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• Size-resolved Effective density of submicron atmospheric particles in Shenzhen were measured online using DMA-CPMA-CPC combined system. • Bimodal distribution feature of particle effective density was identified, including a main density mode and a sub density mode, by bimodal Gaussian fitting. • Particle effective density exhibited a high occurrence frequency of bimodal distribution, and two density modes exhibited opposite size distribution trends. • Effective density variation was highly correlated with the proportion of OA, sulfates and BC. Effective density (ρ eff) is one of the most important physical properties of atmospheric particles, providing important references in exploring the emissions and aging processes of fresh particles. In this study, a combined system of differential mobility analyzer, centrifugal particle mass analyzer, and condensation particle counter was used to periodically measure the ρ eff of atmospheric particles in Shenzhen from Oct. 2021 to Jan. 2022. Results showed that the ρ eff of particles with various size presented a bimodal distribution, which could be divided into main density (ρ m , main peak, corresponding to relatively dense particles after aging) and sub density (ρ s , sub peak, corresponding to fresh particles). The occurrence frequencies of ρ s of particles with diameters of 50 and 80 nm were less than 20%, but were as high as about 40% of that with diameters from 120 to 350 nm. The ρ m showed increasing trend with the size of particles, while ρ s decreased as the increasing of the size of particles. The ρ eff on pollution day varied significantly with chemical compositions. The increasing of the proportion of sulfate could promote the increasing of ρ eff , while black carbon and organic matter caused opposite effects, which may be related to various factors, including the difference of the material density and morphology of various chemical components. The ρ eff of 50, 80 and 120 nm particles decreased considerably during the new particle formation event, indicating that organic condensation was an important contributor to new particle growth. [ABSTRACT FROM AUTHOR]

Wastewater treatment plants (WWTPs) are a crucial source of bioaerosols, which account for both environmental and health hazards. Although various culture-based studies on bioaerosols have been reported, little knowledge remains about distribution and potential risks for more omnipresent non-culturable bacterial aerosols. Here, in summer, an eight-stage Andersen air sampler was applied to capture particles of various sizes from the atmospheric environment of eight treatment units from two WWTPs in northeastern China. Particles of various sizes in aeration tank (AT) were sampled in autumn and winter. The abundance and community composition of the bacterial aerosols were investigated using 16S rRNA gene sequencing. In order to explore the importance of particle size on community composition of bacterial aerosols, this study investigated the particle size distribution of bacterial aerosols in different treatment units. The results indicated that the sludge dewatering room was the major source of bacterial aerosols in both WWTPs, with the abundance of stage VII (0.65–1.1 μm) demonstrating a 4-fold to 9-fold increase when compared to any other treatment unit. The highest relative abundance of bacterial aerosols was in autumn, while the lowest was found in winter. However, most particles detected in autumn were larger than 4.7 µm in diameter, while submicron particles (less than 1.1 µm, over 40%) were detected primarily in winter. The most 15 dominant bacterial aerosol genera in were observed at submicron level, and about half of the genera (6 and 8) were detected as human pathogens, suggesting their easier penetration to human respiratory tracts. This study demonstrates that size distribution characteristics should be crucial information for the comprehensive assessment of the potential health risks of bacterial aerosols from WWTPs. [ABSTRACT FROM AUTHOR]

• NO3- concentrations in coarse particles show elevations in warm seasons. • Size distributions of semi-volatile species have a dependency on ambient temperatures. • Relative humidity plays a role in driving seasonal changes of PM size distributions. • Heterogeneous formations of secondary salts contribute ∼20% of speciated coarse PM. Size-segregated ambient particulate matter (PM) samples were collected seasonally in suburban Nanjing of east China from 2016 to 2017 and chemically speciated. In both fine (< 2.1 µm, PM 2.1) and coarse (> 2.1 µm, PM >2.1) PM, organic carbon (OC) accounted for the highest fractions (26.9% ± 10.9% and 23.1% ± 9.35%) of all measured species, and NO 3 − lead in average concentrations of water-soluble inorganic ions (WSIIs). The size distributions of measured components were parameterized using geometric mean diameter (GMD). GMD values of NO 3 −, Cl−, OC, and PM for the whole size range varied from < 2.1 µm in winter to > 2.1 μm in warm seasons, which was due to the fact that the size distributions of semi-volatile components (e.g., NH 4 NO 3 , NH 4 Cl, and OC) had a dependency on the ambient temperature. Unlike OC, elemental carbon (EC), and elements, NH 4 +, NO 3 −, and SO 4 2− exhibited an increase trend in GMD values with relative humidity, indicating that the hygroscopic growth might also play a role in driving seasonal changes of PM size distributions. Positive matrix factorization was performed using compositional data of fine and coarse particles, respectively. The secondary formation of inorganic salts contributing to the majority (> 70%) of fine PM and 20.2% ± 19.9% of speciated coarse PM. The remaining coarse PM content was attributed to a variety of dust sources. Considering that coarse and fine PM had comparable mass concentrations, more attention should be paid to local dust emissions in future air quality plans. [Display omitted] [ABSTRACT FROM AUTHOR]

The characteristics of airborne bacteria and fungi in different types of buildings are still unclear. This article applied the culturing and next-generation sequencing methods to characterize the airborne bacteria and fungi in five types of buildings during winter in Kunming, China. Results showed that the mean concentrations of fungi in different buildings were similar (approx. 387 ± 388 CFU/m3). The highest culturable bacterial concentration was found in residences, while the lowest was in the library. Lowering relative humidity, PM2.5 concentration and occupant density can reduce the bacterial concentrations. The major bacterial size in residences and in a hospital was 1.1–2.1 μm, while in other buildings was 2.1–3.3 μm. The PM2.5 concentration and occupant activities are key factors that could affect the microorganism size distributions. The community structures of the bacteria in the library and fungi in the hospital showed distinctive differences from the results in other buildings. The community structure of outdoor microorganisms showed great differences between soil and air samples. This study is helpful to give practical implications for assessing microbial characteristics in different types of buildings and provide valuable data for the formulation of indoor bioaerosol standards in China. [ABSTRACT FROM AUTHOR]

In order to understand the organophosphate flame retardants (OPFRs) pollution and evaluate the inhalation exposure risk in formal e-waste recycling facilities, the air concentrations, particle size distribution and gas-particle partitioning of OPFRs in four typical workshops were investigated. The total Σ 15 OPFR concentrations inside workshops were in the range of 64.7-682 ng/m 3 , with 5.80-23.4 ng/m 3 in gas phase and 58.8-658 ng/m 3 in particle phase. Triphenyl phosphate (TPHP) and tris(2-chloroisopropyl) phosphate (TCIPP) were main analogs, both of which contributed to 49.0-85.7% of total OPFRs. In the waste printed circuit boards thermal treatment workshop, the OPFRs concentration was the highest, and particle-bound OPFRs mainly distributed in 0.7-1.1 μm particles. The proportions of TPHP in different size particles increased as the decrease of particle size, while TCIPP presented an opposite trend. The gas-particle partitioning of OPFR analogs was dominated by absorption process, and did not reach equilibrium state due to continuous emission of OPFRs from the recycling activities. The deposition fluxes of OPFRs in respiratory tract were 65.7-639 ng/h, and the estimated daily intake doses of OPFRs were 8.52-76.9 ng/(kg·day) in four workshops. Inhalation exposure was an important exposure pathway for e-waste recycling workers, and deposition fluxes of size-segregated OPFRs were mainly in head airways region., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Jie Guo reports financial support was provided by National Natural Science Foundation of China. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Brown carbon (BrC) is one of the important light absorption substances that have high light absorption ability under short wavelength light. However, limit studies have focused on the BrC emission from ships. In this study, size-segregated particulate matters (PM) were collected from three different types of ships, light absorption characteristics and size distribution of methanol-soluble BrC and water-soluble BrC in PM from ship exhausts were investigated. Results showed that four-stroke low-power diesel fishing boat (4-LDF) had the highest mass concentrations of methanol-soluble organic carbon (MSOC) and water-soluble organic carbon (WSOC), followed by 2-stroke high-power heavy-fuel-oil vessel (2-HHV), and four-stroke high-power marine-diesel vessel (4-HMV). While 2-HHV had obviously higher light absorption coefficients of methanol-soluble BrC (Abs 365,M ) and water-soluble BrC (Abs 365,W ) in unit weight of PM than the other two types of ships. The tested ships presented comparable or higher absorption efficiency of BrC in water extracts (MAE 365,W ) compared with other BrC emission sources. Majority of BrC was concentrated in fine particles, and the particle size distributions of both Abs 365,M and Abs 365,W showed bimodal patterns, peaking at 0.43-0.65 µm and 4.7-5.8 µm, respectively. However, different particle size distributions were found for MAE 365,M between diesel and heavy fuel oil ships. Besides, different wavelength dependence in particles with different size were also detected. Ship exhaust could be confirmed as a non-ignorable BrC emission source, and complex influencing factor could affect the light absorption characteristics of ship emissions. Particle size should also be considered when light absorption ability of BrC was evaluated., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article., (Copyright © 2023. Published by Elsevier B.V.)

