Read: article about research in Agricultural Research.

Keeping Dust on the Farm

It’s hard to believe that airborne particles less than the thickness of a human hair--from blowing soil or smoke--could be a health risk.

But the U.S. Environmental Protection Agency has determined that dust composed of very fine, invisible particles, known as PM 10 and PM 2.5, can exacerbate pre-existing respiratory ailments, sometimes leading to premature deaths among the elderly. EPA’s National Ambient Air Quality Standards sets limits on permissible concentrations. Although little is known about the health effects of farm dust compared to those of smoke stack emissions, for example, the standards make no distinction.

So the U.S. Department of Agriculture is working with EPA to find ways to minimize agriculture’s contribution to the atmospheric dust load. Both agencies also want to avoid repetition of dust-related highway accidents that have claimed a number of lives in recent years.

Of greatest concern are the PM 2.5 particles that may make up part of a dust cloud and an even larger percentage of smoke. PM 2.5 refers to particulate matter less than 2.5 microns in size. PM 10 particles are less than 10 microns. Ten microns equals about 1/7th the diameter of a human hair.

To minimize the contribution to the dust load of the atmosphere and save farm topsoil, a team of U.S. Department of Agriculture and university scientists have developed a computer model to estimate the amount of soil blowing from farmland in the Pacific Northwest’s Columbia Plateau region and its downwind impact. This region’s light volcanic soils make this region one of the world’s most vulnerable to losing topsoil in the wind. Team leader Keith E. Saxton, an agricultural engineer with USDA’s Agricultural Research Service, also serves on a National Agricultural Air Quality Task Force.

The model simulates dust storms, showing the wind picking up farm soil, carrying it in clouds miles above the ground, and then depositing it over urban areas. Researchers are using it to evaluate farming practices that protect the soil from blowing away, such as crop rotations that keep soil covered as long as possible.

An article about the research appears in the March issue of Agricultural Research magazine.

Also, the Discovery Channel will cite this research in a television episode this fall.

Scientific contact: Keith E. Saxton, ARS Land Management and Water Conservation Research Unit, Pullman, Wash., phone (509) 335-2724, fax (509) 335-7786, [email protected].