Research clarifies health costs of air pollution from agriculture

Mar 28, 2014 by Kathryn Hansen
The map shows increase in annual mean surface concentration of particulate matter resulting from ammonia emissions associated with food export. Populated states in the Northeast and Great Lakes region, where particulate matter formation is promoted by upwind ammonia sources, carry most of the cost. Credit: NASA AQAST/Harvard University

(Phys.org) —Ammonia pollution from agricultural sources poses larger health costs than previously estimated, according to NASA-funded research.

Harvard University researchers Fabien Paulot and Daniel Jacob used computer models including a NASA model of in the atmosphere to better represent how interacts in the atmosphere to form harmful particulate matter. The improved simulation helped the scientists narrow in on the estimated health costs from associated with food produced for export – a growing sector of agriculture and a source of trade surplus.

"The 'cost' is an economic concept to measure how much people are willing to pay to avoid a risk," Paulot said. "This is used to quantify the cost for society but also to evaluate the benefits of mitigation."

The new research by Paulot and Jacob calculate the health cost associated with the from agriculture exports to be $36 billion a year – equal to about half of the revenue generated by those same exports – or $100 per kilogram of ammonia. The study was published December 2013 in Environmental Science & Technology.

The new estimate is about double the current estimate by the U.S. Environmental Protection Agency, which suggests a cost of $47 per kilogram of ammonia. The scientists say the new estimate is on the high end of the spectrum, which reflects the need for more research into characterizing the relationship between agricultural ammonia emissions and the formation of the harmful fine particulate matter – a relationship that's not as straightforward as previous estimates assumed.

"The effect of ammonia on fine particulate is complex, and we believe that the models previously used in the United States to price ammonia emissions have not captured this well," Paulot said.

Manure from livestock and fertilizer for crops release ammonia to the atmosphere. In the air, ammonia mixes with other emissions to form microscopic airborne particles, or particulates. The particulates that pose the greatest health risk are those that measure no more than 2.5 micrometers across, or about 1/30 the width of a human hair, which when inhaled can become lodged deep within the lungs. Long-term exposure has been linked to heart and lung diseases and even death. As such, the particles are on the list of six common air pollutants regulated by EPA's National Ambient Air Quality Standards.

An increase in ammonia, however, does not translate to an equal increase in particulates. The relationship depends on meteorology as well as the concentration of other precursors to particulate formation, such as sulfate and nitric acid.

To clarify the effect of ammonia on fine particulates, Paulot and Jacob first modeled the agricultural sources of ammonia emissions utilizing a relatively new ammonia emissions inventory. Next they used the NASA GEOS-Chem model of atmospheric composition to simulate the complex chemistry that converts agricultural emissions – in this case ammonia – into fine particulate matter.

This information was then combined with food export data from the U.S. Department of Agriculture and the United Nations Food and Agriculture Organization, averaged from 2000 to 2009. Results show that U.S. food exports account for 11 percent of the total U.S. emissions of ammonia.

"Our study suggests controls on ammonia emissions from agriculture could help reduce particulate matter and provide significant societal benefits," Paulot said.

The impact, however, is not equal everywhere. Areas downwind of large agricultural regions often set the stage for more mixing of ammonia with man-made emissions from combustion, such as from traffic and power plants. More mixing means the formation of more fine . For this reason, the largest are most often carried by the more populated states in the Northeast and Great Lakes region.

Explore further: Seabird guano releases more ammonia at tropics

add to favorites email to friend print save as pdf

Related Stories

USDA patents method to reduce ammonia emissions

Nov 01, 2012

Capturing and recycling ammonia from livestock waste is possible using a process developed by U.S. Department of Agriculture (USDA) researchers. This invention could help streamline on-farm nitrogen management ...

Researchers study harmful particulates

Feb 26, 2007

Reducing barnyard emissions is one way to help reduce the harmful effects of tiny atmospheric air particles that can cause severe asthma in children, and lung cancer and heart attacks in some adults.

Seabird ammonia emissions contribute to atmospheric acidity

Sep 23, 2008

Ammonia emissions from seabirds have been shown to be a significant source of nitrogen in remote coastal ecosystems, contributing to nutrient enrichment (eutrophication) and acidification in ecosystems. While most ammonia ...

Recommended for you

Far more displaced by disasters than conflict

58 minutes ago

Disasters last year displaced three times more people than violent conflicts, showing the urgent need to improve resilience for vulnerable people when fighting climate change, according to a study issued ...

Coral growth rate plummets in 30-year comparison

7 hours ago

A team of researchers working on a Carnegie expedition in Australia's Great Barrier Reef has documented that coral growth rates have plummeted 40% since the mid-1970s. The scientists suggest that ocean acidification ...

Environmentalists and industry duke it out over plastic bags

9 hours ago

Campaigns against disposable plastic shopping bags and their environmental impact recently scored a major win. In August, California lawmakers passed the first statewide ban on the bags, and Governor Jerry Brown is expected ...

User comments : 5

Adjust slider to filter visible comments by rank

Display comments: newest first

VINDOC
1 / 5 (3) Mar 28, 2014
It's funny my computer models show nothing and I still can't get a government grant.
alfie_null
5 / 5 (2) Mar 29, 2014
It's funny my computer models show nothing and I still can't get a government grant.

That didn't come across the way you may have intended.

Many possible reasons why you see nothing. Extrapolating your intellect from your skill at expressing yourself, I wonder if maybe you forgot to turn your computer on
stephen_bialkowski
5 / 5 (3) Mar 29, 2014
The picture at the top of the article suggests that the study overlooked some of the worst PM2.5 areas in the country. The area along the Wasatch Front, including Logan, Salt Lake City, and Provo often have the worst PM2.5 pollution in the USA. The major chemical constituent of these particulates are ammonium nitrate.
MR166
1 / 5 (3) Mar 29, 2014
There is only one real solution to the problems in the US. Ban oil, gas and coal and farming of any sort. After 90% of the population is dead the progressive elite can rebuild society exactly the way they dreamt.
gopher65
5 / 5 (1) Mar 30, 2014
The picture at the top of the article suggests that the study overlooked some of the worst PM2.5 areas in the country. The area along the Wasatch Front, including Logan, Salt Lake City, and Provo often have the worst PM2.5 pollution in the USA. The major chemical constituent of these particulates are ammonium nitrate.

Stephen: The caption for that image suggests that the concentrations are greatest near the great lakes because the inland emissions are blown and deposited in that area.