Atmospheric particulate matter (PM) was measured continuously at an urban site in Baoji city in northern China in 2018 to investigate the seasonal distribution characteristics. Coarse PM (PM2.5–10) was more prevalent in spring, substantially due to the regional transport of dust. High loadings of coarse PM were found at night compared to daytime, which could result from high production and unfavorable dispersion conditions. Fine PM (PM2.5) constituted, on average, 54% of the total PM mass concentration, whereas it contributed more than 97% of the total PM number concentration. The number and mass concentrations of fine PM increased substantially in the winter, which was possibly due to the enhanced production of atmospheric secondary processes and coal combustion. Precursor gaseous pollutants and meteorology greatly influenced the PM distributions. Fine PM was associated more strongly with gas pollutants than coarse PM, which suggested that it largely originated from secondary production and combustion sources. High relative humidity appeared to promote the production of fine PM, whereas it facilitated the removal of coarse PM. This study highlights that different air-pollution control strategies should be used for coarse and fine PM according to the distribution characteristics and influencing factors in similar medium-sized urban areas. [ABSTRACT FROM AUTHOR]

The vertical structure of meteorological elements, black carbon (BC), and aerosols were in situ characterized by the King Air 350 aircraft measurements over the northeast of China during an East Asian dust storm event from April 10 to 13, 2023. The main causes of this dust storm event were the strong winds generated by the Mongolian cyclone, the cold front on the ground provided dynamic conditions, and the unstable atmospheric state provided thermal conditions and less precipitation in the dust source areas led to exposed the ground surface. The number concentrations of BC and aerosol had significant vertical distribution. The number concentration of aerosol in the dust storm (DS) layer increased rapidly with height, while the number and mass concentrations of BC were higher and varied slightly with height. The BC core mass median diameters (MMD) first increased with height, reaching a maximum value of 0.24 μm at 3000 m; and it rapidly decreased to 0.18 μm at 3200 m and then varied slightly with height above 3200 m. BC's bulk relative coating thickness (coated diameter divided by uncoated core diameter Dp/Dc) first decreased with height, reaching a minimum value of 1.16 at 3000 m, then increased with height, reaching a maximum of 1.38 (4250 m). A wind shear layer (7.9 m s−1 at 1850 m) with a sudden drop in temperature (the cooling rate can reach 7.4 °C·(100 m)−1) at 1900 m hinders the transportation of dust particles to the ground, allowing the dust particles to be transported at long-term distances. There were two stratifications in the dust storm layer: DS1 (1700–3000 m, the vertical wind speed was downward, the horizontal wind speed was small) and DS2 (3000–4500 m, the vertical wind speed was upward, the horizontal wind speed was large). The distinct atmospheric flow field conditions between DS1 and DS2 led to different BC and aerosol pollution characteristics. In DS2, the number concentrations of BC and aerosol were higher, the aging ratio of BC particles was higher, and the size of the core particle of BC was smaller. The concentrations of BC, aerosol, Dp/Dc, and MMD in DS2 were 1.1, 59.0, 1.02, and 0.84 times higher than those in DS1, respectively. Dust particles transported over long distances were primarily small. The number concentrations of aerosols at 0.1–0.12 μm and 0.1–0.24 μm were higher in DS1 and DS2, respectively. Still, the number concentration of aerosol at 0.12–0.28 μm in DS1 was lower than in the planetary boundary layer (PBL) and residual layer (RL). [Display omitted] • Aircraft in situ observations of aerosol and BC during the East Asian dust storm. • Two dust layers: Dust Storm (DS)1/DS2 (vertical wind speed (WS) downward/upward, horizontal WS small/large). • Wind shear layer with T sudden drop at 1900m hinders dust transport to ground. • Dust particles were mainly small particles (0.1–0.24 μm) during the long-term distance transport. [ABSTRACT FROM AUTHOR]

This study addresses the ongoing debate concerning the origin of ambient sulfate in northern China, and provides more evidence for primary sulfate from the perspective of source emission. An extensive field experiment was conducted, involving the collection of size-segregated particulate matter emitted under various coal types and combustion conditions for subsequent analysis. Our findings reveal that residential coal combustion (RCC) emits significant amounts of primary sulfate, constituting approximately 26.48 ± 15.43% of the particulate mass. Moreover, these emissions exhibit a strong association with NH 4 +, leading to the formation of stable ammonium sulfate compounds. The emission of sulfate is intricately linked to both coal quality and combustion conditions. Notably, the oversight of δ34S isotope enrichment in RCC particulate matter, which distinctly differs from the raw coal, introduces uncertainties in the quantitative assessment of sulfate sources and formation pathways. Therefore, more in-depth explorations are necessary to elucidate the precise processes involved in RCC sulfate transformation and to accurately determine its environmental impact. • Increase knowledge of RCC sulfate emission characteristics and influences. • Demonstrate RCC emits stable primary sulfate from multiple evidences. [ABSTRACT FROM AUTHOR]

Size-segregated aerosol particles were collected using a high volume MOUDI sampler at a coastal urban site in Xiamen Bay, China, from March 2018 to June 2020 to examine the seasonal characteristics of aerosol and water-soluble inorganic ions (WSIIs) and the dry deposition of nitrogen species. During the study period, the annual average concentrations of PM1, PM2.5, PM10, and TSP were 14.8 ± 5.6, 21.1 ± 9.0, 35.4 ± 14.2 μg m−3, and 45.2 ± 21.3 μg m−3, respectively. The seasonal variations of aerosol concentrations were impacted by the monsoon with the lowest value in summer and the higher values in other seasons. For WSIIs, the annual average concentrations were 6.3 ± 3.3, 2.1 ± 1.2, 3.3 ± 1.5, and 1.6 ± 0.8 μg m−3 in PM1, PM1-2.5, PM2.5–10, and PM>10, respectively. In addition, pronounced seasonal variations of WSIIs in PM1 and PM1-2.5 were observed, with the highest concentration in spring-winter and the lowest in summer. The size distribution showed that SO42−, NH4+ and K+ were consistently present in the submicron particles while Ca2+, Mg2+, Na+ and Cl− mainly accumulated in the size range of 2.5–10 μm, reflecting their different dominant sources. In spring, fall and winter, a bimodal distribution of NO3− was observed with one peak at 2.5–10 μm and another peak at 0.44–1 μm. In summer, however, the fine mode peak disappeared, likely due to the unfavorable conditions for the formation of NH4NO3. For NH4+ and SO42−, their dominant peak at 0.25–0.44 μm in summer and fall shifted to 0.44–1 μm in spring and winter. Although the concentration of NO3–N was lower than NH4–N, the dry deposition flux of NO3–N (35.77 ± 24.49 μmol N m−2 d−1) was much higher than that of NH4–N (10.95 ± 11.89 μmol N m−2 d−1), mainly due to the larger deposition velocities of NO3–N. The contribution of sea-salt particles to the total particulate inorganic N deposition was estimated to be 23.9—52.8%. Dry deposition of particulate inorganic N accounted for 0.95% of other terrestrial N influxes. The annual total N deposition can create a new productivity of 3.55 mgC m−2 d−1, accounting for 1.3–4.7% of the primary productivity in Xiamen Bay. In light of these results, atmospheric N deposition could have a significant influence on biogeochemistry cycle of nutrients with respect to projected increase of anthropogenic emissions from mobile sources in coastal region. [ABSTRACT FROM AUTHOR]

Bioaerosols have attracted increasing attention as novel contaminants because of their potential role in the spread of disease. In this study, sampling sites were established in a landfill in northwestern China with the aim of investigating the emission and diffusion characteristics of bioaerosols. The results revealed that the counts of airborne bacteria released by landfill cover area (LCA) and waste dumping area (WDA) located in the landfill area reached 18 193 ± 30 CFU/m 3 and 10 948 ± 105 CFU/m 3 , respectively. These two aeras were the main sources of bioaerosol generation. Meanwhile, Corynebacterium spp., Bacteroidetes spp., and Pseudomonas spp. were identified as potential pathogens. A Gaussian model was applied to simulate the diffusion of the bioaerosols; the influence distance was calculated as 12 km from the boundary of the landfill site. The potential health risks of bioaerosol exposure to on-site workers and nearby residents were calculated and evaluated in terms of aerosol concentration, particle size, and pathogenic bacteria. The present study promotes the recognition of the emission behavior of microorganisms in aerosol particles and provides a basis for controlling bioaerosol contamination from landfill sites, particularly those located in cold and arid northwestern regions of China., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This paper studied on the microplastics (MPs) pollution in the surface water of the Songhua River in China. MPs were detected in all sampling sites of the river, the abundance of MPs ranged from 1.09 to 15.97 items/L, and the average abundance was 5.72 ± 4.02 items/L. Human interference had a significant impact on the abundance of MPs, and abundance in the downstream were higher than those in the upstream in the urban area along the Songhua River. In this study, MPs with size <0.5 mm and size [0.5,1) mm were the main sizes; fiber and debris were the most common types; yellow was the dominant color. MPs in the Songhua River might have similar sources and degradation experiences, because the size, type, and color had no significant difference (P>0.05) in different sampling sections. PE, PET, and PS were the most common polymers of MPs, accounting for 33.55%, 29.68%, and 18.71%, respectively. [ABSTRACT FROM AUTHOR]

