The link between toxic air and food is well established. Ammonia from livestock manure and excessive fertiliser use reacts in the air to form tiny, dangerous particles which drift into towns and cities. Almost 40% of the world’s tiny particle pollution forms in this way, according to a 2021 study. In countries that have cut other sources of pollution, like industrial emissions in the UK, the proportion of particles coming from farms rises to 60%.
What had not been closely studied until now is how changing diets could cut this pollution. The new analysis found that a global switch to a flexitarian diet – think red meat just once a week – would significantly reduce livestock-related pollution and save about 100,000 lives a year. A vegetarian diet would prevent 190,000 premature deaths and a vegan diet 235,000 deaths.
In developed countries densely populated by both people and farm animals, like many in Europe and North America, a flexitarian diet would stop 10% of air pollution deaths and a vegan diet 20%. Methane emissions from cattle are also part of the problem, as this gas contributes to ozone production, which at ground level also damages human health.
“Lots of policymakers are very concerned about air pollution,” says Marco Springmann, who led the new research, and they focus on traffic and factories. “They rarely think of diet but we showed that diets are a big contributing factor,” he told me.
Air pollution doesn’t just damage health though – it also reduces people’s physical and mental performance. Springmann’s team estimated that the reduced level of pollution due to the diet changes would improve people’s productivity by about $1 tn a year globally. The cost-benefit analysis is clear in the 2021 study: spend $1 on cutting ammonia, save $23 in health costs.
The issue of livestock-related air pollution has already flared up in the Netherlands, where millions of people, cows and pigs live in close proximity. The manure really hit the fan in 2022 when, following a court order, the government announced that these emissions must fall by 50% by 2030. That meant farms having to close down. Political uproar has followed with a new party opposing the moves, the Farmer-Citizen Movement, sweeping provincial elections.
Food has enormous cultural importance and longstanding traditions, meaning changing diets in rich nations away from meat and dairy and towards plants is challenging. Today, the fightback from vested interests in industry is as powerful as the fight against renewable energy was 20 years ago.
But we know we can’t beat the climate crisis without cutting meat consumption, we know cattle production is a big factor in destroying biodiversity, and we know most people in developed countries already eat more red meat than is healthy for them. We also know the meat industry is heavily subsidised.
This new research on air pollution adds yet another dimension. “It is another piece in the puzzle of assessing the benefits of dietary changes,” says Springmann.
What scientist Joseph Poore told me in 2018 seems even more relevant today: “A vegan diet is probably the single biggest way to reduce your impact on planet Earth.”