Big dust, little harm.Dust storms are blowing away the argument that eroded soil and other relatively large, airborne particles are as hazardous to health as the far smaller particles generated by combustion. Over the past decade, a host of studies has linked the outdoor buildup of combustion particles to a rise in hospital admissions and death rates for respiratory illness Noun 1. respiratory illness - a disease affecting the respiratory system respiratory disease, respiratory disorder adult respiratory distress syndrome, ARDS, wet lung, white lung - acute lung injury characterized by coughing and rales; inflammation of the (SN: 4/6/91, p. 212) and heart disease (SN: 7/1/95, p. 5). Such data convinced the Environmental Protection Agency Environmental Protection Agency (EPA), independent agency of the U.S. government, with headquarters in Washington, D.C. It was established in 1970 to reduce and control air and water pollution, noise pollution, and radiation and to ensure the safe handling and to create new limits (SN: 7/5/97, p. 6)--not yet in effect--for particles that measure 2.5 micrometers ([micro]m) in diameter or smaller (termed PM-2.5). Federal rules already limit a broader class of particles, those with diameters of up to 10 [micro]m (PM-10). Representatives of combustion-intensive industries say that errors in measuring large particles have made the relative health impacts of large and small particles hard to distinguish. Thus, they have argued against rules focusing on PM-2.5, notes Joel Schwartz of the Harvard School of Public Health The Harvard School of Public Health is (colloquially, HSPH) is one of the professional graduate schools of Harvard University. Located in Longwood Area of the Boston, Massachusetts neighborhood of Mission Hill, next to Harvard Medical School and Cambridge, Massachusetts, in Boston. "It's a big fight," he explains, and it has threatened to derail de·rail intr. & tr.v. de·railed, de·rail·ing, de·rails 1. To run or cause to run off the rails. 2. implementation of the PM-2.5 limits. Hoping to settle the controversy, Schwartz teamed up with researchers from two universities in Washington State to study Spokane death rates during 17 major dust storms over 6 years. The average PM-10 concentration on storm days was 263 micrograms per cubic meter Noun 1. cubic meter - a metric unit of volume or capacity equal to 1000 liters cubic metre, kiloliter, kilolitre metric capacity unit - a capacity unit defined in metric terms ([micro]g/[m.sup.3]) of air--well above the current EPA EPA eicosapentaenoic acid. EPA abbr. eicosapentaenoic acid EPA, n.pr See acid, eicosapentaenoic. EPA, n. limit. On the stormless days, PM-10 averaged only 42 [micro]g/[m.sup.3]. During dust storms, PM-10 consists primarily of particles larger than 2.5 [micro]m in diameter, but the amount of fine particles Fine particles are an air pollutant mainly produced by cars running on diesel. Other sources are the combustion of fossil fuels in power plants and various industrial processes. present changes relatively little with weather. Nonaccidental death rates were slightly lower during the dust storms than on calm days of the same date during the study, the researchers report in the May ENVIRONMENTAL HEALTH PERSPECTIVES. These data, they contend, argue against the industry position and confirm results of other studies "that toxicity of coarse particles is substantially less than that of fine particles." |
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