Size-resolved chemical information of particulate matter remains unclear in China due to a paucity of measurement data. One-year observation of water-soluble ions, carbonaceous species and trace elements in size-resolved particles with cutoff points as 0.43, 0.65, 1.1, 2.1, 3.3, 4.7, 5.8 and 9.0 μm were conducted in mega city Beijing. This unique dataset provided multidimensional insights into the sources among different size fractions, seasons or wind flows and between non-haze and haze days.

Clouds transport air from near the surface to higher altitudes. However, the amount of air transported in this way is poorly understood. In this study, measurements from aircraft of small clouds over Texas show that the amount is limited to the volume of the visible cloud and not more. This means that these clouds are not very effective at transporting pollution and moisture to upper reaches of the atmosphere, which in turn affects their redistribution and wider impact.

The spatial distributions and trends of above-cloud aerosol (ACA) events are studied using seven and a half years of MODIS, OMI, and CALIOP data. The active- (CALIOP) and passive-based (MODIS-OMI) methods have their advantages and caveats, and thus both are used to get a thorough and robust comparison of ACA distribution and climatology. For the first time, baseline above-cloud CALIOP aerosol optical depth and OMI aerosol index thresholds are derived and examined for each sensor.

This manuscript describes the emissions from shipping in European sea areas. The work is based on automatic position reports (AIS) sent by ships and reflects realistic activity patterns of ships. The work demonstrates that it is feasible to construct full bottom-up emission inventories based on large-volume activity data sets.

A new Fe dissolution scheme is developed and is applied to an atmospheric chemistry transport model to estimate anthropogenic soluble Fe deposition. Our improved model successfully captured an inverse relationship of Fe solubility and total Fe loading. Our model estimated the low end of Fe solubility compared to the previous studies. Our model results suggest that human activities contribute to about half of bioavailable Fe supply to significant portions of the oceans in the Northern Hemisphere.

Our sensitivity studies based on air parcel trajectories confirm that Polar stratospheric cloud (PSC) formation is quite sensitive to water vapour and temperature changes. Considering water vapour time series from satellite measurements we do not find a consistent, significant trend in water vapour in the lower stratosphere during the past 15 years (2000–2014). Thus, the severe dentrification observed in 2010/2011 cannot be directly related to increases in stratospheric water vapour.

NOx is formed under high-temperature conditions such as combustion. When NOx enters the atmosphere, it alters the chemistry of organic emissions and can form organonitrates. Depending on the conditions, NOx may increase or decrease resulting aerosol concentrations. We expanded the two-dimensional volatility basis set (2D-VBS) to model organonitrates and the effect on aerosol concentrations. We discuss the mathematical framework of the model and include the code in the Supplement.

Heterogeneous nucleation is a phenomenon that starts the condensation of supersaturated vapours on solid surfaces. An example is the formation of cirrus clouds in the atmosphere: their formation is often triggered at relative humidities clearly above 100%. We derive a new theory that can be used to calculate the threshold supersaturation of heterogeneous nucleation of water vapour on nanoparticles and show that it performs significantly better than older theories when compared to lab experiment.

A comprehensive aerosol-cloud-precipitation interaction (ACI) scheme from emissions to precipitation has been developed under the CMA chemical weather modeling system GRAPES/CUACE. The ACI for January 2013 has been studied using this model. The interactive microphysical properties of clouds improve the precipitation, showing 24 to 48 % enhancements of threat score for 6 h precipitation in all regions and reduction of the regional mean bias of temperature by 3 °C in certain precipitation events.

Gravity waves from deep convection along with terrain and coastal effects control the development and movement of squall lines that affect the diurnal cycle of rainfall over New Guinea and its northern coast. Days with offshore propagating systems are governed by background conditions (more mid-tropospheric moisture, CAPE, and low-level convergence) as opposed to days without offshore propagation. Our results shed some light on the physics and dynamics of Maritime Continent organised convection

An aerosol retrieval and error analysis algorithm using OMI measurements based on an optimal-estimation method was developed in this study. The aerosol retrievals were validated using the DRAGON campaign products. The estimated errors of the retrievals represented the actual biases between retrieval and AERONET measurements well. The retrievals, with their estimated uncertainties, are expected to be valuable for relevant studies, such as trace gas retrieval and data assimilation.

