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Air pollution and climate change are potential drivers for the increasing burden of allergic diseases. The molecular mechanisms by which air pollutants and climate parameters may influence allergic diseases, however, are complex and elusive. This article provides an overview of physical, chemical and biological interactions between air pollution, climate change, allergens, adjuvants and the immune system, addressing how these interactions may promote the development of allergies. We reviewed and synthesized key findings from atmospheric, climate, and biomedical research. The current state of knowledge, open questions, and future research perspectives are outlined and discussed. The Anthropocene, as the present era of globally pervasive anthropogenic influence on planet Earth and, thus, on the human environment, is characterized by a strong increase of carbon dioxide, ozone, nitrogen oxides, and combustion- or traffic-related particulate matter in the atmosphere. These environmental factors can enhance the abundance and induce chemical modifications of allergens, increase oxidative stress in the human body, and skew the immune system toward allergic reactions. In particular, air pollutants can act as adjuvants and alter the immunogenicity of allergenic proteins, while climate change affects the atmospheric abundance and human exposure to bioaerosols and aeroallergens. To fully understand and effectively mitigate the adverse effects of air pollution and climate change on allergic diseases, several challenges remain to be resolved. Among these are the identification and quantification of immunochemical reaction pathways involving allergens and adjuvants under relevant environmental and physiological conditions.

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]

A series of Mn and Fe metal oxide catalysts loaded onto USY, as well as single metal oxides, were prepared and characterized. The effects of interactions between the catalytic components and the introduction of gas phase NO on the catalytic ozonation of toluene were investigated. Characterization showed that there existed strong interactions between MnO x , FeO x , and USY, which enhanced the content of oxygen vacancies and acid sites of the catalysts and thus boosted the generation of reactive oxygen species and the adsorption of toluene. The MnFeO x -USY catalyst with MnO x and FeO x dimetallic oxides exhibited the most excellent performance of catalytic ozonation of toluene. On the other hand, the presence of NO x in reaction gas mixtures significantly promoted both toluene conversion and mineralization, which was attributed to the formation of nitrate species on the catalysts surface and thus the increase of both acid sites and toluene oxidation sites. Meanwhile, the reaction mechanism between O 3 and C 7 H 8 was modified in which the strong interactions between MnO x , FeO x , and USY accelerated the reaction progress based on the L-H route. In addition, the formation of the surface nitrate species not only promoted reaction progress following the L-H route but also resulted in the occurrence of the reaction via the E-R route.

Mn-based catalysts hold the promise of practical applications in catalytic ozonation of toluene at room temperature, yet improvement of toluene conversion and CO x selectivity remains challenging. Here, an innovative α-MnO 2 /ZSM-5 catalyst modified with SO 4 2- was successfully prepared, and both characterizations and density functional theory (DFT) calculations showed that SO 4 2- introduction facilitated the formation of oxygen vacancies, Lewis and Brönsted acid sites, and active oxygen species and enhanced the adsorption ability of toluene on α-MnO 2 /ZSM-5. Characterizations also showed that SO 4 2- introduction made the catalyst possess larger specific surface area, superior reducibility, and stronger surface acidity. As a result, α-MnO 2 /ZSM-5 with a S/Mn molar ratio of 0.019 exhibited the best toluene conversion and CO x selectivity, 87 and 94%, respectively, after the reaction for 8 h at 30 °C under an initial concentration of 5 ppm toluene and 45 ppm ozone, relative humidity of 45%, and space velocity of 32,000 h -1 , far superior to those of non-noble catalysts reported to date under comparable reaction conditions. The synergistic role of increased oxygen vacancies and acid sites of α-MnO 2 /ZSM-5 modified with SO 4 2- resulted in excellent toluene conversion and CO x selectivity. The findings represented a critical step toward the rational design and synthesis of highly efficient catalysts for catalytic ozonation of toluene.

A series of Na-OMS-2 catalysts was prepared by a facile solid-state reaction method. Their physiochemical properties were characterized, and the catalytic activity for ozone decomposition was evaluated. The results showed that the introduction of Na + in the tunnel framework of OMS-2 facilitated lattice defect formation, which significantly enhanced oxygen vacancies, which are believed to be the active sites for ozone decomposition. Density functional theory calculations also showed that both the oxygen vacancy formation energy and ozone adsorption energy over Na-OMS-2 decreased because of Na + introduction. Sodium ion introduction significantly improved the OMS-2 catalytic activity for ozone decomposition. The Na-OMS-2 catalyst with a Na/Mn molar ratio of 1/4 exhibited ozone conversion at 92.5% at 25 ± 1 °C after reaction for 6 h under an initial ozone concentration of 45 ± 2 ppm, a relative humidity of 30 ± 2%, and a space velocity of 660 000 h -1 . This showed that this catalyst was far superior to manganese oxide catalysts reported to date. Furthermore, the research results also showed that the catalytic activity of Na-OMS-2 deactivated by the accumulation of oxygen-related intermediates was recovered by calcination at 425 °C under N 2 atmosphere for 0.5 h. Finally, a complete mechanism for ozone decomposition, catalyst deactivation, and regeneration was proposed.

Despite its emerging significant public health concern, the presence of antibiotic resistance genes (ARGs) in urban air has not received significant attention. Here, we profiled relative abundances (as a fraction, normalized by 16S rRNA gene) of 30 ARG subtypes resistant to seven common classes of antibiotics, which are quinolones, β-lactams, macrolides, tetracyclines, sulfonamides, aminoglycosides, and vancomycins, in ambient total particulate matter (PM) using a novel protocol across 19 world cities. In addition, their longitudinal changes in PM 2.5 samples in Xi'an, China as an example were also studied. Geographically, the ARGs were detected to vary by nearly 100-fold in their abundances, for example, from 0.07 (Bandung, Indonesia) to 5.6 (San Francisco, USA). The β-lactam resistance gene blaTEM was found to be most abundant, seconded by quinolone resistance gene qepA; and their corresponding relative abundances have increased by 178% and 26%, respectively, from 2004 to 2014 in Xi'an. Independent of cities, gene network analysis indicates that airborne ARGs were differentially contributed by bacterial taxa. Results here reveal that urban air is being polluted by ARGs, and different cities are challenged with varying health risks associated with airborne ARG exposure. This work highlights the threat of urban airborne transmission of ARGs and the need of redefining our current air quality standards in terms with public health.

