Three-year satellite observations and high-resolution model forecast of XCH₄ are used to derive CH₄ emissions in the USCB region, Poland – a region of intense coal mining activities. The wind-assigned anomalies for two opposite wind directions are calculated and the estimated emission rates are very close to the inventories and in reasonable agreement with the previous studies. Our method is quite robust and can serve as a simple method to estimate CH₄ or CO₂ emissions for other regions.

Ice formation and its evolution in mixed-phase clouds are still uncertain. We evaluate the lidar retrieval of ice-nucleating particle concentration in dust-dominated and continental air masses over the Swiss Alps with in situ observations. A calibration factor to improve the retrieval from continental air masses is proposed. Ice multiplication factors are obtained with a new method utilizing remote sensing. Our results indicate that secondary ice production occurs at temperatures down to −30 °C.

This study explored the chemical properties of secondary organic aerosol (SOA) that formed from photo-oxidation of single and mixed biogenic and anthropogenic precursors. We showed that SOA chemical properties in a mixed vapour system are mainly affected by the higher-yield precursor's oxidation products and products from cross-product formation. This study also identifies potential tracer compounds in a mixed vapour system that might be used in SOA source attribution in future ambient studies.

Emissions from four typical Chinese domestic cooking and fried chicken using four kinds of oils were investigated to illustrate the impact of cooking style and oil. Of the estimated SOA, 10.2 %–32.0 % could be explained by S/IVOC oxidation. Multiway principal component analysis (MPCA) emphasizes the importance of the unsaturated fatty acid-alkadienal volatile product mechanism (oil autoxidation) accelerated by the cooking and heating procedure.

Here we elucidate the production of COOs and their roles in SOA and brown carbon formation from m-xylene oxidation by simultaneously monitoring the evolution of gas-phase products and aerosol properties in an environmental chamber. A kinetic framework is developed to predict SOA production from the concentrations and uptake coefficients for COOs. This functionality-based approach reproduces SOA formation from m-xylene oxidation well and is applicable to VOC oxidation for other species.

The evolution of aerosol in biomass burning smoke plumes that travel over marine clouds off the Atlantic coast of central Africa was studied using measurements made by a lidar deployed on a high-altitude aircraft. The main finding was that the physical properties of aerosol do not change appreciably once the plume has left land and travels over the ocean over a timescale of 1 to 2 d. Almost all particles in the plume are of radius less than 1 micrometer and spherical in shape.

This article reports the measurements of organic compounds emitted from western US wildfires. We identified and quantified 240 particle-phase compounds and 72 gas-phase compounds emitted in wildfire and related the emissions to the modified combustion efficiency. Higher emissions of diterpenoids and monoterpenes were observed, likely due to distillation from unburned heated vegetation. Our results can benefit future source apportionment and modeling studies as well as exposure assessments.

Brewer–Dobson circulation (BDC) controls the composition of the stratosphere, which in turn affects radiation and climate. As the BDC cannot be measured directly, it is necessary to infer its strength and trends indirectly. In this study, we test in the model world different methods for estimating the mean age of air trends based on a combination of stratospheric water vapour and methane data. We also provide simple practical advice of a more reliable estimation of the mean age of air trends.

The study provides baseline Arctic spring and summertime aerosol optical depth climatology, trend, and extreme event statistics from 2003 to 2019 using a combination of aerosol reanalyses, remote sensing, and ground observations. Biomass burning smoke has an overwhelming contribution to black carbon (an efficient climate forcer) compared to anthropogenic sources. Burning's large interannual variability and increasing summer trend have important implications for the Arctic climate.

The study provides a baseline Arctic spring and summertime aerosol optical depth climatology, trend, and extreme event statistics from 2003 to 2019 using a combination of aerosol reanalyses, remote sensing, and ground observations. Biomass burning smoke has an overwhelming contribution to black carbon (an efficient climate forcer) compared to anthropogenic sources. Burning's large interannual variability and increasing summer trend have important implications for the Arctic climate.

The extreme 2019–2020 Australian wildfires produced massive smoke plumes lofted into the lower stratosphere by pyrocumulonimbus convection. Most climate models do not adequately simulate the injection height of such intense fires. By combining aerosol-climate modeling with prescribed pyroconvective smoke injection and lidar observations, this study shows the importance of the representation of the most extreme wildfire events for estimating the atmospheric energy budget.

