We measured (at the molecular level) the 125 organic aerosol (OA) compounds present in Chengdu in winter. OA was dominated by fatty acids, phthalate esters, and anhydrosugars, and it was deeply influenced by anthropogenic sources. As pollution worsened, secondary inorganic species and secondary organic carbon (OC) dominated the increase in PM_2.5, fatty acids and anhydrosugars dominated the increase in OA, and the contributions of secondary formation and biomass burning to OC increased markedly.

This study achieves quantifiable subgrid-scale aerosol–cloud interaction in an atmospheric chemistry system, with better performance in terms of meteorology prediction, and further finds that subgrid-scale actual aerosol can somewhat improve overestimated cumulative precipitation during a typical heavy rainfall event, which helps us better understand the impact of subgrid-scale aerosol–cloud interaction on weather forecasts.

We used 7 climate models that include atmospheric chemistry and find that in a scenario with weak controls on air quality, the warming effects (over 2015 to 2050) of decreases in ozone-depleting substances and increases in air quality pollutants are approximately equal and would make ozone the second highest contributor to warming over this period. We find that for stratospheric ozone recovery, the standard measure of climate effects underestimates a more comprehensive measure. 

Online measurements of bulk aerosol organic nitrogen (ON), in conjunction with a comprehensive array of source markers, have revealed five emission sources and five potentially significant formation processes of nitrogenous organic aerosols. This study provides a first quantitative source analysis of ON aerosol and valuable observational evidence of secondary ON aerosol formation through NH₃ and NO_x chemistries.

Using a single-column model, we investigate the effect of the vertical distribution of clouds on climate sensitivity. We show that, depending on their height, clouds can mask or unmask the radiative response of the clear-sky atmosphere. Our single-column model yields an all-sky climate sensitivity of 2.2 K, slightly less than the clear-sky value. This value can be interpreted as a baseline to which changes in surface albedo and an assumed reduction in cloud albedo would add.

We show distinct seasonal and geographical patterns in the contributions of mineral dust, marine aerosol, and terrestrial biological particles to ice-nucleating particle (INP) concentrations that lead to atmospheric ice formation, a major source of uncertainty in climate projections. Bioaerosols are the major source of INPs at high temperatures, while mineral dust influences the global INP population at lower temperatures. These particles can satisfactorily reproduce INPs in a climate model.

Following a major car industry scandal involving diesel emissions tests, the European Union (EU) introduced new testing procedures. However, concerns remained about their effectiveness. Our independent study examined real-world vehicle emissions and revealed encouraging findings: modern diesel cars perform as well as, or even better than, gasoline cars in terms of nitrogen oxide emissions. We found the same pattern for soot particles, challenging common perceptions about diesel's environmental impact.

We leverage over 2 decades of ground-based ozone observations alongside space-based observations of ozone precursors (NO₂ and formaldehyde) to study the long-term evolution in ozone chemical regimes across global source regions. We find a global trend towards NO_x-limited regimes supported by increasing satellite-based HCHO/NO₂ ratio and a diminishing ozone weekend effect.

Aerosol vertical distribution that plays a crucial role in aerosol–photolysis interaction (API) remains underrepresented in chemical models. We integrated lidar and radiosonde observations to constrain the simulated aerosol profiles over North China and quantified the photochemical responses. The increased photolysis rates in the lower layers led to increased ozone and accounted for a 36 %–56 % reduction in API effects, resulting in enhanced atmospheric oxidizing capacity and aerosol formation.

Oxymethylene ethers are a class of sustainable compounds that could be used to replace harmful organic solvents in a range of applications. In this work, we use lab-based experiments to identify the main breakdown routes of these compounds in the atmosphere. We have determined that they likely contribute less to air pollution than the compounds that they replace.

Energetic electron precipitation (EEP) from the magnetosphere into the Earth's atmosphere can significantly alter the electron density in the D-region ionosphere, impacting its reflective properties and the effectiveness of low-frequency radio wave transmission. A comprehensive understanding of the influence of EEP on the D-region ionosphere can enhance predictive models of ionospheric behavior and mitigate the impacts of space weather.

We use deposition measurements to trace the source of the radioactive isotope ¹⁰⁶Ru released into the atmosphere in 2017, which led to detections in Europe and other parts of the Northern Hemisphere. Most frequently, measurements of air concentration are used for such purposes. Our research shows that, while air concentration data can provide more precise results, deposition measurements can still effectively pinpoint the release location, offering a less costly and more versatile alternative.

The city significantly influences thunderstorm and lightning activity, yet the potential mechanisms remain largely unexplored. Our study has revealed that both city size and building density play pivotal roles in modulating thunderstorm and lightning activity. This research not only deepens our understanding of urban meteorology but also lays an important foundation for developing accurate and targeted urban thunderstorm risk prediction models.

The climate effect of contrails depends on the contrail lifetime. Thus, it is important to know what constrains the lifetime. In this paper, we characterise the two most important contrail dissolution processes via their respective timescales. Both timescales are in the order of a couple of hours, depending on the synoptic situation and the size of the contrail ice crystals. The combined timescale, which combines both processes, is the harmonic mean of the two single timescales.

Limonene, a natural compound from plants, reacts with pollutants to form airborne particles that influence air quality and climate. Using advanced models with explicit chemical mechanisms, we show how different reaction pathways shape organonitrate formation, with some increasing and others decreasing particle levels. This approach enhances predictions of pollution and climate impacts while deepening our understanding of how natural and human-made emissions interact in the atmosphere.

