Study Finds South Asia Faces Highest Climate Impact from Dust-Pollution Aerosols

Aerosols are tiny particles suspended in the atmosphere that originate from sources such as desert dust, vehicle emissions, industrial pollution and forest fires.

A new international study has found that South Asia experiences some of the strongest climate impacts from airborne particles, with a mixture of dust and pollution generating the highest levels of atmospheric heating among the world's major aerosol types. The research, led by scientists from the Indian Institute of Astrophysics (IIA) and the Aryabhatta Research Institute of Observational Sciences (ARIES), provides one of the most comprehensive global analyses of aerosols to date. The findings are expected to improve climate models, satellite monitoring and predictions of how airborne particles influence weather and climate.

South Asia stands out for dust and pollution mix

Aerosols are tiny particles suspended in the atmosphere that originate from sources such as desert dust, vehicle emissions, industrial pollution and forest fires. These particles can either reflect sunlight back into space or absorb it, altering Earth's energy balance and influencing temperatures, cloud formation and rainfall.

The researchers found that dust-dominated mixtures, where desert dust combines with human-made pollution, are the most common aerosol type across South Asia. This combination produces the highest Aerosol Radiative Forcing (ARF) and atmospheric heating rates in the region, making it particularly important for climate studies.

The findings suggest that the interaction between natural dust and pollution creates stronger warming effects than many other aerosol combinations found around the world.

Seven aerosol types mapped across the globe

Published in the journal Atmospheric Environment, the study analysed more than 30 years of observations collected from 171 AERONET monitoring stations spread across six continents.

Using advanced measurements of particle properties, scientists classified aerosols into seven categories: pure dust, dust-dominated mixtures, pollution-dominated mixtures, very weakly absorbing, weakly absorbing, moderately absorbing and strongly absorbing aerosols.

The analysis showed clear regional patterns. Pure dust dominates northern Africa, while Europe and North America are largely characterised by less-absorbing urban and industrial aerosols. Tropical regions affected by biomass burning are mainly dominated by strongly absorbing aerosols.

Black carbon-rich aerosols drive stronger warming

Among the seven categories, strongly absorbing aerosols, which often contain high levels of black carbon, produced the greatest atmospheric warming. These aerosols generated an average atmospheric forcing of 30.14 watts per square metre and the highest heating rates, increasing the potential to influence weather systems and cloud development. By comparison, very weakly absorbing aerosols had the lowest atmospheric forcing, reflecting more sunlight back into space and producing a much smaller warming effect. Researchers said understanding these differences is essential because aerosol composition varies significantly from one region to another, making it difficult to accurately represent their behaviour in climate models.

Findings support climate and air quality research

The study was led by Swagata Mukhopadhyay, Dr Shantikumar Singh Ningombam and Dr Umesh Chandra Dumka, with contributions from scientists at ISRO, NASA's Goddard Space Flight Center, Soka University in Japan and other research institutions. The team said the findings could improve satellite-based remote sensing, air quality monitoring and climate forecasting by helping scientists identify aerosol types more accurately. Better classification of aerosols is also expected to strengthen assessments of air pollution and its effects on human health, ecosystems and long-term climate change.