Laser trapping-Raman spectroscopy for characterizing single suspended atmospheric aerosols

Abstract

Atmospheric aerosols have profound impacts on the environment and human health. Aerosols can absorb or scatter the solar radiation and alter the energy distribution of the global atmosphere. The aerosol particles bearing hazardous pollutants can get into the human body through the respiratory system and lead to various diseases. The key physicochemical properties of aerosol particles such as viscosity, phase state, pH, diffusivity, etc. are crucial for estimating their environmental and health impacts. Most of present techniques take an ensemble of particles as the researching target, hence only average properties can be obtained using these techniques. However, every aerosol particle is a unique micro reactor, the ambiguous treatment of which is considerably problematic. The laser trapping-Raman spectroscopy (LT-RS) can characterize the physicochemical properties and processes of single atmospheric aerosol particle at a natural suspended state. This paper presents an up-to-date review on applying LS-RS technique in the characterization of aerosol particles, including physical properties, chemical compositions, multiphase reactions, etc. Besides, recent technological advances of LT-RS are also reviewed. For each application, we describe the principle and representative examples of studies. The analytical capabilities of the LT-RS technique presented here demonstrate great promise in investigating the chemistry and multidimensional properties of individual atmospheric aerosol particles.