Direct measurement techniques for atmospheric aerosol: Physical properties review

Abstract

Atmospheric aerosols consist of a mixture of solid and liquid particles of complex size, phase, and chemical composition. The investigation of its physical properties holds significant scientific significance for in-depth understanding the intricate dynamics of aerosols, assessing radiation balance and climate change. So, what are the measurement techniques of the physical properties of aerosols? It is undoubtedly meaningful for us to further study the relevant scientific problems of aerosols. This review focuses on the direct measurement techniques of aerosols physical properties in recent 20 years. Here, aerosol physical properties include the particle size, shape, concentration, density, hygroscopicity and liquid water content, etc. The merits, demerits and limitations of each technique in both laboratory and field applications are summarized. Additionally, we also discuss the future research challenges regarding technological improvement and instrument development. Enhancing the accuracy of existing techniques and developing innovative ones is proposed, with the aim of realizing simultaneous multi-parameter measurements wherever possible and expanding the range of measurable aerosols dimensions. These direct measurement techniques facilitate exploration of the microphysical properties of aerosols, aiding in guiding the development direction and application of detection instruments.