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1.
Fig. 3.

Fig. 3. From: Aerosol Monitoring during Carbon Nanofiber Production: Mobile Direct-Reading Sampling.

The mobile aerosol sampling platform used by the authors for detailed workplace investigations as described.

Douglas E. Evans, et al. Ann Occup Hyg. 2010 July;54(5):514-531.
2.
Fig. 2.

Fig. 2. From: Aerosol Monitoring during Carbon Nanofiber Production: Mobile Direct-Reading Sampling.

Process flow diagram. In each instance, materials were manually conveyed and loaded for subsequent operations. Once thermal treatment was completed, bagged CNF product was manually unloaded, weighed, tamped, and the collection bag closed.

Douglas E. Evans, et al. Ann Occup Hyg. 2010 July;54(5):514-531.
3.
Fig. 1.

Fig. 1. From: Aerosol Monitoring during Carbon Nanofiber Production: Mobile Direct-Reading Sampling.

A floor plan of the facility indicating approximate positions of processes and mobile sampling locations (A through D). Sampling probes were generally oriented toward and within a few feet of processes under investigation.

Douglas E. Evans, et al. Ann Occup Hyg. 2010 July;54(5):514-531.
4.
Fig. 7.

Fig. 7. From: Aerosol Monitoring during Carbon Nanofiber Production: Mobile Direct-Reading Sampling.

Particle size distributions (weighted by number) for significant CNF plumes observed in the facility (bag change and dryer dump) in the vicinity of Location C in . Measurements were by aerodynamic diameter (ELPI) and mobility equivalent diameter (FPSS). Distributions were derived by selecting and subtracting appropriate baselines from plumes and are therefore derived from net changes in particle concentration.

Douglas E. Evans, et al. Ann Occup Hyg. 2010 July;54(5):514-531.
5.
Fig. 6.

Fig. 6. From: Aerosol Monitoring during Carbon Nanofiber Production: Mobile Direct-Reading Sampling.

Particle size distribution comparison (weighted by number) for ultrafine particle sources at the facility. Measurements were conducted by aerodynamic diameter (ELPI) and mobility equivalent diameter (FPSS). Data from the FPSS were plotted as lines (see legend). For the ELPI, corresponding impactor stages were used and data (geometric mean diameters) plotted as individual points of the same color. A measurement artifact (electrometer offset) influenced FPSS measurements above ∼100 nm, so data were not included.

Douglas E. Evans, et al. Ann Occup Hyg. 2010 July;54(5):514-531.
6.
Fig. 4.

Fig. 4. From: Aerosol Monitoring during Carbon Nanofiber Production: Mobile Direct-Reading Sampling.

Time series of particle number and respirable mass (upper), active surface area and photoelectric potential (center), and CO and CO2 concentrations (lower) at four locations: A, control room; B, production; C, processing; and D, conference room. See floor plan () for sampling locations. Shaded areas denote specific events in the ‘processing’ area C that resulted in marked increases in one or more monitored metrics. Events were bagging final product (I), opening of dryer (II), dumping dried product (III), and operating gas heater (IV).

Douglas E. Evans, et al. Ann Occup Hyg. 2010 July;54(5):514-531.
7.
Fig. 5.

Fig. 5. From: Aerosol Monitoring during Carbon Nanofiber Production: Mobile Direct-Reading Sampling.

(a) Processing operator exchanges collection bag containing ∼7 kg of thermally treated CNF product in the vicinity of Position C in . The bag was purged with an inert atmosphere during filling. Tamping product and subsequent closing of bag resulted in significant CNF release (Event I in ). (b) An empty collection drum adjacent to the dryer base. Once the drying cycle was complete, dumping of dried CNFs from the dryer above into the bag-lined collection drum below resulted in the largest transient increase in respirable mass concentration observed (Event III in ). A canvas flange can be observed at the base of the dryer to assist in reducing the gap between dryer base and drum. This may not have been performing adequately for this operation.

Douglas E. Evans, et al. Ann Occup Hyg. 2010 July;54(5):514-531.

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