• Three typical crop straws of corn, wheat and rice in northern China were carried in the open burning experiment • A novel open combustion simulation device was employed • Particle number concentrations and mass concentrations were determined in the size ranging of 0.006~9.890 µm • Size distribution characteristics of various chemical components were analyzed and discussed. • Source chemical profiles were constructed for PM 0.1 , PM 1 , PM 2.5 , and PM 10 Crop residue open burning is an important emission source of ambient particles in China. This study analyzed the particle emission characteristics of crop residue open burning through combustion experiments with a novel open combustion simulation device using three typical crop straws in north China (corn, wheat, and rice). Particle samples size ranging from 0.006–9.890 µm were collected by an Electrical Low Pressure Impactor plus, a high size-resolution instrument capable of dividing particles into 14 size stages. The size distributions of organic carbon (OC), elemental carbon (EC), water-soluble ions, and elements were analyzed, and source chemical profiles were constructed for PM 0.1 , PM 1 , PM 2.5 , and PM 10. The number concentration of particles was concentrated in the Aiken nuclei mode (0.006–0.054 µm), accounting for 75% of the total number, whereas the mass concentration was concentrated in the accumulation mode (0.054–0.949 µm), accounting for 85.43% of the mass loading. OC, EC, Cl−, and K(include total K and water-soluble K) were the major chemical components of the particles, whose mass percentage distributions differed from those of other components. These five main components exhibited a bell-shaped size distribution in the 0.006–9.890 µm range, whereas the other components exhibited a U-shaped distribution. Among the chemical profiles for PM 0.1 –PM 10 , OC was the most important component at 10–30%, followed by EC at 2%–8%. The proportions of K+, Cl−, and K varied substantially in different experimental groups, ranging from 0–15%, and K+ and Cl− were significantly correlated (r = 0.878, α = 0.000). [Display omitted] [ABSTRACT FROM AUTHOR]

Environmental context: Amines in the atmosphere play important roles in atmospheric chemistry and have potential climate effects. We characterise the concentrations, size distributions and chemical pathways of aerosol aminiums over a coastal city and marginal seas, and estimated the contribution of marine biogenic sources. This study can facilitate our understanding about the interactions between human activities, biogenic emissions and the atmospheric environment. Atmospheric amines are gaining more and more attention in the field of atmospheric chemistry owing to their important roles in new particle formation and growth. In this study, aerosol aminiums over a coastal city (Shanghai) and the Yellow and East China seas (YECS) were characterised. The concentrations of NH4+, dimethylaminium (DMAH+) and trimethylaminium + diethylaminium (TMDEAH+) over Shanghai were all found to be higher in the winter of 2018 than in the summer of 2019, suggesting their non-negligible terrestrial contributions. DMAH+ and TMDEAH+ concentrations over the YECS in summer were closely correlated and linked to surface phytoplankton biomass, implying that marine biogenic sources might be a predominant contributor to aminiums at this time. Aminiums over Shanghai generally showed a bimodal distribution with a main peak in droplet mode and a secondary peak in condensation mode, suggesting the notable contribution of aqueous-phase or heterogeneous reaction to the formation of aminiums. In contrast, aminiums over the YECS often showed a unimodal distribution, which may be caused by the competition between amines and NH3 for reaction with acidic compounds. We estimated the contributions of marine biogenic sources, ~73.6 % to DMAH+ and 80.1 % to TMDEAH+ over the YECS, using methanesulfonate/non-sea-salt SO42- as an indicator. Our results suggest that marine biogenic emission of amines from China's marginal seas may have a potential impact on coastal cities, and this source should be considered in modelling new particle formation and air quality in coastal areas. [ABSTRACT FROM AUTHOR]

Size-fractionated samples were collected at five coastal urban sites in Fujian Province, southeast China, in 2016 and 2017 to determine the trace elements using ICP-MS. Ca, Fe, Al, Mg, and K were the most abundant elements among the studied elements in TSP, much higher than those of heavy metals. The annual mean concentrations of Pb, As, V, Ni, Cd, and Mn were within the acceptable limits of the World Health Organization and the Ministry of Ecology and Environment of China while Cr(VI) exceeded the limits. Most elements exhibited clear seasonal patterns with maxima over the cold season and minima over the warm season. The spatial variabilities in concentrations of the measured elements were not significant except Ni and V. However, the size distribution pattern of each element was quite similar across the region. Characteristic size distributions of elements allowed identification of three main groups: (a) unimodal distribution in the coarse fraction for Ca, Al, Mg, and Ba; (b) unimodal distribution in the fine fraction for Pb, Se, As, Ag, V, Ni, Zn, and Cd; and (c) bimodal or multimodal distribution for Fe, Mn, Cr, K, and Cu. The combination of the size-fractionated concentrations, enrichment factors, correlation coefficients, and factor analysis offered the identification of mixed sources such as vehicular exhaust and wear, heavy fuel oil combustion, and resuspension of road dust. Non-carcinogenic health risks associated with inhalable exposure to airborne metals were higher than the safety threshold (hazard index > 1) across the region, suggesting non-carcinogenic health risks via inhalation. Mn, V, and Ni contributed 74–83% of the total non-carcinogenic risk. The assessment investigation of carcinogenic health risks revealed V and Cr(VI) as elements with the largest carcinogenic risks, accounting for more than 95% of the overall inhalation risk. Nevertheless, the carcinogenic risks for children and adults were between 10−6 and 10−4, within the range considered acceptable by the US EPA. In terms of the size-fractionated risk, PM2.5 contributed 43–50% and 39–44% of the total non-carcinogenic and carcinogenic risks, respectively, indicating the potential health hazard of coarse particle–bound toxic metals was not negligible. [ABSTRACT FROM AUTHOR]

Amines are important for new particle formation and subsequent growth in the atmosphere. Consequently, the processes involved are receiving more attention in recent years. Here, we conduct a field observation in order to investigate the atmospheric particulate amines at a background site in the Yangtze River Delta (YRD) during the summer of 2018. Four amines in PM2.5, i.e., methylamine (MA), dimethylamine (DMA), diethylamine (DEA), and trimethylamine (TMA), were collected, twice daily and analyzed. During the campaign, our measurements found the concentrations of MA, DMA, DEA, and TMA of 15.0 ± 15.0, 6.3 ± 6.9, 20.4 ± 30.1, and 4.0 ± 5.9 ng m−3, respectively, and the four amines correlated well with each other. The concentration of amines appear to be independent of whether they were collected during the day or night. Both MA and DMA exhibited a bimodal size distribution that had peaks at 0.67 and 1.1 µm, suggesting amines preferably distribute on submicron particles. Boundary layer height (BLH), relative humidity, and pH of aerosols were found have a negative relationship with amines, while aerosol liquid water content (ALWC) was found to have a positive relationship with amines. The PMF (positive matrix factorization) source apportionment results showed that the main source of amines in Chongming Island was of anthropogenic origin such as industrial and biomass emission, followed by marine sources including sea salt and marine biogenic sources. Given that the YRD region is still suffering from complex atmospheric pollution and that the knowledge on aerosol amines is still limited, more field studies are in urgent need for a better understanding of the pollution characteristics of amines. [ABSTRACT FROM AUTHOR]

Bioaerosols have a major negative effect on air quality and on public health by causing the spread of diseases. This study evaluated the bioaerosol composition and variation in a semi‐arid megacity of northwest China from October 2019 to January 2020 using an Andersen six‐stage impactor sampler. The size distribution, diurnal variations of the concentrations of airborne bacteria, airborne fungi, and total airborne microbes (TAM) were investigated in autumn and winter. The mean concentrations of airborne bacteria, fungi, and TAM were 523.5 ± 301.1 colony‐forming units (CFU)/m3, 1318.9 ± 447.8 CFU/m3, and (7.25 ± 1.90) × 106 cells/m3, respectively, in autumn and 581 ± 305.4 CFU/m3, 1234.4 ± 519.9 CFU/m3, and (5.96 ± 1.65) × 106 cells/m3, respectively, in winter. The mean bioaerosol concentrations were slightly higher on nonhaze days than on haze days, but the difference was not statistically significant. Higher ambient particulate matter levels and atmospheric oxidation capacity inhibited bacteria survival. The diurnal maximum bioaerosol concentration was observed in the morning in autumn, whereas in winter, bioaerosols did not exhibit such a distribution, the impact of human activities on bioaerosols was still uncertain. The size of airborne bacteria exhibited a bimodal distribution, whereas a unimodal pattern was observed for fungi and TAM. Most bacteria, fungi, and TAM were distributed in the respirable ranges from trachea and primary bronchi to alveoli, indicating that bioaerosols have a high risk of being inhaled and causing respiratory diseases in Xi'an. Key Points: The diurnal pattern of bioaerosol in autumn was clearly different with that in winterAirborne bacteria exhibited bimodal distribution while unimodal pattern was observed for fungi and total airborne microbesHigh particulate matter levels and atmospheric oxidation capacity inhibited bacteria survival in winter [ABSTRACT FROM AUTHOR]

Hospital size distribution, i.e., the uneven allocation of healthcare resources between hospitals of different size classes, significantly impacts healthcare equality and efficiency and challenges healthcare governance. Yet, its variation is inadequately explained by two prevalent approaches to size distribution – the statistical approach merely works on statistical patterns, while the economic approach has difficulties in calculating hospital cost-returns. This study provides an alternative – a geographical approach – to demystify hospital size distribution. Incorporating the distinctiveness of healthcare into George Stigler's (1958) classic survivor analysis of firm size distribution, we conceptualize hospital size distribution as the result of hospitals' interactions with their socio-economic-technical environment in a defined area, and thus its pattern and variation could be understood through its coevolution with geographical contexts. We substantiate this idea with a study on China's provincial hospital size distributions between 2002 and 2019. During this period, hospitals with 0–99 beds maintained a stable proportion, while the size class of 800+ beds grew significantly, in contrast to the reduction in the size class of 100–799 beds. Cluster analysis identifies four clusters of provinces dominated by different hospital size classes after healthcare delivery reform in 2012. Cross-sectional time-series regression models find evolving impacts from market power, government intervention, and advancement of medical technology. We also offer a novel approach to understanding healthcare resource distribution by examining the structure rather than merely the number of healthcare resources. • Hospital size distribution significantly impacts healthcare equality and efficiency. • A geographical approach is developed to detect hospital size distribution. • This approach overcomes deficiencies in the statistical and economic approaches. • The evolution and variation of China's provincial hospital size distribution are examined. • Introducing a novel way to study healthcare resource distribution by examining healthcare delivery structure. [ABSTRACT FROM AUTHOR]

