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Air and Gas Particle Monitoring

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In this section of the AD030 Learning Center, you can find technical information on regulated methods for air and gas particle monitoring. Workplace particle monitoring of air and gases serves multiple purposes:
  1. Modern industrial processes, such as those involving gyroscopic, mechanical, servo, and electronic systems, are extremely sensitive to dust particles.
  2. Particle contamination can have a damaging effect on the downstream performance of highly sensitive products.
  3. Heightened awareness of worker safety has led to increased monitoring of human exposure to certain particles in the work environment.
Taken together, there is an acute demand for monitoring manufacturing and assembly areas, test laboratories, and clean rooms. Industrial hygienists perform air monitoring for the analysis of hazardous particles, asbestos fibers, chemical vapors, and dust in work areas as well as on personal work clothes.

For industrial particle monitoring of air and gas, we provide:
Explore the following technical aspects of air and gas monitoring by clicking on these links:
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In the U.S., the EPA (Environmental Protection Agency) regulates environmental exposure while OSHA (Occupational Safety and Health Administration) regulates exposure in the workplace. NIOSH (National Institute of Occupational Safety and Health) develops the test methods in association with OSHA, the CDC (Center for Disease Control and Prevention) and the U.S. Department of Health and Human Services. When the EPA adopts a NIOSH standard method, it is referenced in the U.S. Federal Register.
Our online guide to regulated analytical methods references NIOSH, OSHA and ASTM methods. These organizations focus on the workplace and worker safety in developing their procedures. OSHA regulates exposure of over 100 air and fluid contaminants that can be monitored and sampled by membrane filtration.

In Europe, European Union Directives are published in the Official Journal of the European Union (OJEU). For example, the Asbestos International Association has published a comprehensive method in the OJEU for determination of asbestos in environmental and occupational settings. This method recommends monitoring asbestos through an Merck 25 mm all-conductive carbon-filled polypropylene cassette with cowl.

Click to visit Online Guide to Regulated Analytical Methods
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Sampling and Filtration

In air monitoring and sampling procedures, air is drawn by vacuum through a 37 mm two- or three-piece cassette preloaded with the specified filter and support. In order to calculate the particles per unit volume of air, follow the steps:
  1. Calculate total volume of air pumped (in liters): 

    Merck:/Freestyle/BI-Bioscience/Filters-Particle-Monitoring/A030 Images/equation.jpg

    where L = liters (of air), t = unit of time and
    T = total sampling time (in units “t”).
  2. Measure the number of particles on the filter (P) by weight or direct counting, and complete the following equation:

    P / V = particles per liter of air
For personal sampling, place the holder within the worker’s breathing zone (cassette opening facing down) and connect through flexible vacuum tubing to a flow-controlled battery-operated pump attached to the worker’s belt. Sampling is typically carried out long enough to represent a full work shift (minimum of 1/2 the full shift). Flow rate is usually 1 to 4 liters per minute, adjusted according to expected fiber and particle concentrations.

For area sampling, mount the holder vertically on a stand and direct toward a representative air space. Connect the holder to an appropriate vacuum pump through flexible vacuum tubing, and adjust the flow rate. If you use a threaded hose adapter (XX6200004), you can regulate the flow by inserting the appropriate flow-limiting orifice. We supply orifices in a matched set to monitor a range of flow rates.
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