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 Technology & Development Center |
Real-Time
Smoke
Particulate Sampling
Fire Storm 2000
Two Radiance Research nephelometers were operated, one in Missoula and one in Hamilton. Figure 25 shows the results from both instruments. The nephelometer (serial No. 0101) in Hamilton overestimated the mass concentration by 43 percent with a y-intercept of -6.59 µg/m³. The correlation coefficient was 0.99. The nephelometer in Missoula (serial No. 0102) overestimated the mass concentration by 52 percent with a y-intercept of -6.88 µg/m³. The correlation coefficient was 0.94.
Figure 25—Results of the two Radiance Research nephelometers
and the PQ 200 federal reference method samplers. The nephelometer
with serial No. 0101 was in Hamilton and the nephelometer with
serial No. 0102 was in Missoula, MT.
Several of the instruments were moved from Missoula to Hamilton during the test and operated in both locations. These instruments include the Met One GT-640, MIE DataRam, Radiance Research nephelometer, and the Optec NGN-3 nephelometer. We have the opportunity to determine whether the instruments responded differently to the smoke at different locations. Doing so may give us information about the optical scattering characteristics of the smoke at the two sites. Because the fires were closer to Hamilton than to Missoula, we may be able to say that the Hamilton smoke was "newer" than the Missoula smoke. Smoke in Missoula was probably from several different fires, including some near Hamilton. We could say the Missoula smoke was "aged." The results are based on the assumption that the instruments performed similarly in both locations.
Except for the Optec NGN-3 nephelometer, the instruments operated at both locations were in Hamilton longer than they were in Missoula. There are considerably more results from Hamilton than from Missoula. Also, the mass concentrations were much higher in Hamilton than in Missoula. Concentrations in Missoula ranged up to 160 µg/m³ as determined by the gravimetric sampler, while concentrations in Hamilton reached as high as 480 µg/m³. The age of the smoke and the difference in average particulate concentrations between Missoula and Hamilton may explain some of the differences in instrument performance.
Figure 26 shows results from the Met One GT-640. When the instrument was in Missoula, it overestimated the mass concentration by 1.48 times based on 11 filter samples. The instrument overestimated the mass concentration in Hamilton by 1.69 times based on 24 samples.
Figure 26—Results from the Met One GT 640 (serial No. 1466)
deployed first in Missoula and then in Hamilton, MT.
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