Atmospheric Composition, Chemistry and Processes

The Earth’s atmosphere is a dynamic blend of uniform gases—primarily N₂ and O₂—and variable constituents including water vapour, CO₂, CH₄ and trace species such as O₃. These components undergo a web of photochemical and radical-mediated reactions that shape air quality, climate forcing and pollutant lifetimes. Gas-phase kinetics govern the oxidation of volatile organics, with rate coefficients and branching ratios determining product yields and atmospheric lifetimes. Aerosol formation arises from the condensation of low-volatility vapours and multiphase interactions, providing cloud condensation nuclei and influencing radiative balance through direct scattering and indirect cloud effects. Sources and sinks span natural emissions (wetlands, soils, vegetation) and anthropogenic activities (combustion, industrial processes), while transport and deposition processes distribute species on regional to global scales. Photolytic processes in the stratosphere and troposphere control the ozone budget, with stratosphere–troposphere exchange intermittently injecting ozone into the lower layers. Advances in quantum chemistry, structure–activity relationships and remote-sensing inversions have markedly improved our capacity to simulate and observe these chemical processes, underpinning efforts to predict air quality and climate feedbacks.

Research from Nature Portfolio

High-level quantum-chemical studies have elucidated the thermochemistry and kinetics of oxygenated organics such as 2-methoxyethanol, mapping unimolecular decomposition channels and bimolecular oxidation pathways by hydroxyl and methyl radicals. These works provide detailed Arrhenius parameters and branching ratios that enhance mechanism construction in atmospheric models. Satellite-based inversions of methane columns at sub-50 km resolution have revealed that emissions from fossil-fuel exploitation are under-reported by up to 30 % in major producing regions, leading to revised national inventories that constrain global methane budgets. Process-based wetland modelling driven by climatic and hydrological data shows an accelerating response of natural methane emissions to recent warming. Ensemble results indicate that wetland CH₄ fluxes have intensified over the past two decades more rapidly than previously recognised, highlighting an emergent positive feedback on atmospheric composition.

Atmospheric Composition, Chemistry and Processes publication trend

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

Technical terms

Rate coefficient: A parameter quantifying the speed of a chemical reaction per unit concentration and time.

Branching ratio: The fraction of reactant consumed via a specific reaction pathway among multiple competing channels.

Hydroxyl radical (•OH): A highly reactive oxidant that initiates the degradation of many trace gases in the troposphere.

Inverse modelling: A top-down approach that infers emissions by optimising agreement between atmospheric observations and transport simulations.

Structure–activity relationship: A semi-empirical framework linking molecular structural features to kinetic parameters such as rate coefficients.

References

1. Thermochemistry and Kinetics of the Thermal Degradation of 2-Methoxyethanol as Possible Biofuel Additives. Scientific Reports (2019).
2. Computational Studies on the Thermodynamic and Kinetic Parameters of Oxidation of 2-Methoxyethanol Biofuel via H-Atom Abstraction by Methyl Radical. Scientific Reports (2019).
3. Recent intensification of wetland methane feedback. Nature Climate Change (2023).
4. National quantifications of methane emissions from fuel exploitation using high resolution inversions of satellite observations. Nature Communications (2023).
5. Database for the kinetics of the gas-phase atmospheric reactions of organic compounds. Earth System Science Data (2020).
6. Evaluated kinetic and photochemical data for atmospheric chemistry: volume VIII – gas-phase reactions of organic species with four, or more, carbon atoms (≥ C4). Atmospheric Chemistry and Physics (2021).
7. Estimation of rate coefficients and branching ratios for gas-phase reactions of OH with aliphatic organic compounds for use in automated mechanism construction. Atmospheric Chemistry and Physics (2018).