We Oklahomans know dust — perhaps better than anyone. Like it or not, the hardscrabble Joad family is as much a part of our cultural heritage as Curly, Laurey and Jud.

The Dust Bowl completely destroyed the state, and some would argue it took us a half-century to recover.

I mention this because University of Colorado researchers have found the West has become 500 percent dustier in the past 200 years because of human activity.

My first thought was how they measured such a thing. Turns out the researchers used sediment records from dust blown into lakes in Colorado’s San Juan Mountains. Co-author Jason Neff, an assistant professor of geological sciences at CU-Boulder, attributed the “sharp rise” in dust deposits to the railroad, ranching and livestock of western expansion.

“From about 1860 to 1900, the dust deposition rates shot up so high that we initially thought there was a mistake in our data,” Neff said in a press release. “But the evidence clearly shows the western U.S. had it’s own Dust Bowl beginning in the 1800s when the railroads went in and cattle and sheep were introduced into the rangelands.”

A paper on the research was published in the Feb. 24 issue of Nature Geoscience. In it, the scientists described a “dust fall” that exceeded that of the previous 5,000 years. Because of the size of the dust particles, the authors concluded the dust particles came from the Southwest.

Neff said the West’s increasing dustiness isn’t drought-related. Instead, he said, it is because of “intensive land use, primarily grazing.” Researchers used radiocarbon dating and lead isotope analysis of soil cores to determine this.

“There were an estimated 40 million head of livestock on the western rangeland during the turn of the century, causing a massive and systematic degradation of the ecosystems,” he said in the release.

The five-fold increase in nitrogen, phosphorus, potassium, calcium, magnesium and other byproducts of ranching, mining and agriculture can affect ecosystems.

Then, of course, there’s dust’s effect on allergies.

“There seems to be a perception that dusty conditions in the West are just the nature of the region,” Neff said. “We have shown here that the increase in dust since the 1800s is a direct result of human activity and not part of the natural system.”

For more health and medical news and commentary, read The Medicine Bag blog at http://blog.newsok.com/health.

Jeff Raymond, Medical Writer