Fields of pollution: agriculture’s surprising impact on urban air quality

If you live in a European city, you probably feel the air gets too thick at times – and not without reason: 9 out of 10 Europeans living in cities breathe air which is harmful for their health.

Urban air pollution can be suffocating, and as city dwellers we often find ourselves dreaming of a countryside escape, to take a breath of fresh air away from traffic fumes. What we don’t know is that a big share of the pollution that makes our air hard to breathe originates right there, in the fields.

Air pollution in cities has many sources. Road traffic, domestic heating and industrial emissions are among the first ones that come to our mind, but there is another one which is too often forgotten: agriculture.

Emissions from farming are responsible for a surprising amount of urban air contamination. In cities like Paris, they can sometimes account for more than half of background air pollution.

The French National Centre for Scientific Research even determined that 62% of the fine particles in a severe air pollution episode in Paris during spring 2014 were caused by ammonia.

In Europe, agriculture is responsible for 94% of the emissions of ammonia, a highly polluting gas originating from farm activities, and notably from manure management and storage and fertiliser use. Once it enters the air, it threatens ecosystems by causing eutrophication of soil and water, and acidification of soil, lakes and rivers. Ammonia also causes irritation when inhaled.

By their very nature, air-borne pollutants are carried by the wind and can travel over significant distances, making their effects felt beyond the immediate area where they are released. When ammonia blows in over cities, it reacts with emissions of oxides of nitrogen (NOx) from diesel vehicles and sulphur (SO2) from power plants, leading to the formation of minuscule solid particles, less than 2.5 micrometres in diameter. This is also known as PM2.5, and it is one of the most dangerous forms of air pollution. 

Too tiny to be visible to the human eye, these particles can penetrate deep into our respiratory tract and cause lasting damage. Particulate matter can provoke lung and cardiovascular diseases, heart attacks and cancer, influence the central nervous system, and affect reproductive organs. This is why ammonia emissions alone account for about 50% of the health impacts of polluted air in urban areas.

According to Clean Air Farming, an international project supported by the European Environmental Bureau to help reduce emissions from agriculture and food waste, PM2.5 was responsible for 391,000 premature deaths in the EU in 2015. 

While cities and governments have engaged to tackle other sources of air pollution such as traffic, and implemented remedies like limiting the circulation of the most polluting vehicles, emissions from agriculture have been largely ignored.

At the same time, data released by the European Environment Agency show that, although emissions of most air pollutants are on a downward trend across the European Union, ammonia emissions from the agricultural sector continue to rise, and could hinder member states’ strive to meet EU air pollution limits.

Margherita Tolotto, Air and Noise Policy Officer at the European Environmental Bureau, told META there is a lot we can do to tackle ammonia emissions and prevent them from polluting the air we breathe and that engaging farmers in honest conversations and understanding their concerns is essential:

“Several measures can be implemented at farm level to immediately reduce ammonia emissions. Improving manure storage to reduce its exposed surface, choosing low-emission techniques for fertilisers application, and acidifying the slurry are some of them.”

These measures have been proven on farms around the world so Tolotto argues it’s often simply a case of working with farmers to put the solutions into practice.

She argues that Governments have a key role to play: “EU countries should show real commitment to deliver – at least – what is required by existing legislation”.

The NEC Directive, which sets national emission reduction commitments for five important air pollutants, requires member states to cut ammonia emissions by 19% by 2030. “This is far from being an ambitious reduction target, and yet projections are not reassuring”, argued Tolotto.

Six months past the deadline, twelve member states have not submitted their programmes describing their measures to reach the targets and, looking at the available ones, the reduction of ammonia emissions does not seem to be taken as seriously as it should.”

On top of the national implementation of air pollution laws, Tolotto added that the new Common Agricultural Policy should go hand in hand with existing environmental and health protection objectives, and not against them.

Ultimately, coherent policies and measures to support good farming in harmony with nature will also help make our cities able to breathe again.

The Second Clean Air Forum will take place in Bratislava on 28 November.

Together with DUH, FNE and the Lake Constance Foundation, the EEB has launched the ‘Clean Air Farming‘ project to help reduce ammonia and methane emissions from agriculture.

The Project Clean Air Farming (LIFE17 GIE/DE/610 Air & Agriculture) is co-financed by the LIFE-Programme of the European Commission.