The study is about the size distribution and health risks of polycyclic aromatic hydrocarbons (PAHs) in indoor environment of Xuanwei, Southwest China particle samples were collected by Anderson 8-stage impactor which was used to gather particle samples to nine size ranges. Size-segregated samples were collected in indoor from a rural village in Xuanwei during the non-heating and heating seasons. The results showed that the total concentrations of the indoor particulate matter (PM) were 757 ± 60 and 990 ± 78 μg/m 3 in non-heating and heating seasons, respectively. The total concentration of indoor PAHs reached to 8.42 ± 0.53 μg/m 3 in the heating season, which was considerably greater than the concentration in the non-heating season (2.85 ± 1.72 μg/m 3 ). The size distribution of PAHs showed that PAHs were mainly enriched in PMs with the diameter <1.1 μm. The diagnostic ratios (DR) and principal component analysis (PCA) showed that coal and wood for residential heating and cooking were the main sources of indoor PAHs. The results of the health risk showed that the total deposition concentration (DC) in the alveolar region (AR) was 0.25 and 0.68 μg/m 3 in the non-heating and heating seasons respectively. Throughout the entire sampling periods, the lifetime cancer risk (R) based on DC of children and adults varied between 3.53 ×10 -5 to 1.79 ×10 -4 . During the heating season, the potential cancer risk of PAHs in adults was significant, exceeding 10 -4 , with a rate of 96%., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Atmospheric particulate matters in nine size fractions were sampled at Huangshi city, Hubei province. Elemental concentrations occurred unimodal size distribution for Zn, Pb and Ni, dimodal distribution for Ca, S, Fe and Ti, and trimodal distribution for Cl, K, Mn, Cu and Cr. Enrichment factor and principal component analysis identified the main sources from crustal material, biomass burning, waste incineration, vehicular and industrial emission. As for the non-carcinogenic health risk through inhalation, there were certain potential risks for Mn and Sb for children, and Pb for children and adults in PM2.5. It showed certain potential risks for Mn, Sb and Pb for children and adults in PM10. As for the carcinogenic health risk through inhalation, Cr in PM2.5 and Ni, Co and Cr in PM10 indicated unacceptable risk for children and adults. Meanwhile, Co and Ni in PM2.5 represented acceptable risk for children. [ABSTRACT FROM AUTHOR]

Stand structure is an important feature reflecting the status of forests. Here, four typical secondary forests in the Greater Khingan Mountains are examined. Five random plots were selected from each forest, and their tree size distributions and stand spatial structures were compared. The unary distributions of the diameters at breast height (DBH) and tree heights showed consistency, which indicated there was an over-abundance of small-diameter trees in these forests. The joint probability distribution showed that the number of small-diameter trees was significantly larger than that of large-diameter trees. Furthermore, according to the unary distribution of spatial structure characteristics, the stands mostly exhibited a clustered structure, and the competition in the stands was intense, which is not conducive to growth. One-way covariance analysis was used to test the similarities and differences in the spatial parameters of the four stands. There were no significant differences between them in terms of dominance or the uniform angle index. Only mingling was significantly different, where the mixed forest had a significant advantage (p = 0.05). The structure of these secondary stands is poor, so the formation of a stable forest ecosystem by natural succession is hampered. [ABSTRACT FROM AUTHOR]

Dust particles suspended in the atmosphere have been a big headache for electric power transmission industry in China. As transmission lines pass through dusty or air-polluted areas, dust contaminants are likely to deposit and accumulate on line insulators, which is one of the greatest causes of flashover and failure of power transmission. To study the statistical characteristics of this type of contamination, dust samples were collected and measured, and a physical model was set up to explain the deposition and accumulation mechanism of the particles. The trajectories of particles were tracked using fluid mechanics and contact mechanics, and an adhesion criterion was proposed. Simulation software was then applied to validate the model; further different environmental factors were studied that would affect the particle size distribution. The results show that under natural contamination conditions, the particle size distribution on the surface of the insulator shows a certain concentration at size ranges 1~100 μm and basically obeys a log-normal distribution. In addition, relative humidity, air velocity, and the charge accumulated on the surface all have significant influences on particle size distribution characteristics, while the effect of the electric field is mainly reflected in the difference in the number concentration of particle adhesion. [ABSTRACT FROM AUTHOR]

The size and spatial distribution of loess slides are important for estimating the yield of eroded materials and determining the landslide risk. While previous studies have investigated landslide size distributions, the spatial distribution pattern of landslides at different spatial scales is poorly understood. The results indicate that the loess slide distribution exhibits a power-law scaling across a range of the size distribution. The mean landslide size and size distribution in the different geomorphic types are different. The double Pareto and inverse gamma functions can coincide well with the empirical probability distribution of the loess slide areas and can quantitatively reveal the rollover location, maximum probability, and scaling exponents. The frequency of loess slides increases with mean monthly precipitation. Moreover, point distance analysis showed that > 80% of landslides are located < 3 km from other loess slides. We found that the loess slides at the two study sites (Zhidan and Luochuan County) in northern Shaanxi Province, China show a significant clustered distribution. Furthermore, analysis results of the correlated fractal dimension show that the landslides exhibit a dispersed distribution at smaller spatial scales and a clustered distribution at larger spatial scales. [ABSTRACT FROM AUTHOR]

Bioaerosols are an important component of particulate matter in the atmosphere and are harmful to human health. In this study, the concentration, size distribution, and factors influencing culturable airborne bacteria and fungi in the atmosphere were investigated using a six-stage impactor device in the city of Xinxiang, China, during the winter season. The results revealed that the concentration of culturable airborne bacteria and fungi varied significantly during the sampling period: 4595 ± 3410 and 6358 ± 5032 CFU/m3, respectively. The particle sizes of the bioaerosols were mainly within stage V (1.1–2.1 μm), and fine particulate matter accounted for 45.9% ± 18.9% of airborne bacteria and 52.0% ± 18.5% of airborne fungi, respectively. With the deterioration of air quality, the concentration of airborne fungi gradually increased, and that of airborne bacteria increased when the air quality index was lower than 200 and decreased when it was higher than 200. With respect to the diurnal variation pattern of bioaerosol concentration, the highest and lowest concentrations were registered at night and noon, respectively, probably because of changes in ultraviolet radiation intensity. Bioaerosol concentration positively correlated with humidity, concentration of PM2.5, PM10, SO2, and NO2 and negatively correlated with O3 concentration. The risk of exposure of humans to the airborne bacteria was primarily associated with the respiratory inhalation pathway, and the risk of skin exposure was negligible. These results should improve our understanding of the threat of bioaerosols to public health. [ABSTRACT FROM AUTHOR]

Sea-salt aerosol (SSA) has significant impact on the formation of secondary nitrate and its dry deposition in the coastal region. In this study, size-segregated aerosols were collected for water-soluble ions analysis in the coastal cities and sea cruises in the western Taiwan Strait of China from 2016 to 2017 to investigate the impact of SSA on particulate inorganic N deposition. The size distributions of NH 4 + were characterized by a unimodal pattern peaking at 0.44–1.0 μm while NO 3 − exhibited typical bimodal distributions peaking at 0.44–1.0 μm and 2.5–10 μm. Furthermore, the fine mode peaks of NO 3 − became insignificant or disappeared in summer and fall due to the volatilization and dissociation of NH 4 NO 3 at higher temperatures. Elevated sea-salt contributions in the largest size bin (>16 μm) during sea cruises were attributed to vessel induced wave breaking, while there was no peak for NO 3 − at this range due to its short atmospheric lifetime. Although the concentrations of particulate NH 4 +-N showed higher levels than those of NO 3 −-N for both coastal and marine aerosols, the dry deposition fluxes of the particulate NO 3 −-N were significant higher than those of the particulate NH 4 +-N due to their different size distributions. The contribution of SSA to particulate inorganic N deposition was estimated on average to be 20.33% and 36.91% in the coastal and offshore region, respectively, assuming all of the chlorine depletion was caused by the reaction between nitric acid and SSA in the coarse mode. In addition, dry deposition fluxes using constant deposition velocities for fine/coarse particles and NH 4 +/NO 3 − were higher than those using size-dependent dry deposition velocities. Considering the increasing human activities at the coastal urban zone in the western Taiwan Strait, the atmospheric N deposition could have an important ecological impact on the marine environment that is already under pressure from riverine inputs and urban waste discharges. • The size distribution of inorganic N species were determined in the western Taiwan Strait. • The impact of sea-salt aerosols to particulate inorganic N deposition was quantified. • Size-dependent dry deposition velocities greatly improved estimated deposition fluxes. [ABSTRACT FROM AUTHOR]

