Beijing's ozone trends (2013–2023) show a lengthening Ozone Season despite strict emission controls. While low-percentile ozone levels rose, mean and high-percentile values remained stable. Key shifts include a later daily exposure window, flattened diurnal cycles (lower peaks, higher troughs), and reduced ozone production/loss rates. These findings establish a baseline for urban pollution evolution and provide critical insights for future policy formulation and public health protection.

Aerosol-cloud interactions and ice formation processes are key to modelling mixed-phase clouds in cold-air outbreaks. However, no studies have investigated the joint effects of these processes. Here, we used perturbed parameter ensembles and model emulators to show that these processes have strongly interacting effects on the properties of cold air outbreak clouds. Single sensitivity tests may therefore provide incomplete information about cloud-controlling factors.

Soil reactive nitrogen (Nr) gas emissions from the Tibetan Plateau remain poorly quantified, especially nitrous acid (HONO) and nitrogen oxides (NO_x). We find soil HONO and NO_x emissions are substantial across different land use types, with annual emissions of 7.0 ± 3.4 and 20.3 ± 7.0 Gg N yr⁻¹, respectively. Soil HONO emissions contribute approximately 10.5 % of the external daytime atmospheric HONO sources and modulate the regional atmospheric chemical balance by elevating the HONO/NO_x ratio.

We investigated how plants, pollution and weather shape air quality at a forested mountain in southeastern China, with frequent clouds. We measured compounds formed as plant and human emissions react in the atmosphere. Warm conditions favored plant emissions, while cooler periods increased the influence of pollution transported from other regions. Clouds both removed some compounds and changed others through chemical reactions, showing how weather and clouds shape air quality in mountains.

Reactive oxygen species (ROS) produced by airborne particles are linked to adverse health effects, but the organic compounds responsible remain unclear. We developed a new molecular framework to classify complex organic compounds using advanced mass spectrometry. The framework shows that particles rich in oxidized organic compounds produce more ROS per unit mass, while polluted urban air produces more total ROS mainly because of higher particle concentrations.

To understand how air pollution affects climate, we must know where different particles reside in the sky. We combined satellite lidar measurements of specific particle types with a numerical model to build a three-dimensional map of pollution over East Asia. Our method successfully located hidden layers of heat-absorbing soot high in the atmosphere that previous models missed. This greatly improves our ability to calculate how these particles trap sunlight and alter regional temperatures.

Transport model errors represent a major source of uncertainty in greenhouse gas flux estimates derived from inverse modelling, yet they remain challenging to quantify. In our study, we leverage the similarities in the atmospheric transport of methane (CH₄) and radon (²²²Rn) by performing a dual-tracer CH₄-²²²Rn inversion over Europe, with the goal of enhancing the reliability of CH₄ flux estimates. We discuss the benefits and limitations of this dual-tracer approach.

We studied how well idealised models of the nighttime boundary layer capture observed variability above the Amazon rainforest, using observations from the CloudRoots-Amazon22 campaign. The observations indicate large nocturnal variability, caused by non-stationary processes and interactions between the within- and above-canopy atmosphere. Common weather and climate models often miss this variability, highlighting the need to represent the complex forest-atmosphere interactions better.   

Aromatics compounds emitted in the atmosphere, such as benzene and phenol, contribute to the formation of organic aerosols. This study presents and evaluates an updated description of benzene chemistry, in which the most influential pathways are identified, including one developed in this work. The resulting mechanism reproduces laboratory observation with great accuracy and is reduced for use in large-scale air quality models.

We introduce a new thermodynamic framework to derive water vapor supersaturation at warm cumulus cloud base from in situ measurements. The framework describes the local transition between saturated thermodynamic states as an adiabatic and reversible process under quasi-isobaric conditions, in which the latent energy released during condensation is partitioned between changes in internal energy and water-vapor expansion work.

This study establishes a unified framework to assess the consistency of DQ-1 (Da Qi-1) ACDL (Aerosol and Carbon Dioxide Lidar) XCO₂ with passive satellite products while considering sampling and column-definition differences. DQ-1 agrees well with TCCON (Total Carbon Column Observing Network) and shows consistent spatial patterns with OCO-2, OCO-3 (Orbiting Carbon Observatory), GOSAT, and GOSAT-2 (Greenhouse gases Observing SATellite) over selected regions. It provides complementary XCO₂ observations where passive measurements are limited, including nighttime and high latitudes, supporting future joint carbon monitoring and inversion studies.

