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Lefer & Talbot 2001
Lefer, B.L. and Talbot, R.W. (2001). Summertime measurements of aerosol nitrate and ammonium at a northeastern U.S. site. Journal of Geophysical Research 106: doi: 10.1029/2000JD900693. issn: 0148-0227.

Summertime measurements of the atmospheric concentrations and aerodynamic size distributions of NH4+ and NO3- and other major aerosol species were made between 1991 and 1996 at a rural site in central Massachusetts to examine the nature of aerosol chemistry at the Harvard Forest. The bulk aerosol can be described as a mixture of submicron ammonium (bi)sulfate aerosols with smaller amounts of soil-derived particles. Approximately one third of the samples had an anion surplus of greater than 20%, which was assumed to result from unmeasured H+ ions. Aerosols in air masses from the southwest were rarely neutralized, especially when SO42- concentrations were greater than ≈75 nmol m-3. This result suggests that twice this level (i.e., 150 nmol m-3) may describe an upper limit to the amount of gaseous NH3 encountered enroute to this sampling site during the typical summer transport observed from this region. Aerosol NO3- was observed at concentrations 4--8 times lower than NH4+, and while occasionally found in the fine mode, the majority of the NO3- was associated with the water-soluble fraction of supermicron soil-derived Ca2+. The similarity of the ammonium and oxalate particle size distributions suggests that (NH4)2(COO)2 aerosols may result from the reaction of gaseous precursors. ¿ 2001 American Geophysical Union

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Abstract

Keywords
Atmospheric Composition and Structure, Aerosols and particles (0345, 4801), Atmospheric Composition and Structure, Constituent sources and sinks, Atmospheric Composition and Structure, Troposphere—composition and chemistry, Atmospheric Composition and Structure, Troposphere—constituent transport and chemistry
Journal
Journal of Geophysical Research
http://www.agu.org/journals/jb/
Publisher
American Geophysical Union
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