Try contacting Mark Theimens at U. of Calif San Diego.

You wrote: 
>
>Does anyone know of any measurements of nitrogen isotopes on NOx or 
acid
>precipitation, particularly from midwest or Great Lakes region?
>Thanks,
>Dave Hodell
>
>
>______________________________
>David A. Hodell
>Department of Geology
>University of Florida
>1112 Turlington Hall
>Gainesville, FL 32611
>904-392-6137 (voice)
>904-392-9294 (Fax)
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>
>
>