Although use of automobile air conditioning (AC) was shown to reduce in-vehicle particle levels, the characterization of its microbial aerosol exposure risks is lacking. Here, both AC and engine filter dust samples were collected from 30 automobiles in four different geographical locations in China. Biological contents (bacteria, fungi, and endotoxin) were studied using culturing, high-throughput gene sequence, and Limulus amebocyte lysate (LAL) methods. In-vehicle viable bioaerosol concentrations were directly monitored using an ultraviolet aerodynamic particle sizer (UVAPS) before and after use of AC for 5, 10, and 15 min. Regardless of locations, the vehicle AC filter dusts were found to be laden with high levels of bacteria (up to 26,150 CFU/mg), fungi (up to 1287 CFU/mg), and endotoxin (up to 5527 EU/mg). More than 400 unique bacterial species, including human opportunistic pathogens, were detected in the filter dusts. In addition, allergenic fungal species were also found abundant. Surprisingly, unexpected fluorescent peaks around 2.5 μm were observed during the first 5 min use of AC, which was attributed to the reaerosolization of those filter-borne microbial agents. The information obtained here can assist in minimizing or preventing the respiratory allergy or infection risk from the use of automobile AC system.

Here, nonthermal plasma generated by a dielectric barrier discharge (DBD) system was applied to inactivating aerosolized Bacillus subtilis cells and Pseudomonas fluorescens as well as indoor and outdoor bioaerosols. The culturability, viability, and diversity losses of the microorganisms in air samples treated by the plasma for 0.06-0.12 s were studied using culturing, DNA stain as well as polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) methods. In addition, the viable fraction of bacterial aerosols with and without the plasma treatment was also quantified using qPCR coupled with ethidium monoazide (EMA). It was shown that less than 2% of B. subtilis aerosols survived the plasma treatment of 0.12 s, while none of the P. fluorescens aerosols survived. Viability tests, EMA-qPCR results, and Scanning Electron Microscopy (SEM) images demonstrated that both bacterial species suffered significant viability loss, membrane, and DNA damages. Exposure of environmental bacterial and fungal aerosols to the plasma for 0.06 s also resulted in their significant inactivations, more than 95% for bacteria and 85-98% for fungal species. PCR-DGGE analysis showed that plasma exposure of 0.06 s resulted in culturable bacterial aerosol diversity loss for both environments, especially pronounced for indoor environment. The results here demonstrate that nonthermal plasma exposure could offer a highly efficient air decontamination technology.

Here, nonelectrosprayed nanoscale zerovalent iron (NE-nZVI), electrosprayed nZVI (E-nZVI) and preoxidized nZVI (O-nZVI) particles were applied to inactivating Bacillus subtilis, Escherichia coli as well as bacteria in various wastewater samples. In addition, magnetic separation was applied to the mixture of 0.2 mL bacterial sample and 1.8 mL E-nZVI or NE-nZVI suspensions. Bacterial concentrations and optical density of the supernatants were analyzed using culturing, optical adsorption and qPCR tests. In general, for wastewater samples the inactivations were shown to range from 1-log to 3-log. PCR-DGGE analysis indicated that no gene mutation occurred when bacteria were treated with nZVI. Using magnetic separation, significant physical removals, revealed as a function of nZVI type (NE-,E- and O-nZVI) and bacterial concentration, up to 6-log were obtained. E-nZVI and NE-nZVI were shown to react differently with B. subtilis and E. coli, although exhibiting similar inactivation rates. qPCR tests detected higher amount of DNA in the supernatants from mixing E. coli with NE-nZVI, but less for E-nZVI. However, the opposite was observed with B. subtilis. Our data together with optical adsorption analysis suggested that the inactivation and magnetic separation mainly depend on Fe(0)/Fe(3)O(4) shell compositions, the type of bacteria (aerobic and anaerobic) and their concentrations.

Numerous threats from biological aerosol exposures, such as those from H1N1 influenza, SARS, bird flu, and bioterrorism activities necessitate the development of a real-time bioaerosol sensing system, which however is a long-standing challenge in the field. Here, we developed a real-time monitoring system for airborne influenza H3N2 viruses by integrating electronically addressable silicon nanowire (SiNW) sensor devices, microfluidics and bioaerosol-to-hydrosol air sampling techniques. When airborne influenza H3N2 virus samples were collected and delivered to antibody-modified SiNW devices, discrete nanowire conductance changes were observed within seconds. In contrast, the conductance levels remained relatively unchanged when indoor air or clean air samples were delivered. A 10-fold increase in virus concentration was found to give rise to about 20-30% increase in the sensor response. The selectivity of the sensing device was successfully demonstrated using H1N1 viruses and house dust allergens. From the simulated aerosol release to the detection, we observed a time scale of 1-2 min. Quantitative polymerase chain reaction (qPCR) tests revealed that higher virus concentrations in the air samples generally corresponded to higher conductance levels in the SiNW devices. In addition, the display of detection data on remote platforms such as cell phone and computer was also successfully demonstrated with a wireless module. The work here is expected to lead to innovative methods for biological aerosol monitoring, and further improvements in each of the integrated elements could extend the system to real world applications.