The study investigates vehicle fleet emissions of road traffic. Despite technological advances, road traffic is still an important pollution source in urban areas, especially when considering unregulated, but health-relevant, emerging pollutants. We report fuel consumption normalized vehicle fleet emission factors for various regulated and unregulated air pollutants. Also, we show that road traffic has inverse and indirect effects on urban aerosol which are not generally well understood.

Arctic low level mixed-phase clouds were analysed from 14 years of wintertime observations from the North Slope of Alaska. We found that Arctic cloud physical properties are in correlation with changes in upwind sea ice. The cloud liquid and ice water content increases as sea ice decreases, although not at the same magnitude. Moreover, we uncovered that cloud properties have oscillation properties along the years that resemble climate indicators like El Niño Southern Oscillation among others.

Brown carbon (BrC) aerosols absorb solar shortwave radiation and affect the environment and climate. Using a chemical transport model, we investigated the sources and long-term trends of primary BrC in China. Residential and industrial emissions dominate primary BrC in China, unlike the global pattern. Anthropogenic BrC accounts for most of the direct radiative effects and responds significantly to emission changes, indicating potential climate benefits of emission control measures.

Salt particles from the ocean can help marine clouds precipitate more quickly, but their role is not fully understood. Using aircraft observations over the northwest Atlantic Ocean and computer simulations, we studied how these particles affect warm rain formation. We found that clouds containing more large sea salt particles, even at relatively low amounts, produce more rain. These results improve understanding of how sea salt aerosols influence clouds, rainfall, and climate.

We present simultaneous observations of a planetary 26-day wave in mesospheric temperature observed by three different ground-based mid-latitude OH spectrometers at stations in Germany in boreal winter 2016/2017. With supporting information from satellite measurements the event can be linked to a Rossby wave (1,4) mode. The periodic changes are also seen in other atmospheric parameters such as atomic oxygen further illustrating the importance of such events for the atmospheric state.

Particle formation events affect climate and air quality. Using measurements of particle number concentrations down to very small particles (~3 nm) in polluted northern India, we show that these events occur frequently in summer under reduced background particle load. However, in this environment, emissions and changing air masses can mask or distort these events, making them difficult to detect. Such environments require adaptation of standard analytical methods used in cleaner regions.

The Atlantic overturning circulation carries heat northward and may weaken with climate change. We show that this can redistribute natural aerosols, especially Saharan dust, altering clouds and producing strong regional effects over the North Atlantic. Globally, cloud changes largely cancel out, leaving a small warming effect, whereas increased sea ice, snow, and dust produce an overall cooling.

The net land-atmosphere exchange of carbon monoxide remains highly uncertain due to the scarcity of long-term monitoring. This study analyses a 10-year-long data series from a tall-tower eddy covariance system. The flux footprint of this system covers a heterogeneous landscape. Vegetation-dominated areas acted as a weak net source. Solar radiation was identified as the primary driver of the emissions. Emissions from the populated areas significantly exceeded the activity-based estimations.

This study estimates methane emissions across Europe from 2019 to 2023 using atmospheric methane measurements from satellites and ground stations to improve understanding of emission sources. We find that total emissions are slightly higher than official reports, mainly due to livestock and waste, while emissions from fossil fuel production are lower in some regions. These results show that atmospheric measurements can improve independent verification of emissions and support climate policy.

We identified and quantified low-visibility events over land and sea in eastern China using satellite, weather and pollution data. Our model distinguishes polluted fog from clean fog. Model tests show that a 20% cut in fine particle pollution reduces winter polluted fog area by 43%, but population exposure by only 15%, as the most polluted areas are also densely populated. These findings guide air-quality policies to improve visibility, protect health and support transport safety.

In this paper, we use satellite observations to study the relationships between profiles of clouds and profiles of wind from June to October 2020 around India. We show that the wind can be modified by 3 m s^-1 because of the presence of deep convective clouds that spread out between 14 and 17 km of altitude. We also found that cirrus clouds between 14 and 17 km are more frequent over the Arabian Sea because of fast westward winds. 

This study examines whether aerosol impacts on extreme rainfall shift in a warmer world. Using a climate model, we compare identical Asian SO4 forcing under  pre-industrial and 1 K warmer climates. Aerosols reduce extreme rainfall in both, but more strongly over northern India in the warmer climate. A warmer, stabler atmosphere weakens circulation that partly offsets aerosol drying in pre-industrial conditions. Continued warming may strengthen this drying over parts of Asia.

