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The association between PM 2.5 (particulate matter ≤ 2.5 µm) short-term exposure and its health effect is non-linear from the epidemiological studies. And this nonlinearity is suggested to be related with the PM 2.5 heterogeneity, however, the underlying biological mechanism is still unclear. Here, a total of 38 PM 2.5 filters were collected continuously for three weeks in winter Beijing, with the ambient PM 2.5 varying between 10 and 270 µg/m3. Human monocytes-derived macrophages (THP-1) were treated with PM 2.5 water-soluble elutes at 10 µg/mL to investigate the PM 2.5 short-term exposure effect from a proinflammatory perspective. The proinflammatory cytokine tumor necrosis factor (TNF) induced by the PM 2.5 elutes at equal concentrations were unequal, showing the heterogeneity of PM 2.5 proinflammatory potentials. Of the various chemical and biological components, lipopolysaccharide (LPS) showed a strong positive association with the TNF heterogeneity. However, some outliers were observed among the TNF-LPS association. Specifically, for PM 2.5 from relatively clean air episodes, the higher LPS amount corresponded to relatively low TNF levels. And this phenomenon was also observed in the promotion tests by treating macrophages with PM 2.5 elutes dosed with additional trace LPS. Gene expression analysis indicated the involvement of oxidative-stress related genes in the LPS signaling pathway. Therefore, a potential oxidative-stress-mediated suppression on the PM 2.5 -borne LPS proinflammatory effect was proposed to be accounted for the outliers. Overall, the results showed the differential role of LPS in the heterogeneity of PM 2.5 proinflammatory effects from a component-based perspective. Future experimental studies are needed to elucidate the signaling pathway of LPS attached on PM 2.5 from different air quality episodes. [Display omitted] [ABSTRACT FROM AUTHOR]

Interactions of particulate matter (PM) and respiratory tract play a crucial role in PM-related respiratory diseases. The majority of the work focuses on the oxidative stress induced by reactions between PM-borne redox-active components and lung lining fluid (LLF). The effects of PM-borne biological components are largely unknown. Of all PM-borne biologicals, bacteria, as living microorganisms, are closely related with inflammatory immune responses. However, its inhalation risk is usually determined without considering the respiratory physiological conditions. In this study, a surrogate lung fluid (SLF) with four typical antioxidants was applied to characterize the ambient bacteria, including concentrations of total bacteria/viable bacteria/culturable bacteria, metabolic activity, bacteria-derived endotoxin, as well as the community structure. Comparing to those determined by SLF, we find that use of PBS leads to an underestimation of the bacterial culturability and metabolic activity. No effect was seen regarding the number of total bacteria and viable bacteria (with intact membrane). Population structure change was seen for bacteria cultured from SLF-collected samples, when compared to that from PBS. Spore-forming bacteria, e.g., genus Bacillus , were found to be easily recovered with SLF. This implies that use of PBS could underestimate the bacteria inhalation risk, especially those bacterial endospores. Our work highlights the necessity to consider the respiratory airway environment when evaluating microbial inhalation risk. Unlabelled Image • Surrogate lung fluid (SLF) was applied to assess the lung-bioaerosol interaction. • Bacterial aerosols were characterized with SLF under different levels of air quality. • The culturability and metabolic activity of bacterial aerosols were enhanced by SLF. • Spore-forming bacteria are prone to recover and outgrow within SLF. • Bacterial exposure risk was underrated without considering lung fluid. [ABSTRACT FROM AUTHOR]

Probing interactions of biological systems at the molecular level is of great importance to fundamental biology, diagnosis, and drug discovery. A rational bioassay design of lithographically integrating individual point scattering sites into electrical circuits is capable of realizing real‐time, label‐free biodetection of influenza H1N1 viruses with single‐molecule sensitivity and high selectivity by using silicon nanowires as local reporters in combination with microfluidics. This nanocircuit‐based architecture is complementary to more conventional optical techniques, but has the advantages of no bleaching problems and no fluorescent labeling. These advantages offer a promising platform for exploring dynamics of stochastic processes in biological systems and gaining information from genomics to proteomics to improve accurate molecular and even point‐of‐care clinical diagnosis.A bioassay design involving lithographically integrating point scattering sites into electrical circuits is capable of realizing real‐time, label‐free biodetection of H1N1 viruses with single‐molecule sensitivity and high selectivity by using Si nanowires as local reporters in combination with microfluidics. This architecture is complementary to conventional optical techniques but has the advantages of no bleaching or fluorescent labeling. [ABSTRACT FROM AUTHOR]

Probing interactions of biological systems at the molecular level is of great importance to fundamental biology, diagnosis, and drug discovery. A rational bioassay design of lithographically integrating individual point scattering sites into electrical circuits is capable of realizing real-time, label-free biodetection of influenza H1N1 viruses with single-molecule sensitivity and high selectivity by using silicon nanowires as local reporters in combination with microfluidics. This nanocircuit-based architecture is complementary to more conventional optical techniques, but has the advantages of no bleaching problems and no fluorescent labeling. These advantages offer a promising platform for exploring dynamics of stochastic processes in biological systems and gaining information from genomics to proteomics to improve accurate molecular and even point-of-care clinical diagnosis. [ABSTRACT FROM AUTHOR]

