کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9456381 | 1309193 | 2005 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Trends in atmospheric ammonium concentrations in relation to atmospheric sulfate and local agriculture
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم محیط زیست
شیمی زیست محیطی
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چکیده انگلیسی
Ammonium (NH4+) concentrations in air and precipitation at the Institute of Ecosystem Studies (IES) in southeastern New York, USA declined over an 11-year period from 1988 to 1999, but increased from 1999 to 2001. These trends in particulate NH4+ correlated well with trends in particulate SO42â over the 1988-2001 period. The NH4+ trends were not as well correlated with local cattle and milk production, which declined continuously throughout the period. This suggests that regional transport of SO42â may have a greater impact on concentrations of NH4+ and subsequent deposition than local agricultural emissions of NH3. Ammonium concentrations in precipitation correlated significantly with precipitation SO42â concentrations for the 1984-2001 period although NH4+ in precipitation increased after 1999 and SO42â in precipitation continued to decline after 1999. The correlation between NH4+ and SO42â was stronger for particulates than for precipitation. Particulate NH4+ concentrations were also correlated with particulate SO42â concentrations at 31 of 35 eastern U.S. CASTNet sites that had at least 10 years of data. Air concentrations of NH4+ and SO42â were more strongly correlated at the sites that were located within an agricultural landscape than in forested sites. At most of the sites there was either no trend or a decrease in NH4+ dry deposition during the 1988-2001 period. The sites that showed an increasing trend in NH4+ dry deposition were generally located in the southeastern U.S. The results of this study suggest that, in the northeastern U.S., air concentrations of NH4+ and subsequent deposition may be more closely linked to SO42â and thus SO2 emissions than with NH3 emissions. These results also suggest that reductions in S emissions have reduced NH4+ transport to and NH4+-N deposition in the Northeast.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Environmental Pollution - Volume 135, Issue 3, June 2005, Pages 363-369
Journal: Environmental Pollution - Volume 135, Issue 3, June 2005, Pages 363-369
نویسندگان
Victoria R. Kelly, Gary M. Lovett, Kathleen C. Weathers, Gene E. Likens,