We refined the traditional isotopic mathematical model, originally predicated on the assumption of exhaustive sulfur dioxide oxidation, to account for the incomplete oxidation processes observed in our field campaigns. By constraining this modified framework with in-situ isotopic data, we demonstrated that conventional models, which overlook this partial oxidation, tend to significantly underestimate sulfate source contributions during the summer.

Current satellite water vapor fusion and calibration methodologies predominantly rely on high-density ground-based station networks, rendering them unsuitable for sparsely monitored regions. This study pioneers the investigation of response relationships between station distribution patterns and satellite water vapor calibration, offering crucial insights for reference station selection in water vapor fusion within sparse monitoring areas.

Carcinogenic nitrosamines are pervasive in air pollution, yet their origins remain elusive. Using Born–Oppenheimer molecular dynamics, we demonstrate that nitrosamines form rapidly at the air–water interface via the reaction of amines with dinitrogen tetroxide. This mechanism also yields nitrous acid, thereby exacerbating pollution. By identifying this critical missing source of airborne carcinogens, our work underscores the necessity of integrating interfacial chemistry into atmospheric models.

Many tiny particles are formed high in the tropical atmosphere, but their impact lower down is unclear. We studied how these particles move downward using long-term computer simulations. We found that particles can reach middle levels of the atmosphere within a week, carried by winds. These results help us understand how pollution and clouds might change as particles spread around the world.

Our manuscript presents a six-year, high-resolution inversion of European methane emissions using the Community Inversion Framework and FLEXPART. Leveraging an expanded in situ network, we reconcile inventories with observations, reveal regional biases, refine European methane budgets, and highlight the dominance of agricultural emissions. Results provide policy-relevant insights for mitigation and inventory verification.

Mineral dust can initiate ice formation in clouds, affecting cloud properties and regional climate. Using an improved model, we examined their contrasting impacts in mixed-phase and ice clouds over East Asia. In mixed-phase clouds, dust promotes liquid-to-ice conversion and reduces cloud reflectivity, causing moderate warming, whereas in ice clouds, it greatly enhances ice formation and leads to stronger warming. This study advances understanding of aerosol–cloud–climate interactions.

Marine atmospheric aerosols remain a major uncertainty in climate models. We report gas and particle phase measurements of two important aerosol forming vapours, sulfuric acid and methanesulfonic acid in the Indo-Pacific. We find that the latter typically dominates over sulfuric acid and contributes significantly to free tropospheric aerosol. Deep convection transports the precursor of both acids to the upper troposphere, providing a key aerosol source in the pristine remote Pacific Ocean.

We studied four major dust events from the Sahara and the Middle East over the Mediterranean. Saharan dust events exhibited coarser and more scattering particles, while Middle Eastern dust was finer and mixed with pollution. Differences in absorption could not be explained by mineralogy and are attributed to mixing.

Tropical cyclones forming in the southwest Indian Ocean frequently affect mountainous island nations. However, their role in modulating rainfall has not yet been thoroughly investigated. Using both observational data and a high-resolution numerical model, we aim to improve our understanding of the orographic effects of Madagascar and Réunion Island on approaching tropical cyclone (TC) track, intensity, and, ultimately, heavy rainfall using a representative case: TC Batsirai (2022).

This is a closure and polarimetric study using a variety of airborne observations to disentangle hydrometeor microphysical properties and their vertical distribution. This work paves a concrete step in assuring timely delivery of high-quality science products for several future sub-mm radiometer missions as well as possibilities of new science products beyond the mission requirements.

We studied how sulfur dioxide in air becomes sulfuric acid through a chemical route that has often been underestimated. By updating reaction data, running chemistry simulations, and using an explainable machine-learning framework, we found that this pathway makes a meaningful contribution and changes how sulfuric acid responds to changes in air pollutants. These findings suggest that reducing emissions of alkene-related organic gases may help limit sulfuric acid formation and particle pollution.

