In this collaborative webinar, Alex Watts and Bevan Meade from ALS Global join Hunter Wack of RAECO Rents to discuss the critical components of a successful personal air sampling campaign. The session emphasizes the partnership between the rental provider (for equipment like the GilAir Plus) and the analytical lab to ensure regulatory compliance and data accuracy.
Rental vs. Analytical Lab: Who Does What? [03:02]
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Rental Companies (RAECO Rents): Provide real-time monitoring equipment like noise dosimeters, PIDs, and dust monitors for immediate concentration readings [03:08].
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Analytical Labs (ALS Global): Handle complex analyses for metals, VOCs, pesticides, and 8-hour TWA exposure assessments from filters and sorbent tubes [03:58].
2. Active vs. Passive Sampling [18:13]
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Active Sampling: Uses a pump (like the GilAir Plus) to pull air through a filter or tube. It offers precise control and lower reporting limits, making it ideal for short-term (STEL) samples [19:24].
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Passive Sampling: Relies on diffusion. These "badges" are less intrusive for employees and don't require pumps or calibration, but they may have higher detection limits [20:04].
3. Calibration & Field Setup [27:03]
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The Train: Always calibrate with a "representative" filter in-line. Calibrating without the media ignores the backpressure, leading to inaccurate flow rates [27:22].
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Primary vs. Secondary: Use primary calibrators (like the Defender) for the highest traceability to NIST standards [28:08].
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Breathing Zone: Clip the sampler within the employee's breathing zone (approx. a 9-inch radius around the head) and check the pump every hour to ensure it hasn't shut off or kinked [32:12].
4. Common Sampling Pitfalls [45:48]
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Breakthrough: Occurs when the flow rate is too high or the time is too long, pushing the contaminant from the primary sorbent layer into the backup layer [46:22].
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Overloading: For silica or metals, do not exceed 2mg of dust on a filter. Overloading can cause biased low results as particles fall off the filter or clog the system [48:40].
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Field Blanks: Crucial for identifying contamination during transport. Simply open and close a blank cassette in a clean area and label it clearly for the lab [33:22].
5. Interpreting Lab Reports [41:08]
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RL vs. PEL: The Lab Reporting Limit (RL) is in micrograms per sample. You must provide the air volume to the lab so they can convert this to milligrams per cubic meter ($mg/m^3$) or PPM for comparison to OSHA PELs [41:36].