Promoting Photocatalytic Direct C-H Difluoromethylation of Heterocycles using Synergistic Dual-Active-Centered Covalent Organic Frameworks.

Difluoromethylation reactions are increasingly important for the creation of fluorine-containing heterocycles, which are core groups in a diverse range of biologically and pharmacologically active ingredients. Ideally, this typically challenging reaction could be performed photocatalytically under mild conditions. To achieve this separation of redox processes would be required for the efficient generation of difluoromethyl radicals and the reduction of oxygen. A covalent organic framework photocatalytic material was, therefore, designed with dual reactive centers. Here, anthracene was used as a reduction site and benzothiadiazole was used as an oxidation site, distributed in a tristyryl triazine framework. Efficient charge separation was ensured by the superior electron-donating and -accepting abilities of the dual centers, creating long-lived photogenerated electron-hole pairs. Photocatalytic difluoromethylation of 16 compounds with high yields and remarkable functional group tolerance was demonstrated; compounds included bioactive molecules such as xanthine and uracil. The structure-function relationship of the dual-active-center photocatalyst was investigated through electron spin resonance, femtosecond transient absorption spectroscopy, and density functional theory calculations.

Vertical Conductive Metal-Organic Framework Single-Crystalline Nanowire Arrays for Efficient Electrocatalytic Hydrogen Evolution.

The construction of crystalline metal-organic frameworks with regular architectures supportive of enhanced mass transport and bubble diffusion is imperative for electrocatalytic applications; however, this poses a formidable challenge. Here, a method is presented that confines the growth of nano-architectures to the liquid-liquid interface. Using this method, vertically oriented single crystalline nanowire arrays of an Ag-benzenehexathiol (BHT) conductive metal-organic framework (MOF) are fabricated via an "in-plane self-limiting and out-of-plane epitaxial growth" mechanism. This material has excellent electrocatalytic features, including highly exposed active sites, intrinsically high electrical conductivity, and superhydrophilic and superaerophobic properties. Leveraging these advantages, the carefully designed material demonstrates superior electrocatalytic hydrogen evolution activity, resulting in a low Tafel slope of 66 mV dec-1 and a low overpotential of 275 mV at a high current density of 1 A cm-2. Finite element analysis (FEA) and in situ microscopic verification indicates that the nanowire array structure significantly enhances the electrolyte transport kinetics and promotes the rapid release of gas bubbles. The findings highlight the potential of using MOF-based ordered nanoarray structures for advanced electrocatalytic applications.

Simultaneously Engineering the First and Second Coordination Shells of Single Iron Catalysts for Enhanced Oxygen Reduction.

The atomically dispersed Fe-N4 active site presents enormous potential for various renewable energy conversions. Despite its already remarkable catalytic performance, the local atomic microenvironment of each Fe atom can be regulated to further enhance its efficiency. Herein, a novel conceptual strategy that utilizes a simple salt-template polymerization method to simultaneously adjust the first coordination shell (Fe-N3S1) and second coordination shell (C-S-C, a structure similar to thiophene) of Fe-N4 isolated atoms is proposed. Theoretical studies suggest that this approach can redistribute charge density in the MN4 moiety, lowering the d-band center of the metal site. This weakens the binding of oxygenated intermediates, enhancing oxygen reduction reaction (ORR) activity when compared to only implementing coordination shell regulation. Based on the above discovery, a single Fe atom electrocatalyst with the optimal Fe-N3S1-S active moiety incorporated in nitrogen, sulfur co-doped graphene (Fe-SAc/NSG) is designed and synthesized. The Fe-SAc/NSG catalyst exhibits excellent alkaline ORR activity, exceeding benchmark Pt/C and most Fe-SAc ORR electrocatalysts, as well as superior stability in Zn-air battery. This work aims to pave the way for creating highly active single metal atom catalysts through the localized regulation of their atomic structure.

Balloon-shaped fiber surface nanoscale axial photonic microresonator for micro-displacement measurement.

