Atmospheric Aerosols

Atmospheric aerosols are suspensions of solid and liquid particles ranging from a few nanometres to tens of micrometres in diameter. They originate from natural sources—such as sea‐spray, dust storms, volcanic eruptions and biogenic emissions—and from human activities including fossil‐fuel combustion, biomass burning and industrial processes. Once airborne, primary particles can undergo chemical transformation and coagulation, giving rise to secondary aerosols that alter their size, composition and optical properties. Aerosols influence climate through direct interactions with solar and terrestrial radiation and indirectly by modifying cloud microphysics and precipitation. They also affect air quality and human health by penetrating deep into the respiratory tract and catalysing oxidative stress. The spatial and temporal distribution of aerosols is governed by emission patterns, meteorological transport, atmospheric chemistry and removal by wet and dry deposition. Because of their heterogeneous nature and complex feedbacks, aerosols remain a leading source of uncertainty in climate predictions and an urgent focus for air‐quality management.

Research from Nature Portfolio

Observational and modelling work in China has documented a substantial nationwide decrease in organic aerosol concentrations from 2013 to 2020. The decline in primary organic aerosol emissions, driven largely by reductions in residential fuel burning, outpaced that of secondary organic aerosol, while changes in nitrogen oxides and sulphur dioxide emissions had contrasting effects on secondary formation. This study highlights the interplay between policy measures, precursor emissions and meteorological variability in shaping fine‐particle levels.

In the high Arctic, blowing snow events have been found to generate unexpectedly high concentrations of fine sea‐salt aerosol. Sublimation of lofted snow produces particles smaller than 300 nm that can increase cloud condensation nuclei concentrations by up to tenfold under winter and spring conditions. Model estimates suggest that sea‐salt from blowing snow accounts for over a quarter of particle number north of 70° N, with important implications for cloud radiative properties and surface warming.

Aircraft campaigns over the Arctic have revealed that atmospheric black carbon concentrations in spring are up to four times higher than in summer. Vertically resolved measurements show strong seasonal and inter‐annual variability that current global models fail to reproduce. These results underscore the need for improved representation of seasonal transport pathways and wet‐deposition processes in polar climate simulations.

Atmospheric Aerosols publication trend

The graph below shows the total number of articles in atmospheric aerosols across all publications each year (not limited to Nature Index journals).

Technical terms

Primary aerosol: Particle emitted directly into the atmosphere from sources such as combustion or wind‐blown dust.

Secondary organic aerosol (SOA): Particulate matter formed in the atmosphere by oxidation of volatile organic compounds.

Mass absorption cross‐section (MAC): The efficiency with which a unit mass of aerosol absorbs light at a given wavelength.

Cloud condensation nucleus (CCN): A particle on which water vapour condenses to form cloud droplets under supersaturated conditions.

Oxidation flow reactor: Laboratory apparatus that accelerates atmospheric oxidation processes to simulate aerosol ageing under controlled conditions.

References

1. Widespread 2013-2020 decreases and reduction challenges of organic aerosol in China. Nature Communications (2024).
2. Arctic warming by abundant fine sea salt aerosols from blowing snow. Nature Geoscience (2023).
3. Atmospheric concentrations of black carbon are substantially higher in spring than summer in the Arctic. Communications Earth & Environment (2023).
4. Marked impacts of transient conditions on potential secondary organic aerosol production during rapid oxidation of gasoline exhausts. npj Climate and Atmospheric Science (2023).
5. Rapid transformation of wildfire emissions to harmful background aerosol. npj Climate and Atmospheric Science (2023).