Heterogeneous Chemistry of Atmospheric Mineral Aerosols

The heterogeneous chemistry of atmospheric mineral aerosols encompasses the suite of reactions that occur when gas-phase species interact with solid dust particles suspended in the troposphere. These interactions alter both the composition and reactivity of the atmosphere by converting trace gases into particulate products, modifying aerosol surface properties and influencing key processes such as cloud formation and light scattering. Mineral dust surfaces provide reactive sites for uptake and transformation of oxidants (for example OH, NO3 and O3), acid gases (SO2, HNO3) and organic vapours, often mediated by surface coatings or adsorbed water films. The balance between reactive uptake and desorption governs the atmospheric lifetime of many trace constituents, thereby affecting air quality, human health and climate forcing. Humidity, particle mineralogy and surface morphology exert pronounced control on reaction pathways, while the resultant secondary inorganic aerosols contribute directly to particulate matter loadings and indirectly to tropospheric oxidation capacity. Recent insights from laboratory kinetics, field observations and numerical modelling have sharpened our understanding of these multiphase processes, revealing their global significance and guiding strategies for emission control and climate mitigation.

Research from Nature Portfolio

Recent modelling studies have incorporated heterogeneous reactions of SO₂ on dust surfaces into regional air-quality frameworks, leading to improved simulations of secondary inorganic aerosol distributions. These analyses demonstrate that dust particles act as catalytic surfaces for sulphate formation under high humidity, strongly modulating particulate pollution during haze events and underscoring the need to address dust emissions in policy measures. Complementary experimental work has examined the uptake of SO₂ on different manganese oxide crystallographies, revealing that both particle morphology and relative humidity exert a decisive influence on the rate of heterogeneous oxidation to sulphate. This transition-metal-mediated pathway is shown to be most efficient at intermediate humidities, highlighting an under-appreciated mechanism for acid formation in mineral-rich atmospheres.

Heterogeneous Chemistry of Atmospheric Mineral Aerosols publication trend

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

Technical terms

Heterogeneous chemistry: Reactions occurring between gas-phase species and the surfaces of solid or liquid aerosol particles.

Uptake coefficient: A dimensionless parameter representing the probability that a gas molecule colliding with a particle surface will be taken up by that surface.

Secondary inorganic aerosols (SIA): Fine particulate matter composed primarily of inorganic ions, such as sulphate, nitrate and ammonium, formed through gas-to-particle conversion.

Mineral dust aerosol: Airborne particles derived from soil and rock erosion, rich in minerals such as silicates, oxides and carbonates.

Tropospheric oxidation capacity: The ability of the lower atmosphere to remove pollutants through reactions driven by oxidants such as hydroxyl radicals.

References

1. Modeling analysis of secondary inorganic aerosols over China: pollution characteristics, and meteorological and dust impacts. Scientific Reports (2016).
2. Heterogeneous Reaction of SO2 on Manganese Oxides: the Effect of Crystal Structure and Relative Humidity. Scientific Reports (2017).
3. Heterogeneous reactions of mineral dust aerosol: implications for tropospheric oxidation capacity. Atmospheric Chemistry and Physics (2017).
4. Impact of mineral dust on nitrate, sulfate, and ozone in transpacific Asian pollution plumes. Atmospheric Chemistry and Physics (2010).
5. The effects of nitrate on the heterogeneous uptake of sulfur dioxide on hematite. Atmospheric Chemistry and Physics (2014).