In climate models, organic carbon (OC) in wildfire smoke has been treated as an atmospheric cooling component by reflecting sunlight back to space. This study incorporates the observationally identified absorbing brown carbon component of OC into the Community Earth System Model, improving the agreement between the model and observations and effectively increasing absorption of solar radiation. This change contributes to altered atmospheric dynamics and changes in cloud cover in the model.

Aerosol impacts visibility and human health in large cities. Sources of aerosols are still highly uncertain, especially for cities surrounded by numerous other cities. We use observations collected during the Korea–United States Air Quality study to determine sources of organic aerosol (OA). We find that secondary OA (SOA) is rapidly produced over Seoul, South Korea, and that the sources of the SOA originate from short-lived hydrocarbons, which originate from local emissions.

We demonstrate the use of solid-phase extraction (SPE) disks for the untargeted analysis of gas-phase intermediate volatility and semi-volatile organic compounds emitted from biomass burning. SPE and Teflon filter samples collected from laboratory fires were analyzed by two-dimensional gas chromatography, with distinct differences in the observed chromatographic profiles as a function of fuel type. Fuel-dependent emissions and volatility differences among benzenediol isomers were captured.

Measurements of air pollutants at a ground site near Fort McKay in the Athabasca oil sands region in the summer of 2013 are presented. A large number of intermediate-volatility organic compounds (IVOCs) were observed; these molecules were shown previously to generate atmospheric particles downwind of the region. A principal component analysis was performed to identify major pollution source types, including which source(s) is(are) associated with IVOC emissions (e.g., freshly mined bitumen).

It is clear that considerable uncertainties still exist in understanding the magnitude of aerosol absorption on a global scale and its contribution to global warming. This manuscript provides a comprehensive assessment of the optical absorption by organic aerosols (brown carbon) from residential wood combustion as a function of atmospheric aging.

Understanding the connections between aerosols, solar radiation and photosynthesis in terrestrial ecosystems is important for estimates of the CO₂ balance in the atmosphere. Atmospheric aerosols and clouds influence solar radiation. In this study, we quantify the aerosol effect on solar radiation in boreal forests and study forest ecosystems response to this change in the radiation conditions. The analysis is based on atmospheric observations from several remote stations in Eurasian forests.

Our paper provides an automatic method to classify new particle formation events into four classes based on the accompanying air ion concentrations. The method is applied to 10 years of data measured within the SMEAR II station and was capable of eliminating the undefined class as well as defining the start, peak and end times of a regional event by monitoring the initial steps of cluster formation. Our method can be modified and applied to different locations where particle formation occurs.

The Arctic is experiencing warming trends higher than the global mean. Arctic ecosystems are a large store of carbon. As the soil organic carbon thaws and decomposes, some fraction of this store will eventually be released to the atmosphere as methane. We show that a previously used measurement-based metric to identify changes in Arctic methane emissions does not reliably quantify these changes because it neglects the effect of atmospheric transport. A better metric will combine data and models.

Volcanic sulfur can have climatic impacts for the planet via sulfate aerosol formation, leading also to pollution events. We provide model constraints on tropospheric volcanic sulfate formation, with implications for its lifetime and impacts on regional air quality. Oxygen isotope investigations from our model suggest that in the poor tropospheric plumes of halogens, the O2/TMI sulfur oxidation pathway might significantly control sulfate production. The produced sulfate has no isotopic anomaly.

A 1-month field campaign of ozone (O₃) flux measurements along a five-level vertical profile of a mature broadleaf forest highlighted that the biosphere–atmosphere exchange of this pollutant is modulated by complex diel dynamics occurring within and below the canopy. The canopy removed nearly 80 % of the O₃ deposited to the forest; only a minor part was removed by the soil and the understorey (2 %), while the remaining 18.2 % was removed by chemical reactions with NO mostly emitted from soil.

Balloon-borne measurements performed over Lhasa in August 2013 are investigated using CLaMS trajectory calculations. Here, we focus on high ozone mixing ratios in the free troposphere. Our findings demonstrate that both stratospheric intrusions and convective transport of air pollution play a major role in enhancing middle and upper tropospheric ozone.

The paper describes the synoptic development during the ACLOUD/PASCAL airborne and ship-based field campaign near Svalbard in spring 2017. This development is presented using near-surface and upper­air meteorological observations, satellite, and model data. We first present time series of these data, from which we identify and characterize three key periods. Finally, we put our observations in historical and regional contexts and compare our findings to other Arctic field campaigns.

Warm-temperature ice nucleating particles (INPs) were observed during a springtime transition period of the melting of frozen surfaces in Northern Alaska. Such INPs were likely biological and from marine and terrestrial (tundra) sources. Influxes of these efficient INPs may have important implications for Arctic cloud ice formation and, consequently, the surface energy budget.

The Atlantic aerosols are characterized based on high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) measurements during four open-ocean cruises. This unique data set provides the latitudinal distribution of source contributions of organic aerosols (OAs) over the Atlantic Ocean, showing that marine sources could control the OA formation over the South Atlantic, while strong continental influence was found near Africa and Europe.

In the last decade, four temporal regimes of SO₂ in China have been identified. After an initial rise, SO₂ undergoes two sharp drops in 2007–2008 and 2014–2016, during which 5-year rebounding is sustained. Different mechanisms are tied to North and South China. The industrial emission is responsible for SO₂ variation in North China, while in South China the meteorological conditions make a large contribution. The result is crucial to the understanding of SO₂ changes and future polices.

This study presents a detailed analysis of regional and sectoral sources of black carbon (BC), sulfate (SO₄), and PM_2.5 over the Arctic. We find that anthropogenic emissions from Europe and China are the major contributors (~ 46 % and ~ 25 %) to the Arctic surface BC annually. Emissions from the residential sector within Europe and China are the primary contributors (~ 25 % and ~ 14 %) to Arctic surface BC. Additionally, the contribution of each source region varied significantly by altitude and season.

Since 2007 atmospheric methane (CH₄) has been unexpectedly increasing following a 6-year hiatus. We have used an atmospheric model to attribute regional sources and global sinks of CH₄ using observations for the 2003–2015 period. Model results show the renewed growth is best explained by decreased atmospheric removal, decreased biomass burning emissions, and an increased energy sector (mainly from Africa–Middle East and Southern Asia–Oceania) and wetland emissions (mainly from northern Eurasia).

This paper investigates frequently occurring foehn at the Dead Sea, which strongly impacts the local climatic conditions, in particular temperature and humidity, as well as evaporation from the Dead Sea, the aerosol load, and visibility. A statistical classification exposes two types of foehn and first-time, high-resolution measurements reveal trigger mechanisms and relevant characteristics, such as wind velocities, affected air layers, and resulting phenomena such as hydraulic jumps and rotors.

East Asia is characterized by severe anthropogenic pollution and dust storms due to fuel consumption and the downwind location of dust sources. We studied the mixing states of dust and pollutants using an optical particle counter equipped with a polarization detection module, providing a deeper understanding of possible mechanisms of aerosols’ morphological change. In Beijing, the heterogeneous processes in the mixture of dust and emitted pollutants have a great influence on smog formation.