The sequential extraction method was used to determine the fraction of arsenic (As) in different-sized particulate matters (PMs) (i.e., PM2.5, PM10, and total suspended particles (TSP)). Samples were collected from Baoding, a typical medium-sized city with the serious haze pollution in China. The bioavailabilities of As in the samples were estimated based on the fraction results. A large percentage of fine particles were detected in TSP, with the average PM2.5/PM10 and PM10/TSP ratios all above 0.69. The total concentrations of As in PM2.5, PM10, and TSP samples were in the range of 4.5–296.4, 14.1–708.0, and 32.8–798.0 ng m−3, respectively. The mass percentages of As in PM2.5, PM2.5–10, and PM10–100 were calculated; the results indicated that As tended to concentrate in fine particles. PM-bound As mainly presented in the nonspecifically sorbed fraction (F1) during all of the sampling periods. The percentages of F1-As and bioavailability of As were higher in PM2.5, followed by PM10 and TSP. By contrast, the residual fraction (F5-As) contents declined in the order of TSP > PM10 > PM2.5. Significant differences in the speciation and bioavailability of As in different-sized PMs were found, and the influence of particle size on the speciation and bioavailability of As in PMs was verified. Fine particles adsorbed more As with higher bioavailability, and potentially led to more serious adverse effects on human health than the larger ones. [ABSTRACT FROM AUTHOR]

The size-resolved chemical composition and mixing state of single particles were observed by using single particle aerosol mass spectrometry (SPAMS) from May 12 to June 8, 2017. A total of 979,899 particles were successfully ionized to identify 6 main particle groups including carbon-rich particles (47.66%), K-rich particles (28.78%), heavy-metal particles (10.12%), sodium particles (8.86%), dust particles (3.89%), and ammonium particles (0.67%). The wind direction and speed had large impacts on the proportion of carbonaceous aerosol particles and had little influence on heavy-metal particles. The relative humidity (RH) had great impacts on the chemical components of aerosol particles. The proportion of secondary particles increased, while the primary particles diminished as RH increased. The proportion of carbon-rich particles decreased with increasing particle size. However, the size distributions varied significantly for different types of carbonaceous particles. Sodium particles and heavy-metal particles were mainly concentrated at sizes larger than 1 μm. K-rich particles had a maximum proportion at 0.5–1.0 μm. The number fraction of ammonium particles predominated chiefly at 0.6–2.0 μm. It has been found that aerosol particles, mainly from burning processes, were mixed with 36 [C 3 ]+ to different degrees at Mt. Tai. A high proportion of ammonium particles were mixed with organics and elemental carbon (OCEC), elemental carbon-sulfate (EC-sulfate), and elemental carbon-secondary (EC-secondary) particles, while few of these particles were mixed with EC-nitrate particles, which indicated that the ammonia in the air was inclined to combine with organic species and sulfate. A higher proportion of atmospheric particles mixed with nitrate were observed compared to those mixed with sulfate. Image 1 • SPAMS was used for the first time to observe at Mt. Tai. • The proportion of primary/secondary particles diminished/increased as RH increased. • Higher proportions of particles mixed with nitrate than with sulfate. [ABSTRACT FROM AUTHOR]

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The "Campaign on Atmospheric Aerosol Research" network of China (CARE-China) is a long-term project for the study of the spatio-temporal distributions of physical aerosol characteristics as well as the chemical components and optical properties of aerosols over China. This study presents the size-segregated sugars from the CARE-China network. Sugars associated with size-segregated particulate matter at 8 regions (North China (NC), East China (EC), Northeast China (NE), and Central China (CC), South China (SC), Northwest China (NE), Southwest China (SW) and the Tibetan Plateau (TP)) including 14 sites over China from January 2013 to December 2014 were analyzed via gas chromatography mass spectrometry. Mass concentrations of measured sugars varied considerably with location and season, ranging from 0.20 to 5588 ng m−3, with the majority from levoglucosan (170 ± 207 ngm−3, accounting for 48% of total sugars), followed by sucrose (44.6 ± 39.6 ngm−3, accounting for 11.3% of sugar), and sorbitol (35.5 ± 42.2 ng m−3, accounting for 10.0% of sugars). The highest levels of sugars were observed in urban sites in Central and Southwest China, whereas the lowest concentrations occurred in background and Tibetan Plateau sites. A distinct seasonal variability of sugars was observed, with higher in the winter or autumn and lower during the summer at urban sites. Inconsistent seasonal trends were observed at the background sites located in the higher latitudes, which were characteristic with the highest concentration occurred in spring. Levoglucosan, galactosan and mannosan were found to be dominant in fine size range <1.1 μm, accounting approximately 59% of all size-segregated sugars. Sucrose was enriched in the size range of 3.3–9.0 μm for almost all sampling sites. Concentrations of trehalose and sorbitol in the three size particles were similar. The OC from biomass burning was estimated to be in the range of 0.93–58.7 μg C m−3, with the highest level OC BB % were observed in urban sites in summer and winter. The contributions of biomass burning to OC in the rest of sites were higher in autumn and winter than in spring and summer. Higher OC BB % was observed in spring at the background sites located in Northwest and Northeast China. Image 1 • Spatio-temporal distributions of size-segregated sugars in China were investigated. • Sugars were more abundant in Central, Southwest, North China and northeastern areas than that in East and Northeast China. • Levoglucosan, galactosan and mannosan were found to be dominant in fine particles. • Higher contribution levels of biomass burning to OC were observed in the urban sites in autumn. [ABSTRACT FROM AUTHOR]

Abstract Size-resolved samples were collected using a 14-stage impactor during four seasons in Zhengzhou and analyzed for 26 elements to calculate the health risks from atmospheric particle-bound metals. High concentrations of heavy metals were observed in ultrafine (10.2 (Ni)–66.9 (Cd) ng m−3) or submicrometer (11.4 (Ni)–134 (Pb) ng m−3) mode in winter. Two size-dependent models were used to estimate the deposition of inhaled toxic metals in various regions of the human respiratory system. Results show that heavy metals deposited in the alveolar region ranged from 7.6 (As)–375 (Al) ng m−3 and were almost concentrated in ultrafine and fine modes. Cd (2.2–8.6) may cause accumulative non-carcinogenic health effects on children, and Cr (1.0 × 10−4–2.2 × 10−4) may lead to carcinogenic health risks for nearby residents around the sampling site. The major sources by principal component analysis that contributed to Cr and Cd in ultrafine and fine particles were coal combustion, vehicular and industrial emissions. The atmospheric dry deposition fluxes of Cr and Cd were between 0.7 and 1.9 μg m−2 day−1 calculated by a multi-step method. From the environmental and public health perspective, environmental agencies must control the emission of heavy metals in the atmosphere. Graphical abstract Image 1 Highlights • High concentrations of heavy metals were observed in ultrafine or submicrometer mode in winter. • Heavy metals deposited in alveolar region were concentrated in ultrafine and fine modes. • Health risks from Cr and Cd deposited in alveolar region were high. Cr and Cd in ultrafine and fine particles emitted from coal combustion, vehicle and industry were easily deposited in the alveolar region and led to high health risks for residents. [ABSTRACT FROM AUTHOR]

Abstract In this study, the characteristics of fine particles before and after wet flue gas desulfurization (WFGD) in three coal-fired heating boilers in northern China were investigated by using a dilution-based emission sampling experimental system. The influences of the WFGD process on the mass and number concentrations as well as the chemical composition of fine particles were analyzed. The removal efficiency of desulfurization processes on particulate matter mass was 30.06%–56.25% for the three study units. The WFGD had a great influence on the size distributions of particle mass concentration and number concentration. A significant increase in the number and mass concentration of particles in the size range of 0.094–0.946 μm was observed. The water-soluble ion content accounted for a very large proportion of PM 2.5 mass, and its proportion in PM 2.5 increased from 28.39%–41.08% to 48.96%–61.21% after the WFGD process for the three units. The desulfurizing process also drastically increased the proportion of cation component (Ca2 + for unit A, Mg2 + for unit B, and Na+ for unit C) and the proportion of SO 4 2 − in PM 2.5 , and it increased the CE/AE values of PM 2.5 from 0.82–0.98 to 0.93–1.27 for the three study units. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

In order to provide a sound basis for the performance evaluation of a local government's air pollution prevention and abatement measures, the mass concentrations of PM2.5 and PM10 and the concentrations of different sized particles were measured in August 2013. Meanwhile, the influencing factors and sources of atmospheric particulate matters were analyzed by combining meteorological factors and gaseous pollutants. The results indicated that PM2.5 and PM10 in Zhuzhou were (30.3±12.2) μg·m-3 and (56.4±26.6) μg·m-3, respectively. The mean values of the particle number concentration in the size range of 0.5~1 μm and 1~2.5 μm on sunny days were (121.2±75.9) cm-3 and (6.8±3.7) cm-3, respectively, whereas in the rainy days they sharply increased to (868.7±262.1) cm-3 and (347.9±238.6) cm-3, which accounted for 71.0% and 28.4% of the total number of concentrations, respectively. Backward trajectory analysis demonstrated that the air masses in Zhuzhou city mainly came from three directions: southeast (52.2%), southwest (24.7%), and northeast (23.1%). Although accounting for a minor fraction, the northeast air mass had the largest effect on particle concentrations in Zhuzhou and also carried a lot of gaseous primary pollutants. [ABSTRACT FROM AUTHOR]