Probing interactions of biological systems at the molecular level is of great importance to fundamental biology, diagnosis, and drug discovery. A rational bioassay design of lithographically integrating individual point scattering sites into electrical circuits is capable of realizing real-time, label-free biodetection of influenza H1N1 viruses with single-molecule sensitivity and high selectivity by using silicon nanowires as local reporters in combination with microfluidics. This nanocircuit-based architecture is complementary to more conventional optical techniques, but has the advantages of no bleaching problems and no fluorescent labeling. These advantages offer a promising platform for exploring dynamics of stochastic processes in biological systems and gaining information from genomics to proteomics to improve accurate molecular and even point-of-care clinical diagnosis. [ABSTRACT FROM AUTHOR]

Bioaerosol charge information is of vital importance for their electrostatic collection. Here, electrostatic means and molecular tools were applied to studying bioaerosol charge dynamics. Positively or negatively charged bioaerosols were collected using an electrostatic sampler operated with a field strength of 1.1 kV cm at a flow rate of 3 L min for 40 min. Those with fewer or no charges bypassing the sampler were also collected using a filter at the downstream of the electrostatic sampler in one environment. The experiments were independently conducted three times in three different environments. The collected bacterial aerosols were cultured directly on agar plates at 26°C, and the colony forming units (CFU) were manually counted. In addition, the CFUs were washed off from the agar plates, and further subjected to polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) for culturable diversity analysis. The results revealed remarkable differences in positively and negatively charged culturable bacterial aerosol concentration and diversity among the studied environments. In the office environment, negatively charged culturable bacterial aerosols appeared to dominate ( P = 0.0489), while in outdoor and hotel environments both polarities had similar concentration levels ( P = 0.078, P = 0.88, respectively). DGGE patterns for positively charged culturable bacterial aerosols were shown strikingly different from those of negatively charged regardless of the sampling environments. In addition, for each of the environments positively charged culturable bacterial aerosols collected were found to have more band pattern similarity with those positively charged for respective regions of agar plates than those negatively charged, and vice versa. The information developed here is useful for developing efficient electrostatic sampling protocols for bioaerosols. [ABSTRACT FROM AUTHOR]

In this study, the bacterial and fungal abundances, diversities, conductance levels as well as total organic carbon (TOC) were investigated in the snow samples collected from five different snow occurrences in Beijing between January and March, 2010. The collected snow samples were melted and cultured at three different temperatures (4, 26 and 37°C). The culturable bacterial concentrations were manually counted and the resulting colony forming units (CFUs) at 26°C were further studied using V3 region of 16 S rRNA gene-targeted polymerase chain reaction -denaturing gradient gel electrophoresis (PCR-DGGE). The clone library was constructed after the liquid culturing of snow samples at 26°C. And microscopic method was employed to investigate the fungal diversity in the samples. In addition, outdoor air samples were also collected using mixed cellulose ester (MCE) filters and compared with snow samples with respect to described characteristics. The results revealed that snow samples had bacterial concentrations as much as 16000 CFU/ml for those cultured at 26°C, and the conductance levels ranged from 5.6×10−6 to 2.4×10−5 S. PCR-DGGE, sequencing and microscopic analysis revealed remarkable bacterial and fungal diversity differences between the snow samples and the outdoor air samples. In addition, DGGE banding profiles for the snow samples collected were also shown distinctly different from one another. Absent from the outdoor air, certain human, plant, and insect fungal pathogens were found in the snow samples. By calculation, culturable bacteria accounted for an average of 3.38% (±1.96%) of TOC for the snow samples, and 0.01% for that of outdoor air samples. The results here suggest that snow precipitations are important sources of fungal pathogens and ice nucleators, thus could affect local climate, human health and agriculture security. [ABSTRACT FROM AUTHOR]

In this study, a simple impedance based technology for measuring bacterial concentrations was developed. The measurement system includes the signal amplification, copper probes and a sample loader. During the experiments, the conductance of Bacillus subtilis var niger, Pseudomonas fluorescens, and Escherichia coli were measured using the combination of a pre-amplifier and a lock-in amplifier. The conductance data were modeled verses the bacterial concentrations. Results indicated that the relationship between the conductance of bacterial suspensions and their concentrations follows a generic model: $$Y = C_1 + C_2 \times e^{\left( { - X/C_3 } \right)}$$, where Y is the conductance (S), X is the bacterial concentration (Number/mL: abbreviated to N/mL) for all species tested, and C are constants. Gram negative P. fluorescens and E. coli assumed similar conductance curves, which were flatter than that of gram positive B. subtilis var niger. For P. fluorescens and E. coli the culturing technique resulted in higher concentration levels (statistically significant) from 2 to 4 times that measured by the impedance based technology. For B. subtilis var niger, both methods resulted in similar concentration levels. These differences might be due to membrane types, initial culturability and the obtained conductance curves. The impedance based technology here was shown to obtain the bacterial concentration instantly, holding broad promise in realtime monitoring biological agents. [ABSTRACT FROM AUTHOR]

