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Below please find the recommended membrane based on your contaminant:
Below please find the recommended membrane based on your test method:

Air Monitoring Filters

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Air monitoring filters help detect pollutants.
Environmental Pollution Webinar
Merck:/Freestyle/BI-Bioscience/Filters-Particle-Monitoring/environmental-pollution-webinar.jpg“PM2.5 sampling best practices and regulatory guidance,” presented by Dr. Haider A. Khwaja, Research Scientist from University at Albany

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Millipore filters were among the first to be used for ambient air monitoring, as early as the 1970s. Particulates and contaminants in the air affect human capital, the most precious natural resource our planet supports. Recognizing the need to protect this resource, industries, governments, and associated regulatory agencies around the world monitor ambient air. Air monitoring methods have been developed to detect and quantify diverse contaminants and particulates, including PM2.5, PM10, sulfur dioxide, fluorides, heavy metals, and radioactive particles. Many of these methods involve gravimetric analysis and monitoring systems that use membrane filter discs and filter holders.

Download brochure: Air monitoring around the world

Merck’s Filters for Use in Air Monitoring Methods

Millipore filters, now supplied by Merck, are used in regulated ambient air monitoring methods. Use the selector wizard below to determine the correct filter to use for your air monitoring needs, or follow these links to the application of your choice: 

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Examples of Other Regulated Air Monitoring Methods Are:

Recommended product(s)
NIOSH 5006 Air Monitoring, Carbaryl M000037A0
OSHA Standard 1910.1001 App A Air Monitoring MAWP025AC

Radioactive Alpha Particle Monitoring

Nuclear power is relatively clean and renewable, and through radiation monitoring, can be a safe source of energy for the planet. Although there are many naturally occurring radioisotopes that make up water, air, soil and organisms, the challenge in radiation monitoring is to detect the “non-natural” radiation signal above the naturally occurring background radiation levels. To support efficient, convenient radiation monitoring, Merck has developed a special Fluoropore™ membrane filter designed for alpha particle collection in continuous air monitors.
The Fluoropore™ filter for alpha particle monitoring provides:
  • Improved data collection: Unlike fibrous filter media that trap particles in their matrix, Fluoropore™ (hydrophobic PTFE) membranes collect particles on their surface. This surface collection provides better detection efficiencies and improved resolution.
  • Choice of pore sizes: Fluoropore™ membranes are available in 3 and 5 μm pore sizes. The smaller pore size provides high resolution. The larger pore size has very low pressure drop and greater throughput capacity, which minimizes the number of filter changeouts.
  • Contrasting backing material: The 5 μm Fluoropore™ membrane is bonded to a contrasting backing made from high density polyethylene fiber. The contrast between the top and bottom of the filter prevents incorrect installation in sampling devices. The backing also reduces the electrostatic charge of the filters and makes them easier to handle.
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Heavy Metal Contamination Testing

Merck provides membranes with low ash content as well as IC-compatible syringe filters to prepare your reconstituted samples prior to ion chromatography.

Filter Discs for Air Monitoring

Filter Holders for Air Monitoring

PM2.5 Monitoring

Recently, the focus has been on PM2.5 levels, which have been linked to respiratory problems, cancer, and aging-related disorders such as Alzheimer’s disease and bone damage. Major regulatory agencies have now issued guidance and methods for monitoring PM2.5, as outlined in the table below:

Regulated MethodsAnnual limitFilter diameterFilter materialMerck Catalog No.
US, Japan
US EPA 40 CFR part 50
≤35 µg/m3 46.2 mm ±0.25 mm
  • PTFE with a ring (For reference / manual method)
  • Glass fiber roll for automated / equivalent methods
Call for ordering information
EN12341 – 2014
≤25 µg/m3 50 mm
  • PTFE with a ring (For reference / manual method)
  • Glass fiber
  • Quartz fiber
HJ 656-2013
≤35 µg/m3
  • Low Flow: 47 ±0.25 mm
  • Moderate Flow: 90 ±0.25 mm
  • High Flow: 200 x 250 mm
  • PTFE with a ring (For reference/manual method)
  • Glass fiber
  • Quartz fiber

Merck:/Freestyle/BI-Bioscience/Filters-Particle-Monitoring/BI-LC-Filters-Particle-Monitoring-Images/pm2-membrane.jpgMerck Ensures That Membrane Discs Match Regulatory Specifications.

Certification documents for each product will be shipped in each box. Detailed test results can be obtained by contacting Merck Technical Support.

TestSpecification*AP20 Glass FiberAQFA Quartz FiberPTFE Filter with Ring
Temperature Stability ≤20 µg/filter disc 4 16 -4.0
Loose Particle Test ≤20 µg/filter disc 22 39 1.0
Particle Retention ≥99.7% >99.9% >99.9% >99.9%
Pressure Drop ≤3 kPa @ 0.45 m/s air flow rate ~1 kPa ~1 kPa 0.65 kPa
Additional tests performed for certified PTFE filters as per U.S. EPA guidelines**
Alkalinity ≤25 µeq/g filter 0.3
XRF Analysis Low background signal Meets
*(As Per Chinese PM2.5 Sampling Standard)
**Certification documents for each product, stating that all tests were carried out according to United States Environmental Protection Agency (EPA) requirements, will be shipped in each box.

PM 2.5 Membrane Characteristics and Detailed Test Specifications

Tested as per: 40 CFR Part 50, Appendix L

Click here to view the table

No.ParameterSpecificationTest Method/Comments
1 Size 46.2 ±0.25 mm Using a Template
2 Medium Polytetrafluoroethylene (PTFE) with internal support ring
3 Support Ring PMP or equivalent Polypropylene
3a A: Thickness 0.38 ±0.04 mm By Design
3b B: Outer Diameter 46.2 ±0.25 mm By Design
3c C: Width 3.68 mm (+0.0 mm, -0.51 mm) By Design
4 Pore Size 2 µm Maximum pore size (Using ASTM- F316-94- Bubble Point)
5 Filter Thickness 40 ±10 µm
6 Maximum Pressure Drop (at 16.67 L/min) ≤ 30 cm water Using ASTM D2986-95A
7 Maximum Moisture pickup ≤10 µg/filter disc Section 2.12 EPA/600/R-94/038b
8 Collection Efficiency ≥99.7% Using 0.3 µm DOP particles (ASTM D 2986-95A)
9a Filter Weight Stability: Test for Loose, surface particle contamination ≤20 µg/filter disc Section 2.12 EPA/600/R-94/038b (0.1% based on total lot size tested)
9b Filter Weight Stability: Test for Temperature stability ≤20 µg/filter disc Section 2.12 EPA/600/R-94/038b (0.1% based on total lot size tested)
10 Alkalinity ≤25 µeq/g filter Section 2.12 EPA/600/R-94/038b
11 Packaging 50 (2 packs of 25 filters with filter serialization)

XRF Background Signal (ng/cm2) 
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PM10 Monitoring

Airborne particles in the range of 10 µm in size have also been linked to negative effects on our breathing and respiratory systems. Merck provides filter media designed for PM10 testing that complies with government-established standards.

Learn more about filters for PM10 monitoring