Owing to the potential influence of light-absorbing organic carbon (OC), also termed "brown carbon" (BrC), on the planetary radiation budget, many studies have focused on its absorption in single-sized ranges of particulate matter (PM). However, the size distribution and organic tracer-based source apportionment of BrC absorption have not been extensively investigated. In this study, size-resolved PM samples were collected using multi-stage impactors from eastern Nanjing during each season in 2017. The light absorption of methanol-extractable OC at 365 nm (Abs 365 , Mm−1) was determined using spectrophotometry, and a series of organic molecular markers (OMMs) was measured using a gas chromatography-mass spectrometer. Fine PM with an aerodynamic diameter <2.1 μm (PM 2.1) dominated Abs 365 (79.8 ± 10.4%) of the total size ranges with maxima and minima in winter and summer, respectively. The distributions of Abs 365 shifted to larger PM sizes from winter to spring and summer due to lower primary emissions and increased BrC chromophores in dust. Except for low-volatility (p o,* L < 10−10 atm) polycyclic aromatic hydrocarbons (PAHs), the non-polar OMMs, including n- alkanes, PAHs, oxygenated PAHs, and steranes, showed a bimodal distribution pattern. Secondary products of biogenic precursors and biomass burning tracers presented a unimodal distribution peaking at 0.4–0.7 μm, while sugar alcohols and saccharides were enriched in coarse PM. Their seasonal variations in average concentrations reflected intense photochemical reactions in summer, more biomass burning emissions in winter, and stronger microbial activity in spring and summer. Positive matrix factorization was used for the source apportionment of Abs 365 in fine and coarse PM samples. Biomass burning contributed an average of 53.9% to the Abs 365 of PM 2.1 extracts. The Abs 365 of coarse PM extracts was associated with various dust-related sources where the aging processes of aerosol organics could occur. [Display omitted] • Fine particles dominated the light absorption of methanol extracts of total PM. • Low-volatile n- alkanes and steranes in coarse PM increased during warm periods. • Biomass burning contributed more than 50% to BrC absorption in fine PM. • Aging processes of organics in coarse particles could lead to BrC formation. [ABSTRACT FROM AUTHOR]

To explore air contamination resulting from special biomass combustion and suspended dust in Lhasa, the present study focused on the size distribution and chemical characteristics of particulate matter (PM) emission resulting from 7 types of non-fossil pollution sources. We investigated the concentration and size distribution of trace elements from 7 pollution sources collected in Lhasa. Combining Lhasa's atmospheric particulate matter data, enrichment factors (EFs) have been calculated to examine the potential impact of those pollution sources on the atmosphere quality of Lhasa. The highest mass concentration of total elements of biomass combustion appeared at PM 0.4 , and the second highest concentration existed in the size fraction 0.4-1 µm; the higher proportion (12 %) of toxic metals was produced by biomass combustion. The elemental composition of suspended dust and atmospheric particulate matter was close (except for As and Cd); the highest concentration of elements was all noted in PM 2.5-10 (PM 3-10 ). Potassium was found to be one of the main biomass markers. The proportion of Cu in suspended dust is significantly lower than that of atmospheric particulate matter (0.53 % and 3.75 %), which indicates that there are other anthropogenic sources. The EFs analysis showed that the Cr, Cu, Zn, and Pb produced by biomass combustion were highly enriched (EFs > 100) in all particle sizes. The EFs of most trace elements increased with decreasing particle size, indicating the greater influence of humanfactors on smaller particles., Competing Interests: Declaration of Competing Interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and /or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled., (Copyright © 2023. Published by Elsevier B.V.)

Black carbon (BC) has a significantly negative impact on air quality, climate and human health. Here we investigated the sources and health effects of BC in urban area of the Pearl River Delta (PRD) based on online data measured by Aerodyne soot particle high-resolution time of flight aerosol mass spectrometer (SP-AMS). In urban PRD, BC particles mainly came from vehicle emissions especially heavy-duty vehicle exhausts (contributing 42.9 % of total BC mass concentration), long-range transport (27.6 %), and aged biomass combustion emissions (22.3 %). Indicated by source analysis using simultaneous aethalometer data, BC associated with local secondary oxidation and transport may also be originated from fossil fuel combustion, especially traffic sources in urban and surrounding areas. Size-resolved BC mass concentrations provided by SP-AMS, for the first time to our best knowledge, were used to calculate BC deposition in the human respiratory tract (HRT) of different populations (children, adults, and the elderly) by the Multiple-Path Particle Dosimetry (MPPD) model. We found that submicron BC was deposited more in the pulmonary (P) region (49.0-53.2 % of the total BC deposition dose), while less in the tracheobronchial (TB, 35.6-37.2 %) and head (HA, 11.2-13.8 %) regions. Adults suffered the highest BC deposition (1.19 μg day -1 ) than the elderly (1.09 μg day -1 ) and children (0.25 μg day -1 ). BC deposition rate was greater at night (especially 18:00-24:00) than during the daytime. The maximum deposition in the HRT was found for BC particles around 100 nm, mainly in deeper respiratory regions (TB and P), which may cause more serious health effects. Adults and the elderly group are confronted with the notable carcinogenic risk of BC in the urban PRD, up to 29 times higher than the threshold. Our study emphasizes the need to control BC pollution in the urban area, especially nighttime vehicle emissions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

To understand the contribution of new particle formation (NPF) events to ambient fine particle pollution, measurements of particle size distributions, trace gases and meteorological conditions, were conducted at a suburban site (NJU) from October to December 2016 and at an industrial site (NUIST) from September to November 2015 in Nanjing. According to the temporal evolution of the particle size distributions, three types NPF events were observed: typical NPF (Type A), moderate NPF events (Type B) and strong NPF (Type C) events. The favorable conditions for Type A events included low relative humidity, low concentration of pre-existing particles, and high solar radiation. The favorable conditions of Type B events were similar to Type A, except for a higher concentration of pre-existing particles. Type C events were more likely to happen with the higher relative humidity, lower solar radiation and continuous growth of pre-existing particle concentration. The formation rate of 3 nm (J 3 ) was the lowest for Type A events and highest for Type C events. In contrast, the growth rates of 10 nm and 40 nm particles were the highest for Type A, and lowest for Type C. Results show that NPF events with only higher J 3 would lead to the accumulation of nucleation mode particles. Sulfuric acid was important for the formation of particles but had little effect on the growth of particle size., (Copyright © 2022. Published by Elsevier B.V.)

Abstract Despite of extensive efforts on investigation into characteristics of severe haze pollution in megacities of China, the accurate relationships among the aerosol composition, mass-size distribution and optical properties during pollution episodes remain poorly understood. Here, we conducted in situ measurements of the mass size distribution of submicron aerosol (PM 1) species by using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS), particle light scattering by a Cavity Attenuated Phase Shift ALBedo monitor (CAPS-ALB) and a Photoacoustic Extinctionmeter (PAX) during the winter of 2017 in Shanghai, China. The average PM 1 concentration was 85.9 ± 14.7 μg/m3 during the haze episodes, of which was ∼7 times higher than that of clean period (12.1 ± 3.1 μg/m3). Organic aerosol (OA) and inorganic species (SO 4 2− + NO 3 − + NH 4 +) contributed 39.9% and 51.2% of the total mass of PM 1 during the haze episodes, respectively. OA exhibited a single or bimodal distribution during the haze episodes with the peak concentration of 51.8 μg/m3. There were no obvious differences between ammonium nitrate (NH 4 NO 3) and ammonium sulfate ((NH 4) 2 SO 4) during the haze episodes, which exhibited single peak distributions at the sizes of 650–700 nm and ∼700 nm, respectively. The peak positions of OA, NH 4 NO 3 and (NH 4) 2 SO 4 in clean period were in the range of 450–500 nm, 550–600 nm and 450–500 nm with the peak concentrations of 5.5 μg/m3, 3.1 μg/m3 and 3.8 μg/m3, respectively. The increased scattering coefficients in the haze episodes were positively correlated with higher secondary inorganic aerosols and organic aerosol (OA). The high scattering coefficient contribution fraction peak diameter of NH 4 NO 3 and (NH 4) 2 SO 4 were in the range of 600–800 nm and 600–750 nm with the peak scattering coefficient of 352.6 Mm−1 and 165.7 Mm−1, respectively. The size distribution of scattering for OA showed bimodal modes during all episodes. OA and NH 4 NO 3 were the largest contributors to scattering coefficients of PM 1 during the haze episodes, accounting for 45.5% and 37.8%, respectively. The contribution of (NH 4) 2 SO 4 to the scattering (24%) exceeded that of NH 4 NO 3 during clean period. Our results elucidated that substantial changes in the aerosols optical properties due to the changes in chemical compositions and size distribution during the haze events. Highlights • Hourly size distribution of PM 1 species and optical properties were measured. • Particle size increased from 450 to 600 to 600–800 nm and triggered the haze events. • OM and NH 4 NO 3 contributed 46% and 38% of scattering coefficient during haze events. [ABSTRACT FROM AUTHOR]

Abstract Household air pollution is one important environmental risk to human health in China, however, rural air pollution is often underappreciated and field measurements are limited compared to studies in urban area. The present study investigated indoor and outdoor polycyclic aromatic hydrocarbons (PAHs), and population inhalation exposure from two rural counties in Shanxi and Guizhou provinces, respectively. The indoor levels were higher than the corresponding outdoor concentration in both sites, which was mainly affected by the indoor fuel combustion emissions. A majority of particulate PAHs was found in submicron PM 1.0. Fuel types had significant impacts on the total PAHs mass concentration but also composition profiles. In homes using electricity, the PAHs concentration was lower than those burning solid fuels, and there were relatively more fractions of low molecular weight PAHs with 2–3 rings, while for those burning solid fuels, higher fractions of high molecular weight PAHs with 5–6 rings may pose larger adverse health impacts. Although the daily inhalation exposure level for the population using electricity was much lower than those using solid fuels, the estimated Incremental Lifetime Cancer Risk still exceeded the deemed safe risk of 10−6. Inhalation exposure amounts measured by using portable carried samplers were compared to the estimation based on area concentration. The substantial discrepancy between them confirmed a preferable use of portable carried samplers in exposure evaluation and health risk assessment. Graphical abstract Image 1 Highlights • Higher fractions of particulate PAHs in fine PM 2.5 and submicron PM 1.0. • For cooking fuel, burning of coal briquette had lower PAHs pollution that from wood combustion. • For heating fuel, raw coal chunk may produce lower pollution in comparison with low-quality peats. [ABSTRACT FROM AUTHOR]