In this Letter, we demonstrate a micro-displacement sensor based on a balloon-shaped fiber surface nanoscale axial photonic (SNAP) microresonator. The SNAP microresonator is fabricated by fiber bending to introduce nanoscale effective radius variations (ERVs) on the fiber surface. Displacement measurement based on the balloon-shaped SNAP microresonator is realized based on the ERV modulation resulting from the change in the bending radius of the balloon-shaped structure. An advantage of this approach is that the displacement measurement range is not limited to the axial length of the SNAP region. The experimental results show that the displacement measurement range of the balloon-shaped fiber SNAP microresonator can reach 2500 µm and that the minimum measurement resolution is 0.1 µm. This large-range, high-resolution, and low-cost micro-displacement sensor has the potential to be a promising candidate in high-precision displacement measurement applications.

Nanocellulose for Sustainable Water Purification.

Nanocelluloses (NC) are nature-based sustainable biomaterials, which not only possess cellulosic properties but also have the important hallmarks of nanomaterials, such as large surface area, versatile reactive sites or functionalities, and scaffolding stability to host inorganic nanoparticles. This class of nanomaterials offers new opportunities for a broad spectrum of applications for clean water production that were once thought impractical. This Review covers substantial discussions based on evaluative judgments of the recent literature and technical advancements in the fields of coagulation/flocculation, adsorption, photocatalysis, and membrane filtration for water decontamination through proper understanding of fundamental knowledge of NC, such as purity, crystallinity, surface chemistry and charge, suspension rheology, morphology, mechanical properties, and film stability. To supplement these, discussions on low-cost and scalable NC extraction, new characterizations including solution small-angle X-ray scattering evaluation, and structure-property relationships of NC are also reviewed. Identifying knowledge gaps and drawing perspectives could generate guidance to overcome uncertainties associated with the adaptation of NC-enabled water purification technologies. Furthermore, the topics of simultaneous removal of multipollutants disposal and proper handling of post/spent NC are discussed. We believe NC-enabled remediation nanomaterials can be integrated into a broad range of water treatments, greatly improving the cost-effectiveness and sustainability of water purification.

Optimizing the Electronic Structure of Atomically Dispersed Ru Sites with CoP for Highly Efficient Hydrogen Evolution in both Alkaline and Acidic Media.

Developing efficient and stable electrocatalysts for hydrogen evolution reaction (HER) over a wide pH range and industrial large-scale hydrogen production is critical and challenging. Here, a tailoring strategy is developed to fabricate an outstanding HER catalyst in both acidic and alkaline electrolytes containing high-density atomically dispersed Ru sites anchored in the CoP nanoparticles supported on carbon spheres (NC@RuSA -CoP). The obtained NC@RuSA -CoP catalyst exhibits excellent HER performance with overpotentials of only 15 and 13 mV at 10 mA cm-2 in 1 m KOH and 0.5 m H2 SO4 , respectively. The experimental results and theoretical calculations indicate that the strong interaction between the Ru site and the CoP can effectively optimize the electronic structure of Ru sites to reduce the hydrogen binding energy and the water dissociation energy barrier. The constructed alkaline anion exchange membrane water electrolyze (AAEMWE) demonstrates remarkable durability and an industrial-level current density of 1560 mA cm-2 at 1.8 V. This strategy provides a new perspective on the design of Ru-based electrocatalysts with suitable intermediate adsorption strengths and paves the way for the development of highly active electrocatalysts for industrial-scale hydrogen production.

Characterizing emission factors and oxidative potential of motorcycle emissions in a real-world tunnel environment.

