Monitor 29154 was identified as the most critical in this
network. All other monitors had a relatively small index value,
typically less than 0.200. The rank of the three most critical monitors
did not vary in either of the two sensitivity analyses. All ranks
remained the same in the first sensitivity analysis. Rank variations
occurred in the second sensitivity analysis for monitors initially
ranked from 5 to 8, which are the least critical monitors in the
network. We present the error in estimating the air pollution field
because of the removal of both the highest ranked monitor and the
lowest ranked monitor in Fig. 3, for the hour when monitor 29154
had its highest cost for removal