Influenza epidemics worldwide result in substantial economicand human costs annually. However, rapid and reliable flu diagnosismethods are significantly lacking. Here we have demonstrated the selectivedetection of influenza A viruses down to 29 viruses/μL in clinicalexhaled breath condensate (EBC) samples (diluted by 100-fold) withinminutes using silicon nanowire (SiNW) sensor devices. For 90% of thecases, we have observed that EBC samples tested positive or negativeby gold standard method RT-qPCR generated corresponding positive ornegative SiNW sensor responses. High selectivity of SiNW sensing wasalso demonstrated using H1N1 viruses, 8 iso PGF 2a, and inert nanoparticles.Finally, magnetic beads were shown capable of enhancing SiNW sensingdirectly for low level viruses and 8 iso PGF 2a. When calibrated byvirus standards and EBC controls, our work suggests that the SiNWsensor device can be reliably applied to the diagnosis of flu in aclinical setting with 2 orders of magnitude less time compared tothe gold standard method RT-qPCR. [ABSTRACT FROM AUTHOR]

In this study, the pure influenza A virus (H5N1) nucleotides, dermatophagoides allergens (Der f 1 and Der p 1), and Bacillus subtilis vegetative cells were aerosolized and collected by a Button Aerosol Sampler equipped with gelatin filter and a BioSampler, which were operated at 4 and 12.5L/min, respectively, for 1–5min. The collected air samples were analyzed by quantitative polymerase chain reaction (qPCR) and enzyme-linked immuosorbent assay (ELISA). In addition, the performances of the samplers when quantifying total outdoor bacteria were also studied. The cycle threshold (Ct) value for 0.1fg/μl RNA positive control was observed around 26, and the Ct value for the negative control was about 30. Gelatin filters were shown to report 1-2 times higher nucleotides and B. subtilis concentrations than those obtained by the BioSampler. When sampling outdoor bacteria, both samplers however obtained similar concentration levels (p-value=0.36). In contrast, the BioSampler reported substantially higher dust mite allergen concentration levels, especially for Der f 1 than the gelatin filters in this study. The sampling time up to 5min was shown not to have a statistically significant effect on the performance of qPCR when the gelatin filter was used. Such finding was also observed with the performance of ELISA for the sampling time up to 15min. This study suggests that the bioaerosol sampler, collection medium and analysis methods such as qPCR and ELISA would play overall roles in characterizing airborne biological materials. [Copyright &y& Elsevier]

• Airborne endotoxins increased in the air filtered through a previously used HEPA-air-purifier. • Replacement of HEPA helped to mitigate the risk of increased endotoxins in larger size. • Broken bacteria on the HEPA contributed to the increase of endotoxins. Stand-alone portable air purifiers (APs) have become an increasingly popular method of controlling individual inhalation exposure. Exposure to bacterial endotoxins has a causative role in respiratory inhalation health. Here, we studied the changes in endotoxin levels in indoor air before and after purification by a portable AP equipped with HEPA (high-efficiency particulate air) filters. An increase in endotoxins was observed when a previously used AP was turned on to clean the air. Replacing the HEPA filters in the AP helped to mitigate the increase in endotoxins of larger sizes but not endotoxins of smaller sizes. Consequently, the use of APs could lead to increased endotoxin deposition in airways, especially in the alveolar region. The endotoxin concentrations on the HEPA filters were well correlated with the free DNA concentrations on the HEPA filters. This correlation indicates that the disrupted bacteria, which released free DNA, could also release endotoxins, thus making HEPA filters a source of indoor airborne endotoxins. Our results illustrate a potential endotoxin inhalation risk associated with HEPA-APs as an air cleaning strategy and highlight the importance of composition-specific air cleaning while reducing the particle number/mass. [ABSTRACT FROM AUTHOR]

The front cover design of the international edition of volume 53, number 20, 2014 issue of the journal "Angewandte Chemie" is presented.

Poor air hygiene as a result of bioaerosol contamination has caused diverse forms of adverse health effects and diseases. In addition, global biosecurity is threatened by purposeful use of biowarfare agents and the vulnerability of people to the infectious agents. Accordingly, developments in high-volume biosampling, including aerosol-to-hydrosol techniques with low cut-off size, real-time bioaerosol detection, adequate biological quantification, and exposure control, as well as the investigation of the link between disease outcome and bioaerosol exposure, are current areas of bioaerosol research. Although milestone progress has been achieved both in bioaerosol sampling and analysis techniques since late 1800s, compared to atmospheric chemistry the bioaerosol field is still understudied. This is partially because of the lack of both bioaerosol scientists and multidisciplinary collaboration. It is becoming necessary to develop a pool of scientists with different expertise, e.g., bioaerosol scientists, environmental engineers, biomedical engineers, epidemiologists, microbiologists, chemists, physicists, as well as researchers in other engineering fields, in mitigating bioaerosol-related adverse health effects, eliminating diseases, and preventing and controlling epidemic outbreaks. This work is conducted to broadly review current state-of-the-art sciences and technologies in the bioaerosol field. In tackling the challenges ahead, the review also provides perspectives for bioaerosol research needs, and further reminds bioaerosol scientists of those existing technologies in other fields that can be leveraged. In view of the past, forward-looking hypotheses and revolutional perspectives are needed to be formed in order to allow the bioaerosol research have major impacts in the academic community in this new millennium. [ABSTRACT FROM AUTHOR]

