UD’s long-term monitoring shows 60 percent reduction in acidity of Delaware rain
Several decades ago,precipitation in Delaware was among the most acidic in the country. Pollutants in the air reacted with rainwater to sprinkle sulfuric, nitric and carbonic acids onto the ground below, affecting crops and ecosystems statewide.
The scientific consensus is that pollution controls enacted through the Clean Air Act Amendments in the 1990s and other measures have helped decrease the acidity of rain by approximately 60 percent to less harmful levels, as reflected in data gathered nationwide and by UD researchers in Lewes, Del., as part of a longstanding study. (more…)
WASHINGTON, D.C. — Measurable improvements in air quality and visibility, human health, and water quality in many acid-sensitive lakes and streams, have been achieved through emissions reductions from electric generating power plants and resulting decreases in acid rain. These are some of the key findings in a report to Congress by the National Acid Precipitation Assessment Program, a cooperative federal program.
The report shows that since the establishment of the Acid Rain Program, under Title IV of the 1990 Clean Air Act Amendments, there have been substantial reductions in sulfur dioxide (SO2) and nitrogen oxides (NOx) emissions from power plants that use fossil fuels like coal, gas and oil, which are known to be the primary causes of acid rain. As of 2009, emissions of SO2 and NOx declined by about two-thirds relative to levels in the 1990s. These emissions levels declined even further in 2010, according to recent data compiled by the U.S. Environmental Protection Agency. (more…)
Nitrogen derived from human activities has polluted lakes throughout the Northern Hemisphere for more than a century and the fingerprint of these changes is evident even in remote lakes located thousands of miles from the nearest city, industrial area or farm.
The findings, published in the journal Science Dec. 16, are based on historical changes in the chemical composition of bottom deposits in 36 lakes using an approach similar to aquatic archeology. More than three quarters of the lakes, ranging from the U.S. Rocky Mountains to northern Europe, showed a distinctive signal of nitrogen released from human activities before the start of the 20th century, said Gordon Holtgrieve, a postdoctoral researcher at University of Washington School of Aquatic and Fishery Sciences and lead author of the report. The UW and a dozen other research institutions contributed to the research. (more…)
ANN ARBOR, Mich.— The number of sugar maples in Upper Great Lakes forests is likely to decline in coming decades, according to University of Michigan ecologists and their colleagues, due to a previously unrecognized threat from a familiar enemy: acid rain.
Over the past four decades, sugar maple abundance has declined in some regions of the northeastern United States and southeastern Canada, due largely to acidification of calcium-poor granitic soils in response to acid rain. (more…)
