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What is Air Sampling?

Our new Introduction to Air Sampling Brochure.

 

Intro Air Sampling front cover 109x153

Filters and Cassettes

Filter CassettesSKC remains on the leading edge of particulate air sampling through active research and collaboration with leading experts around the globe and can offer Membrane Filters, Depth Filters, Coated (Treated) Filters and Cassettes, as well as a range of filter and cassette accessories.

SKC has made significant contributions to particulate sampling technology with its exclusively designed particulate samplers that provide highly efficient, sensitive, and accurate sampling.

A typical filter has a rough side and a shiny side. The shiny side is easier to read under a microscope. Therefore, expose the shiny side to the air when collecting samples for microscopic analysis. The rough side holds the dust more effectively, so the rough side is exposed for gravimetric sampling.

Filter Pore Size Rating

Filter pore size ratings are based on liquid filtration ratings. Filters will retain much smaller particles from air (e.g. a 0.8 µm liquid rated filter will retain >50% of particles as small as 0.08 µm).

A nominal or approximate rating is usually applied to depth filters. Unlike membrane filters, depth filters do not contain a uniformly defined pore structure, but rather fibres or sintered particles that intertwine to create a torturous path of openings that allow air to pass through, but trap particles throughout the depth of the filter. Because of this structure, depth filters are usually tested for pore size by passing liquid containing particles of a certain size through the filter. If the filter traps an acceptable amount of the specific-sized particles (despite the openings in the filter being larger that the test particles), that particle size becomes the "liquid nominal" pore size rating for the filter. Nominal pore size ratings are typically stated as "Filter removes >xx% of particles ≥ µm".

 

Material Common Pore Sizes Main Properties Applications
Mixed Cellulose Ester (MCE) Membranes 0.45 μm

0.8 μm

1.2 μm

5.0 μm
  • Hydrophilic
  • Ready Soluble for atomic absorption analysis
  • Readily rendered transparent for light transmitted microscopy
  • Dissolve and clear easily
  • Metal Dust Analysis
  • Asbestos
  • Man-made fibres
GLA 5000 PVC Membrane Filters

Polyvinyl Chloride (Pure Homopolymer)
5.0 μm
  • Hydrophilic
  • Non-oxidising surface
  • Silica free
  • Low tare weight for gravimetric analysis
  • Low ash
  • Gravimetric analysis
  • Hexavalent chromium
PTFE (Polytetrafluoroethylene) Membrane Filters 0.5 μm

1.0 μm

2.0 μm

5.0 μm
  • Hydrophilic
  • Inert to solvents, acids and bases
  • Autoclavable
  • Alkaline dusts
  • Polynuclear aromatics
  • Isocyanates
  • Pesticides
Polycarbonate Membrane Filters 0.4 μm

0.8 μm
  • Microscopically smooth surface
  • Extremely thin (10-20 μm) and transparent
  • Autoclavable
  • Scanning electron microscopy
  • Asbestos fibres
Silver Membrane Filters 0.45 μm

0.8 μm
  • Wide solvent compatibility
  • Higher temperature tolerance
  • Autoclavable
  • Uniform porosity and thickness
  • Bromine
  • Asbestos by TEM
  • Silica by x-ray diffraction
Glass Fibre Depth Filters Liquid

Nominal

Rating 1 μm
  • Partially hydrophobic
  • Higher temperature tolerance
  • High particulate retention
  • Pesticides
  • Coarse gravimetric
  • Isocyanates
  • Ethylene glycol
Quartz Depth Filters Liquid

Nominal

Rating 1.2 μm
  • Same as glass fibre
  • Low level metals content
  • Autoclavable
  • Gases
  • Aerosols
  • PM10
  • Diesel particulates
Cellulose Depth Filters Nominal
  • Autoclavable
  • Uniform Strength
  • Ashless (Type 40)
  • AA
  • HPLC
Gelatin Filters Nominal
  • Maintain viability of microorganisms
  • Microorganisms
DPM Cassettes Nominal
  • Tamper evident seal
  • Single use
  • Diesel Particulates
BestChek Asbestos Cassettes 0.45 μm

0.8 μm

1.2 μm
  • Preloaded including cellulose supports
  • With cowl
  • Banded
  • Asbestos
Coated (Treated) Filters Various
  • Ready to use
  • Isocyanates
  • Gases and vapours

 

Filter and Cassette Accessories:

Cassette Blanks

Cassette Shrink Bands

Filter Holders

Filter Supports

Tubing

Filter Sampling Accessories