Air quality is often assessed using particulate matter (PM) mass concentration without considering its toxicity, thus possibly leading to improper control policies or inadequate health protection. Here, we studied differences in oxidative potentials (OPs) of PM samples collected using automobile air conditioning (AC) filters from 19 global cities, as well as influences from microbial contents. Dithiothreitol (DTT) assay showed remarkable differences in the PM OPs among cities (p -values ≤ 0.001, Kruskal-Wallis test). For example, the normalized index of oxidant generation (NIOG) of PM samples in San Francisco (2.20 × 10−2, annual average PM 10 = 16 μg/m3) was found to be twice that in Beijing (1.14 × 10−2, annual average PM 10 = 135 μg/m3). Limulus amebocyte lysate (LAL) assay found that PM-borne endotoxin ranged from 12.16 EU/mg (Florianopolis, Brazil) to 2518.23 EU/mg (Chennai, India) among cities. Besides, culturing method and real-time qPCR revealed significant differences of up to ∼100-fold in both bacterial and fungal levels among 19 cities. Spearman's correlation analysis implied that PM-borne microbes such as bacteria and fungi as well as metals could strongly influence the PM OP. As an example, our results in Xi'an, China further suggest that the PM 2.5 OP evolves for a particular city over the time, which is attributable to both the urbanization and air pollution control measures. This work highlights the importance in optimizing the current air quality control measures by considering the toxicity factor and its microbial constituents. Image 1 • Ambient PM toxicity per unit of mass was shown to vary greatly with different cities across the world. • PM-borne biologicals were shown to exhibit remarkable differences across major cities, contributing to the difference of PM toxicity. • PM toxicity was shown to evolve over the time as a result of ground human activities as well as air pollution control measures. • This work highlights the need of taking into account of PM toxicity for future air pollution control efforts. [ABSTRACT FROM AUTHOR]

Although free hydroxyl radical (·OH) generated on OMS-2-based catalysts during the catalytic ozonation process have been shown as important reactive oxygen species (ROSs) for toluene degradation, improvement of surface ·OH formation ability remains challenging. Here, Na, K, Rb, and Cs-OMS-2-SO 4 2-/ZSM-5 catalysts were prepared, characterized and evaluated for catalytic ozonation of toluene. Both characterizations and DFT calculations showed that the appropriate alkali metal introduction made the catalyst possess with appropriate crystalline, reducibility, and acidity, which was favorable for catalytic ozonation of toluene. Characterizations also showed that alkali metal introduction resulted in water molecule adsorption on Brönsted acid sites of the catalysts, which made water molecule activation by ozone to form ·OH more easily. The introduction of K+ content of ∼ 5.9 wt% yielded K-OMS-2-SO 4 2-/ZSM-5 catalyst with the highest Brönsted acid sites and thus formed the most ·OH among the five prepared catalysts. As a result, the catalyst exhibited excellent toluene conversion and CO x selectivity for catalytic ozonation of toluene at room temperature and ambient humidity. Furthermore, the catalytic activity of deactivated K-OMS-2-SO 4 2-/ZSM-5 catalyst was recovered after regeneration by a combination of water washing and heat treatment. Finally, a complete mechanism for toluene catalytic ozonation, catalyst deactivation, and regeneration was proposed. [Display omitted] • The alkali metal introduction promoted ·OH formation in OMS-2-SO 4 2-/ZSM-5 catalyst. • The increased ·OH facilitated toluene conversion over OMS-2-SO 4 2-/ZSM-5 catalyst. • A complete mechanism for toluene catalytic ozonation and deactivation was proposed. • A strategy for efficient regeneration of K-OMS-2-SO 4 2-/Z catalyst was developed. [ABSTRACT FROM AUTHOR]

