Aerosol Chemistry and Climate Impacts

Aerosols are minute particles or liquid droplets suspended in the atmosphere, arising from both natural processes and human activities. Primary aerosols originate directly from sources such as sea spray, dust storms, wildfires and combustion, while secondary aerosols form in the atmosphere through gas‐to‐particle conversion, driven by photochemical oxidation of volatile organic compounds and sulphur precursors. Once present, aerosols undergo dynamic ageing processes, including coagulation, condensation, heterogeneous chemistry and dry or wet deposition. Through interactions with incoming and outgoing radiation (the direct effect) and with cloud microphysics (the indirect effect), aerosols exert a net influence on Earth’s radiative balance. They can scatter and absorb sunlight, alter cloud droplet number and lifetime, and affect precipitation efficiency. The magnitude and sign of these effects remain among the largest uncertainties in climate projections, owing to complex feedbacks involving cloud albedo, atmospheric stability and regional aerosol distributions. Beyond radiative impacts, aerosols play roles in atmospheric chemistry by providing surfaces for heterogeneous reactions, influencing ozone formation and modifying air quality. Understanding aerosol life cycles and their climate forcing is therefore crucial for accurate simulation of past, present and future climate change, as well as for informing mitigation and adaptation strategies.

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Aerosol Chemistry and Climate Impacts publication trend

The graph below shows the total number of articles in aerosol chemistry and climate impacts across all publications each year (not limited to Nature Index journals).

Technical terms

Aerosol radiative forcing: The change in Earth’s energy balance at the top of the atmosphere due to aerosol–radiation interactions, excluding climate feedbacks.

Secondary organic aerosol (SOA): Particulate matter formed from the atmospheric oxidation of volatile organic compounds, often semi-volatile and contributing significantly to fine particulate mass.

Volatility Basis Set (VBS): A framework that represents organic vapours across discrete volatility bins to simulate gas–particle partitioning and chemical ageing of organic aerosols.

Cloud condensation nuclei (CCN): Aerosol particles capable of acting as embryos for cloud droplet formation under supersaturated conditions.

References

1. Identifying climate model structural inconsistencies allows for tight constraint of aerosol radiative forcing. Atmospheric Chemistry and Physics (2023).
2. Advecting Superspecies: Efficiently Modeling Transport of Organic Aerosol With a Mass‐Conserving Dimensionality Reduction Method. Journal of Advances in Modeling Earth Systems (2023).