The restriction measures adopted to contain the COVID-19 virus offered a unique opportunity to study urban particulate emissions in the near absence of traffic, which is one of the main emission sources in the urban environment. However, the drastic decrease in this source of particulate matter during the months of national lockdown did not lead to an equal decrease in the total particulate load. This is due to the inverse behavior shown by different sources, especially secondary sources.

Three different methods were applied to estimate the vertical aerosol particle flux in the marine boundary layer (MBL) and between the MBL and free troposphere. For the first time, aerosol fluxes derived from these three methods were estimated and compared using airborne aerosol measurements using data from the ACORES field campaign in the northeastern Atlantic Ocean in July 2017. The amount of fluxes was small and directed up and down for different cases, but the methods were applicable.

The focus of this work is to study and improve our understanding of processes involved in the formation and growth of new particles in a remote Arctic marine environment. We run the 1D model ADCHEM along air mass trajectories arriving at Ny-Ålesund in May 2018. The model finds that ion-mediated H₂SO₄–NH₃ nucleation can explain the observed new particle formation at Ny-Ålesund. The growth of particles is driven via H₂SO₄ condensation and formation of methane sulfonic acid in the aqueous phase.

This paper helps to improve the recognition of severe thunderstorms in advance by giving a general understanding of how long the storm lasts, how fast the cluster moves and how much area the storm affects via information about the kinematic features of thunderstorms, which are the duration, valid area, the velocity, the direction and the farthest distance, and ideally to establish a foundation for future research that may contribute to the development of a new or improved prediction paradigm.

We present the first measurements of gas-phase sulfuric acid from the Amazon basin and evaluate the efficacy of existing sulfuric acid parameterizations in this understudied region. Sulfuric acid is produced during the daytime and nighttime, though current proxies underestimate nighttime production. These results illustrate the need for better parameterizations of sulfuric acid and its precursors that are informed by measurements across a broad range of locations.

Gaseous oxygenated organic molecules (OOMs) are able to form atmospheric aerosols, which will impact on human health and climate change. Here, we find that OOMs in urban Beijing are dominated by anthropogenic sources, i.e. aromatic (29 %–41 %) and aliphatic (26 %–41 %) OOMs. They are also the main contributors to the condensational growth of secondary organic aerosols (SOAs). Therefore, the restriction on anthropogenic VOCs is crucial for the reduction of SOAs and haze formation.

We use atomistic simulations to study heterogeneous ice nucleation on silver iodide surfaces in slit and wedge geometries at low supercooling which serve as a model of irregularities on real atmospheric aerosol particle surfaces. The revealed microscopic ice nucleation mechanisms in confined geometries strongly support the experimental evidence for the importance of surface features such as cracks or pits functioning as active sites for ice nucleation in the atmosphere.

This paper presents an evaluation of the aerosol analysis incorporated into the Clouds and the Earth's Radiant Energy System (CERES) data products as well as the aerosols' impact on solar radiation reaching the surface. CERES is a NASA Earth observation mission with instruments flying on various polar-orbiting satellites. Its primary objective is the study of the radiative energy balance of the climate system as well as examination of the influence of clouds and aerosols on this balance.

Biomass-burning-influenced oxygenated organic aerosol (OOA-BB), formed from the photochemical oxidation and aging of biomass burning OA (BBOA), was resolved in urban Xi’an. The aqueous-phase processed oxygenated OA (aq-OOA) concentration was more dependent on secondary inorganic aerosol (SIA) content and aerosol liquid water content (ALWC). The increased aq-OOA contribution during SIA-enhanced periods likely reflects OA evolution due to the addition of alcohol or peroxide groups

We investigated photochemistry of a secondary organic aerosol under three different conditions: in a dilute aqueous solution mimicking cloud droplets, in a solution of concentrated ammonium sulfate mimicking deliquesced aerosol, and in an organic matrix mimicking dry organic aerosol. We find that rate and mechanisms of photochemistry depend sensitively on these conditions, suggesting that the same organic aerosol compounds will degrade at different rates depending on their local environment.

