Air pollution from duststorms in the Great Plains
1973
Hagen, L.J. | Woodruff, N.P.
Great Plains states are adopting air pollution regulations to limit particulate concentrations. Because little information is available about duststorms, an important source of particulates in those states, hourly observations of the weather on dusty days during the 1950's at 37 weather stations were analyzed. Wind direction was southerly, and windspeeds were usually 8.9-13.4 m s-1 (20-30 miles h-1); relative humidity was less than 70 in 92 per cent of the dusty hours. During periods of low precipitation, most Great Plains locations have a significant number of hours with dust. Our study revealed that the median annual hours of dust was 45, but more than 150 dusty hours were recorded in 20 per cent of the reports. Though urban air pollution episodes last longer than duststorms, duststorms have larger particles and higher particulate concentrations. We found the average duststorm lasted 6.6 h, and median dust concentration was 4.85 mg m-3. Because of high concentrations of coarse particles in duststorms, air pollution laws in the Great Plains probably should specify particulate size distributions to which various sections of the laws apply as well as limits on particulate concentrations.
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