Atmospheric Aerosols: Origins, Composition, and Optical Properties: Origins, Make-Up, and Optical Characteristics of Atmospheric Aerosols Contributions examining the origins, composition, and light-absorbing properties of atmospheric aerosols are welcome for this collection. We encourage research on source allocation, regional variability, primary and secondary aerosol formation, and the radiative effects of black and brown carbon. Interdisciplinary research that combines field observations, lab tests, and modeling to comprehend the role of aerosols in air quality and climate dynamics is of particular interest.

Analytical Techniques for Environmental and Smoke Aerosol Characterization: Analytical Methods for Characterizing Smoke and Environmental Aerosols Recent developments in analytical techniques for characterizing aerosols related to combustion and the environment are the focus of this collection. Method development or application of GC-MS, HPLC-MS/MS, ICP-MS, HR-ToF-AMS, and other platforms for the analysis of particulate matter, volatile and semi-volatile compounds, and trace elements are examples of submissions. The focus is on innovations in sample preparation, quantification accuracy, and approaches for dealing with complex matrices like smoke, air, and biological samples.

Keywords: Atmospheric Aerosols; Source Allocation; Radiative Effects; Analytical Techniques; Sample Preparation

Aerosols play a critical role in modulating the hydrological cycle by acting as cloud condensation nuclei (CCN) and ice nuclei (IN), thereby altering cloud microphysical structure, precipitation efficiency, and the spatial distribution of rainfall. Over South Asia - one of the world's most aerosol-laden and climate-sensitive regions rapidly increasing anthropogenic aerosol loading from industrial, agricultural, and urban sources has emerged as a major driver of changes in precipitation patterns, monsoon dynamics, and the frequency of extreme hydrometeorological events such as cloudbursts, droughts, and floods.

This Collection invites original research articles, review papers, and methodological contributions that advance our understanding of aerosol–cloud–precipitation interactions across tropical and South Asian environments. We particularly encourage studies that leverage:

Multi-source remote sensing observations (satellite platforms such as MODIS, CALIPSO, CloudSat, GPM, and TRMM; and ground-based radar and radiometry)

In-situ aerosol and cloud microphysical measurements from field campaigns

Numerical modelling approaches (WRF, WRF-Chem, GFS, regional and global climate models)

Machine learning and data-driven frameworks applied to large atmospheric datasets

Radiative transfer modelling to quantify aerosol direct and indirect radiative forcing

Topics of interest include - but are not limited to the aerosol indirect effect on cloud droplet size distributions, rain drop size distributions (DSD), lightning genesis, boundary layer dynamics, convective initiation, and monsoon variability. Studies addressing aerosol–climate feedback mechanisms against the backdrop of global warming are especially welcome. This Collection aims to bring together observational evidence, model-based diagnostics, and theoretical frameworks, thereby providing a comprehensive, multi-scale perspective on one of the most pressing problems in atmospheric science.

Keywords: Aerosol–cloud interactions; Aerosol indirect effect; Precipitation microphysics; South Asian monsoon; Convective precipitation; Rain drop size distribution; Radiative forcing; Cloud condensation nuclei; WRF-Chem modelling; Extreme rainfall events