A series of MnFe catalysts were prepared by hydrothermal synthesis combined with heat treatment at different temperatures. The characterizations demonstrated that MnFe-120 with both surface -OH and -NO 3 , MnFe-175 with surface -OH, MnFe-300 containing neither surface -OH nor -NO 3 , and MnFe-300-NO 3 containing surface -NO 3 were gained by drying or calcination and impregnation. The activity evaluation showed that the order of catalytic activity was MnFe-120 > MnFe-175 > MnFe-300-NO 3 > MnFe-300. Further, characterizations and experiment results revealed that O 3 adsorbed on the surface of the catalyst can interact with surface -OH and generated hydroxyl radicals (·OH). The presence of surface -NO 3 provided more Lewis acid sites, thereby promoting H 2 O adsorption and conversion to the surface -OH, which supplemented the surface -OH consumed by the interaction with O 3. It was deduced that the coexistence of surface -OH and -NO 3 improved the production of·OH, which synergistically promoted the catalytic ozonation of toluene. [Display omitted] • A series of MnFe catalysts with different amounts of surface -OH and -NO 3 were prepared. • MnFe catalyst containing both surface -OH and -NO 3 had a optimal catalytic ozonation performance for toluene. • O 3 adsorbed on the surface -OH sites and hydroxyl radicals (·OH) to oxidize toluene was produced. • H 2 O adsorbed on the surface -NO 3 sites and was converted to the surface -OH, which supplemented the surface -OH consumed. • The synergistic effect of surface -OH and -NO 3 increased the amount of·OH production. [ABSTRACT FROM AUTHOR]

The heat desorption of styrene from adsorbents is impracticable owing to its spontaneous polymerization under heating conditions. However, the feature also brings a potential promoting effect on styrene adsorption. Therefore, it is expected to develop the non-regenerative adsorbents with large adsorption capacity by strengthening the polymerization effect. In this work, C–Cl grafted silica gel adsorbents were prepared by introducing (Chloromethyl)dimethylchlorosilane (CMDMCS) and FeCl 2 into silica gel. The C–Cl grafted silica gel exhibited excellent styrene adsorption performance, its adsorption amounts for styrene were 4.67 times and 9 times of unmodified silica gel under dry air condition and high humidity condition (RH = 80%), respectively. In addition, the adsorption of styrene on C–Cl grafted silica gel was almost unaffected by the presence of toluene. The characterization of adsorbents after styrene adsorption indicated that the improvement of adsorption capacity of C–Cl grafted silica gel for styrene can be attributed to atom transfer radical polymerization (ATRP) of styrene molecules on modified silica gel during adsorption process. [Display omitted] • C–Cl grafted SiO 2 adsorbents were prepared by introducing CMDMCS and FeCl 2. • The adsorption capacity of SiO 2 -1.5 for styrene was 4.7 times of SiO 2. • The adsorption of styrene on C–Cl grafted SiO 2 was almost unaffected by toluene. • C–Cl grafted SiO 2 showed excellent moisture resistance for styrene adsorption. • ATRP occurred during the adsorption process of styrene on C–Cl grafted SiO 2. [ABSTRACT FROM AUTHOR]

Adsorptive removal of gas phase low concentration macromolecular organic component, represented by naphthalene, from the enclosed space using ordered mesoporous carbon (OMC) has been studied by molecular simulation and experimental investigation. The simulation results indicated that both adsorption capacity and adsorption stability of the OMCs for naphthalene decreased with the increase of pore sizes from 2 nm to 8 nm. Characterizations showed that the prepared OMCs had the pore structure similar to the simulated OMCs except for the rough surface. In particular, the adsorption performance of the prepared OMCs was significantly lower than that of the simulated OMCs when pore size was 2 nm and 3 nm, which was attributed to the rough inner surface of these adsorbents, blocking the narrow pore channels and significantly reducing the pore volume. OMC with pore size of 4 nm had the highest adsorption amount for naphthalene. The co-adsorption experiments in the presence of both naphthalene and toluene, acetone or water showed the adsorption performance of OMCs for naphthalene were almost unaffected by the presence of low concentration toluene and acetone, as well as high relative humidity. [Display omitted] • Adsorption of naphthalene by OMCs were investigated by simulation and experiment. • Realistic molecular models for OMCs were constructed by "delete atom" method. • The impact of pore structure on the adsorption of naphthalene was revealed. • OMC with pore size of 4 nm has the highest adsorption capacity for naphthalene. • OMCs show excellent adsorption selectivity and good moisture resistance. [ABSTRACT FROM AUTHOR]

The chemical characteristics of airborne particulate matter (PM) have been extensively studied; however, little information exists for its biological components (bioaerosol) especially during a haze event in mega cities. Herein, we studied the bioaerosol (fluorescent particle) dynamics on both haze and sunny days in Beijing from Dec. 2013 to March 2014 by employing a widely used real-time bioaerosol sensor-ultraviolet aerodynamic particle spectrometer (UV-APS). Firstly, we studied the fluorescent particle (BioPM) concentration and size distributions during three independent haze and three independent sunny days. Secondly, we investigated BioPM dynamics over a two-week long monitoring period which included consecutive haze days and alternated sunny days. In addition, we analyzed bacterial community structures and endotoxin levels in the air samples using pyrosequencing and Limulus amebocyte lysate (LAL) method, respectively. More than 6-fold higher fluorescent particle concentrations up to 5 × 10 5 /m 3 with peaks at night or early dawn were detected at the time of haze occurrences than those observed on sunny days. When the haze episode progressed for 3–5 days, the BioPM concentrations were observed to decrease to the levels that were typically observed on sunny days. In general, ozone levels were found to be elevated at noon, while BioPM, NO x and relative humidity were reduced. Gene sequence analysis revealed no significant difference in abundances and community structures for top 13 bacterial genera between haze and sunny days, yet about twice higher endotoxin levels (12.4 EU/m 3 ) were detected on haze days than on sunny days. The results here facilitate a better understanding of atmospheric fluorescent particle dynamics including those under haze events. [ABSTRACT FROM AUTHOR]