Transportation emissions significantly affect human health, air quality, and climate in urban areas. This study conducted experiments in an urban tunnel in Taipei, Taiwan, to characterize vehicle emissions under real driving conditions, providing emission factors of PM2.5, eBC, CO, and CO2. By applying multiple linear regression, it derives individual emission factors for heavy-duty vehicles (HDVs), light-duty vehicles (LDVs), and motorcycles (MCs). Additionally, the oxidative potential using dithiothreitol assay (OPDTT) was established to understand PM2.5 toxicity. Results showed HDVs dominated PM2.5 and eBC concentrations, while LDVs and MCs influenced CO and CO2 levels. The CO emission factor for transportation inside the tunnel was found to be higher than those in previous studies, likely owing to the increased fraction of MCs, which generally emit higher CO levels. Among the three vehicle types, HDVs exhibited the highest PM2.5 and eBC emission factors, while CO and CO2 levels were relatively higher for LDVs and MCs. The OPDTTm demonstrated that fresh traffic emissions were less toxic than aged aerosols, but higher OPDTTv indicated the impact on human health cannot be ignored. This study updates emission factors for various vehicle types, aiding in accurate assessment of transportation emissions' effects on air quality and human health, and providing a guideline for formulating mitigation strategies.

An In-Situ Cyanidation Strategy To Access Tetracyanodiacenaphthoanthracene Diimides with High Electron Mobilities Exceeding 10†cm2 †V-1 s-1.

A family of novel highly π-extended tetracyano-substituted acene diimides, named as tetracyanodiacenaphthoanthracene diimides (TCDADIs), have been synthesized using a facile four-fold Knoevenagel condensation strategy. Unlike conventional cyano substitution reactions, our approach enables access to a large π-conjugated backbone with the in-situ formation of four cyano substitutents at room temperature while avoiding extra cyano-functionalization reactions. TCDADIs decorated with different N-alkyl substituents present good solubility, near-coplanar backbones, good crystallinity, and low-lying lowest unoccupied molecular orbital energies of -4.33 eV, all of which contribute to desirable electron-transport performance when applied in organic field-effect transistors (OFET). The highest electron mobility of an OFET based on a 2-hexyldecyl-substituted TCDADI single crystal reaches 12.6 cm2  V-1 s-1 , which is not only among the highest values for the reported n-type organic semiconductor materials (OSMs) but also exceeds that of most n-type OSMs decorated with imide units.

Alkyl-Substituted N,S-Embedded Heterocycloarenes with a Planar Aromatic Configuration for Hosting Fullerenes and Organic Field-Effect Transistors.

Cycloarenes and heterocycloarenes display unique physical structures and hold great potential as organic semiconductors. However, the synthesis of (hetero)cycloarenes remains a big challenge, and there are limited reports on their applications. Herein, a series of nitrogen- and sulfur-codoped cycloarenes NS-Octulene-n (n = 2, 3, 4) with branched alkyl substituents containing linear spacer groups from C2 to C4 have been conveniently synthesized. Compared with their isoelectronic analogues Octulene and S-Octulene, both having a saddle-shaped configuration, the coincorporation of two nitrogen atoms and two sulfur atoms leads to a fully coplanar aromatic backbone structure. Each of these three planar heterocycloarenes acts as a supramolecular host for encapsulation of both fullerenes C60 and C70 with a stronger donor-acceptor interaction for the complexation between the heterocycloarene and C70 due to the unique molecular geometry and defined cavity. Meanwhile, the electron-rich nitrogen atoms also slightly increase the energies of both highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) in this series of planar heterocycloarenes, indicating that they can be used as p-type semiconductors. Most importantly, benefitting from the planar π-conjugated backbone structure accompanied by excellent crystallinity and ordered molecular packing, as well as upon the engineering of the alkyl chain branching position, thin-film field-effect transistors of NS-Octulene-3 with moderate alkyl branching point exhibit the maximum hole mobility of 0.86 cm2 V-1 s-1, which is the highest for (hetero)cycloarene-based organic semiconductors. This study will shed new light on designing novel high-performance macrocyclic polycyclic aromatic hydrocarbon (PAH) semiconductors.

Single Atom Catalysts with Out-of-Plane Coordination Structure on Conjugated Covalent Organic Frameworks.

