Privacy | Legal

Table of Contents Back | Next | Home

Missoula Technology & Development Center

Evaluation of Optical Instruments for Real-Time Continuous Monitoring of Smoke Particulates

Evaluation Results and Discussion (continued)

Real-Time Continuous Monitoring Results (continued)

Optec NGN-3 Nephelometer

The Optec NGN-3 was not available for the 1998 laboratory or field tests.

2000 Laboratory Tests—The Optec NGN-3 underestimated the mass concentrations by 33 percent (slope = 0.68, R² = 0.81, N = 14) when compared to the average results from the two FRM samplers (figure 34). The results for the tests were presented using a conversion factor of 3.0 from Bscat to mass concentration, the factory preset value. At high humidities, the NGN-3 with the correction factor set at 3.0 underestimated the mass concentrations by 6 percent (slope = 0.94, R² = 0.84, figure 35).

Discussion—The Optec NGN-3 is a new instrument and was not available for all the tests. The 2000 laboratory results were consistent with the other real-time continuous instruments. No instrument comparison results are available because only one instrument was included in the study.

Figure 34—The 2000 laboratory results of the Optec NGN-3
nephelometer and the average of the two Federal Reference
Method gravimetric samplers.

Figure 35—Results of the high-humidity tests for the Optec
NGN-3 nephelometer compared to the gravimetric results.
Gravimetric results are from a Federal Reference Method sampler.

E-mail: wo_mtdc_webmaster@fs.fed.us

Back | Next Table of Contents

Missoula Technology & Development Center

---

This page last modified October 21, 2002
Visitor since October 21, 2002