Acid deposition is still an important environmental issue in China. Rainwater samples in 320 cities in China were collected to determine the acidic ion concentrations and identify their spatiotemporal variations and sources. The higher acidic ions showed higher concentrations in winter. Furthermore, the highest acidic ion concentrations were mainly distributed in YRD and SB. These acidic ions were mainly sourced from industrial emissions and agricultural activities.

A novel method to determine the concentration and the isotopes of WSOC in aerosols is established and applied in the analysis of a severe haze in eastern China. The results show that the studied site is affected by the photochemical aging, biomass burning and dust aerosols in different episodes during the sampling period. The analysis of WSOC and its isotopes offers a great potential to better understand the source emission, the atmospheric aging and the secondary production of WSOC.

In 2015, a large fire episode occurred in Indonesia, reducing air quality. Fires occurred predominantly on peatland, where large uncertainties are associated with emissions. Current fire emissions datasets underestimate peat fire emissions. We created new fire emissions data, with data specific to Indonesian peat fires. Using these emissions in simulations of particulate matter and aerosol optical depth shows an improvement over simulations using current data, when compared with observations.

We present findings from a summertime field campaign at the remote island of Lampedusa in the central Mediterranean Sea. We show that the aerosol loading is similar to coastal sites around the Mediterranean. We observe higher loadings of sulfate and aged organic aerosol from air masses transported over the central and eastern Mediterranean in comparison to those from the western Mediterranean. These results highlight the rarity of pristine air masses, even in remote marine environments.

We characterized size-segregated airborne ice-nucleating particles (INPs) during dust storm events in the eastern Mediterranean. We found that particle size can predict its activity, and in general, larger particles are better INPs. The activity of supermicron particles dominated by desert mineral dust was similar between the different dust events regardless of the high variability of the geographic source desert and atmospheric journey.

The Arctic is warming faster than the rest of Earth. Black carbon (BC) aerosol contributes to this Arctic amplification by direct and indirect aerosol radiative effects while distributed in air or deposited on snow and ice. The aerosol-climate model ECHAM-HAM is used to estimate direct aerosol radiative effect (DRE). Airborne and near-surface BC measurements are used to evaluate the model and give an uncertainty range for the burden and DRE of Arctic BC caused by different emission inventories.

China is undergoing ever-increasing demand for electricity, and launched the Green Light Program (GLP), which is an effective reduction of the coal consumption for power generation. The estimated potential coal saving induced by the GLP can reach a massive value of 120–323 million tons. There was a massive resultant potential emission reduction of air pollutants, which is inherently connected to the haze formation, because the NO_x and SO₂ are important precursors for the formation of particles.

Nordic countries experience the deterioration of air quality in springtime due to high PM₁₀ concentrations. Non-exhaust emissions from vehicular traffic are regarded as the most significant source of particulate air pollution during this time of year. The results from this study demonstrate the fact that changes in winter tyre types and adjustments to road maintenance could substantially reduce non-exhaust emissions.

Although a total ban on straw burning has been enforced in eastern China, the regionally transported biomass burning emissions remarkably impacted the chemical and optical properties of carbonaceous aerosols in Nanjing, which were quantified by a calculation based on measured data and a simulation based on a model. Results showed that regionally transported biomass burning emissions significantly contributed to the carbonaceous aerosols and impacted the solar radiation balance of the atmosphere.

A new approach coupling aerosol chemical and optical properties in one source apportionment study is proposed. Besides a more robust identification of sources, it was possible to retrieve a source-specific absorption Ångström exponent and a mass absorption cross section at different wavelengths as well as optical apportionment. This piece of information can be very useful for formulating strategies for pollutant abatement to improve air quality and to face climate challenges.

Isoprene is the most abundantly emitted reactive organic gas globally, and thus it is important to understand its fate and role in aerosol formation and growth. A major product of its oxidation is an epoxydiol, IEPOX, which can be efficiently taken up by acidic aerosol to generate substantial amounts of secondary organic aerosol (SOA). We present chamber experiments exploring the properties of IEPOX SOA and reconcile discrepancies between field, laboratory, and model studies of this process.

This study shows that there were often co-occurrences of high PM_2.5 and O₃ concentrations, which were related to high HONO, in eastern China. This result suggests that high daytime HONO can be photodissociated to OH radicals, enhancing the chemical production of O₃ and suggesting that under high aerosol conditions, the chemical oxidizing process for O₃ production can occur in eastern China.

The Weather Research and Forecasting model (WRF), coupled with greenhouse gas (GHG) modules (WRF-GHG), is considered to be a suitable basis for precise GHG transport analysis in urban areas, especially when combined with differential column methodology (DCM). DCM is an effective method not only for comparing models to observations independently of biases caused, for example, by initial conditions, but also for detecting and understanding sources of GHG emissions quantitatively in urban areas.

A 5-year Clean Air Action Plan was implemented in 2013 to improve ambient air quality in Beijing. Here, we applied a novel machine-learning-based model to determine the real trend in air quality from 2013 to 2017 in Beijing to assess the efficacy of the plan. We showed that the action plan led to a major reduction in primary emissions and significant improvement in air quality. The marked decrease in PM_2.5 and SO₂ is largely attributable to a reduction in coal combustion.

We assess the feasibility of ground-based and spaceborne lidars to retrieve profiles of cloud-relevant aerosol concentrations and ice-nucleating particles. The retrieved profiles are in good agreement with airborne in situ measurements. Our methodology will be applied to satellite observations in the future so as to provide a global 3D product of cloud-relevant properties.

