H-shift and cyclization reactions in unsaturated alkylperoxy radicals near room temperature: propagating or terminating autoxidation?

The autoxidation of alkylperoxy radicals (RO2, where R is organic) is an important degradation pathway for organic compounds in a wide range of chemical systems including Earth's atmosphere.

Observational evidence reveals the significance of nocturnal chemistry in seasonal secondary organic aerosol formation

Oxidized Organic Aerosol (OOA), a major component of fine atmospheric particles, impacts climate and human health. Previous experiments and atmospheric models emphasize the importance of nocturnal OOA formation from NO3· oxidation of biogenic VOCs.

The MESSy DWARF (based on MESSy v2.55.2)

Adaptation of Earth system model (ESM) codes to modern computing architectures is challenging, as ESMs consist of a multitude of different components. Historically grown and developed by scientists rather than software engineers, the codes of the individual components are often interwoven, making the optimisation of the ESMs on modern computing architectures rather challenging, if not impossible.

The effect of aging conditions at equal OH exposure in an oxidation flow reactor on the composition of toluene-derived secondary organic aerosols

Oxidation flow reactors (OFRs) have been increasingly used to conduct research on secondary aerosol formation potential and composition in laboratory and field studies by exposing aerosols to high levels of oxidants in short time periods.

Effect of the Alkoxy Radical Chemistry on the Ozone Formation from Anthropogenic Organic Compounds Investigated in Chamber Experiments

The photooxidation of five anthropogenic volatile organic compounds (propane, propene, isopentane, n-hexane, trans-2-hexene) at different levels of nitric oxide (NO) was investigated in the atmospheric simulation chamber SAPHIR, Forschungszentrum Jülich.

The influence of plant water stress on vegetation–atmosphere exchanges: implications for ozone modelling

Evapotranspiration is important for Earth's water and energy cycles as it strongly affects air temperature, cloud cover, and precipitation. Leaf stomata are the conduit of transpiration, and their opening is sensitive to weather and climate conditions. This feedback can exacerbate heat waves and can play a role in their spatiotemporal propagation.

Temperature-dependent emissions dominate aerosol and ozone formation in Los Angeles

Despite declines in transportation emissions, urban North America and Europe still face unhealthy air pollution levels. This has challenged conventional understanding of the sources of their volatile organic compound (VOC) precursors.

Decomposition of Clusters of Oxygenated Compounds with NO3– by Applying Voltage Scanning to Chemical Ionization Mass Spectrometry in Steady-State Experiments

Oxygenated volatile organic compounds (OVOCs) contribute to atmospheric secondary organic aerosols. To better constrain OVOC distributions, e.g., from the oxidation of phenolics, voltage scanning was applied for the targeted destruction of product nitrate (NO3–) clusters in a chemical ionization mass spectrometer.

Global aviation contrail climate effects from 2019 to 2021

The current best-estimate of the global annual mean radiative forcing (RF) attributable to contrail cirrus is thought to be 3 times larger than the RF from aviation's cumulative CO2 emissions.

Development of a multiphase chemical mechanism to improve secondary organic aerosol formation in CAABA/MECCA (version 4.7.0)

During the last few decades, the impact of multiphase chemistry on secondary organic aerosols (SOAs) has been demonstrated to be the key to explaining laboratory experiments and field measurements.

European air quality in view of the WHO 2021 guideline levels: Effect of emission reductions on air pollution exposure

Although anthropogenic emissions have decreased during the last 2 decades, air pollution is still problematic in Europe. This study analyzes the air quality in Europe using simulations by EURopean Air pollution Dispersion—Inverse Model for the year 2016 with updated emissions in view of the annual guideline levels for particulate matter (PM2.5), nitrogen dioxide (NO2), and ozone (O3) released in 2021 by the World Health Organization (WHO).

Opinion: New directions in atmospheric research offered by research infrastructures combined with open and data-intensive science

The acquisition and dissemination of essential information for understanding global biogeochemical interactions between the atmosphere and ecosystems and how climate–ecosystem feedback loops may change atmospheric composition in the future comprise a fundamental prerequisite for societal resilience in the face of climate change.

