Thursday, April 6, 2017

Univ. of Maryland study finds animal waste, increased temperatures and fertilizer use caused increased amounts of airborne ammonia in agricultural regions

Story Highlights:

  • United States had largest increase in airborne ammonia followed by China and the EU
  • Animal livestock waste, fertilizer usage, climate change and changes in the atmosphere's chemistry are all contributing factors
  • NASA satellite gathered data from 2002 to 2016
A University of Maryland research team recently published a study identifying airborne ammonia “hotspots” around the world. NASA funded the study, which was released in March and published in the journal, Geographical Research Letters.

The research team analyzed data collected by NASA’s Atmospheric Infrared Sounder (AIRS) instrument from 2002 to 2016. According to a press release, the team found “steadily increasing ammonia concentrations” in agricultural regions throughout the American Midwest and southern California, European countries including the Netherlands, Germany, Denmark, Po Valley and Italy, east central China and parts of South Asia including India, Bangladesh, Pakistan Cambodia and Vietnam. 

Ammonia can be difficult to measure and this study is the first of its kind measuring the gas from space on a global and long-term scale. Dr. Juying Warner, one of the authors of the study and associate research scientist in atmospheric and oceanic science at the University of Maryland, said when in excess, “[ammonia] damages the ecosystem and water and can cause air quality problems…it is harmful for human health.”

In the lowest part of the atmosphere, ammonia reacts with various acids to form aerosols that can be dangerous for humans “by penetrating the human respiratory systems, depositing in the lungs and alveolar regions, and causing premature mortality,” the study states.

The data collected by the AIRS instrument was displayed in the study indicating that the United States had the largest increase of airborne ammonia concentration over the 14 year study at around 2.61%, while China had a 2.27% increase and the European Union had a 1.83% increase.

Reasoning for these increases can be attributed to a combination of fertilizer usage, animal livestock waste and warming temperatures due to climate change. The authors of the study indicated which of these factors may have been the largest contributors in different parts of the globe. 

They believe that in the United States, the growing amounts of ammonia are due to “a combination of decreased chemical loss, and increased soil temperatures.” While in China, it could also be the result of a lack of chemical loss, along with rising temperatures and fertilizer use.  In Europe they believe the trend is due to “decreased scavenging by acid aerosols.”

While many chemicals and gases in agricultural practices are regulated, most countries do not currently track ammonia with the exception of a few countries in Europe. Dr. Warner hopes that due to this study, there will be more awareness about the presence of ammonia, which will translate into regulating it in agricultural practice.

“Right now we’re only looking at land data and near surface,” Dr. Warner said, “the coastal area is critical because it effects the ecosystem.” The AIRS instrument is still collecting data, which may allow more studies on this same topic in the future.