In-Situ Elemental Composition Analysis of Large Inhalable Aerosol Using Laser Induced Breakdown Spectroscopy

Area of Science:

• Environmental Science and Engineering
• Analytical Chemistry
• Occupational Health and Safety

Background:

• Assessing airborne particle composition is crucial for identifying and mitigating toxic material exposure risks, particularly in occupational settings.
• Existing aerosol sampling instruments often lack real-time elemental analysis capabilities for large inhalable particles (aerodynamic diameter > 20 µm).

Purpose of the Study:

• To develop and validate a novel method for real-time elemental composition analysis of large inhalable particles.
• To integrate this method with existing particle sizing technology for comprehensive airborne particle characterization.

Main Methods:

• Development of a prototype sensor utilizing laser-induced breakdown spectroscopy (LIBS) for elemental analysis.
• Implementation of a passive inlet and optical triggering system to ablate falling particles.
• Quantification of particle composition via emission spectra analysis using a real-time material classification algorithm.

Main Results:

• Validation performed on 1480 experimental spectra from four aerosol test materials.
• Optimized detection thresholds achieved high agreement with truth values (F1 score ≥ 0.9).
• The LIBS elemental analysis method was successfully combined with a direct-reading particle sizer (DRPS).

Conclusions:

• The developed LIBS-based method enables real-time elemental composition analysis of large inhalable particles.
• The integrated system provides comprehensive capabilities for counting, sizing, and elemental analysis of airborne particles.
• This advancement offers improved tools for occupational exposure monitoring and risk assessment.