Coordinated ground-based and airborne measurements in Paris revealed urban-to-downwind aerosol differences over transport times of 2–6 h. Downwind organic aerosol was more oxidized, and aerosols exhibited higher single-scattering albedo, higher real and lower imaginary refractive indices, and stronger wavelength dependence of absorption. These findings highlight the need to represent evolving aerosol properties in atmospheric models and remote-sensing retrievals.

Ice formation by dust is an important way of forming mixed-phase clouds. Tengger desert dust exhibited an efficient ice nucleation ability, which have influenced by feldspar. Internal mixing with ammonium sulfate significantly enhanced immersion freezing ability of dust, associating with interactions between ammonium ion and dust surface. These results underscore the importance of mineral composition and aging processes on atmospheric ice formation by dust.

Fireworks release metal-rich particles that affect air quality. We tracked barium from fireworks in Guangzhou, China. Barium levels rose up to 1000 times above background, with the highest peaks at a suburban site where fireworks were restricted. Single-particle measurements showed that barium particles rich in chloride transformed into nitrate-rich particles within hours and mixed with other mineral particles. This means firework particles continue to change after they are released.

We use a size-resolved aerosol-cloud model to analyze the effects of aerosol size and hygroscopicity in modulating marine liquid-phase cloud responses under the winter monsoon. Our findings highlight the environmental dependence of the impacts of aerosol physicochemical properties on aerosol-cloud interactions, their pronounced effects under specific conditions, and the relative contributions of aerosol size and hygroscopicity.

Carbon monoxide pollution is difficult to track across Central Asia, where monitoring is limited. We used satellite observations and weather data to estimate emissions from 2019 to 2024 and assessed how uncertainty in the observations influenced the results. Average emissions fell by 37.9%, while the strength of major pollution hotspots declined by 40.8%. The study also identified emissions linked to persistent coal fires and changing industries, helping improve pollution records and monitoring.

Fairbanks, Alaska experiences episodes of high concentrations of PM_2.5 pollution in the wintertime. The sources and mixing ratios of gas-phase pollution, and the extent to which it affects the formation of PM_2.5, are not well understood. Here, we examine the sources of gas-phase species measured in wintertime Fairbanks. We compare these results with other PM_2.5 measurements to determine how various sources can affect the formation of PM_2.5 pollution.

The Tibetan Plateau has little available moisture and energy, so convection is hard to develop. Large-eddy simulations indicates the lake promotes low-level moistening and lowers the barrier to convective initiation, produces shallow clouds and week rain. Mountain alone force lifting, yet the lack of moisture limits terrain-driven precipitation. Lake-mountain coupling is key: the mountain lifts lake-supplied moisture but also block low-level moisture transport, reshaping precipitation patterns. 

We analyzed observations from the ARM (Atmospheric Radiation Measurement) EPCAPE (Eastern Pacific Cloud Aerosol Precipitation Experiment) campaign at coastal California, and satellite cloud properties to understand how large-scale weather patterns influence marine low clouds and aerosols. Using ERA5 data and Self-Organizing Maps, we identified nine synoptic regimes linked to cloud cover, depth, and liquid water path. Satellite data show anticyclone position strongly affects cloud properties, while aerosol–cloud covariability depends on turbulence and supersaturation.

Evaluation of satellite greenhouse gas data is crucial for climate monitoring and mitigation. We assessed four XCO₂ Proxy XCH₄ results using Hefei and Xianghe Total Carbon Column Observing Network (TCCON) sites in China. We found that the accuracy of retrieval products varies between both sites. Fundamental assumption of Proxy method leaves uncertainties. Independent XCO₂ proxy comparison with TCCON data show discrepancies requiring continuous evaluation for proper determination of XCH₄.

This study explored how ammonia reacts with secondary organic aerosols over northern China using model simulations constrained by observational data. The reaction had little effect on overall fine particle pollution but  may provide an additional source of nitrogen-containing organic particles, improving understanding of atmospheric pollution formation and chemical processes in air quality models.

Coastal waters receive nitrogen from the air, but its chemical forms are poorly understood. We sampled airborne particles during a cruise in the Guangdong–Hong Kong–Macau Greater Bay Area and at an urban site in Hong Kong. Nitrogen chemistry differed between urban and marine air, and carbon-containing nitrogen declined offshore. Fine particles supplied nitrogen to coastal waters, highlighting the need to consider its chemical form when assessing nutrient inputs and potential ecosystem effects.

Surface ozone pollution in China keeps rising despite cleaner primary emissions. We used national observations from 2015 to 2024 and machine learning to separate weather effects from longer-term changes. Ozone increased in both warm and cold seasons, and recent unfavorable weather further worsened pollution, suggesting that future control plans should consider seasonal and regional differences.