Adjusting the local coordination environment of single-atom electrocatalysts is a viable way to improve catalytic performance. The diversity of coordination geometric structures is limited to the traditional in-plane configuration, with only a little consideration paid to out-of-plane configurations due to the lack of suitable carriers and fabrication methods. This study reports out-of-plane coordination of Co-based single-atom catalysts mediated by the conjugated bipyridine-rich covalent organic framework (COF). The bipyridine nitrogen on the COF layer backbone of these catalysts serves as the linker center for cobalt sites anchoring, while the complementary moieties are coordinated at the other side of the Co metal and reside beyond the COF backbone plane, thus yielding out-of-plane coordination. The electrochemical experiments and density functional theory calculations reveal that catalysts with multiple out-of-plane coordinations exhibit different electrocatalytic oxygen evolution activities and catalytic pathways. The out-of-plane coordination enabled by COFs provides a strategy for designing single-atom electrocatalysts, expanding the application of COFs in the field of electrocatalysis.

Evaluation of a laboratory-developed multiplex real-time PCR assay for diagnosis of syphilis, herpes and chancroid genital ulcers in four public health laboratories in the USA.

OBJECTIVE: To evaluate the field performance of a multiplex PCR (M-PCR) assay for detection of herpes simplex virus (HSV)-1 and HSV-2, Treponema pallidum (T. pallidum) and Haemophilus ducreyi (H. ducreyi) in genital ulcer disease (GUD) specimens. METHODS: GUD M-PCR was performed on 186 remnant specimens, previously collected for HSV testing, by four public health laboratories (PHLs) and the Laboratory Reference and Research Branch (LRRB) at the Centers for Disease Control and Prevention. The results from the PHLs were compared with those of LRRB, which served as the reference testing method, and percentage agreement was calculated. RESULTS: HSV was detected in 31 of 52 (59.6%), 20 of 40 (50%), 43 of 44 (97.7%) and 19 of 50 (38.0%) specimens from PHL1, PHL2, PHL3 and PHL4, respectively. There were seven discrepant results for HSV, and the overall percent agreement between the PHLs and the LRRB was 94%-100%, with a kappa value of 0.922, which demonstrates high agreement. T. pallidum was identified in 7 of 51 (13.7%) specimens from PHL1 with 94.1% agreement and in 2 of 40 (5.0%) specimens from PHL2 with 100% agreement. The LRRB identified three additional T. pallidum-positive specimens from PHL1. The kappa value (0.849) for T. pallidum testing suggests good agreement. Consistent with the LRRB results, no T. pallidum was detected in specimens from PHL3 and PHL4, and H. ducreyi was not detected at any of the study sites. CONCLUSIONS: The GUD M-PCR assay performed well in four independent PHLs and 12 suspected syphilis cases were identified in this study. The M-PCR assay could provide improved diagnostic options for GUD infections in state and local PHLs.

Detection of Lymphogranuloma Venereum-Associated Chlamydia trachomatis L2 Serovars in Remnant Rectal Specimens Collected from 7 US Public Health Laboratories.

ABSTRACT: The frequency of lymphogranuloma venereum or invasive Chlamydia trachomatis infection with serovar L1, L2, or L3 is unknown in the United States. While no diagnostic test is commercially available, we used a laboratory-developed test and detected lymphogranuloma venereum-associated serovar L2 in 14% of 132 remnant C. trachomatis-positive rectal swabs.

Antibody Responses to Two Recombinant Treponemal Antigens (rp17 and TmpA) before and after Azithromycin Treatment for Yaws in Ghana and Papua New Guinea.

WHO and its partners aim to interrupt yaws transmission in countries of endemicity and to certify others as being yaws-free. Transmission can be assessed using rapid plasma reagin (RPR) tests, reflecting current or recent infection, but RPR is operationally impractical. We evaluated changes in antibody levels against two recombinant treponemal antigens, rp17 (also known as Tp17) and TmpA, after antibiotic treatment given as part of a randomized controlled trial for yaws in Ghana and Papua New Guinea. Paired serum samples from children aged 6 to 15 years with confirmed yaws, collected before and after treatment, were tested for antibodies to rp17 and TmpA using a semiquantitative bead-based immunoassay. Of 344 baseline samples, 342 tested positive for anti-rp17 antibodies and 337 tested positive for anti-TmpA antibodies. Six months after treatment, the median decrease in anti-rp17 signal was 3.2%, whereas the median decrease in anti-TmpA was 53.8%. The magnitude of change in the anti-TmpA response increased with increasing RPR titer fold change. These data demonstrate that responses to TmpA decrease markedly within 6 months of treatment whereas (as expected) those to rp17 do not. Incorporating responses to TmpA as a marker of recent infection within an integrated sero-surveillance platform could provide a way to prioritize areas for yaws mapping.