Impact of HO2∕RO2 ratio on highly oxygenated α-pinene photooxidation products and secondary organic aerosol formation potential

Highly oxygenated molecules (HOMs) from the atmospheric oxidation of biogenic volatile organic compounds are important contributors to secondary organic aerosol (SOA).

A storyline of ozone pollution extremes in warmer climates

High ozone levels pose a significant threat to human health and ecosystems, especially during extreme weather events. These are expected to become more frequent and intense with climate change, exacerbating the interactions between weather, vegetation, and air pollution.

How non-equilibrium aerosol chemistry impacts particle acidity: the GMXe AERosol CHEMistry (GMXe–AERCHEM, v1.0) sub-submodel of MESSy

Aqueous-phase chemical processes in clouds, fog, and deliquescent aerosols are known to alter atmospheric composition and acidity significantly. Traditionally, global and regional models predict aerosol composition by relying on thermodynamic equilibrium models and neglect non-equilibrium processes.

Application of fuzzy c-means clustering for analysis of chemical ionization mass spectra: insights into the gas phase chemistry of NO3-initiated oxidation of isoprene

Oxidation of volatile organic compounds (VOCs) can lead to the formation of secondary organic aerosol (SOA), a significant component of atmospheric fine particles, which can affect air quality, human health, and climate change. However, the current understanding of the formation mechanism of SOA is still incomplete, which is not only due to the complexity of the chemistry but also relates to analytical challenges in SOA precursor detection and quantification.

Quantum yields of CHDO above 300 nm

The photolysis of mono-deuterated formaldehyde, CHDO, is a critical process in the deuterium enrichment of stratospheric hydrogen formed from methane. In this work, a consistent description of the quantum yields of the molecular and radical channels of the CHDO photolysis is deduced from literature data.

Implementation of the ISORROPIA-lite aerosol thermodynamics model into the EMAC chemistry climate model (based on MESSy v2.55): implications for aerosol composition and acidity

This study explores the differences in performance and results by various versions of the ISORROPIA thermodynamic module implemented within the ECHAM/MESSy Atmospheric Chemistry (EMAC) model. Three different versions of the module were used, ISORROPIA II v1, ISORROPIA II v2.3, and ISORROPIA-lite.

A revised dry deposition scheme for land–atmosphere exchange of trace gases in ECHAM/MESSy v2.54

Dry deposition to vegetation is a major sink of ground-level ozone and is responsible for about 20 % of the total tropospheric ozone loss. Its parameterization in atmospheric chemistry models represents a significant source of uncertainty for the global tropospheric ozone budget and might account for the mismatch with observations.

Parameterizations of US wildfire and prescribed fire emission ratios and emission factors based on FIREX-AQ aircraft measurements

Extensive airborne measurements of non-methane organic gases (NMOGs), methane, nitrogen oxides, reduced nitrogen species, and aerosol emissions from US wild and prescribed fires were conducted during the 2019 NOAA/NASA Fire Influence on Regional to Global Environments and Air Quality campaign (FIREX-AQ).

Impact of temperature-dependent non-PAN peroxynitrate formation, RO2NO2, on nighttime atmospheric chemistry

The formation of peroxynitrates (RO2NO2) from the reaction of peroxy radicals (RO2) and nitrogen dioxide (NO2) and their subsequent redissociation are typically not included in chemical mechanisms.

New insights from the Jülich Ozone Sonde Intercomparison Experiment: calibration functions traceable to one ozone reference instrument

Although in principle ECC (electrochemical concentration cell) ozonesondes are absolute measuring devices, in practice they have several “artefacts” which change over the course of a flight.

Intercomparison of Air Quality Models in a Megacity: Toward an Operational Ensemble Forecasting System for São Paulo

An intercomparison of four regional air quality models is performed in the tropical megacity of São Paulo with the perspective of developing a forecasting system based on a model ensemble. Modeled concentrations of the main regulated pollutants are compared with combined observations in the megacity center, after analyzing the spatial scale of representativeness of air monitoring stations.

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Identifying and correcting interferences to PTR-ToF-MS measurements of isoprene and other urban volatile organic compounds

Proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) is a technique commonly used to measure ambient volatile organic compounds (VOCs) in urban, rural, and remote environments. PTR-ToF-MS is known to produce artifacts from ion fragmentation, which complicates the interpretation and quantification of key atmospheric VOCs.