Sharratt B S, Lauer D
USDA-ARS, 213 LJ Smith Hall, Washington State Univ., Pullman, WA, USA.
J Environ Qual. 2006 Oct 27;35(6):2011-6. doi: 10.2134/jeq2006.0212. Print 2006 Nov-Dec.
The USEPA has proposed to regulate PM(coarse) (particulate matter 2.5 to 10 microm in diameter). Exceedance of the proposed National Ambient Air Quality Standard (NAAQS) for PM(coarse) is expected within the Columbia Plateau of the Pacific Northwest United States based on the high frequency of dust storms and the large contribution of crustal material to fugitive dust in the region. The objective of this study was to explore the implication of the proposed NAAQS for PM(coarse) on air quality. Concurrent observations of both PM10 (particulate matter </=10 microm in diameter) and PM(fine) (particulate matter </=2.5 microm in diameter) were made at Kennewick, WA from 1999 through 2005. Daily PM(coarse) concentration was determined as the difference between PM10 and PM(fine) concentrations. The number of exceedances of the proposed USEPA NAAQS for PM(coarse) was determined for various levels of the standard (the proposed daily level is 70 microg m(-3)). Over the 7 yr of this study, the PM10 standard was exceeded on 16 d with PM(fine) constituting 4 to 7% of PM10. The proposed PM(coarse) standard would have been exceeded on 35 d and represents a 120% increase in the number of exceedances over the current PM10 standard. Changing the level of the proposed PM(coarse) standard to that of the current PM10 standard (150 microg m(-3)) would result in a 20% decrease in the number of exceedances of the PM standard. The results of this study suggest that the proposed NAAQS for PM(fine) and PM(coarse) will be exceeded more frequently than the current PM(fine) and PM10 standard in a region subject to seasonal dust storms.
美国环境保护局（USEPA）已提议对粗颗粒物（直径为2.5至10微米的颗粒物）进行监管。基于美国太平洋西北部哥伦比亚高原地区沙尘暴频发以及地壳物质对该地区扬尘的巨大贡献，预计该地区粗颗粒物将超过提议的国家环境空气质量标准（NAAQS）。本研究的目的是探讨提议的粗颗粒物NAAQS对空气质量的影响。1999年至2005年期间，在华盛顿州肯纳威克对直径小于等于10微米的颗粒物（PM10）和直径小于等于2.5微米的颗粒物（细颗粒物，PM(fine)）进行了同步观测。每日粗颗粒物浓度通过PM10浓度与细颗粒物浓度之差来确定。针对不同标准水平（提议的每日标准水平为70微克/立方米），确定了USEPA提议的粗颗粒物NAAQS的超标次数。在本研究的7年期间，有16天超出了PM10标准，其中细颗粒物占PM10的4%至7%。提议的粗颗粒物标准预计将有35天超标，比当前的PM10标准超标次数增加了120%。将提议的粗颗粒物标准水平改为当前的PM10标准（150微克/立方米），将使颗粒物标准超标次数减少20%。本研究结果表明，在一个受季节性沙尘暴影响的地区，提议的细颗粒物和粗颗粒物NAAQS将比当前的细颗粒物和PM10标准更频繁地被超过。