We quantify the processes responsible for methane growth rate variability in the period 1990 to 1995, a period with variations in climate and radiation due to the Pinatubo eruption. We find significant contributions from changes in the methane emission from wetlands, and in the methane removal by OH caused by stratospheric aerosols, by the decrease in temperature and water vapour, by stratospheric ozone depletion and by changes in emissions of CO and NMVOC.

Fifteen years of gas and particle measurements at eight monitoring sites comprising the Southeastern Aerosol Research and Characterization (SEARCH) network offer insights into the sources of organic aerosol in the southeastern United States. Between 1999 and 2013, mean organic aerosol concentrations declined due to decreasing particle emissions from motor vehicles and to less secondary organic aerosol with declining emissions of sulfur dioxide, nitrogen oxides, and volatile organic compounds.

Tar balls (TBs) are a specific particle type which is abundant in the global troposphere, in particular in biomass smoke plumes. These particles belong to the family of atmospheric brown carbon (BrC), which can absorb light in the visible range of the solar spectrum. The refractive index of TBs falls much closer to that of soot than of other light-absorbing species such as humic-like substances. These findings may have substantial influence on the understanding of global radiative energy fluxes.

Aerosol radiative effects are of great importance for climate studies over South Asia, such as the weakening of the South Asian monsoon in the 20th century. This study reveals the altitude dependence of commonly underestimated aerosol radiative properties over this region. It further demonstrates the importance of constraining aerosol vertical distributions and partitioning of scattering vs absorbing aerosols in simulating the subsequent regional dynamical and hydrological responses to aerosols.

“Breathing” ozone can have harmful effects on sensitive vegetation when sufficient ozone enters the plant leaves through the stomatal pores. Here we show that cis-abienol, a semi-volatile organic compound secreted by the leaf hairs (trichomes) of various tobacco varieties, protects the leaves from breathing ozone. Ozone is efficiently removed by chemical reactions with cis-abienol at the plant surface, forming oxygenated VOC (formaldehyde and methyl vinyl ketone) that are released into the air.

The hygroscopicity of nucleated nanoparticles was measured in the presence of sulfuric acid, sulfuric acid-dimethylamine, and sulfuric acid-organics derived from α-pinene oxidation during CLOUD7 at CERN in 2012. The hygroscopicity parameter κ decreased with increasing particle size, indicating decreasing acidity of particles.

We have studied the impacts of a volcanic eruption during solar radiation management (SRM) using an aerosol-climate model ECHAM5-HAM-SALSA and an Earth system model MPI-ESM. A volcanic eruption during stratospheric sulfur geoengineering would lead to larger particles and smaller amount of new particles than if an volcano erupts in normal atmospheric conditions. Thus, volcanic eruption during SRM would lead to only a small additional cooling which would last for a significantly shorter period.

Concentrations and depositions of various nitrogen species of water-soluble fraction in aerosols were observed during spring over the eastern China seas and northwestern Pacific Ocean. Results revealed nitrogen deposition associated with the sea fog weather was 6 times higher than that of spring supply from the Yangtze River to the ECS shelf. The DON emission had occurred most likely during sea spray. Weather conditions modulate the nitrogen exchange at the ocean-atmosphere boundary.

We report regional and global emissions estimates of HFC-152a using high frequency measurements from 11 observing sites and archived air samples dating back to 1978 together with atmospheric transport models. The "bottom-up" emissions of HFC-152a reported to the UNFCCC appear to significantly underestimate those reported here from observations. This discrepancy we suggest arises from largely underestimated USA and undeclared Asian emissions.

We evaluate aerosol size distributions predicted by GEOS-Chem-TOMAS using measurements from the peak of Whistler Mountain. We improve model-measurement comparisons of aerosol number, size, and composition during periods of free-tropospheric and boundary-layer influence by developing simple filtering techniques, and determine the influence of Asian anthropogenic and biomass burning emissions. The low-cost filtering techniques and source apportionment methods can be used for other mountain sites.

We evaluate the performance of high-resolution simulations of the Weather Research and Forecasting model coupled with Chemistry in capturing spatiotemporal variability of aerosol optical properties by comparison with ground- and space- based remote-sensing observations and investigate causes of model biases. This work contributes to assessing the model's ability to describe drivers of aerosol direct radiative forcing in the contemporary climate and to improving confidence in future projections.