A 10‐year spatial and temporal trend of sulfate across the United States
A 10‐year spatial and temporal trend of sulfate across the United States
复制标题
美国硫酸盐十年时空趋势
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
K. Gebhart
中科院分区：
文献类型：
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作者：
W. Malm;B. Schichtel;Rodger B. Ames;K. Gebhart
在美国东部和西部，立法和监管要求已经导致二氧化硫（SO2）排放量的减少，预计环境中SO2、SO42−和雨水酸度的同步水平将会下降。本文研究了1988 ~ 1999年大气SO42−浓度和1990 ~ 1999年大气SO2排放量的时空变化趋势，以及二者之间的关系。SO42−浓度数据来自受保护视觉环境的机构间监测（IMPROVE）和清洁空气状况和趋势网络（CASTNet）的数据。这项分析考虑了遍布美国大陆的70多个地点。从空间上看，夏季第90百分位硫酸盐浓度沿俄亥俄河流域和田纳西州中部最高，SO2排放密度最大。这些浓度是东北、密歇根北部和东南部沿海地区的2倍，是美国中西部的15倍。在东部，第80百分位浓度最大的SO42 -下降发生在俄亥俄河谷以北，而肯塔基州和弗吉尼亚州以南的大多数监测点呈现增减趋势，但没有统计学意义。德克萨斯州的大本德国家公园、北卡罗来纳州的蔓越莓国家公园和加利福尼亚州的拉森火山国家公园是仅有的SO42 -质量浓度在统计上显著增加的地区。将1990-1999年年度第80百分位SO42−时间序列与美国四个大地区的年度SO2排放进行了比较。各区域的SO42−浓度和SO2排放量在10年的时间序列中具有密切的相关性。东北部和西部地区的SO42−和SO2排放量均下降了28%和15%，而东南部地区变化不大，德克萨斯州、新墨西哥州和科罗拉多州增加了15%。
[1] Legislative and regulatory mandates have resulted in reduced sulfur dioxide (SO2) emissions in both the eastern and western United States with anticipation that concurrent levels of ambient SO2, SO42−, and rainwater acidity would decrease. This paper examines spatial and temporal trends in ambient SO42− concentration from 1988 to 1999, SO2 emissions from 1990 to 1999, and the relationship between these two variables. The SO42− concentration data came from combining data from the Interagency Monitoring of Protected Visual Environments (IMPROVE) and the Clean Air Status and Trends Network (CASTNet). Over 70 sites spread across the continental United States are considered in this analysis. From a spatial perspective, the 90th percentile summer sulfate concentrations are highest along the Ohio River Valley and in central Tennessee where the emission density of SO2 is greatest. These concentrations are a factor of 2 greater than the Northeast, northern Michigan, and coastal areas of the Southeast and about a factor of 15 greater than the central western United States. In the East, the largest SO42− decreases in the 80th percentile concentrations occurred north of the Ohio River Valley, while most monitoring sites south of Kentucky and Virginia showed increasing and decreasing trends that were not statistically significant. Big Bend National Park, Texas, Cranberry, North Carolina, and Lassen Volcanic National Park, California, are the only areas that show a statistically significant increase in SO42− mass concentrations. The 1990–1999 annual 80th percentile SO42− time series were compared to the annual SO2 emissions over four broad United States regions. Each region had a unique time series pattern with the SO42− concentrations and SO2 emissions closely tracking each other over the 10-year period. Both the SO42− and SO2 emissions decreased in the Northeast (28%) and the West (15%), while there was little change in the Southeast and a 15% increase over Texas, New Mexico, and Colorado.