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In order to investigate the seasonal variations in the chemical characteristics of PM2.5 at the plateau slope of a mountain city in southwest China, 178 PM2.5 filters (89 quartz and 89 Teflon samples for PM2.5) were collected to sample the urban air of Wenshan in spring and autumn 2016 at three sites. The mass concentrations, water-soluble inorganic ions, organic and inorganic carbon concentrations, and inorganic elements constituting PM2.5 were determined, principal component analysis was used to identify potential sources of PM2.5, and the backward trajectory model was used to calculate the contribution of the long-distance transmission of air particles to the Wenshan area. The average concentration of PM2.5 in spring and autumn was 44.85 ± 10.99 μg/m3. Secondary inorganic aerosols contributed 21.82% and 16.50% of the total PM2.5 in spring and autumn, respectively. The daily mean value of OC/EC indicated that the measured SOC content was generated by the photochemical processes active during the sampling days. However, elements from anthropogenic sources (Ti, Si, Ca, Fe, Al, K, Mg, Na, Sb, Zn, P, Pb, Mn, As and Cu) accounted for 99.38% and 99.24% of the total inorganic elements in spring and autumn, respectively. Finally, source apportionment showed that SIA, dust, industry, biomass burning, motor vehicle emissions and copper smelting emissions constituted the major components in Wenshan. This study is the first to investigate the chemical characterizations and sources of PM2.5 in Wenshan, and it provides effective support for local governments formulating air pollution control policies. [ABSTRACT FROM AUTHOR]

Airborne fungi have posed potential threats to public health. However, limited information about their variations in haze episodes was available, especially for the air polluted regions in Northeast China. This study aimed to investigate the disparity of fungal richness, taxonomy, and pathogens between hazy days and non-hazy days at an urban site in Northeast China. This study also aimed to explore the potential influence of air mass trajectories and environmental factors on airborne fungi. This study identified six pathogenic fungal species and four pathogenic fungal genera, accounting for 1.15% of the total fungi. The analysis results suggested that fungi were found more prone to attach to coarse particles. Fungal richness, fungal taxonomy, and pathogenic types in hazy samples were significantly higher than those in non-hazy samples with statistical significance. Furthermore, air masses passed through densely-populated and polluted regions were found associated with higher 18S rRNA concentrations. Increased concentrations of particulate matter and water-soluble ions during polluted episodes contributed to higher fungal abundance. However, no significant disparities in community diversity were detected. This study observed the strong wind, dry air, and high temperatures in favor of fungal survival. The seasonal variation of these factors promoted fungal communities in the same episodes or approaching sampling time more easily clustered together. The results of this study have implications for revealing multifaceted information of inhalable particles on hazy days and provide references to public health exposure assessment. Image 1 • Haze pollution contributes to more fungal abundance, taxonomy, and pathogenic types. • Air masses from polluted regions are associated with higher 18S rRNA concentrations. • Fungal abundance was related more closely to PM and ions than meteorologic factors. [ABSTRACT FROM AUTHOR]

The sweet chestnut (Castanea sativa Mill.) is the only native species of this genus in Europe, where it faces various threats that are causing a severe decrease in populations, with the resulting loss of genetic diversity. In the Iberian Peninsula, it is of high economic and ecological importance, being well represented, especially in northern areas, whilst it is limited to isolated populations in medium-range mountains in southern Spain (Andalusia region). Taking advantage of this fragmented distribution, this study analyzes the dynamics of atmospheric transport of Castanea pollen through Andalusia region in order to obtain a better understanding of the pollination pathways as a key aspect of the floral biology of this partially anemophilous species. The aerobiological characteristics of this species are also of special interest since its pollen has been recognized as allergenic. Pollen transport pathways were studied by applying back-trajectories analysis together with aerobiological, phenological, land cover, and meteorological data. The results reveal that airborne Castanea pollen concentrations recorded in the city of Cordoba, in the center of Andalusia region, reach medium- and even long-range distances. The backward-trajectory analysis indicates that most of the pollen data detected outside the Castanea flowering season were related to westerly slow and easterly airflows. Furthermore, some of the case studies analyzed indicate the presence of southerly airflow patterns, which could influence medium- and long-range transport events from chestnut populations further south, even from those located in north African mountains. The integrated analysis of the results offers us better knowledge of the cross-pollination pathways of this endangered species, which help us to understand its genetic flows, as a basis for designing conservation strategies for this highly fragmented species in southern Spain. [ABSTRACT FROM AUTHOR]

