Particulate pollution Fewer deaths with less fertilizer use

Experts are studying the effects of agriculture on particulate matter pollution

So-called fine dust is particularly harmful to health because the small particles can penetrate deep into the human lung. The fine dust comes from many different sources, such as exhaust from factories and cars. Researchers have now discovered that there is another source of particulate matter that most people may not be aware of. These are agricultural emissions from fertilization and livestock.

The scientists of the Max Planck Institute for Chemistry in Mainz found in their study that a reduction of agricultural emissions could significantly reduce the amount of harmful particulate matter. The experts published the results of their study in the journal "Atmospheric Chemistry and Physics".

Fertilization and animal husbandry mean that the burden of fine dust continues to increase. By using less fertilizer in agriculture, thousands of lives could be saved. (Image: Dusan Kostic / fotolia.com)

Fertilization and livestock have an impact on particulate matter pollution

When it comes to particulate matter pollution, many people think about traffic first. Few have fertilization and livestock in mind. But a reduction in these agricultural emissions could significantly reduce the amount of harmful particulate matter, researchers say. In North America and Europe in particular, a reduction in ammonia emissions (NH3) from fertilization and livestock could greatly reduce the concentration of particulate matter. If emissions from agriculture were 50 percent lower, it would be possible to prevent 250,000 deaths a year from air pollution worldwide, the researchers report.

Particulate matter particles smaller than 2.5 microns (PM2.5) are particularly dangerous

The World Health Organization (WHO) states that fine dust particles smaller than 2.5 microns (PM2.5) in diameter are particularly harmful to health. Such particles can penetrate deeply into the human lung and cause cardiovascular and respiratory diseases.

Air pollution ranks fifth among the causes of death worldwide

Particulate matter in many countries of the world significantly reduces life expectancy, say the doctors. Air pollution ranks fifth in the list of risk factors for causes of death worldwide, experts explain. "The public is currently the particulate matter pollution by traffic discussed, other sources such as agriculture are thereby neglected," said Jos Lelieveld, Director of the Department of Atmospheric Chemistry at Mainz Institute in a press release. Particulate emissions from motorized vehicles affect the local air pollution in urban areas. Most of the particulate matter (PM2.5) is produced by chemical processes in the atmosphere during wind transport, says the expert. A general avoidance of ammonia emissions in agriculture could significantly reduce the concentration of particulate matter in the air, adds Lelieveld.

In 2010, 3.3 million people died of air pollution

A previous study by the Max Planck Institute showed that in 2010 alone, 3.3 million people around the world died prematurely from the effects of air pollution. The figures in such estimates have increased significantly in recent years. It was usually assumed that industry and traffic cause the dangerous pollution of the air. But also the use of fuels for heating and cooking and agriculture play an important role in the problem, explain the scientists.

How do fine dust particles develop during fertilization and animal husbandry??

In Europe, the main cause of air pollution is the release of ammonia from livestock and fertilization, say the authors. Ammonium-containing nitrogen is an important nutrient for plants. However, ammonia escapes in the decomposition of manure or by the fertilization of crops. Ammonia then enters the atmosphere and reacts there with various inorganic substances. Thus, sulfuric and nitric acid ammonium sulfate and nitrate salts, from these then arise particulate matter, explain the researchers.

North America, Europe, South and East Asia are particularly hard hit

Especially in North America, Europe, South and East Asia, the limits of air pollution are often exceeded. A 50 percent reduction in all agricultural emissions would, according to the researchers, prevent around 8 percent of premature deaths caused by air pollution globally. In other words, that would save the lives of some 250,000 people every year. If all ammonia emissions were completely eliminated, theoretically, even the lives of 800,000 people could be saved worldwide, the authors add.

The effect of ammonia reduction on fine dust formation is not linear

The effect of ammonia reduction on fine dust formation is not linear. The efficient improvement of air quality begins only after a certain value of the reduction. "At that point, the effect is exponential," explains lead author Andrea Pozzer, according to the press release from the Max Planck Institute.

How would a reduction of particulate matter exposure affect??

In analyzing a model, it was possible to calculate the effects of particulate matter exposure on the mortality rate due to lung cancer, cardiovascular and respiratory diseases. For example, Europe would reduce the PM2.5 mortality rate by nearly 20 percent by reducing NH3 by 50 percent, say the researchers. In Europe alone, around 50,000 deaths per year could be avoided. In the US, a reduction of this magnitude would result in a reduced death rate of 30 percent. In East and South Asia, however, the computer models showed only minor improvements. In East Asia, this was eight percent, in South Asia, it was three percent. (As)