‘Aerosols over South Asia have highest heating rates across the globe’: Study

Identifying regional variations in the distribution of aerosols across various parts of the world, researchers have found that South Asia is largely affected by dust mixed with pollution which produces the highest atmospheric heating rates.

Accurately identifying aerosol types is crucial for developing more reliable algorithms and assessing the impacts of air pollution on human health and ecosystems, besides optimising satellite-based remote sensing operations.

The researchers analysed data from 171 ground-based monitoring stations across six continents, spanning over 30 years, and classified aerosols into seven specific types to study their characteristics using advanced methods, according to information shared by the Ministry of Science and Technology.

Aerosols are tiny particles suspended in the atmosphere that play a crucial yet complex role in shaping climate. From desert dust storms to urban emissions and forest fires, these microscopic particles scatter, absorb and interact with sunlight in different ways, altering the planet’s energy balance and affecting weather, clouds and rainfall.

The seven main aerosol types that were identified include pure dust, dust-dominated mixtures, pollution-dominated mixtures, very weakly absorbing, weakly absorbing, moderately absorbing and strongly absorbing.

While pure dust aerosols dominate in northern Africa, a mixture of dust and pollution or dust-dominated mixtures are common in South Asia. Tropical regions, prone to biomass burning, are dominated by strongly absorbing aerosols which contribute the highest atmospheric forcing and heating rate. Urban and industrial regions in Europe and North America are characterised by other aerosols that have relatively lower heating rates.

These differences in aerosol composition have profound implications for the planet’s energy budget and climate, according to the researchers.

The study revealed that strongly absorbing aerosols, such as those rich in black carbon, contribute significantly to atmospheric heating, with the potential to disrupt regional weather patterns and cloud formation. In contrast, very weakly absorbing aerosols have a relatively minor impact on the atmosphere, primarily reflecting sunlight back into space and cooling the surface.

“Aerosols are a key player in the complex climate system, but their diversity and regional variations make them challenging to represent accurately,” the study states.

“By shedding light on the global distribution of aerosols and their radiative effects, the comprehensive study offers valuable insights into climate science.”

“The study offers a global, long-term perspective of aerosols that can help refine climate models and improve predictions,” the Ministry’s statement read. “The findings also have important implications for satellite-based remote sensing and air quality monitoring,” the statement added.

Experts from the Indian Institute of Astrophysics, Pondicherry University, Aryabhatta Research Institute of Observational Sciences, Indian Institute of Science Education and Research, National Atmospheric Research Laboratory, University of Maryland, USA, Soka University, Japan and NASA were involved in the study.