Return to the point in the document where this figure is located.

Figure 8-2 provides a decision tree to estimating existing concentrations depending upon the availability of applicable monitoring data.
Local monitoring data available? |
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Step 1. If no, is there another area to compare with? |
If yes, use worst value, averaged over up to five years of data if available. If no, make a worst-case assumption. Refer to examples in the document. |
Step 2. If yes, is there full year data? |
If no, follow Step 1. If yes, use worst value, averaged over up to five years of data if available. |