 750 breeding pigs must submit its estimated emissions under the terms of its environmental permit. There are 1,064 such farms in England and 108 in Wales that currently report their emissions.

Our analysis cross-referenced these figures with Defra’s own estimates for “damage costs” per tonne of pollutant. These costs also include damage to ecosystems and buildings. Our final figure was £131,011,091.

The analysis, in the third part of our Muck Files project, looked at the latest pollution data for around 1,200 of the largest factory pig and poultry farms. Their health and environmental costs, it was calculated, was more than that of 3.5 million petrol cars.

Much of that cost is borne by the NHS. Dr Helen Wood of Queen Mary University of London explains that ammonia can react to form tiny pollution particles that can enter the bloodstream and “once they’re in the blood, travel all around the body”.

“Damage to the cells and the tissues can cause or worsen lung conditions. The inflammation can make asthma worse or cause cardiovascular disease,” she added.

“These are chronic conditions that need managing over time. People often get chronically sicker. They may not be able to work, they may need care. Their healthy life expectancy is reduced. This all comes at a price.”

What’s more, our figures do not include emissions from cattle farms, which have been responsible for more than 40% of ammonia in the UK.

Ruth Westcott, campaign director at the advocacy group Foodrise: “This evidence is clear; industrial animal production is a risk to our health. To prevent more people getting sick, we need to regulate this industry much better.”

Struggling to breathe

Roy lives in Norfolk, less than a mile from the intensive pig farm where he worked for a number of years, and says that his health conditions have been exacerbated by pollution and airborne bacteria from the farm.

“I was always going back and forth with my doctor because I couldn’t get my breath,” he told us. “My doctor told me, ‘It’s part and parcel with where you’re working. It’s everything you’re breathing in.’ It was very scary – all my life I’d never been in hospital.”

Although he’s retired now, Roy says the pollution blows over his house and the neighbouring village – “That’s when I go into the house and don’t come out.

“I feel it all the time. I take an inhaler every day, and I have one I carry with me for an emergency if I can’t get my breath.”

People living near megafarms have repeatedly raised alarm bells about the health impacts. In 2019, we revealed that halving air ammonia pollution from farms in the UK could avoid 3,000 deaths each year. Five years later, though, we reported soaring ammonia emissions in areas saturated with industrial chicken farms.

Our investigation with DeSmog found that East Anglia had the highest ammonia emissions from intensive pig and poultry farms, with over 220 farms emitting a combined total of nearly 2.5 million kg every year. Yorkshire, Lincolnshire and Northamptonshire, and the West Midlands had the next highest emissions.

The regions are home to some of the worst asthma rates in the UK: Mundesley, a coastal village in East Anglia where one in nine residents suffers from asthma, has the highest rate in the country.

Alastair Lewis, professor of atmospheric chemistry at the University of York, said that farming pollution isn’t just a problem for the local areas: “Ammonia emissions from farming drift long distances in the air, sometimes many hundreds of kilometres, and can impact huge numbers of people.”

Paul Behrens, a professor specialising in food systems at the University of Oxford, said the health effects of the particulate matter formed by ammonia could also be far greater than we think. “Every time I look at the literature there are more problems … We now know it affects birth outcomes and increases type 2 diabetes, we’ve learned how it can trigger lung cancer in people who have never smoked.

“There’s growing evidence linking it to dementia and depression. The impacts have kept growing and we have repeatedly underestimated the costs.”

Litter loophole

The calculations that brought us our £130m figure included estimates of the cost of NHS care and lost economic productivity, as well as early deaths linked to air pollution.

They did not, however, include the huge quantities of animal litter that are taken away from a farm to be incinerated or used as fertiliser – the emissions from which can be several times more than those produced by the farms themselves.

Near to the south-England chicken farm we visited, a huge mound of poultry litter had been left in an arable field, presumably destined for use as fertiliser. Air tests detected significant ammonia levels nearby, but these emissions would not have been accounted for by the farm.

We also found that a loophole in government rules exempts cattle farms from reporting their emissions. This is because they don’t require environmental permits, something the government has said it plans to address. In the meantime, the sector responsible for a huge portion of the UK’s ammonia pollution remains under the radar.

Campaigners are now calling on Defra to improve its environmental controls in light of the findings. “Right now you need an environmental permit if you run a dry cleaners or a petrol station, but not for [farms that] produce as much faecal matter as a small town,” said Westcott of Foodrise.

“The government promised to reform [the permit scheme] in 2019 but we are still waiting. In the meantime, people are getting sick.”

A sprawling chicken farm in England

While Defra claims that the scheme has played a significant role in cutting ammonia from pigs and poultry in recent years, reductions have been offset by major increases in emissions from dairy cattle. The government said in June that it would reopen consultations on whether to include cattle farming in its permit regime.

Paul Tompkins, deputy president of the National Farmers Union, told us: “British farmers take their roles in protecting the environment and public health extremely seriously.

“Our members are committed to reducing their emissions on farms and the NFU will continue working with the government on this matter.”

A Defra spokesperson said: “We are committed to improving air quality, whilst supporting a productive, modern and sustainable farming sector.

“As part of this, we are helping farms invest in sustainable infrastructure that improves the use of organic nutrients, supports productivity, and reduces pollution.”

• Once a consultation period is over, the government has said it will report back on plans to extend environmental permits for intensive beef and dairy farms, which would likely require operators to report their annual emissions

• Planning applications for new factory farms are increasingly facing objections over a range of issues, including air pollution – forcing planning officials to take it into account