Aspects of Passive Air Sampling

Significance of the Topic

Passive air sampling offers a cost-effective, pump-free approach to monitoring airborne chemicals across diverse environments. By relying on diffusion rather than active airflow, it enables simultaneous, low-impact deployment at multiple sites, including hazardous or noise-sensitive locations. This makes it valuable in environmental surveillance, indoor air quality studies, industrial hygiene and long-term exposure assessments.

Objectives and Overview

The original work examines the principles and performance of diffusive samplers, with a focus on the radiello® radial design and Chromline’s SPME diffusive fiber holder. It outlines key features, uptake rates, application areas, official standard methods, and supporting laboratory services.

Methodology

Sampling is based on Fick’s law of diffusion, where analyte mass collected over time is proportional to diffusion coefficient, surface area and concentration gradient. Two geometries are compared:

• Axial samplers – uptake rates of 7–8 ml/min for benzene on activated charcoal.
• Radial (radiello®) samplers – enhanced rates (~80 ml/min) via cylindrical geometry.

Desorption strategies vary by compound class:

• Chemical desorption (CS₂ or derivatization) for VOCs, BTEX, aldehydes.
• Thermal desorption (TD-GC/FID or TD-GC/MS) for phenols, anaesthetics, C4 dienes.

Sampling durations can range from minutes to weeks depending on target concentration and sampler configuration.

Used Instrumentation

• radiello® diffusive bodies (white, blue, yellow, silicone membrane).
• Adsorbent cartridges (charcoal, graphitized carbon, DNPH-coated florisil, acid-impregnated media).
• Chromline DFH holder and FFA fast-fit SPME assemblies.
• Analytical platforms: HPLC for DNPH derivatives, GC/FID, GC/MS, photometry, ion chromatography.

Main Results and Discussion

Empirical evaluation shows radiello® samplers deliver tenfold higher uptake rates and greater capacity with minimal back-diffusion compared to axial filters. Uptake rates are characterized in atmospheric chambers and corrected for temperature. Validation through EU validation studies and standardized EN/ISO methods confirms reliable performance for ozone, NO₂, SO₂, VOCs, aldehydes and acid gases. Chromline’s DFH supports time-weighted-average sampling with adjustable flow paths, extending passive approaches to SPME fibers.

Benefits and Practical Applications

• No power or pumps needed; silent operation suitable for indoor/outdoor and personal monitoring.
• Parallel multi-site sampling reduces logistical burden.
• Reusable hardware; only cartridges or fibers require replacement.
• Adaptable to harsh weather with protective shelters and water-repellent materials.

Future Trends and Opportunities

Integration with wireless data loggers, miniaturized detectors and advanced sorbent materials promises enhanced real-time feedback and lower detection limits. Expanding passive SPME into multiplexed fiber arrays and coupling with next-generation mass spectrometry will broaden analyte scope and field applicability. Automated exchange systems will streamline high-throughput environmental surveys.

Conclusion

Passive diffusive sampling, exemplified by radiello® and Chromline DFH, provides robust, accurate and scalable solutions for air monitoring across regulatory, research and industrial settings. Its simplicity and validated performance support widespread adoption for long-term and high-resolution exposure assessments.

References

• EN 838, EN 13528-1/2/3, EN 14412, EN 14662-4/5, ISO 16000-4, ISO 16017-2, ISO 16200-2.
• LIFE MACBETH, RESOLUTION, ARTEMIDE air monitoring projects.
• EUR 19594 EN, EUR 20860 EN, EUR 21754 EN validation studies.