There is an increasing interest in understanding ambient bioaerosols due to their roles both in health and in climate. Here, we deployed an Ultraviolet Aerodynamic Particle Sizer to monitor viable (fluorescent) bioaerosol concentration levels at city centers (highly polluted) and their corresponding suburbs (near pristine) (total 40 locations) in 11 provinces featuring different climate zones in China between July 16 and 28, 2013. The concentration levels of viable bioaerosol particles (BioPM) of >0.5 µm were measured, and corresponding percentages of BioPM% (biological fraction of total PM) and BioPM% (biological fraction of PM) in particulate matter (PM) and BioPM, respectively, were determined. For some key cities, indoor viable bioaerosol levels were also obtained. In addition, bacterial structures of the air samples collected across these monitoring locations were studied using pyrosequencing. BioPM concentration levels ranged from 2.1 × 10 to 2.4 × 10/m for city centers [BioPM% = 6.4 % (±6.3 %)] and 0.5 × 10 to 4.7 × 10/m for suburbs [BioPM% = 10 % (±8.7 %)]. Distinctive bioaerosol size distribution patterns were observed for different climate zones, e.g., some had fluorescence peaks at 3 µm, while the majority had peaks at 1 µm. Ambient bacterial aerosol community structures were also found different for different geophysical locations. Results suggest that there was a poor overall relationship between PM and BioPM across 40 monitoring locations ( R = 0.081, two-tailed P value = 0.07435). Generally, city centers had higher PM concentrations than suburbs, but not BioPM and BioPM%. Indoor bioaerosol levels were found at least tenfold higher than those corresponding outdoors. Bacillus was observed to dominate the bacterial aerosol community in the air sample. [ABSTRACT FROM AUTHOR]

Characterizing marine biotoxins (MBs) composition in coastal aerosol particles has become essential to tracking sources of atmospheric contaminants and assessing human inhalable exposure risks to air particles. Here, coastal aerosol particles were collected over an almost 3-year period for the analysis of eight representative MBs, including brevetoxin (BTX), okadaic acid (OA), pectenotoxin-2 (PTX-2), domoic acid (DA), tetrodotoxin (TTX), saxitoxin (STX), ciguatoxin (CTX) and ω-Conotoxin. Our data showed that the levels of inhalable airborne marine biotoxins (AMBs) varied greatly among the subcategories and over time. Both in daytime and nighttime, a predominance of coarse-mode AMB particles was found for all the target AMBs. Based on the experimental data, we speculate that an ambient AMB might have multiple sources/production pathways, which include air-sea aerosol production and direct generation and release from toxigenic microalgae/bacteria suspended in surface seawater or air, and different sources may make different contribution. Regardless of the subcategory, the highest deposition efficiency of an individual AMB was found in the head airway region, followed by the alveolar and tracheobronchial regions. This study provides new information about inhalable MBs in the coastal atmosphere. The coexistence of various particle-bound MBs raises concerns about potential health risks from exposure to coastal air particles. [Display omitted] • The levels of inhalable airborne marine biotoxins (AMBs) vary greatly among the marine biotoxin subcategories and over time. • A predominance of coarse-mode AMB particles is found for all the target AMBs. • Our findings reveal for the first time that an ambient AMB may originate from multiple sources. • Humans living in the coastal areas may inhale various AMBs at nonnegligible rates. [ABSTRACT FROM AUTHOR]

[Display omitted] • Adsorption of toluene and naphthalene by OMS were investigated by simulation. • The adsorption selectivity of toluene and naphthalene was predicted by IAST. • The mechanism of selective adsorption was elucidated at molecular level. • Adsorbents with the desired pore size were prepared by template synthesis method. • The experimental results are in good agreement with the simulation results. In order to ensure regeneration property of adsorption materials in the air pollution purification system of the airtight cabin, such as submarine and space station, it is necessary to selectively separate semi-volatile organic compounds whose desorption is difficult. For this reason, the effects of pore size on the adsorption capacity and adsorption selectivity of toluene and naphthalene were investigated by both molecular simulation and experimental investigation. The ordered porous silica-based adsorbents with pore sizes ranging from 1.0 nm to 2.8 nm were constructed by simulation and were prepared by template synthesis method in this study. Both simulation and experiment show that the adsorption capacity of toluene and naphthalene firstly increased and then decreased with the increase of the pore size of adsorbents from 1.0 nm to 2.8 nm, and the pore diameter (1.3 nm) corresponding to the maximum adsorption amount of toluene was smaller than that (2.3 nm) of naphthalene. Simulation results show that the adsorption energy and adsorption stability of naphthalene are higher than those of toluene, and binary-component co-adsorption experiments also testified that toluene molecules could be replaced by naphthalene molecules. The optimum pore size for selective adsorption of naphthalene is 2.3 nm. [ABSTRACT FROM AUTHOR]

