Whatman PM 2.5 membranes have low tare mass for accurate gravimetric determinations. The thermally stable design eliminates curling, keeps the membrane flat, and makes the filter robot-friendly. The PM 2.5 PTFE membranes are manufactured under clean room conditions. These chemically resistant, low chemical background filters permit sensitive, interference-free determinations. No glues or adhesives are used in making these 46.2 mm diameter products. Statement of Conformance
PTFE Filters for EPA PM 2.5 Reference Method.Under the requirements of 40 CFR Part 50, Appendix L, shown below, the manufacturer must perform the following tests as listed. Any filter manufacturer or vendor who sells or offers to sell filters specifically identified for use with this PM 2.5 reference method shall certify that the required number of filters from each lot (0.1% or 10, whichever is greater) of filters offered for sale have been tested as specified for the following tests and meet 90% of each of the design and performance specifications: - Loose, surface particle contamination. (drop test – weight loss stability)
- Temperature Stability. (temperature – weight loss stability)
Any filter manufacturer or vendor who sells or offers to sell filters specifically identified for use with this PM 2.5 reference method shall certify that a minimum number of 50 filters from each lot of filters offered for sale have been tested as specified for the following tests and meet 90% of each of the design and performance specifications: - Filter type
- Filter diameter
- Filter thickness
- Filter pore size
- Support ring width
- Support ring thickness (total)
- Maximum pressure drop (clean filter)
- Maximum moisture pick-up
- Collection efficiency
- Alkalinity
- Special requirements
These include trace metal analysis by XRF and visual inspection for defects such as pinholes, support ring separation, chaff or flashing, loose material, discoloration, filter non-uniformity or any other obvious filter defect. Whatman hereby states that every manufacturing lot that is offered for sale, and is identified for use with the PM 2.5 reference method, conforms to EPA acceptance criteria. | 
