Dust More Accurately Measured
By Don Comis
May 10, 2004
Agricultural dust isn't as serious a
potential health problem as previously thought, according to an
Agricultural Research Service scientist
who has found a more accurate way to measure dust pollution from agricultural
Agricultural engineer Michael Buser and colleagues at the ARS
Cropping Systems Research
Laboratory in Lubbock, Texas, have found that it is more accurate to use
total suspended particulate (TSP) samplers to obtain a total concentration of
dust, followed by a lab analysis of the sampling filter. The analysis
determines particle-size distributions, as well as the percentage of the dust
sample's total mass that is made up of smaller dust particles.
Buser evaluated U.S. Environmental Protection Agency (EPA) air samplers and found they tend to
overestimate the amount of fine particles in agricultural dust. EPA has a
network of ambient air samplers in place across the United States. To measure
dust from an individual operation, a region's air quality agency may require
the use of "stack" samplers.
Buser found that both types of samplers are very accurate for urban dust,
which has a high proportion of fine dust particles. But they fall short when
measuring agricultural dust, in which larger, less harmful particles tend to
As awareness grows regarding the human health dangers posed by fine dust
particles, so does air quality regulation by federal and state governments.
Farmers face the prospect of having to get air pollution permits before plowing
a field to plant. Already, agribusinesses such as cotton gins are required to
have such permits.
The key is the accuracy of the samplers. Buser is one of a very few ARS
researchers dealing with air quality compliance research. His goal is to
provide scientific information that will allow agricultural producers and
processors to obtain and keep operating permits without harm to air quality.
more about this dust-sampling research in the May issue of Agricultural
ARS is the U.S. Department of
Agriculture's chief scientific research agency.