Ice-nucleating particles (INP) are aerosol particles important for ice formation in clouds droplets and thereby influence climate. This study uses airborne measurements over Europe to show how INP are transported through thunderstorms. We show which particles are washed out and which are are transported into the higher troposphere, where they can again affect cloud ice formation. The findings improve understanding of atmospheric particle distribution and help refine climate models.

This study examined biogenic volatile organic compounds in a suburban Tokyo forest using tower and supplemental drone measurements. Isoprene showed clear seasonal and vertical variations, while drone observations indicated spatial heterogeneity. Comparison with the Model of Emissions of Gases and Aerosols from Nature showed that site-specific parameter refinement is needed.

This study presents a cellular automaton (CA) model of tropical oceanic rain clusters based on atmospheric stability and gravity-wave interactions. The model reproduces power-law distributions for cluster area and rain rate, exhibiting criticality similar to 2D percolation. The scaling exponent for cluster area is robust to model parameters and matches simulations over the Indian Ocean and Atlantic, although it differs from some observational estimates, suggesting further model tuning is needed.

Fog is a vital water source in the Namib Desert, but its year-to-year variability is poorly understood. Using satellite observations and reanalysis data, we show that fog and low-cloud variability is closely tied to sea surface temperatures in the Benguela upwelling system. Warm events driven by tropical water intrusions are followed by reduced fog in the northern Namib, indicating that ocean state carries predictive information for fog in this hyper-arid ecosystem.

Using satellite radiation observations and a surface energy framework, we show that recent cloud changes weakly affect global mean warming but strongly modulate regional warming, enhancing warming in low- and mid-latitudes while mitigating it in polar regions. This effect is driven by changes from low- and mid-level clouds to high-level thin clouds, reducing planetary albedo and weakening longwave emission, with distinct controls in the two hemispheres.

Mineral dust emissions are simulated for the first time from proglacial valleys of the St. Elias Mountains (western Canada/Alaska) to elucidate their contributions to regional climate forcing and global mineral dust loading. We implement a regional-scale dust emission model and evaluate simulated meteorology, dust emissions, and boundary layer processes for a holistic evaluation of how well aerosol dispersion can be simulated within this remote, mountainous landscape. 

This study focuses on improving models that simulate how mineral dust is emitted and transported in the atmosphere. We created two new, more detailed maps of soils and terrain to better represent where dust is generated. As a case study, we use dust events coming from North Africa affecting the Iberian Peninsula. Results show that the improved data helps the model match observed air pollution better, especially during dust episodes in inland areas.

This study provides the first field evidence of the impact of downward transport of residual layer pollutants on planetary boundary layer pollution, which holds significant implications for pollution control in complex terrain regions.

Liquid-containing Arctic clouds have a strong influence on surface temperature and sea ice extent in winter, but how weather conditions impact cloud cover remains a mystery. This study uses observations from northern Alaska to investigate this relationship. We find that, contrary to expectations, the amount of cloud liquid is remarkably insensitive to temperature, moisture, wind direction, and the large-scale atmospheric flow.

Nitrogen dioxide can react on wet surfaces, producing pollutants that affect air quality. To understand why this process is stronger in coastal regions, we conducted field measurements in a Chinese coastal city during sea–land breeze periods. We found that chloride from sea salt greatly enhances nitrogen dioxide uptake, increasing the formation of nitrous acid and nitrate. This highlights a key role of chlorine in coastal air pollution and improves predictions of nighttime atmospheric chemistry.

Cities are particularly vulnerable to heat-waves because of their dense population combined with an amplification of the heat hazard caused by the urban heat island phenomenon. Heat event are sometimes associated with aerosol plume in the atmosphere, which affect the thermal comfort. This study shows that aerosol plumes can result in a heat stress reduction of up to 1 °C in sunny areas in cities while no difference in the shade of suburban areas.

