Atmospheric chemistry

  • Article
    | Open Access

    Sea spray aerosol (SSA) are an important way through which oceans can influence the atmosphere’s radiative properties. Here, the authors present measurements taken over a 42,000 km ship cruise in the Atlantic and Pacific Ocean and show that SSA number concentrations vary over a 24-hour cycle, possibly linked to surface water bubble-bursting dynamics.

    • J. Michel Flores
    • , Guillaume Bourdin
    •  & Ilan Koren
  • Article
    | Open Access

    Nowhere is biomass burning more abundant than on the African continent, but the biogeochemical impacts on forests are poorly understood. Here the authors show that biomass burning leads to high phosphorus deposition in the Congo basin, which scales with forest age as a result of increasing canopy complexity.

    • Marijn Bauters
    • , Travis W. Drake
    •  & Pascal Boeckx
  • Article
    | Open Access

    How climate change influences the lifecycle of stratospheric volcanic aerosols and the associated radiative forcing is unknown. Here, the authors present model experiments suggesting that climate change amplifies the forcing of large-magnitude tropical eruptions but reduces the forcing of moderate-magnitude tropical eruptions.

    • Thomas J. Aubry
    • , John Staunton-Sykes
    •  & Anja Schmidt
  • Article
    | Open Access

    Despite a ban on ozone depleting substances, ozone depletion during cold winters in the Arctic stratosphere has been increasing in recent decades. Here, the authors show conditions favourable for Arctic ozone depletion could worsen as a response of stratospheric temperature and water to continued release of greenhouse gases.

    • Peter von der Gathen
    • , Rigel Kivi
    •  & Markus Rex
  • Article
    | Open Access

    The production of chlorofluorocarbons (CFC) was phased-out under the Montreal, but renewed emissions of CFC-11 have been reported recently. Here, the authors present a joint analysis of multiple factors and find that emissions of CFC-11, but also CFC-12 and CFC-113 are higher than expected, indicating renewed emissions.

    • Megan Lickley
    • , Sarah Fletcher
    •  & Susan Solomon
  • Article
    | Open Access

    Sunlight can change the composition of atmospheric aerosol particles, but the mechanisms through which this happens are not well known. Here, the authors show that fast radical reaction and slow diffusion near viscous organic particle surfaces can cause oxygen depletion, radical trapping and humidity dependent oxidation.

    • Peter A. Alpert
    • , Jing Dou
    •  & Markus Ammann
  • Article
    | Open Access

    Oxidation of volatile organic compounds leads to aerosol formation in the atmosphere, but the mechanism of some fast reactions is still unclear. The authors, using quantum chemical modelling and experiments, reveal that in key monoterpenes the cyclobutyl ring that would hinder the reactivity is broken in the early exothermic steps of the reaction.

    • Siddharth Iyer
    • , Matti P. Rissanen
    •  & Theo Kurtén
  • Article
    | Open Access

    The regulation of aircraft engine NOx emissions was introduced to improve local air quality and reduce NOx emissions at altitude. Here, the authors find that greater fuel efficiency of aircrafts, and therefore lower CO2 emissions, could be preferable to reducing NOx emissions in terms of the aviation industries future climate impacts.

    • Agnieszka Skowron
    • , David S. Lee
    •  & Bethan Owen
  • Article
    | Open Access

    Wildfires produce aerosols known to impact the climate, but the wider-reaching effects of this biomass burning are poorly constrained in models. Here the authors use a suite of observations from 12 campaigns around the globe to determine that the values used by most climate models overestimate the contribution of biomass burning aerosols.

    • Hunter Brown
    • , Xiaohong Liu
    •  & Duli Chand
  • Article
    | Open Access

    In the habitable zone concept, a planet’s carbon dioxide-water greenhouse maintains surface liquid water. Here, the authors estimate how many Earthlike exoplanets are needed to detect a relationship between stellar flux and the atmospheric carbon dioxide predicted by carbon cycle modeling.

    • Owen R. Lehmer
    • , David C. Catling
    •  & Joshua Krissansen-Totton
  • Article
    | Open Access

    Ice nucleating particles impact the global climate by altering cloud formation and properties, but the sources of these emissions are not completely characterized. Here, the authors show that secondary organic aerosols formed from the oxidation of organic gases in the atmosphere can be a source of ice nucleating particles.

    • Martin J. Wolf
    • , Yue Zhang
    •  & Daniel J. Cziczo
  • Article
    | Open Access

    Which vapors are responsible for new particle formation in the Arctic is largely unknown. Here, the authors show that the formation of new particles at the central Arctic Ocean is mainly driven by iodic acid and that particles smaller than 30 nm in diameter can activate as cloud condensation nuclei.

    • Andrea Baccarini
    • , Linn Karlsson
    •  & Julia Schmale
  • Article
    | Open Access

    The methane emissions from natural gas vehicles (NGVs) are unclear. Here the authors report high methane emissions from heavy-duty NGVs, and by using a scenario analysis show that strictly implementing the upcoming China VI standard could reduce GHG emissions by 509 Mt CO2eq for 2020-2030.