Mineral dusts are a source of ice-nucleating particles (INPs) in the atmosphere. Here we present a comprehensive survey of the ice-nucleating ability of naturally occurring quartz. We show the ice-nucleating variability of quartz and its sensitivity to time spent in water and air. We propose four new parameterizations for the minerals quartz, K feldspar, albite and plagioclase to predict INP concentrations in the atmosphere and show that K-feldspar is the dominant INP type in mineral dusts.

We present an over 10-year-long time series of aerosol optical properties (AOPs) measured at a rural boreal forest site. Knowledge of AOPs is needed in determining the direct effect of aerosol particles on climate. We observed decreasing trends in scattering and absorption and increasing trends in backscattering fraction and single-scattering albedo. Trends of single-scattering albedo and backscattering fraction increased the efficiency of aerosol particles to scatter radiation back into space.

Modern climate models are affected by systematic biases that harm their ability to produce reliable seasonal forecasts and climate projections. In this study, we investigate causes of biases in wind patterns over the tropical Atlantic during northern spring in three related models. We find that the wind biases are associated with an increase in excess rainfall and convergence in the tropical western Atlantic at the start of April, leading to the redirection of trade winds away from the Equator.

This study reports the first flaring in situ measurements in southern West Africa. According to the measurements, oil rig flaring plumes in Ghana lead to increases in NO₂ and aerosols but not always in CO and not in SO₂. Flaring measurements can be reproduced using FLEXPART model, adjusting both the emission flux and the injection height. The DACCIWA satellite flaring inventory provides a reasonable estimate of flaring emission.

The scientific community often focuses on the vertical transport of pollutants by clouds for those with bases at the planetary boundary layer (such as typical fair-weather cumulus) and the outflow from thunderstorms at their tops. We demonstrate complex aerosol and cloud features formed in mid-level thunderstorm outflow. These layers have strong relationships to mid-level tropospheric clouds, an important but difficult to model or monitor cloud regime for climate studies.

Sounding rockets are the only means of measuring small-scale structures (i.e., spatial scales of kilometers to centimeters) in the Earth's middle atmosphere (50–120 km). We present and analyze brand-new high-resolution measurements of atomic oxygen (O) concentration together with high-resolution measurements of ionospheric plasma and neutral air parameters. We found a new behavior of the O inside turbulent layers, which might be essential to adequately model weather and climate.

Box model simulations, based on the volatility basis set approach, of smog chamber wood combustion experiments conducted at different temperatures (−10 °C, 2 °C, 15 °C), emission loads, combustion conditions (flaming and smoldering) and residential stoves fabricated in the last 2 decades. Novel parameterization methods based on a genetic algorithm approach allowed estimation of precursor class contributions to SOA and evaluation of the effect of emission variability on SOA yield predictions.

We combined the online observations of aerosol components and a regional chemical transport model to investigate the response of aerosol chemistry to the stringent clean air actions in Beijing. We found a rapid transition in winter aerosol composition from 2014 to 2017 with decreased sulfate contribution and increased nitrate fraction and evaluated the underlying drivers. The anthropogenic emission reductions in Beijing and its surrounding regions are identified to play a major role.

The Arabian Peninsula is a global hot spot of ozone pollution. Our measurements, made on a ship in summer 2017, indicate underlying reasons. Despite being at sea, we observed ozone-forming reactive trace gases (measured as so-called total OH reactivity) comparable to highly populated urban regions in amount and composition. This is due to strong emissions from oil extraction and ship traffic. These emissions were quickly converted to ozone due to intense solar irradiation and high temperatures.

We conducted airborne vertical profile measurements of water vapor stable isotopes to examine how boundary layer, cloud, and mixing processes influence the vertical structure of deuterium excess in the lower troposphere. We discuss reasons our observations are consistent with water vapor isotope theory on some days and not others. Deuterium excess may be useful for understanding complex processes occurring at the top of the boundary layer, including cloud formation, evaporation, and air mixing.

Black carbon (BC) contributes two-thirds of the climate impact of carbon dioxide, pushing methane into third place of the human contributors to global warming. This study shows that contributions from biomass burning (producing marginal lensing effect) have a strong spatial variation, from 20 % in Europe to 60 % in Africa. Thus, the inclusion of strong lensing-related absorption enhancement to all BC particles in previous estimates may lead to overestimating their positive radiative forcing.

We perform the first multi-model comparison of the impact of nudged meteorology on the stratospheric residual circulation (RC) in chemistry–climate models. Nudging meteorology does not constrain the mean strength of RC compared to free-running simulations, and despite the lack of agreement in the mean circulation, nudging tightly constrains the inter-annual variability in the tropical upward mass flux in the lower stratosphere. In summary, nudging strongly affects the representation of RC.

We find a pronounced maximum in aerosol extinction in the upper troposphere and lower stratosphere over the Tibetan Plateau during the Asian summer monsoon, caused mainly by mineral dust emitted from the northern Tibetan Plateau and slope area, lofted to and accumulating within the anticyclonic circulation. Mineral dust, water-soluble compounds, such as nitrate and sulfate, and associated liquid water dominate aerosol extinction around the tropopause within the Asian summer monsoon anticyclone.

We analyse and quantify the effect of above-cloud aerosol (AAC) loading on the underlying cloud properties in the South Atlantic Ocean. We use a synergy of remote sensing retrievals collocated with ERA-Interim meteorological profiles. The results show that for larger loads of AACs, clouds are optically thicker, with an increase in liquid water path by 20 g m⁻² and lower cloud-top altitudes. We also observe a strong covariation between the aerosol plume and the presence of water vapour.