[Display omitted] • An innovative Li-K-OMS-2 catalyst for ozone decomposition was designed and prepared. • The catalyst possessed specific H 2 O adsorption sites and thus displayed excellent water resistance for ozone decomposition. • Tuning the Li+-K+ into the OMS-2 tunnels facilitated oxygen vacancy formation. • The water resistance mechanism of Li-K-OMS-2 for ozone catalytic decomposition was proposed. OMS-2-based catalysts hold the promise of practical applications in ozone decomposition for their excellent activity, yet improvement of water resistance property remains challenging. Here, we reported an innovative Li-K-OMS-2 catalyst which possessed specific non-oxygen vacancy sites for H 2 O adsorption in the tunnel framework. This catalyst showed the decrease of only ∼10 % of ozone conversion after reaction for 6 h under the RH of 90 %, the initial ozone concentration of 45 ppm and GHSV of 660,000h−1 at 25 °C, which was superior to the currently documented MnO 2 -based catalysts. Both physiochemical characterization and DFT calculations revealed that the excellent water resistance property of Li-K-OMS-2 could be attributed to the formation of designed novel non-oxygen vacancy sites for H 2 O adsorption, which effectively alleviated the catalyst deactivation caused by non-dissociative adsorption of H 2 O on oxygen vacancies. The findings represented a critical step towards the rational design and synthesis of high water-resistant catalyst for ozone decomposition. [ABSTRACT FROM AUTHOR]

As a bioaerosol sampling standard, Andersen type impactor is widely used since its invention in 1950s, including the investigation of the anthrax attacks in the United States in 2001. However, its related problems such as impaction and desiccation stress as well as particle bounce have not been solved. Here, we improved its biological collection efficiencies by plating a mineral oil layer (100 µL) onto the agar plate. An Andersen six-stage sampler and a BioStage impactor were tested with mineral-oil-spread agar plates in collecting indoor and outdoor bacterial and fungal aerosols. The effects of sampling times (5, 10 and 20 min) were also studied using the BioStage impactor when sampling environmental bioaerosols as well as aerosolized Bacillus subtilis (G+) and Escherichia coli (G-). In addition, particle bounce reduction by mineral-oil-plate was also investigated using an optical particle counter (OPC). Experimental results revealed that use of mineral-oil-spread agar plate can substantially enhance culturable bioaerosol recoveries by Andersen type impactors (p-values<0.05). The recovery enhancement was shown to depend on bioaerosol size, type, sampling time and environment. In general, more enhancements (extra 20%) were observed for last stage of the Andersen six-stage samplers compared to the BioStage impactor for 10 min sampling. When sampling aerosolized B. subtilis, E. coli and environmental aerosols, the enhancement was shown to increase with increasing sampling time, ranging from 50% increase at 5 min to ∼100% at 20 min. OPC results indicated that use of mineral oil can effectively reduce the particle bounce with an average of 66% for 10 min sampling. Our work suggests that enhancements for fungal aerosols were primarily attributed to the reduced impaction stress, while for bacterial aerosols reduced impaction, desiccation and particle bounce played major roles. The developed technology can readily enhance the agar-based techniques including those high volume portable samplers for bioaerosol monitoring. [ABSTRACT FROM AUTHOR]

Exposure to indoor airborne microbiomes (bioaerosols) is closely associated with human health. However, knowledge regarding the characteristics of indoor bioaerosols in areas affected by serious ambient air pollution is still limited. In this study, indoor bioaerosols were characterized in winter Beijing via quantitative polymerase chain reaction (qPCR) and amplicon sequencing, and compared to outdoor bioaerosols. Concentrations of indoor bioaerosol were significantly lower than those of the adjacent outdoor bioaerosol, and were not significantly affected by outdoor air pollution. Community structures of indoor bioaerosol were distinct from those of outdoor environment, and were differentially affected by ambient air pollution. Specifically, significant change was observed in indoor fungal community impacted by hazy air pollution, while not in bacteria and archaea. Compared to outdoor air, indoor air was preferentially enriched with fungi (~10%) in winter. Besides, about 40% of the bacteria indoors were likely contributed by outdoor bacteria. The results provide useful information regarding the impact of ambient air pollution on indoor bioaerosols, and furtherly highlight the distinction between indoor and outdoor bioaerosol assemblies. [Display omitted] • Impact of winter haze pollution on indoor airborne bacteria, fungi and archaea was delineated. • The abundance and diversity of indoor bioaerosols were lower than those outdoors. • The percentage of fungi in bioaerosols indoors was higher that outdoors. • Nearly 40% of indoor bacterial communities were contributed by outdoor air. • Ambient haze pollution differentially affected the indoor and outdoor fungal aerosols. [ABSTRACT FROM AUTHOR]

