P 16513

Nanomaterial dustiness

Administrative data

Endpoint:

nanomaterial dustiness

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27-10-2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2021

Report date:

2021

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: DIN EN 17199-3

Version / remarks:

Workplace exposure - Measurement of dustiness of bulk materials that contain or release respirable NOAA or other respirable particles - Part 3: Continuous drop method

Deviations:

yes

Remarks:

1 meaurement performed

GLP compliance:

no

Type of method:

continuous drop

Details on methods and data evaluation:

In the continuous drop method, the bulk material falls continuously into a slight vertical counter air flow. The dust released by the falling bulk material is directed by the air stream (53 l/min) into a sampling section where direct reading aerosol measuring devices (SMPS/OPS) measure the time-resolved particle concentrations and the time-resolved particle size distribution of the aerosol.
The number size distribution of particles between 10 and 417 nm is determined using a TSI SMPS (model 3910) equipped with isopropanol based CPC (condensation particle counter). The number size distribution of particles between 0.3 and 10 μm is determined using a TSI OPS (model 3330) integrated in the SMPS.
A special downpipe was used for the detection of possibly released product nanoparticles (including submicron agglomerates) according to the above mentioned method and following the standard DIN EN 15051-3 "Workplace exposure -Measurement of the dustiness of bulk materials - Part 3: Continuous drop method.
In the downpipe described above, the counterflow is provided by cleaned, almost particle-free air (upstream ULPA filter type U15), so that possible background pollution in the room air is eliminated and measured nanoparticles can be clearly assigned to the product.

Sampling:

The test material was used without further treatment (e.g. drying). 45.3 g (172.2 cm3) test material are used for the measurement, dosing rate: 4.53 g/min

Test material

Test material information

Constituent 1

Reference substance name:

Strontium 4-chloro-2-[2-hydroxy-6-sulfonatonaphthalen-1-yl)diazenyl]benzoate

Cas Number:

474814-88-5

Molecular formula:

C17H9ClN2O6SSr

IUPAC Name:

Strontium 4-chloro-2-[2-hydroxy-6-sulfonatonaphthalen-1-yl)diazenyl]benzoate

Test material form:

solid: nanoform, no surface treatment

Results and discussion

Dustiness index

Dustiness index 1

Key result

Mean:

60 650.4 other: 1/mg

Remarks on result:

other: dustiness index as number of airborne particles per mg in the nanoscale (10 nm - 100 nm)

Dustiness index 2

Mean:

5 183.9 other: N/cm3

Remarks on result:

other: number of airborne nanoparticles per cm3

Any other information on results incl. tables

temperature: 28.6°C, rel. air humidity 45 %

The cleaned, almost particle-free air had a total particle count of 8 particles/cm3 in the range of 10 nm - 417 nm, the nanoscale fraction (10 - 100 nm) contained 7 particles/cm3.

Table 1: summary SMPS (scanning mobility particle sizer)

Range [nm]	Mean [nm]	Concentration [N/cm3]	ICD [1/mg]	ECD [1/mg·s]
10-100	57.2	5183.9	60650.4	101.1
100-417	227.9	12721.1	148834.4	248.1
10-417	178.5	17905	209484.8	349.1

ICD: dustiness index as number of airborne particles per mg

ECD: emission rate as number of particles per mg per second

mean: average particle diameter in nm
N: number of airborne particles

Table 2: summary OPS (optical particle sizer)

Range [μm]	Mean [μm]	Concentration [N/cm3]	ICD [1/mg]	ECD [1/mg·s]
0.3 - 10	4.9	165.1	1931.9	3.2

Applicant's summary and conclusion

Executive summary:

The dusting behaviour of the test material was investigated using DIN EN 17199 -3: 2019 -12 "workplace exposure - measurement of dustiness of bulk materials that contain or release respirable nano objects and their aggregates and agglomerates or other respirable particles- Part 3: Copntinuous drop method".

The dust released by the falling test material was measured by a scanning mobility particle sizer (SMPS, 10 - 417 nm) and an optical particle sizer (3 - 10 μm). The counterflow was provided by cleaned, almost particle-free air.

The SMPS counted 5183.9 particles per cm3 in the nanoscale (10 - 100 nm) (12721.1 particles per cm3 in the range of particles 10 -417 nm) corresponding to a dustiness index of 60650.4 particles per mg in the nanoscale (10 - 100 nm) (148834.4 particles per mg in the range of particles 10-417 nm).

The mean size of the nanoparticles was 57.2 nm, the mean size of particles in the range 10 - 417 nm was 227.9 nm.

The OPS (0.3 - 10 μm) counted 165.1 particles per cm3 corresponding to a dustiness index of 1931.9 particles per mg. The mean size of the particles was 4.9 μm.