In this study, by using ion chromatography, we analyzed the chemical composition of snow deposited in 1976–2012 at three sites within the Indian Ocean sector of East Antarctica (VK-55, SW-42, and PV-10) to establish the relationships between the formation of the chemical composition of snow and varying mechanisms of atmospheric circulation. Dating of samples was carried out on the basis of sulphate peaks related to the material derived from the Pinatubo volcanic eruption (1991). Chemical compositions of snow showed spatial inhomogeneity even over relatively short distances (of about 40 km) in central East Antarctica. The reasons for the inhomogeneity may have been related to local topography and snow redistribution by wind in areas with extremely low accumulation, as well as to peculiarities of atmospheric circulation processes. According to the principal component analysis (PCA) and 5-day backward trajectories, it was determined that for site PV-10 (400 km from the Indian Ocean coast), zonal circulation in the lower troposphere associated with the cyclonic centers of the Southern Ocean was a leading process while the inland sites (VK-55 and SW-42) were influenced by a combination of processes involving meridional circulation, air mass transport, and transformation in the troposphere over the Antarctic continent. [ABSTRACT FROM AUTHOR]

Quantification of suspended particulate matter (SPM) measurements—together with statistical tools, polar contour maps and backward air mass trajectory analyses—were implemented to better understand the main local and remote sources of contamination in this pristine region. Field campaigns were carried out during the austral summer of 2016–2017 at the "Gabriel de Castilla" Spanish Antarctic Research Station, located on Deception Island (South Shetland Islands, Antarctic). Aerosols were deposited in an air filter through a low-volume sampler and chemically analysed using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES). Elements such as Al, Ca, Fe, K, Mg, Na, P, S, Cu, Pb, Sr, Ti, Zn, Hf, Zr, V, As, Ti, Mn, Sn and Cr were identified. The statistical tools together with their correlations (Sr/Na, Al/Ti, Al/Mn, Al/Sr, Al/Pb, K/P) suggest a potentially significant role of terrestrial inputs for Al, Ti, Mn, Sr and Pb; marine environments for Sr and Na; and biological inputs for K and P. Polar contour graphical maps allowed reproducing wind maps, revealing the biological local distribution of K and P (penguin colony). Additionally, backward trajectory analysis confirmed previous affirmations and atmospheric air masses following the Antarctic circumpolar pattern. [ABSTRACT FROM AUTHOR]

Based on hourly concentration data of PM 10 and PM 2.5 from 2017 to 2019 and wind speed and direction data at the corresponding times in Yangquan, an urban valley of the Taihang Mountains, the characteristics of air transport in a cross-valley urban area and their influence on aerosols in Yangquan were analyzed using the HYSPLIT model, cluster analysis, and the potential source contribution factor and concentration weight trajectory methods. The pollutant transport characteristics on the east and west sides of the Taihang Mountains were evaluated. The diurnal variation of the aerosols showed a single peak and single valley, with continuous improvements in aerosol concentration from evening to the morning of the next day. The maximum aerosol concentration occurs at 10:00-11:00 in winter and at 09:00 in other seasons, whereas the minimum value occurs at 15:00-16:00. The monthly mean aerosol concentration in Yangquan was highest in January and lowest in August, and PM 10 was also high in March and April. The most frequent surface wind directions in Yangquan are easterly and westerly due to the topography of the cross valley. The average concentrations of aerosols were highest in the calm wind weather. Furthermore, the dust weather caused by the westerly wind in spring and autumn and the easterly transport in winter also causes an increase in aerosol concentration in Yangquan. The backward trajectories in combination with the pollution characteristics showed that 26.2% of the pollution trajectories are in spring, 36.4% are in autumn, and 33.7% are in winter, and that these are mainly distributed in the southwest and southeast of Yangquan and also in the northeast in winter. There was significant fine particle transport on both sides of the mountains, and the trajectories originating from or passing through the west side of the Taihang Mountains also transport coarse particles. As indicated by the pollution trajectory, the westerly air transport has an impact on PM 10 in excess of the standard rate. The easterly transport has larger noise and mainly affects the exceedance rate of PM 2.5 . The main potential source areas of aerosol pollution in Yangquan differ in different seasons. The potential source areas are to the southwest and southeast of Yangquan in spring, the southwest and south of Yangquan in autumn, and the south and east of Yangquan in winter. The areas with high PSCF and CWT in PM 2.5 were in the southeast region, but those for PM 10 were in the southwest region. The area southeast of Shanxi and the border area north of Henan are the main source areas. Based on the influence of aerosol pollution transmission in Yangquan, the cross-valley urban area is affected simultaneously by the areas east and west of the Taihang Mountains, especially by PM 2.5 transport from east to west.

