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From: Prakash Doraiswamy (pdorai@utk.edu)
Date: 3/31/2002
Time: 9:01:28 PM
Remote Name: 160.36.157.147
Sir, I have downloaded the IMPROVE data for GRSM and had few questions with respect to it: 1. What do negative values for concentration of certain species such as for ions (such as Chloride ion, Nitrite ion etc.) mean ? I find it hard to believe it is an error because there are many of them. Does it mean that these concentrations are below MDL ? Please advise as to how the data should be interpreted or if infact those are errors.
2. Why is it that the NH4+ conc. data does not show up (not present in the data file) if we download the whole file using the download option while it shows up if we use the query option to choose what we want and then download ? Does it mean that the NH4 values are still undergoing quality check ?
Thanks, Prakash University of Tennessee, Knoxville