Abstract Size-resolved biogenic secondary organic aerosols (BSOA) derived from isoprene and monoterpene photooxidation in Qinghai Lake, Tibetan Plateau (a continental background site) and five cities of China were measured using gas chromatography/mass spectrometry (GC/MS). Concentrations of the determined BSOA are higher in the cities than in the background and are also higher in summer than in winter. Moreover, strong positive correlations (R 2 = 0.44–0.90) between BSOA and sulfate were found at the six sites, suggesting that anthropogenic pollution (i.e. , sulfate) could enhance SOA formation, because sulfate provides a surface favorable for acid-catalyzed formation of BSOA. Size distribution measurements showed that most of the determined SOA tracers are enriched in the fine mode (< 3.3 μm) except for cis -pinic and cis -pinonic acids, both presented a comparable mass in the fine and coarse (> 3.3 μm) modes, respectively. Mass ratio of oxidation products derived from isoprene to those from monoterpene in the five urban regions during summer are much less than those in Qinghai Lake region. In addition, in the five urban regions relative abundances of monoterpene oxidation products to SOA are much higher than those of isoprene. Such phenomena suggest that BSOA derived from monoterpenes are more abundant than those from isoprene in Chinese urban areas. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Polar polycyclic aromatic hydrocarbons (PAHs) derivatives like nitrated and oxygenated PAHs have higher toxic potentials than the parent one, and are receiving growing interests. In this study, we investigated household air pollution and personal exposure to nitro- and oxy-PAHs during a winter period in rural Shanxi, northern China. The overall arithmetic means of 24-h average indoor nitro-PAHs and oxy-PAHs were 10.2 ± 3.6 and 76.8 ± 51.8 ng/m 3 , respectively, that were much higher than the 7.98 ± 4.30 and 54.7 ± 45.4 ng/m 3 in the outdoor air. Nearly 90% of particulate PAHs derivatives were enriched in fine PM 2.5 and even finer PM 1.0 fraction. Daily inhalation exposure to nitro- and oxy-PAHs for the rural population were 8.41 ± 3.08 and 68.5 ± 79.7 ng/m 3 , respectively. Residents burning briquette for cooking were found to have lower household air pollution and exposure levels compared with those burning wood. The calculated time-weighted average concentration overestimated, though correlated positively, the daily inhalation exposure compared to the that from personal carried samplers. [ABSTRACT FROM AUTHOR]

The splash erosion characteristics of the herbaceous-dominant area in northern China remain uncertain. A total of 21 plots (3-m wide × 3-m long) were installed to investigate splash characteristics under different vegetation coverages (0%, 5%, 10%, 20%, 40%, 60%, and 80%) and rainfall intensities (40, 80, and 120 mm/h) using an artificial simulated rainfall device and an improved splash tray. Splashed particles were collected and analyzed for mass and size distribution. This study demonstrated that a vegetation coverage of 40% would help protect soil from splash erosion. Total splash amount generally decreased exponentially with increasing vegetation coverage and splash distance, but rose with increasing rainfall intensity. Vegetation coverage played a more important role in the mass-weighted average splash distance, with a significant Pearson correlation of −0.934 ( p  ˂ 0.01), compared to the rainfall intensity, with no significant correlation ( p  > 0.05). Moreover, splashed particles were finer than the original soil matrix because finer soil particles (clay, fine silt, and coarse silt) were transported preferentially by raindrops, and almost all mean weight diameters were lower than that of the soil matrix. Coarse silt showed the largest mass percentage at all splashed distances relative to the least mass percentage of coarse sand. The mass percentages of clay, fine silt, and coarse silt were generally positively correlated with vegetation coverage and splash distance and negatively correlated with rainfall intensity ( p  ˂ 0.05). Furthermore, the opposite was true for fine and coarse sand ( p  ˂ 0.05). These results could facilitate the further understanding of splash erosion characteristics and provide some suggestions for erosion control practices in northern China where herbaceous plants are important ingredients. [ABSTRACT FROM AUTHOR]

An understanding of the species of chlorine is crucial in the metropolis-Beijing, which is suffering serious haze pollution with high frequency. Particulate Matters (PMs) with five different sizes were collected in Beijing from July 2009 to March 2016, and characterized non-destructively by X-ray absorption near edge structure spectroscopy. PM <0.2 , PM 0.2-0.5 and PM >2.5 contributed for the major PMs mass in spring and summer, PM 0.5-1.0 and PM 1.0-2.5 contributed for the major PMs mass in autumn and winter. The concentrations of the three chlorine species were in the order of inorganic chlorine (Cl inorg ) > aliphatic chlorine (Cl ali ) > aromatic chlorine (Cl aro ), indicating that Cl inorg constituted the primary chlorine fraction and less toxic Cl ali constituted the primary total organic chlorine (Cl ali + Cl aro , abbreviated as Cl org ) in the PMs in Beijing. In addition, these three chlorine species exhibited identical seasonal variation in PM 2.5 : winter > autumn > spring > summer. Wet precipitation is an important factor to result in the lower mass concentrations of these three chlorine species in summer. The temporal variations of both size resolved PM mass concentrations and chlorine species concentrations suggested that the air pollution prevention and control in Beijing has just won initial success. [ABSTRACT FROM AUTHOR]

The formation of new atmospheric aerosol particles and their subsequent growth have been observed under different environmental conditions globally; such observations are few over northwest China. Here, we present an analysis of some case studies for new particle formation (NPF) events from two distinct suburban locations in northern China during May and June of two consecutive years, and provide more information to understand the characteristics of NPF events in North China. Particle number size distribution was measured at suburbs of Beijing (39.75° N, 116.96° E) during 1 June to 2 July 2013 and at suburbs of Xi'an (34.09° N, 108.55° E) during 1 to 25 May 2014. The average of total particle number concentration in the similar size range of 10-487 nm at the suburbs of Beijing (9.0 x 10³ cm-3) was about two times higher than those observed at Xi'an (4.7 x 10³ cm-3), and the mean particle mode diameter at Beijing was 1.4-fold higher than that at Xi'an. The estimated total condensation sink (CS) at Beijing (3.11 x 10-2 s-1) was also higher than at Xi'an (1.13 x 10-2 s-1). The frequency of NPF events at suburb of Beijing was 24%, lower than that in Xi'an (50%), and also lower than urban site of Beijing (35% in June) and another suburb of Beijing (over 50% in June). The NPF events with (Class I) or without (Class II) subsequent growth were both observed at the two suburb sites. The derived GR at the suburb of Beijing (range from 4.6 to 8.6 nm h-1) was a little higher than that at Xi'an (range from 3.3 to 6.7 nm h-1), which are generally comparable to typical values in mid-latitude reported in previous studies. The air masses coming from north or northwest China favor the occurrence ofNPF event under lowcondensation sink and clear days. The number size distributions of freshly nucleated particles showed clear bimodal distributions on both sites. Additionally, Mode Dp of nucleated particles at the two sites was 17 ± 1 nm and 22 ± 4 nm, respectively during the periods with NPF events. The case study of NPF events at the two suburb sites shows that the surface area concentration and total scattering coefficient (SC) was significant decreased during the NPF events at both sites. High temperature, lowcondensation sink and lowrelative humidity furthered the occurrence of NPF events, and wind direction shifts were important for the subsequent growth of particles. NPF events in the suburbs of Beijing usually occurred when relative humidity (RH) < 55%, CS < 0.02 s-1, or 55%< RH< 68%, CS < 0.01 s-1. However, there is no clear range for Xi'an. Furthermore, we observed that some NPF events occurred at higher RH and very low CS in this study on both sites, which means that low CS may be more important than low RH for the particle formation on clear days. [ABSTRACT FROM AUTHOR]

Coking is regarded as a major source of atmospheric polycyclic aromatic hydrocarbons (PAHs), but few researches have been conducted on the emission characteristics of PAHs from coke production. In this study, emissions of size-segregated particulate matter (PM) and particle-bound PAHs emitted from charging of coal (CC) and pushing of coke (PC) in four typical coke plants were determined. The emission factors on average, sums of CC and PC, were 4.65 mg/kg, 5.96 mg/kg, 19.18 μg/kg and 20.69 μg/kg of coal charged for PM 2.1 (≤ 2.1 μm), PM, PAHs in PM 2.1 and total-PAHs, respectively. PM and PAHs emission from plants using stamp charging were significantly more than those using top charging. The profile of PAHs in PM with size ≤ 1.4 μm (PM 1.4 ) emitted from CC process were similar with that from PC, however, it revealed obviously different tendency for PAHs in PM with size > 1.4 μm, indicating the different formation mechanism for coarse particles emitted from CC and PC. Size distributions of PM and PAHs indicated that they were primarily connected with PM 1.4 , and the contributions of PM 1.4 to PM and PAHs emitted from the plants using stamp charging were higher than those using top charging. Some improved technology in air-pollution control devices should be considered in coke production in future based on the considerable impacts of PM 1.4 and PAHs on human health and ambient air quality. [ABSTRACT FROM AUTHOR]