    • Da Pan
    • , Lei Tao
    •  & Mark A. Zondlo
  • Article
    | Open Access

    “How iodine-bearing molecules contribute to atmospheric aerosol formation is not well understood. Here, the authors provide a new gas-to-particle conversion mechanism and show that clustering of iodine oxides is an essential component of this process while previously proposed iodic acid does not play a large role.”

    • Juan Carlos Gómez Martín
    • , Thomas R. Lewis
    •  & Alfonso Saiz-Lopez
  • Article
    | Open Access

    Selective reduction of carbon dioxide to high-value products is key for advancing carbon capture and utilization technologies. Here the authors prepare a copper catalyst for electrocatalytic conversion of carbon dioxide to C2+ products with enhanced selectivity that is attributed to a high density of surface defects.

    • Taehee Kim
    •  & G. Tayhas R. Palmore
  • Article
    | Open Access

    A cloud of enhanced ruthenium concentrations has been observed over Europe in 2017, but no country has acknowledged responsibility for this nuclear release. Here, the authors show that the stable isotopic composition of ruthenium emitted from nuclear fuel reprocessing during the 2017 event is consistent with the isotopic signature of civilian Russian nuclear reactor fuel.

    • Timo Hopp
    • , Dorian Zok
    •  & Georg Steinhauser
  • Article
    | Open Access

    How sulfur dioxide emitted through coal combustion is oxidized to sulfate particles during winter haze pollution events has been the subject of debate. Here, the authors show that rapid oxidation takes place by nitrogen dioxide and nitrous acid, producing nitrous oxide together with sulfate.

    • Junfeng Wang
    • , Jingyi Li
    •  & Daniel J. Jacob
  • Article
    | Open Access

    Following international agreements, the use of chlorofluorocarbons in production is supposed to be phased out. Here, the authors present a new estimate of these products already in use and their emissions and show that they are larger than expected and that not recovering these banks leads to a substantial delay in the polar ozone hole recovery.

    • Megan Lickley
    • , Susan Solomon
    •  & Kane Stone
  • Article
    | Open Access

    The Middle East is known to emit large amounts of non-methane hydrocarbon pollutants to the atmosphere, but the sources are poorly characterized. Here the authors discover a new source—deep water in the Red Sea—and calculate that its emissions exceed rates of several high gas-production countries.

    • E. Bourtsoukidis
    • , A. Pozzer
    •  & J. Williams
  • Article
    | Open Access

    International agreements have been implemented to reduce emissions of hydrofluorocarbons (HFCs) to reduce their radiative forcing. Even though reported HFC-23 emissions are at a historical low, observations indicate that emissions have actually increased over recent years to higher levels than previously.

    • K. M. Stanley
    • , D. Say
    •  & M. Rigby
  • Article
    | Open Access

    The Antarctic ozone hole is decreasing in size due to policies implemented following the Montreal Protocol. Here, model simulations show that if recently discovered increase in unreported CFC-11 emissions continue, they could delay the recovery of the ozone hole by well over a decade.

    • S. S. Dhomse
    • , W. Feng
    •  & M. P. Chipperfield
  • Article
    | Open Access

    Aerosol-cloud interactions are a large source of uncertainty in radiative forcing estimates. Here, the authors show that the radiative effects of clouds are influenced by a combination of aerosol particle distribution, environmental conditions and atmosphere dynamics.

    • S. J. Lowe
    • , D. G. Partridge
    •  & I. Riipinen
  • Article
    | Open Access

    The loss of anomalous sulfur isotope compositions from sedimentary rocks has been considered a symptom of permanent atmospheric oxygenation. Here the authors show sulfur and oxygen isotope evidence from < 2.31 Ga sedimentary barium sulphates (barites) from the Turee Creek Basin, W. Australia, demonstrating the influence of local non-atmospheric processes on anomalous sulfur isotope signals.

    • B. A. Killingsworth
    • , P. Sansjofre
    •  & S. V. Lalonde
  • Article
    | Open Access

    Condensation of organic vapors is a main factor controlling the growth of atmospheric particles. Here the authors identify a distribution of organic vapors in a forested environment able to explain nanoparticle growth at the same location, contributing to understanding aerosol climate effects.

    • Claudia Mohr
    • , Joel A. Thornton
    •  & Taina Yli-Juuti
  • Article
    | Open Access

    Forests emit compounds into the atmosphere that are oxidized into highly oxygenated molecules that serve as precursors for cloud condensation nuclei–a process that impacts the climate, but is poorly represented in models. Here the authors create a new model that accurately depicts highly oxygenated molecule and climate dynamics over Boreal forests.

    • Pontus Roldin
    • , Mikael Ehn
    •  & Michael Boy
  • Article
    | Open Access

    Gigantic jets, lightning discharges originating from tropical thunderstorms that can reach the base of the ionosphere at 90 km altitude, have not been captured using high-speed video cameras before. Here, the first such images are reported, showing a step-wise evolution of gigantic jets during their rising phase.

