Detection of Ultra-Trace Heavy metals in Aerosols with pg^m3 Sensitivity Using Filament-Induced Fluorescence Spectroscopy

TL;DR

This study demonstrates a highly sensitive remote detection method for ultra-trace heavy metals in aerosols using Filament-Induced Fluorescence Spectroscopy, achieving detection limits in the picogram per cubic meter range at 10 meters distance.

Contribution

The paper introduces an optimized FIFS technique capable of detecting multiple heavy metals in aerosols at ultra-trace levels with high stability and potential for further sensitivity improvements.

Findings

Detection limits as low as 0.3 pg/m^3 for Pb.

Stable detection over a wide concentration range.

Versatile detection of multiple heavy metals.

Abstract

Heavy metal pollution, particularly in the form of airborne aerosols such as lead (Pb), cadmium (Cd), mercury (Hg), and cobalt (Co), poses serious health and environmental risks, necessitating highly sensitive remote detection techniques. In this study, Filament-Induced Fluorescence Spectroscopy (FIFS) was employed to detect ultra-trace concentrations of heavy metal aerosols with high sensitivity and stability. By systematically optimizing the balance between filament length and detection distance, the optimal detection distance under the current experimental conditions was determined. With a detection distance of 10 m, this work achieved a minimum detectable concentration of 0.47 pg m^-3 for Pb and an extrapolated limit of detection (LOD) of 0.3 pg m^-3, with excellent signal stability (RSD < 7%) over a concentration range from 0.47 pg m^-3 to 0.47 g m^-3. Additionally, Cd, Hg, and Co aerosols were also successfully detected under the same conditions, with detection limits of 2 pg m^-3, 0.25 pg m^-3, and 3 pg m^-3, respectively, further confirming the versatility of FIFS in detecting diverse heavy metals. Theoretical predictions suggest that increasing laser power could further enhance the detection capability. These results highlight the ultra-sensitive remote detection capability of FIFS for heavy metal aerosol detection and provide valuable insights for optimizing system parameters to enhance its application performance in environmental monitoring.