Understanding long-term organic aerosol (OA) trends and their driving factors is important for air quality management. Our modeling revealed that OA in China increased by 5.6 % from 1990 to 2019, primarily due to a 32.3 % increase in secondary organic aerosols (SOAs) and an 8.1 % decrease in primary organic aerosols (POAs), both largely driven by changes in anthropogenic emissions. Biogenic SOA increased due to warming but showed little response to changes in anthropogenic nitrogen oxide emissions.

Using a one-dimensional radiative–convective equilibrium model, we show that in clear-sky conditions, stratospheric sulfate aerosol forcing weakens with increasing surface temperature while CO₂ forcing varies much less. This effect arises as sulfate aerosol, unlike CO₂, absorbs mainly at wavelengths where the atmosphere is optically thin. It thereby masks the surface emission, which increases with warming. The spectral masking also results in weaker radiative feedback when aerosol is present.

Our study explores how certain aerosols, like sea salt, affect infrared heat radiation in the Arctic, potentially speeding up warming. We used advanced technology to measure aerosol composition and found that these particles grow with humidity, significantly increasing their heat-trapping effect in the infrared region, especially in winter. Our findings suggest these aerosols could be a key factor in Arctic warming, emphasizing the importance of understanding aerosols for climate prediction.

This study reports an observation of organic nitrate (including total peroxy nitrates and total alkyl nitrates) in Shanghai, China, during the summer of 2021, by homemade thermal dissociation cavity-enhanced absorption spectroscopy (TD-CEAS; Atmos. Meas. Tech., 14, 4033–4051, 2021). The distribution of organic nitrates and their effects on local ozone production are analyzed based on field observations in conjunction with model simulations.

Aerosol acidity is an important parameter in atmospheric chemistry, while its driving factors, especially chemical profiles versus meteorological conditions, are not yet fully understood. Here, we established a hierarchical quantitative analysis framework to understand the driving factors of aerosol acidity on different timescales. Its application in Changzhou, China, revealed distinct driving factors and corresponding mechanisms of aerosol acidity from annual trends to random residuals.

Understanding how clouds affect the climate, especially in the Arctic, is crucial. This study used data from the largest polar expedition in history, MOSAiC, and the CERES satellite to analyse the impact of clouds on radiation. Simulations showed accurate results, aligning with observations. Over the year, clouds caused the atmospheric surface system to lose 5.2 W m⁻² of radiative energy to space, while the surface gained 25 W m⁻² and the atmosphere cooled by 30.2 W m⁻².

Here we use an Earth system model to simulate a long-lasting volcanic eruption at 65° N and investigate its impact on the stratospheric circulation. We show a polar vortex strengthening in winter 1, followed by a weakening in winters 2–3 due to surface cooling, where ocean–atmosphere interactions play a major role in the detected response. This weakening appears to trigger sudden stratospheric warming events that can cause severe cold spells throughout the Northern Hemisphere.  

Halogenated polycyclic aromatic hydrocarbons (XPAHs) are emerging pollutants. Stability during atmospheric transformation processes is crucial for predicting their environmental fate and assessing the associated risks. Here, we conducted field studies and laboratory simulation experiments to reveal the mechanisms, influencing factors and products for XPAHs' heterogeneous phototransformation. Results revealed that the conversion of XPAHs led to a reduction in environmental risk.

In this study, we discuss the enhanced detection capabilities of a fluorescence lidar in the case of optically thin aerosol layers in the upper troposphere and lower stratosphere (UTLS) region. Our results suggest that such thin aerosol layers are not so rare in the UTLS and can potentially trigger and impact cirrus cloud formation through heterogeneous ice nucleation. By altering the microphysical cloud properties, this could affect clouds' evolution and lifetime and thus their climate effect.

Monitoring of atmospheric water vapor isotopes for 1 year at Matara, Sri Lanka, revealed clear seasonal variations in δ¹⁸O and d-excess. The results showed lower amplitudes of δ¹⁸O during the southwest monsoon and higher amplitudes of δ¹⁸O during the northeast monsoon. Sea surface evaporation and regional convective activity influenced the isotopic compositions. Our results facilitate an understanding of the impacts of local meteorological conditions on tropical water vapor isotope signals.

We target the challenge of detecting methane super-emitters in oil and gas fields, which is critical for mitigating climate change. Traditional satellite-based detectors struggle due to interference from complex surfaces. We developed a novel method using deep transfer learning that improves detection efficiency and accuracy by reducing artifacts and adapting methane knowledge to different regions. Application revealed significant methane emissions, demonstrating the potential of our method.

This work explores the dynamics of the momentum and energy of propagating mesospheric gravity waves (GWs). A photometer was used to observe the vertical component of the GWs, whereas the horizontal component was observed by an all-sky imager. Using the parameters from these two instruments and background wind from meteor radar, the momentum flux and potential energy of the GWs were determined and studied. It is noted that the dynamics of the downward-propagating GWs were controlled by observed ducts.