An assessment of the potential impacts of Stratospheric Aerosol Injection, a proposed method to offset global warming, on stratospheric ozone projections over the 21^st century using the new multi-model GeoMIP (Geoengineering Model Intercomparison Project) G6-1.5K-SAI (Stratospheric Aerosol Injection) experiment. We discuss drivers of the responses, identify areas of model agreement and disagreement and sources of uncertainty. Our results highlight the need to assess any projected SAI impacts in wider strategy and scenario dimension using a multi-model framework.

Most atmospheric models only use 1D radiation, neglecting any 3D radiative effects. Here, we show that the dynamic TenStream solver provides a computationally efficient way to represent these effects. Like full 3D radiation, it causes daytime clouds to organize into streets, grow larger, and contain more liquid water. We show that this occurs because 3D radiation does not shade cloud updrafts and modifies the surface energy balance, resulting in an increased latent heat flux into the atmosphere.

Cooking fumes change in the air. Fresh emissions rapidly form tiny particles; within half a day, reactions create medium-sized secondary particles that linger and can be inhaled. The study maps gas-particle partitioning, showing most secondary products reach equilibrium quickly, while some early and large molecules are limited by surface processes. These insights help improve air quality models and strategies to reduce exposure risks from cooking emissions in cities and indoors.

Source identification of atmospheric aerosols is crucial for understanding their properties and resulting environmental impacts. By mass spectrometry for aerosol samples, organic aerosols in a European boreal forest were apportioned to five source-related types based on chemical structure, highlighting the importance of biomass-originated organics. Polarity-based fractionation advanced source apportionment, which is expected to improve the capability of property analysis for organic aerosols.

Fog modelling remains a significant challenge due to the complex, interrelated physical processes involved, including microphysics. We evaluated the ability of an advanced microphysical scheme to reproduce the fog life cycle by comparing it with new vertical microphysical observations obtained using a tethered balloon during an extensive field campaign. Although realistic modelling performance was achieved, some biases remain that require further microphysics observations.

New particle formation is thought to be unlikely in the remote marine boundary layer. Using a process-based atmospheric model, we show that new particle formation can occur under various meteorological and hydrological conditions from DMS-derived H₂SO₄ and natural emissions of NH₃. The particles are able to grow into the cloud condensation nuclei size range, with the potential to affect clouds and climate.

We investigated the physical characteristics (sizes, shapes, and composition) of mineral dust particles preserved in a Peruvian ice core to gain insights into what has been deposited since 1960. We show that the dust originates from a mix of local and distal source areas and note that the information reported in our study has important implications for reconstructing dust emissions and circulation patterns, as well as for estimating the dust’s radiative impacts.

Reducing methane emissions offers a near-term climate mitigation opportunity. Cities contain large and often underestimated methane sources. In New York City, methane emissions peak during heating and cooling seasons, with natural gas as a dominant source. Emissions track gas consumption and show significant incomplete combustion signatures. We estimate a 1.7 % loss rate, ~300M USD/year in wasted gas, highlighting mechanisms of inefficient natural gas combustion as a future mitigation focus.

Indonesian peatlands store vast carbon reserves, but can release large quantities of greenhouse gases and other species with significant environmental impacts, including hydrogen cyanide (HCN), when fires occur. Analyzing three major El Niño years with satellites and models, we found that emissions depend on local hydrological conditions, not just El Niño strength. Including soil moisture and burn depth can improve emission estimates and climate strategies.

Targeting a huge transatlantic smoke transport from the western US to Europe in September 2020, a smoke dataset was constructed based on Aeolus observations, in synergy with multi-platform data. The selected cross-sections show the vertical structure of the smoke layers at different transport stages. Statistical analyses of the complete dataset reveal the evolution of the smoke plume throughout its transport.

Biomass burning emits large amounts of pollutants that undergo atmospheric transformation. This study examined organic vapor emissions from three biomass fuels and their transformation under different oxidation regimes in a smog chamber by real-time mass spectrometry. OH-driven oxidation rapidly altered organic vapor composition than dark oxidation, eliminating differences in chemical vapor composition arising from fuel types or combustion conditions.