In this study, the 24-hour backward trajectories of air mass at ground level(10 m)in Nanjing were calculated by using the HYSPLIT model with the NCEP global reanalysis data from April 1st to October 31st, 2017. The backward trajectories were then combined with the hourly concentration data of O 3 in Nanjing for trajectories clustering analysis and potential pollution sources analysis. The results show that in 2017, the maximum daily 8 h running average O 3 level in Nanjing was around 12-261 μg·m -3 with 58 days of O 3 pollution in Nanjing, mainly in the spring and summer. The monthly variation of O 3 showed a single peak, with the highest O 3 concentration, as well as the most days exceeding the standard, occurring in June; the diurnal variation of O 3 was unimodal and reached its peak around 14:00. A total number of 5136 trajectories were obtained by simulation, among which the exceeded trajectories accounted for approximately 10%. The exceedance trajectories in May and June were significantly higher, accounting for 60% of the total exceedance trajectories. Six ground-level air mass transporting pathways were identified through clustering analysis, from the NNE, NW, SW, SSE, SE, and NE directions. The SE and SSE directions with higher O 3 levels were the dominant transport routes of O 3 pollution, contributing to 23.33% and 20.76% of backward trajectories, respectively. As for the potential pollution source analysis, the area with high WCWT value distribution matched the WPSCF result, indicating that the potential sources of O 3 pollution were mainly distributed in Changzhou, Wuxi, Suzhou, Huzhou, and other cities around Taihu Lake. Additionally, cities located around Nanjing, such as Taizhou, Ma'anshan, Wuhu, Chuzhou, Nantong, and Lianyungang, were considered the secondary potential sources. The results indicate that O 3 pollution in Nanjing is a regional issue and its control requires joint prevention and control strategies in the Yangtze River Delta.

Suspended particulate matter (SPM) measurements and backward air mass trajectory analysis using the HYSPLIT model were performed to better understand the main sources and transport pathways of heavy metals in atmospheric aerosols reaching the Antarctic region. Field campaigns were carried out during the austral summer 2016-2017 at the "Gabriel de Castilla" Spanish Antarctic Research Station, located on Deception Island. Aerosols were deposited in an air filter through a low-volume sampler and chemically analysed using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The study of air masses and high enrichment factor values of several elements (Hf, Zr, As, Cu, Sn, Zn, Pb) together with their correlations (Hf/Zr, V/As, Ti/Mn and Cu/Sn) suggests a potentially significant role of three main sources in this area: remote maritime traffic, local petrol combustion (generators and/or tourist cruises), and remote/local crust. Additionally, the investigation of atmospheric flow patterns through backward trajectory analysis revealed that Hf/Zr correlation was related to a remote crustal origin, V/As to anthropogenic local pollution, Ti/Mn to terrestrial inputs on the island and Cu/Sn to remote anthropogenic sources. Overall, the present study demonstrates the existence of anthropogenic pollution at this remote site from distant as well as local sources following the Antarctic circumpolar wind pattern., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

• Primitive e-waste dismantling led to the highest OPE levels in the atmosphere. • OPEs in the urban region were largely derived from industrial emissions. • Surface evaporation and air advection also contributed OPEs in the urban air. • The compositions at the background site suggest atmospheric reaction loss of OPEs. • Emission sources of TEP and TDCIPP nearby the background site were observed. Organophosphate esters (OPEs) are a focus of research because they are ubiquitous in the environment; however, there is still a limited understanding of the behaviors and fate of OPEs in the environment. In this study, we measured OPEs in fine particulate matter (PM 2.5) collected from three regions in South China that have potentially different sources. The concentrations of ∑OPEs in the rural electronic waste (e-waste) recycling area (3852–57,695 pg/m3 with a median of 10,955 pg/m3) were significantly higher than those in the urban and background areas with concentrations of 314–9721 pg/m3 (median = 2346 pg/m3) and 667 and 109,599 pg/m3 (median = 2170 pg/m3), respectively. The OPE compositions in the urban and e-waste areas were generally similar. Correlations analysis with other components of PM 2.5 (organic carbon, elemental carbon, and water soluble ions) indicated primary industrial and e-waste sources of OPEs in the urban and e-waste regions, respectively. Correlation analysis also revealed that relative humility played an important role in their air concentrations in the urban and background regions. The air-parcel backward trajectories of the background site demonstrated regional atmospheric transport of OPEs to this region from both the eastern industrial cities and the northern e-waste recycling region. [ABSTRACT FROM AUTHOR]

Online monitoring data of atmospheric pollutants and meteorological parameters in Zhengzhou from 2014 to 2017 were collected to analyze the concentration levels, seasonal variations, and the ratio characteristics of atmospheric pollutants, as well as the effects of meteorological conditions on these pollutants. Results show that the annual average concentrations of PM 2.5 and PM 10 in the four years were (88±49.8), (95.8±60.2), (78.6±70.3), and (72.0±53.5) μg·m -3 , and (158.5±65.3), (167.7±82.6), (144.5±91.5), and (132.7±70.3) μg·m -3 , respectively, and were approximately two times higher than the grade Ⅱ annual limits set by China. Fuel combustion and the formation of secondary pollutants were the main sources of PM 2.5 in Zhengzhou. Moreover, the contribution of coal combustion was found to be decreased, while that of traffic sources increased year by year. Low wind speed, high humidity, and reduced precipitation are important meteorological factors that contribute to serious air pollution. In addition, the Potential Source Contribution Function and the Concentration-Weighted Trajectory were used to analyze the potential sources, and the contribution of these sources to the distribution of PM 2.5 . The potential source areas of PM 2.5 were mainly distributed in neighboring cities and provinces, such as Shanxi, Shaanxi, Hubei, Shandong, and Hebei. The short-distance transmission was found to contribute significantly to the mass concentration of PM 2.5 .