Marine phytoplankton emit dimethyl sulfide (DMS), which forms methanesulfonic acid (MSA) and sulfate. MSA concentrations in ice cores decreased over the industrial era, which has been attributed to pollution-driven changes in DMS chemistry. We use a model to investigate DMS chemistry compared to observations of DMS, MSA, and sulfate. We find that modeled DMS, MSA, and sulfate are influenced by pollution-sensitive oxidant concentrations, characterization of DMS chemistry, and other variables.

This study presents the first source apportionment of organic aerosol at Mace Head via high-resolution mass spectrometry. Introducing transfer entropy as a novel method reveals that aged organic aerosol originates from both open-ocean ozonolysis and local peat-burning oxidation. Methanesulfonic acid and organic sea spray both mirror phytoplankton activity, with the former closely tied to coccolithophore blooms and the latter linked to diatoms, chlorophytes, and cyanobacteria.

This study uses ERA5 data to better understand the relative importance of the factors limiting persistent contrail formation. We develop climatological relationships to estimate potential persistent contrail formation for existing as well as future aircraft and propulsion system designs. We identify latitudes and pressure levels where the introduction of novel aircraft designs would result in significant changes in potential persistent contrail formation compared to existing conventional aircraft.

To understand the effect of aerosols on the vertical distribution of stratocumulus microphysical quantities in southwest China, the daily variation characteristics and formation mechanism of the vertical profiles of stratocumulus microphysical characteristics in this region were described using the data of nine cloud-crossing aircraft observations over Guangxi from 10 October to 3 November 2020.

The area-wide radar-based distinction between riming and aggregation is crucial for model microphysics and data assimilation. This study introduces a discrimination algorithm based on polarimetric radar networks only. Exploiting the unique opportunity to link fall velocities from Doppler spectra to polarimetric variables in an operational setting enables us to set up and evaluate a well-performing machine learning algorithm.

We present a 17-year stratospheric age-of-air dataset derived from ACE-FTS satellite measurements of sulfur hexafluoride. This is the longest continuous, global, and vertically resolved age of air time series available to date. In this paper, we show that this dataset agrees well with age-of-air datasets based on measurements from other instruments. We also present trends in the midlatitude lower stratosphere that indicate changes in the global circulation that are predicted by climate models.

This study utilizes a regional climate–air quality coupled model to first investigate the complex interaction between irrigation, climate and air quality in China. We found that large-scale irrigation practices reduce summertime surface ozone while raising secondary inorganic aerosol concentration via complicated physical and chemical processes. Our results emphasize the importance of making a tradeoff between air pollution controls and sustainable agricultural development.

Ground-level ozone pollution has emerged as a significant air pollutant in China. Chemical transport models (CTMs) serve as crucial tools in addressing ozone pollution. This study reviews CTM applications for simulating ozone in China and proposes goal and criteria benchmark values for evaluating ozone. Along with prior work on PM₂₅ and other pollutants, this effort establishes a comprehensive framework for evaluating CTM performance in China.

We implemented a new global land-use-change (LUC) dataset from 1982 to 2010 into a compact earth system model and carried out extensive multiple model scenario simulations. Our result reveals that the global radiative forcing (RF) induced by LUC driving surface albedo change is −0.12 W m⁻², 20 % lower than the Intergovernmental Panel on Climate Change (IPCC), and vegetation changes play a key role in RF evolution, which provides an important reference for the assessment of earth energy balance.

This study introduces a new method to derive adjusted water vapor (H₂O) climatologies for the upper tropopshere and lower statosphere (UT/LS) using data from 60 000 flights under the IAGOS program. Biases in the IAGOS water vapour dataset are adjusted, based on the more accurate IAGOS-CARIBIC data. The resulting highly resolved H₂O climatologies will contribute to a better understanding of the H₂O variability in the UT/LS and its connection to various transport and mixing processes.

We investigated NO_x emission contributions to NO_y loadings across five regions of East Asia during the 2022 winter–spring transition through chemical transport modeling informed by satellite data. As seasons progress, local contributions within each region to its NO_y budget decreased from 32 %–43 % to 23 %–30 %, while transboundary contributions increased from 16 %–33 % to 27 %–37 %, driven by a shift in synoptic settings that allowed pollutants to spread more broadly across the regions.

We used quantum chemistry methods to investigate the oxidation mechanisms of acyl peroxy radicals (APRs) with various monoterpenes. Our findings reveal unique oxidation pathways for different monoterpenes, leading to either chain-terminating products or highly reactive intermediates that can contribute to particle formation in the atmosphere. This research highlights APRs as potentially significant but underexplored atmospheric oxidants that may influence future approaches to modelling climate.

A balloon was launched in 2021 in the Arctic to carry instruments for trace gas measurements up to 32 km. One purpose was to compare measurement techniques. We focus on the major greenhouse gases. To measure these, air was sampled with the AirCore technique and with flask sampling, and samples were analysed after the flight. In flight, observations were done with an optical method. In a companion paper, we report on observations of chlorine and bromine containing trace gases.