Fire plus non-fire GHG emissions associated with draining peatlands are the largest per area of any land use change considered by the IPCC. To characterize average and variability for tropical peat fire emissions, highly mobile smoke sampling teams were deployed across four Indonesian provinces to explore an extended interannual, climatic, and spatial range. Large adjustments to IPCC-recommended emissions are suggested. Lab data bolster an extensive emissions database for tropical peat fires.

We use the WRF-Chem model with new implementations of GOES-16 wildfire emissions and plume rise based on fire radiative power (FRP) to interpret aerosol observations during the 2019 NASA–NOAA FIREX-AQ field campaign and perform model evaluations. The model shows significant improvements in simulating the variety of aerosol loading environments sampled during FIREX-AQ. Our results also highlight the importance of accurate wildfire diurnal cycle and aerosol chemical mechanisms in models.

An aerosol-aware microphysics scheme is evaluated for fog cases in Namibia. AEROCLO-sA campaign observations are used to access and parameterise the model. The model cloud condensation nuclei activation is lower than the observations. The scheme is designed for clouds with updrafts, while fog typically forms in stable conditions. A pseudo updraft speed assigned to the lowest model levels helps achieve more realistic cloud droplet number concentration and size distribution in the model.

Using spaceborne lidar-radar retrievals, we show that seasonal changes in cloud phase outweigh changes in cloud-phase statistics across cloud morphologies at given cloud-top temperatures. These results show that cloud morphology does not seem to pose a primary constraint on cloud-phase statistics in the Southern Ocean. Meanwhile, larger changes in in-cloud albedo across cloud morphologies are observed in supercooled liquid rather than mixed-phase stratocumuli.

We compare retrievals of wildfire smoke particle size, shape, and light absorption from the MISR satellite instrument to modeling and other satellite data on land cover type, drought conditions, meteorology, and estimates of fire intensity (fire radiative power – FRP). We find statistically significant differences in the particle properties based on burning conditions and land cover type, and we interpret how changes in these properties point to specific aerosol aging mechanisms.

A detailed size-resolved assessment of the chemical characteristics of outdoor and indoor aerosols collected in low-income urban settlements in South Africa indicated the significance of household combustion for cooking and space heating – an important source of pollutants in the developing world – to atmospheric chemical composition. The regional impact of industrial sources in the highly industrialised and densely populated north-eastern interior of South Africa was also evident.

Using the COVID-19 lockdown periods as an example, we show how Sentinel-5P/TROPOMI trace gas data (NO₂, SO₂, CO, HCHO and CHOCHO) can be used to understand impacts on air quality for regions and cities around the globe. We also provide information for both experienced and inexperienced users about how we created the data using state-of-the-art algorithms, where to get the data, methods taking meteorological and seasonal variability into consideration, and insights for future studies.

Stable water isotopes in marine boundary layer vapour are strongly influenced by the strength of air–sea fluxes. Here, we investigate a distinct vapour isotope signal observed in the warm sector of Southern Ocean cyclones. Single-process air parcel models are used together with high-resolution isotope-enabled simulations with the weather prediction model COSMOiso to improve our understanding of the importance of air–sea fluxes for the moisture cycling in the context of extratropical cyclones.

We quantify global ammonia (NH₃) emissions over the period from 2008 to 2018 using an improved fast top-down method that incorporates Infrared Atmospheric Sounding Interferometer (IASI) satellite observations and GEOS-Chem atmospheric chemical simulations. The top-down analysis finds a global total NH₃ emission that is 30 % higher than the bottom-up estimate, largely reconciling a large discrepancy of more than a factor of 2 found in previous top-down studies using the same satellite data.

Long-range transport of Asian dust to the Arctic was considered an important source of Arctic air pollution. Different transport routes to the Arctic had divergent effects on the evolution of aerosol properties. Depositions of long-range-transported dust particles can reduce the Arctic surface albedo considerably. This study implied that the ubiquitous long-transport dust from China exerted considerable aerosol indirect effects on the Arctic and may have potential biogeochemical significance.

We present a comprehensive characterization of water-soluble organic aerosol and the first mass spectral characterization of water-insoluble organic aerosol in the cold season in Beijing by integrating online and offline aerosol mass spectrometer measurements. WSOA comprised dominantly secondary OA and showed large changes during the transition season from autumn to winter. WIOA was characterized by prominent hydrocarbon ions series, low oxidation states, and significant day–night differences.