We reveal for the first time the global variations of PAHs and derivatives in marine air. We found that marine aerosols in East China Sea (ECS) and Western Pacific (WP) were significantly affected by coal and engine combustion, while those in Bismarck Sea (BS) and East Australian Sea (EAS) were mainly influenced by wildfire and coal combustion. The Antarctic Ocean (AO) was dominated by biomass burning and local shipping emissions. This finding helps elucidate the mechanism of the global PAH cycle.

Photochemical reactions altered the properties of kerosene-operated jet engine burner exhaust emissions, which were studied in a laboratory using an oxidation flow reactor. Particle mass increased 300-fold as particles and gases became more oxidized. Light absorption increased, but the total direct radiative forcing efficiency was estimated to have shifted from positive to negative. The results highlight the importance of considering secondary aerosol formation when assessing the impacts of aviation.

We aim to understand how tiny particles in the air, called aerosols, affect rain clouds in the Houston–Galveston area. More aerosols generally do not make these clouds grow much taller, with an average height increase of about 1 km. However, their effects on rainfall strength and cloud expansion are less certain. Clouds influenced by sea breezes show a stronger aerosol impact, possibly due to factors that are unaccounted for like vertical winds in near-surface layers.

Analysis of the interaction between the climate and ozone in the stratosphere is complicated by the inability of climate models to simulate the quasi-biennial oscillation (QBO) – an important climate mode in the stratosphere. We use a set of model simulations that realistically simulate QBO and a novel ozone diagnostic tool to separate temperature- and circulation-driven QBO impacts. These are important for diagnosing model–model differences in QBO–ozone responses for climate projections.

Black carbon, primary brown carbon and secondary brown carbon are the leading light-absorbing carbonaceous aerosols (LACs) that contribute significantly to climate change. We modified the GEOS-Chem model to simulate the climate change by LACs based on a local emission inventory and explored the impacts of LAC properties and atmospheric variables on the corresponding direct radiative forcings (DRFs) in seven regions of China. The study confirms the warming effect of LACs and deepens our knowledge of their climatic effects.

The distribution problems appear in atmospheric sciences at almost every corner when describing diverse processes. This paper presents a general formulation for addressing all these problems.

This study examines optical properties and the variability of the mass absorption coefficient of carbonaceous aerosols produced by the combustion of different fuels. Experiments, conducted in an atmospheric simulation chamber, tested different methods of sampling and analyzing carbonaceous aerosols, with a focus on workplace environments. Results highlight the need to understand the variability in aerosol optical properties for accurate monitoring and health and environmental impact assessments.

Concerns about climate change are growing due to its widespread impacts, including rising temperatures, extreme weather events, and disruptions to ecosystems. To address these challenges, urgent global action is needed to monitor the distribution of trace gases and understand their effects on the atmosphere.

This paper introduces a novel approach for improving the computational efficiency and scalability of source-oriented chemical mechanisms by simplifying the representation of reactions involving source-tagged species and implementing a source-oriented Euler backward iterative (EBI) solver. These advancements reduce simulation times by up to 74 % while maintaining accuracy, offering significant practical benefits for long-term source apportionment studies.

Our work reveals the impact of forest fires on climate. We found that fire-related particles not only absorb sunlight and warm the atmosphere, but also scatter light, which cools it. At our remote Amazonia site, most particles had different chemical makeups than direct fire emissions and were the main drivers of how much sunlight was blocked or redirected.

High-resolution airborne observations reveal that mixing between the free troposphere and surface evapotranspiration flux primarily modulates the water vapor isotopic composition in the lower troposphere. Water vapor isotope structure variations occur on the scale of hundreds of meters, underlining the utility of stable isotopes for studying microscale atmospheric dynamics. This study also provides the basis for better validation of water vapor isotope remote sensing retrievals with surface observations.

China has carried out staged low-sulfur fuel policies since 2017. This study simulated the changing spatiotemporal patterns of the impacts of ship emissions on PM_2.5 from 2017 to 2021 based on the updated emission inventories and mapping of chemical species in the CMAQ (Community Multiscale Air Quality). Fuel policies caused evident relative changes in inorganic and organic components of the shipping-related PM_2.5 over China’s port cities. The driving factors of the interannual, seasonal, and diurnal patterns were discussed.

We used an atmospheric transport model and satellite data to study CH₄ observations  in Xianghe, China. Our study shows the key source sectors that influence the concentrations and their respective importance. Furthermore, meteorological factors such as wind direction are discussed. This research highlights the challenges in accurately simulating these kinds of measurements and helps us to better understand CH₄ variability in the region.

We observed a strong increase in deseasonalized ozone at urban stations in the Tibetan Plateau from 2015 to 2019, far exceeding the trend at the baseline station Waliguan and the Tibetan Plateau average trend of four tropospheric ozone products. By combining multiple datasets and modeling approaches, we identified the main contributing factors as more frequent transport passing through the lower layers of high-emission regions and the increase in local and non-local anthropogenic emissions.

High-latitude cities like Fairbanks, Alaska, experience severe wintertime pollution episodes. While conventional wisdom holds that oxidation is slow under these conditions, field measurements find oxidized products in particles. To explore this, we measured oxidants in aqueous extracts of winter particles from Fairbanks. We find high concentrations of oxidants during illumination experiments, indicating that particle photochemistry can be significant even in high latitudes during winter.