OR/16/028 Appendix 1

Beriro, D J, Field, L P and Cave, M R. 2016. Validation of a gravimetric PM2.5 impactor using particle sizing techniques. British Geological Survey Internal Report, OR/16/028.

Images of cellulose filters

The filters were imaged after a one-quarter segment was removed for STEM analysis. The following images show each filter in turn for reference. An image has also been included of the one-quarter segment for Filter #44 post-sonication to show the amount of material removed from the filter by this preparation method.

Morphological SEM images were taken of each filter to record a general record of the density and particle size range for each filter.

BA-F-47-100216

Plate 4    (left) Photograph of filter 47 following sub-sampling for STEM analysis.
Plate 5    (centre) BSED image showing the density of particle coverage on the filter surface.
Plate 6    (right) BSED image of a large particle in-situ within the particle coating of the filter. The measurement was carried out live within the FEI software.

BA-F-10-100216

Plate 7    (left) Photograph of filter F10 following sub-sampling for STEM analysis.
Plate 8    (centre) BSEM image showing the general coating of particles across the filter.
Plate 9    (right) BSED image showing three larger particles within the coating on the filter. Measurements were carried out live within the FEI software.

BA-F-44-190216

Plate 10    (top left) Photograph of filter 44 following sub-sampling for STEM analysis.
Plate 11    (top right) Photograph of the one-quarter segment taken for STEM analysis following sonication. Almost all the particulate material has been removed from the filter. The darker spots are where the filter membrane has been damaged by handling by tweezers and cut by scalpel.
Plate 12    (bottom left) BSEM image showing the particle distribution across the filter.
Plate 13    (bottom right) BSEM image showing two larger particles within the particle coating. Measurements were carried out live within the FEI software.

BA-F-52-190216

Plate 14    (left) Photograph of filter 44 following sub-sampling for STEM analysis.
Plate 15    (centre) BSEM image showing the general distribution of particles across the filter surface.
Plate 16    (right) BSEM image of a larger particle. The majority of particles are clearly around 2.5 microns or less in diameter.

BA-F-06-260216

Plate 17    (left) Photograph of filter 06 following sub-sampling for STEM analysis. This sample was quite thickly coated and the centre of the sample has suffered de-lamination as some of the particulate material has come away from the filter. This had occurred pre-subsampling.
Plate 18    (centre) An LFD image showing the morphology of the delamination in the centre of the sample. This is also an indication of how thickly coated the filter is.
Plate 19    (right) A BSEM image at the edge of the delamination (see lower left corner of image), showing a larger particle. The measurement was carried out live within the FEI software.

BA-F-53-260216

Plate 20    (left) Photograph of filter 53 following sub-sampling for STEM analysis. Like its counterpart filter, BA-F-06-260216, filter 53 had also suffered from some delamination in the centre of the filter.
Plate 21    (centre) BSEM image showing the general distribution of particles on filter 53.
Plate 22    (right) BSEM image showing a larger particle within the sample. The measurement was carried out live within the FEI software.