Events of new particle formation (NPF) were analyzed objectively in a 10-year data set of hourly particle size distributions recorded on Mt. Zeppelin, Spitsbergen, Svalbard. Three different types of NPF events were identified that were hypothesized to be different expressions of related source processes. Back trajectories and ancillary atmospheric and marine data strongly point to marine biogenic sources causing new particle formation in the summer Arctic.

This paper presents atmospheric black carbon (BC) data collected in South Africa (SA). In general, BC level were higher than in the developed world. At one site, five sources were identified, with household combustion as well as savannah and grassland fires the most significant sources during winter and spring, while coal-fired power stations, pyrometallurgical smelters and traffic contributed year round.

Predicting air pollution events over megacities requires, notably, continuous and accurate determination of the boundary layer height (BLH). Based on gravity wave theory, a new approach (CRGM) is developed to overcome existing algorithms' weakness in order to accurately reproduce the fluctuations of the BLH under various atmospheric pollution conditions from lidar observation. Comprehensive evaluation highlights strong effectiveness of this new method.

We studied new particle formation under clear-sky conditions in the boreal forest in southern Finland. We compared varying conditions between new particle events and nonevents. We then formulated a threshold value that separates new particle events from nonevents and reached a probability distribution for the frequency of new particle formation. This study serves as the basis for scientists aiming to improve their understanding of new particle formation.

The influence of pollution on the precipitation formation in warm conveyor belts (WCBs), the most rising air streams in low-pressure systems is investigated. We investigate in detail the cloud properties and resulting precipitation along these rising airstreams which are simulated with a global climate model. Overall, no big impact of aerosols on precipitation can be seen, however, when comparing the most polluted/cleanest WCBs, a suppression of precipitation by aerosols is observed.

Nitro-polycyclic aromatic hydrocarbons (NPAH) are ubiquitous and formed in polluted air, but little is known about their abundance in background air and long-range transport potential. We studied NPAHs in the gas and particulate phases of aerosols in the marine (Mediterranean) and continental (Gt. Hungarian Plain) environment in summer. The NPAH levels determined in the southeastern outflow of Europe are the lowest ever reported and confirm intercontinental transport potential.

This paper compares the particle linear depolarization ratio retrieved by AERONET with respect to the one measured by lidar. We can confirm that AERONET derived linear particle depolarization ratio can be used to retrieve the dust ratio in mixed dust plumes. We expect that our results can increase availability of AERONET sun–sky radiometer data in the atmospheric aerosol research and aerosol type classification.

A unique environmental electron microscope was used for monitoring the evaporation of salty frost flowers. We observe a cohesive villous brine surface layer facilitating the formation of NaCl microcrystals at temperatures below −10°C as the brine oversaturation is achieved. This finding confirms the increased surface area and thus also the enhanced heterogeneous reactivity; however, no support for the easiness of fragmentation to produce aerosols can be provided.

We use observations from 2004 to 2012 to obtain estimates of the aerosol–cloud radiative effect, including its uncertainty, for dust aerosol influencing Atlantic marine stratocumulus clouds (MSc) off the coast of north Africa. Saharan dust modifies MSc in a way that acts to cool the planet. There is a strong seasonal variation, with the aerosol–cloud radiative effect switching from significantly negative during the boreal summer to weakly positive during boreal winter.

Heterogeneous uptake is one of the mechanisms influencing the amounts of alkylamines and ammonia in atmospheric particles. The present study investigates the simultaneous uptake of dimethylamine and ammonia at different gas molar ratios into sulfuric and oxalic acid particles at low and high relative humidity. Results showed that the particulate dimethylaminium/ammonium molar ratios changed substantially during the uptake process, depending on the extent of neutralisation and phase state.

Peroxyacetyl nitrate (PAN) plays a key role in atmospheric chemistry and long-range transport of pollution. In this paper, we present measurements of PAN from the Tropospheric Emission Spectrometer, an instrument on board the NASA Aura satellite since 2004. We focus on measurements of PAN in tropical regions, where data from ground-based and aircraft campaigns are particularly sparse. We observe temporal changes in PAN associated with changes in fires, convection and emissions.

Mercury is a toxic, global pollutant released to the air from human activities like coal burning. Chemical reactions in air determine how far mercury is transported before it is deposited to the environment, where it may be converted to a form that accumulates in fish. We use a 3-D atmospheric model to evaluate a new set of chemical reactions and its effects on mercury deposition. We find it is consistent with observations and leads to increased deposition to oceans, especially in the tropics.

Isotope studies can constrain budgets of secondary organic aerosol (SOA) that is pivotal to air pollution and climate. SOA from α-pinene ozonolysis was found to be enriched in ¹³C relative to the precursor. The observed difference in ¹³C between the gas and particle phases may arise from isotope-dependent changes in branching ratios. Alternatively, some gas-phase products involve carbon atoms from highly enriched and depleted sites, giving a non-kinetic origin to the observed fractionations.

We analyze differences in existing air pollutant emission estimates to better understand the magnitude of emissions as well as the source regions and sectors of air pollution in China. We find large disagreements among the inventories, and we show that these differences have a significant impact on regional air quality simulations. Better understanding of air pollutant emissions at more disaggregated levels is essential for air pollution mitigation in China.

The study presents a new method for estimating particulate matter emissions from large wildfires. The method relies solely on satellite observations of fire activity and particles suspended in the atmosphere. The results indicate that temperate and boreal forest fires in North America emit similar amounts of particles per unit of fire radiative power. The findings differ from estimates by modelling studies which suggest much larger emissions for boreal events compared to temperate fires.

Geoengineering is a controversial proposal to counteract global warming by reducing the incoming solar radiation. Solar dimming could restore preindustrial temperatures, but global rainfall patterns would be altered. We analyze the global rainfall changes in 11 climate model simulations of solar dimming to better understand the underlying processes. We conclude that tropical precipitation would be substantially altered, in part due to changes in the large-scale atmospheric circulation.

The first observations made by a complete PANSY radar system (Program of the Antarctic Syowa MST/IS radar) installed at Syowa Station were successfully performed from 16 to 24 March 2015. Over this period, quasi-12 h period disturbances in the mesosphere at heights of 70 to 80 km were observed. Combining the observational data and numerical simulation outputs, we found that quasi-12 h disturbances are due to large-scale inertia–gravity waves, not to semi-diurnal migrating tides.

There are less long-term surface ozone measurements on the Southern than on the Northern Hemisphere, which makes it difficult to thoroughly understand global ozone chemistry. We have analyzed a new, 20-year-long ozone dataset measured at 2200 m asl at El Tololo, Chile, and show that the annual cycle of ozone is mainly driven by ozone transport from the stratosphere to the troposphere. As well, we illustrate that the timing of the annual maximum is regressing to earlier in the year.

Nitrogen oxides (NO_x) largely control the ozone budget in the troposphere globally. Dinitrogen pentoxide (N₂O₅) is an important species as a nighttime reservoir for nitrogen oxides. Loss of N₂O₅ to aerosol particles is therefore important for the budget of NO_x and the oxidation capacity. Here we provide direct evidence for its efficient accommodation into aqueous aerosol particles and its fast dissociation, which has not been elucidated as directly in previous studies.

Particulate matter levels were monitored at six major roadway intersections in the Kathmandu Valley during two seasons in 2014. The study documented distinct seasonal (dry season versus wet season) and diel variations in particulate matter levels. This study suggests traffic-related emissions, and soil–dust–construction materials were found to be a major source of particulate matter at these locations.