To investigate the characterization of chemical compositions in size-segregated particles during severe haze pollution episodes in different regions of China, a campaign was conducted in Tianjin, Hangzhou and Chengdu. Size-segregated particles were collected with eight-stage Anderson cascade impactor in these cities in winter respectively. Ten major compositions of particles including (Na + , NH 4 + , K + , Mg 2 + , Ca 2 + , Cl − , NO 3 − , SO 4 2 − , OC and EC) were analyzed. A similar bimodal distribution of particles was found between northern and southern cities peaked at 0.7–2.1 and 9.0–10.0 μm. OC, EC, SO 4 2 − , NO 3 − , Cl − and NH 4 + were the major chemical compositions of fine-mode particles, whereas OC, EC, SO 4 2 − , NO 3 − and Ca 2 + were the major compositions of coarse-mode particles. In the three cities, Cl − , SO 4 2 − , NO 3 − , NH 4 + and K + of all compositions were unimodal distributions peaked at 0.7–2.1 μm. Different sources to particles in the three cities were inferred based on the size distribution characteristics of chemical compositions. For Tianjin, the influence of sea salt was greater to Hangzhou and Chengdu based on the concentrations and distributions of Na + and the Cl − . Fine-mode Cl − and SO 4 2 − were highest in Tianjin, meaning the greater contribution of coal burning to particles during severe pollution. For Hangzhou, the NO 3 − concentration was higher than Tianjin and Chengdu. Contribution of nitrate to PM was higher than that of sulfate. For Chengdu, carbonaceous species contributed mostly to fine particles. However, sulfate and nitrate contributed mostly to fine particles in Tianjin and Hangzhou. The contributions of EC and Ca 2 + to coarse-mode particles was much higher than that in other cities, implying the greater influence of soil particles, construction dust or falling dust to PM in Chengdu. In addition, there were greater emission source of NH 4 + in Chengdu. Northwest, west and southeast were the major transport pathways of air masses for Tianjin, Hangzhou and Chengdu. [ABSTRACT FROM AUTHOR]

In order to investigate the size distributions and seasonal variations of carbonaceous aerosols (organic carbon (OC) and elemental carbon (EC)), the carbonaceous species were collected in Nanjing, a typical industrial city located in Yangtze River Delta, China, in the summer, autumn, and winter of 2013 and spring of 2014, and then analyzed by using a 9-stage Anderson-type aerosol sampler and DRI Model 2001A Thermal/Optical Carbon Analyzer. OC, EC, secondary organic carbon (SOC), and primary organic carbon (POC) exhibited obvious seasonal variations, with the highest levels in winter (39.1±14.0, 5.7 ± 2.1, 23.6 ± 11.7, and 14.1 ± 5.7 µg⋅m-3, respectively) and the lowest levels in summer (20.6 ± 6.7, 3.3 ± 2.0, 12.2 ± 3.8 and 8.4 ± 4.1 µg⋅m-3, respectively), and were mainly centralized in PM1.1 in four seasons. The concentrations of OC in PM1.1 varied in the order of winter > autumn > spring > summer, while EC ranked in the order of autumn > winter > summer > spring. In the PM1.1-2.1 and PM2.1-10, the concentrations of OC and EC decreased in the sequence of winter > spring > autumn > summer. The size spectra of OC, EC, and SOC had bimodal distributions in four seasons, except for EC with four peaks in summer. The size spectra of POC varied greatly with seasons, exhibiting bimodal distribution in winter, trimodal distribution in spring and summer, and four peaks in autumn. The OC/EC ratios were 7.0, 6.3, 7.6, and 6.9 in spring, summer, autumn and winter, respectively, which demonstrated the abundance of secondary organic aerosols in Nanjing. The sources of carbonaceous aerosol varied significantly with seasons, and were dominated by vehicle exhaust, and coal and biomass burning in PM2.1, and dominated by dust, and coal and biomass burning in PM2.1-10. [ABSTRACT FROM AUTHOR]

Particle number concentration and size distribution are important for better understanding the characteristics of aerosols. However, their measurements are scarce in western China. Based on the first measurement of particle number size distribution (10–487 nm) in the suburb of Xi'an, northwest China from November 2013 to December 2014, the seasonal, monthly and diurnal average particle number concentrations were investigated, and the characteristics of new particle formation (NPF) events and their dependencies on meteorological parameters also discussed. The results showed that the annual average particle number concentrations in the nucleation (N NUC ), Aitken (N AIT ), and Accumulation (N ACC ) size ranges were 960 cm −3 , 4457 cm −3 , 3548 cm −3 , respectively. The mean total particle number concentration (N TOT ) was 8965 cm −3 and largely dominated by particles in Aitken mode. The number concentration was dominated by particles around 67.3 nm in spring, summer and fall, while about 89.8 nm in winter. The percentage of the ultrafine size range (UFP, particles of diameter below 100 nm) to total particle number concentration was 63.2%, 69.6%, 62.2% and 58.1% in four seasons. The diurnal variation of the nucleation mode particles was mainly influenced by NPF events in summer, while by both traffic densities and NPF events in spring, fall and winter. The diurnal variation of the number concentration of Aitken mode particles correlated with the traffic emission in spring, fall and winter, while in summer it more correlated with contribution of the growth of the nucleation mode particles. The burst of nucleation mode particles typically started in the daytime (08:15–16:05, LST). The growth rates of nucleated particles ranged from 2.8 to 10.7 nm h -1 with an average of 5.0 ± 1.9 nm h -1 . Among observed 66 NPF events from 347 effective measurement days, 85 percent of their air masses came from north or northwest China, resulting in a low concentration of pre-existing particles, and only 15 percent came southerly from Qingling Mountains. Based on their growth rate, 64 and 36 percent of their subsequent particles, corresponding to types 1 and 2 NPF events, grew and seldom grew after the burst of nucleation mode particles. For type 1 NPF event, the nucleated particles could grow up to 40 nm or larger when surface winds shifted from westerly to easterly or southeasterly (from village areas). For type 2 NPF events, the particles kept almost unchanged when the winds stayed westerly. This implied that the surface wind direction with different emissions might play an important role in new particle growth in suburb of Xi'an. [ABSTRACT FROM AUTHOR]

Understanding particle size distribution and size-resolved gas-particle partitioning of semi-volatile organic compounds (SVOCs) is important for characterizing their fate in atmosphere. However, the size-resolved gas-particle partitioning characteristics of SVOCs has not been adequately considered. To address this issue, the present study collected gaseous and size-fractioned particulate samples both in and outside of schools, offices, and residences in three districts of different urbanization levels in a megacity, Guangzhou, South China during two seasons. Typical SVOCs, including 15 polycyclic aromatic hydrocarbons (PAHs), six organophosphate esters and seven phthalic acid esters were measured. Emission sources, physicochemical properties, and environmental conditions at the sampling sites considerably impacted the spatiotemporal distribution patterns and particle size distribution of target SVOCs. Not all observed gas-particle partition coefficients (K p) of target SVOCs were negatively correlated with subcooled liquid-vapor pressures (P L 0), probably because certain factors, such as the non-exchangeable part of the particle-bound SVOCs, were not considered in traditional gas-particle partition theories. Particle size was an important factor affecting gas-particle partitioning. Adsorption was the dominant mechanism for PAHs with high molecular weight in different particle modes. A new model was established to predict size-resolved K p of PAHs with high molecular weight based on P L 0 and particle size. [Display omitted] • Observed log K p of PAEs and OPEs were not well correlated with log P L 0. • Observed log K p of 3- and 4-rings PAHs were negatively related with log P L 0. • Adsorption was the dominant gas-particle partition mechanism of 3- and 4-rings PAHs. • Particle size affects gas-particle partitioning of semi-volatile organic compounds. • The established model greatly predicted size-resolved K p of 3- and 4-rings PAHs. [ABSTRACT FROM AUTHOR]

Seasonal atmospheric particulate matter samples with different particle sizes (< 2.5 μm [PM 2.5 ], 2.5-5 μm [PM 2.5-5 ], 5-10 μm [PM 5-10 ], and 10-100 μm [PM 10-100 ]) were collected to analyze the mass concentration and distribution characteristics of nine water-soluble ions (WSIs; F - , Cl - , NO 3 - , SO 4 2- , Na + , NH 4 + ) in Lvliang in China. The results of chemical composition analysis indicated that the average concentration of total WSIs was 29.08 µg·m + , Mg 2+ , and Ca 2+ ) in Lvliang in China. The results of chemical composition analysis indicated that the average concentration of total WSIs was 29.08 µg·m -3 and accounted for 40.45% of PM 2.5 , 80.99% of which was attributable to SO 4 2- , NH 4 + , and NO 3 - ; the concentration demonstrated obvious distribution characteristics. NO 3 - and NH 4 + primarily exist as NH 4 NO 3 and (NH 4 ) 2 SO 4 , respectively, in fine particles but as NaNO 3 and NH 4 Cl, respectively, in coarse particles. The PM 2.5 was alkaline overall, and K + and NH 4 + caused the highest R C/A values in autumn. Stationary sources contribute more to WSIs in particulates than mobile sources. The secondary transformation degree of SO 2 was higher than that of NOx, especially in fine particles. The positive matrix factorization (PMF) and potential source contribution function (PSCF) models were combined to determine the sources of WSIs in PM 2.5 . Through use of the PMF model, five source factors were categorized: secondary aerosols (43.0%), biomass combustion (21.7%), coal combustion (17.6%), dust (10.9%), and vehicular traffic (6.8%). The results of the PSCF model suggested that the transport of pollutants from Shanxi, northwestern Shaanxi, Gansu, Inner Mongolia and Henan, had the greatest effect on air quality in Lvliang., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)