Health Less fertilizer lowers mortality rate from air pollution

Use less fertilizer: Reduce mortality through particulate matter

The pollution of our environment is associated with a high health risk. Even small amounts of fine dust can be dangerous. The pollution with particulate matter not only increases through traffic, but also through agricultural emissions. By reducing the use of fertilizer, researchers also believe mortality from air pollution could be reduced.

Air pollution is causing more and more deaths

According to the World Health Organization (WHO), air pollution causes more and more deaths worldwide. Particulate pollution endangers especially the lungs, the particles can reach via the bloodstream but also into the heart. German researchers have now shown in a study that reducing atmospheric ammonia emissions could significantly reduce mortality from air pollution.

Every year millions of people worldwide die prematurely from the effects of air pollution. According to researchers, mortality from particulate matter pollution could be significantly reduced by reducing agricultural ammonia emissions. (Image: VanderWolf Images / fotolia.com)

For fine dust there are many sources

Air pollution is a major health hazard. It is known that the inhaled tiny dust particles damage the lungs and significantly increase the risk of cancer, respiratory and cardiovascular diseases.

Various studies have shown that high levels of particulate matter significantly increase the risk of cardiovascular events such as heart attacks or strokes.

In addition, the risk of atherosclerosis (arteriosclerosis) increases.

There are many sources of particulate matter - not just traffic, which is currently receiving a lot of attention.

A reduction in agricultural emissions could also significantly reduce the amount of harmful particulate matter, as a study by researchers at the Max Planck Institute for Chemistry in Mainz shows.

Reduction of ammonia emissions

According to a statement from the institute, the scientists calculated that, especially in Europe and North America, the reduction of ammonia emissions (NH3) from fertilization and livestock would greatly reduce the concentration of particulate matter in the atmosphere.

Thus, if agricultural emissions were 50 percent lower, 250,000 deaths from air pollution worldwide could be avoided each year.

The results were published in the journal "Atmospheric Chemistry and Physics", a journal of the "European Geosciences Union".

Tiny particulate matter especially harmful to health

Particulate matter with a diameter of less than 2.5 micrometers (PM2.5) is particularly harmful to health, according to the WHO, because the particles penetrate deep into the lungs and can cause cardiovascular and respiratory diseases.

In this way, they significantly reduce life expectancy in many parts of the world. According to the Global Burden of Disease study, global air pollution ranks fifth among the risk factors for causes of death.

The study, involving more than 1,800 scientists, quantifies fatalities after illness, accidents and risk factors.

"The public is currently mainly the particulate matter pollution by the traffic discussed, other sources such as agriculture are thereby neglected," said Jos Lelieveld, Director of the Department of Atmospheric Chemistry at Mainz Institute.

Although particulate emissions from motorized vehicles can make a decisive contribution to local air pollution in urban areas, most of the particulate matter (PM2.5) is produced only by chemical processes in the atmosphere during wind transport.

"Therefore, the concentration of particulate matter in the atmosphere could be significantly reduced if ammonia emissions were avoided in agriculture," said Lelieveld, whose research team confirms this with current calculations.

Estimates of deaths increased significantly

In their previous study, Max Planck researchers pointed out that in 2010, 3.3 million people worldwide died prematurely from the effects of air pollution. In the meantime, the estimates for the last few years have risen sharply again.

The scientists emphasize that in many regions of the world, not industry and transport are the main sources of air pollution, as is generally assumed, but agriculture can play an important role alongside the use of fuels for heating and cooking.

Scientists have identified the release of ammonia from livestock and fertilization as the main cause of air pollution, especially in much of Europe.

Although the nitrogen contained in the ammonium is an important nutrient for plants. However, ammonia escapes into the atmosphere through the decomposition of manure and through the fertilization of crops, where it reacts with other inorganic substances, such as sulfuric and nitric acid, to form ammonium sulfate and nitrate salts. This in turn results in particulate matter.

50 percent less NH3 would kill 250,000 people a year worldwide

In their current study, scientists focused on four regions where air pollution limits are often exceeded: North America, Europe, South and East Asia.

Their calculations showed that a reduction of all agricultural emissions by 50 percent worldwide would cause a decrease of around eight percent of the premature deaths caused by air pollution. This corresponds to a figure of 250,000 people per year.

A complete stop of all ammonia emissions could theoretically save as many as 800,000 people worldwide from death from diseases caused by air pollution.

"The effect of ammonia reduction on fine dust formation is not linear. An efficient air improvement starts only after a certain reduction value. At that point, however, the effect will be exponential, "explained Andrea Pozzer, group leader at the Max Planck Institute for Chemistry and lead author of the study.

Reducing ammonia emissions by more than 50 percent would therefore, according to Pozzer, be very effective and desirable.

Europe would benefit in particular

The scientists determined the mortality rates in two steps: first, using an atmospheric chemistry model, they calculated how much less fine dust would be produced at lower ammonia concentrations.

Accordingly, halving emissions worldwide in Europe would result in eleven percent, in the US 19 percent and in China 34 percent less PM2.5 particulate matter.

In Germany, the average pollution of particulate matter of this size in 2015 was around 14 micrograms per cubic meter of air, which would drop to around 12.5 micrograms per cubic meter in the 50 percent reduction scenario of Mainz researchers.

On the basis of another model that describes the health effects of particulate matter exposure, the researchers then calculated the influence on the mortality from lung cancer, cardiovascular and respiratory diseases.

In particular, Europe would benefit from a reduction in ammonia emissions and the resulting reduction in particulate matter: for example, a Europe-wide 50% NH3 reduction would reduce the PM2.5 mortality rate by nearly 20%, avoiding around 50,000 deaths per year.

In the US, ammonia reduction of this magnitude would result in a 30 percent reduction in the air pollution-related mortality rate, as calculated by Andrea Pozzer and his colleagues.

In contrast, the computer models showed smaller improvements for East Asia with eight percent and only three percent for South Asia.

Based on the results, Jos Lelieveld concludes: "Emission regulations should set stricter limits for ammonia, particularly in North America and Europe, to effectively reduce particulate matter levels."

Although measures to reduce sulfur dioxide (SO2) and nitrogen oxides (NOx) are crucial for air quality control, they should be supplemented by reducing ammonium from agriculture, which is also relatively easy to implement. (Ad)