To understand the characteristics and potential impacts of fungal aerosols in waste disposal treatments, we performed observations at a landfill and an incineration plants in Guangzhou, Southern China. Size-segregated airborne fungal concentrations were measured based on culture-dependent method, and fungal compositions in PM 2.5 were obtained using high-throughput sequencing method. Concentrations of airborne fungi varied from 376 to 9318 CFU/m3 in the landfill plant and from 53 to 8491 CFU/m3 in the incineration plant, respectively. The temporal and spatial variations of fungal aerosols indicate that waste disposal operation, garbage transport, air mixing, and meteorological factors can significantly influence the variations of airborne fungi in the outdoor environment in both plants. Among the meteorological factors, light/moderate rain could significantly increase the airborne fungal concentrations while heavy rain could decrease the concentrations due to wet scavenge. We observed that culturable fungal aerosols predominantly resided in the size range of 2.1–3.3 μm. Different fungal community structures in PM 2.5 were found between the landfill and the incineration plants, suggesting the influence of different waste sorts and treatment procedures. We further identified the pathogenic/allergenic fungal taxa (e.g., Alternaria, Epicoccum sp. and Stachybotrys sp.) in the two plants, implying the potential human health risks with long-term exposure for on-site workers and surrounding residents. The fungal genera producing microbial volatile organic compounds (MVOCs, e.g., Cladosporium , Fusarium sp., Penicillium sp. and Candida) were found in both plants. These MVOCs generation related fungal genera could contribute to the odor in the plants and, more importantly, affect the downwind area after aerosolization and transportation. Unlabelled Image • Culturable concentration and DNA of fungal aerosols were measured in waste plants. • Culturable airborne fungi predominantly resided in the size range of 2.1–3.3 μm. • Different fungal communities may be due to waste sorts and treatment procedures. • Pathogenic and MVOCs related fungi were identified to reveal potential impacts. [ABSTRACT FROM AUTHOR]

Archaea have an important role in the elemental biogeochemical cycle and human health. However, characteristics of airborne archaea affected by anthropogenic and natural processes are unclear. In this study, we investigated the abundance, structures, influencing factors and assembly processes of the archaeal communities in the air samples collected from Beijing in springtime using quantitative polymerase chain reaction (qPCR), high-throughput sequencing technology and statistical analysis. The concentrations of airborne archaea ranged from 101 to 103 copies m−3 (455 ± 211 copies m−3), accounting for 0.67% of the total prokaryote (sum of archaea and bacteria). An increase in airborne archaea was seen when the air quality shifted from clean to slightly polluted conditions. Sandstorm dust imported a large number of archaea to the local atmosphere. Euryarchaeota, Thaumarchaeota and Crenarchaeota were the dominant phyla, revealing the primary role of soil in releasing archaea to the ambient environment. Dispersal-related neutral processes play an important role in shaping the structure of airborne archaeal assembly. Of all phyla, methanogenic Euryarchaeota were most abundant in the air parcels come from the south of Beijing. Air masses from the west of Beijing, which brought sandstorm to Beijing, carried large amounts of ammonia oxidizing archaea Nitrososphaera. The results demonstrate the importance of air mass sources and local weather conditions in shaping the local airborne archaea community. Unlabelled Image • Airborne archaea were characterized under various weather conditions. • Quantitative PCR and high-throughput sequencing were applied. • Archaea accounted for <1% of the prokaryote. • Archaea compositions differed on days with air masses from different sources. • Sandstorm dust imported a large number of ammonia-oxidizing archaea Nitrososphaera. [ABSTRACT FROM AUTHOR]

• A series of ε-MnO 2 catalysts with Mn vacancies and appropriate amounts of Li+ were prepared. • Fabricating Mn vacancies in ε-MnO 2 via selective dissolution of Mn-Li precursors in HCl solution facilitated oxygen vacancy formation. • Mn vacancies and appropriate amounts of Li+ in ε-MnO 2 promoted the ozone decomposition. • A mechanism for ozone decomposition by the synergy of Li+, Mn vacancies, and oxygen vacancies in ε-MnO 2 was proposed. ε-MnO 2 catalysts with Mn vacancies and appropriate Li+ were designed with the help of density functional theory calculations (DFT) and prepared by a novel selective dissolution strategy. Their physiochemical properties were characterized and catalytic activity for ozone decomposition evaluated. DFT calculations showed that Mn vacancies and appropriate amounts of Li+ in ε-MnO 2 facilitated the formation of oxygen vacancies, decreased adsorption ability for H 2 O and O 2 , and maintained high adsorption ability for O 3 on these oxygen vacancies. Characterization results showed that preparing ε-MnO 2 by selective dissolution of Mn-Li precursors with 0.5 M HCl produced more Mn vacancies, and, thus, weaker crystallinity, larger specific surface area, superior reducibility, better oxygen storage capacity, and higher oxygen vacancies. This catalyst exhibited excellent activity and stability for ozone decomposition. Furthermore, a possible mechanism for ozone decomposition by the synergy of Li+, Mn vacancies, and oxygen vacancies in ε-MnO 2 was proposed. [ABSTRACT FROM AUTHOR]