    • Oscar A. van der Velde
    • , Joan Montanyà
    •  & Steven A. Cummer
  • Article
    | Open Access

    “Reconstruction of precipitation variability from oxygen isotopes in the Mesoamerican and Caribbean region is made difficult by the occurrence of tropical cyclones. Here, the isotopic evolution of a tropical cyclone is studied in detail which helps disentangle the key processes governing rainfall isotope variability in the region.”

    • Ricardo Sánchez-Murillo
    • , Ana M. Durán-Quesada
    •  & Kim M. Cobb
  • Article
    | Open Access

    Isoprene is a key component of the atmosphere, with impacts on oxidation, ozone and organic aerosols, but in-situ measurements are limited. Here, the authors present a full-physics measurement framework based on satellite data that enables the direct observation of atmospheric isoprene from space.

    • Dejian Fu
    • , Dylan B. Millet
    •  & Annmarie Eldering
  • Article
    | Open Access

    How the water use efficiency of trees changes with atmospheric CO2 variations has mostly been studied on short time scales. Here, a newly compiled data set covering 1915 to 1995 shows how rates of change in water use efficiency vary with location and rainfall over the global tropics on a decadal scale.

    • Mark A. Adams
    • , Thomas N. Buckley
    •  & Tarryn L. Turnbull
  • Article
    | Open Access

    Tropical land ecosystems contain vast carbon reservoirs, but their influence on atmospheric CO2 is poorly understood. Here the authors use new carbon-observing satellites to reveal a large emission source over northern tropical Africa, where there are large soil carbon stores and substantial land use changes.

    • Paul I. Palmer
    • , Liang Feng
    •  & Peter Somkuti
  • Article
    | Open Access

    Global average, geographical distribution and temporal variations of the 13C isotopic signature of enteric fermentation emissions are not well understood. Here the authors established a global dataset and show a larger emission increase between the two periods (2002–2006 and 2008–2012) than previous studies.

    • Jinfeng Chang
    • , Shushi Peng
    •  & Philippe Bousquet
  • Article
    | Open Access

    The relative importance of crustal vs. anthropogenic dust deposition for iron cycling in the surface ocean is unclear. Based on analysis of iron isotope data from North Atlantic aerosol samples, the authors can reveal the relative importance of anthropogenic iron emissions and its impact on marine biogeochemistry.

    • Tim M. Conway
    • , Douglas S. Hamilton
    •  & Seth G. John
  • Article
    | Open Access

    State‐of‐the‐art aerosol nanoparticle techniques are limited by the shortcomings of removing the nanoparticles from their original environment. Here, the authors apply small angle X‐ray scattering as an in‐situ measurement technique, enabling the measurement of the primary particles and the aggregates.

    • P. S. Bauer
    • , H. Amenitsch
    •  & P. M. Winkler
  • Article
    | Open Access

    It remains unclear how urban emissions influence the formation of secondary organic aerosols (SOA), including in the Amazon forest. Here, the authors simulate the formation of SOAs in the Amazon using a high-resolution regional chemical transport model. They find that urban emissions of NOx from Manaus enhance the production of biogenic SOA by 60–200%.

    • Manish Shrivastava
    • , Meinrat O. Andreae
    •  & Chun Zhao
  • Article
    | Open Access

    Chinese government has implemented regulations to reduce mining-related methane emission since 2010. Here the authors estimated methane emissions in China using GOSAT satellite observation and results reveal a business-as-usual increase in methane emissions since 2010 despite those ambitious targets.

    • Scot M. Miller
    • , Anna M. Michalak
    •  & Stefan Schwietzke
  • Article
    | Open Access

    Organic nucleation is an important source of atmospheric aerosol number concentration, especially in pristine continental regions and during the preindustrial period. Here the authors find a 16% reduced radiative forcing associated with anthropogenic aerosols when including organic nucleation together with climate and land use change.

    • Jialei Zhu
    • , Joyce E. Penner
    •  & Hugh Coe
  • Article
    | Open Access

    Short-lived natural bromocarbons, which contribute to ozone depletion in the atmosphere, are believed to be produced through light-driven processes, mainly in oceans. Here the authors present bromocarbon measurements in snow, sea ice, and air during polar winter that show an unexpected source of bromine to the polar atmosphere during periods of no sunlight.

    • Katarina Abrahamsson
    • , Anna Granfors
    •  & Alfonso Saiz-Lopez
  • Article
    | Open Access

    Salt particles in the Amazon basin are typically attributed to marine aerosols transported from the Atlantic Ocean. Here the authors show the potential importance of fungal spores as a source of sodium-salt particles in the Amazon rainforest.

    • Swarup China
    • , Susannah M. Burrows
    •  & Alexander Laskin
  • Article
    | Open Access

    Reduction of gaseous Hg(II) compounds drives atmospheric mercury wet and dry deposition to Earth surface ecosystems. Global Hg models assume this reduction takes place in clouds. Here the authors report a new gas-phase Hg photochemical mechanism that changes atmospheric mercury lifetime and its deposition to the surface.

    • Alfonso Saiz-Lopez
    • , Sebastian P. Sitkiewicz
    •  & Jeroen E. Sonke