The data recorded by the monitoring team helps the Unified Command make decisions about the in-situ burn operation.
The graph below was created from data collected during a test burn in Mobile, Alabama in September, 1997. On the day of that burn, the wind blew hard and the smoke from the small burn stayed close to the ground. (Usually, in the case of larger burns in calmer wind, the smoke lofts to several hundred feet.) Notice that while the instantaneous readings (represented by the green line) varied greatly, the time-weighted average (TWA) readings (represented by the blue line) remained relatively steady and consistently below the level of concern (LOC) (represented by the red line).
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In this graph, as in most graphs of ISB data, the time-weighted average (TWA) readings provide a much better indication of particulate concentration trends, and are the readings used by the recorder when reporting particulate concentration trends to the Unified Command. |
Revised: July 17, 2001
Office of Response and Restoration, National Ocean Service, National Oceanic
and Atmospheric Administration