Immediate Effect of Whole Body Vibration on Knee Extensor Tendon Stiffness in Hemiparetic Stroke Patients.

Background and Objectives: Whole body vibration is widely used to enhance muscle performance, but evidence of its effects on the tendon stiffness of the knee extensor tendon in stroke remains inconclusive. Our study was aimed to determine the difference in patellar and quadriceps tendon stiffness between hemiparetic and unaffected limbs in stroke patients and to investigate the immediate effect of whole body vibration on tendon stiffness. Materials and Methods: The patellar and quadriceps tendon stiffness of first-ever hemiplegic stroke patients was evaluated with elastography to compare the differences between hemiparetic and unaffected limbs. After one 20 min session of whole body vibration exercise in the standing position, tendon stiffness was again measured to evaluate the immediate effects of whole body vibration on tendon stiffness. Results: The results showed no significant differences in the tendon stiffness of the patellar and quadriceps tendons between hemiparetic and unaffected limbs. However, significant associations were found between the tendon stiffness of the patellar and quadriceps tendons and knee extensor spasticity on the hemiparetic side (ρ = 0.62; p = 0.044). There were no significant changes in tendon stiffness after a single session of whole body vibration. Conclusions: In conclusion, knee extensor tendon stiffness in hemiparetic limbs is positively correlated to the degree of knee extensor spasticity in stroke patients. However, a single session of whole body vibration does not alter tendon stiffness.

Increased Discrimination of Treponema pallidum Strains by Subtyping With a 4-Component System Incorporating a Mononucleotide Tandem Repeat in rpsA.

A guanine mononucleotide repeat in the rpsA (tp0279) gene was evaluated for improved strain discrimination using 72 Treponema pallidum-positive specimens. The tandem repeat combined with the enhanced Centers for Disease Control and Prevention typing system resulted in increased discrimination and should be useful for molecular epidemiologic studies on syphilis especially in outbreaks and among men who have sex with men.

Measurement of PCNs in sediments collected from reservoir and river in northern Taiwan.

Sediment samples were collected from a large reservoir and a river in northern Taiwan to investigate the occurrence and characteristics of Σ73PCNs analyzed. Results indicate that total concentrations of PCNs (Di- to Octa-CNs) measured in sediments collected in reservoir (29.2 ±â€¯7.11 pg/g-dw) are significantly lower than that of samples collected in river (987 ±â€¯440 pg/g-dw). The increasing trend of PCN concentration from upstream to downstream is found for the sediments collected in reservoir. PCN concentrations measured in surface sediments are relatively higher than that measured in sub-surface sediments collected in reservoir. Tetra-CNs consistently dominate in reservoir sediments, however, Penta-, Tetra- and Mono-CNs dominate in sediments collected at different sampling sites of the river investigated, suggesting that various sources contribute to PCNs collected from river. Indeed, diagnostic ratios indicate that mix-source contribute to PCNs measured in sediments collected from the reservoir and river in northern Taiwan.

Nonoperative Choice of Anterior Cruciate Ligament Partial Tear: Ultrasound-Guided Platelet-Rich Plasma Injection.

Anterior cruciate ligament (ACL) injury is one of the common musculoskeletal injuries. The most serious condition shall be managed by surgery, while the partial tear prefers conservative treatment, rehabilitation, exercise training, or platelet-rich plasma (PRP) injection. We describe the case of a 25-year-old female started to have right knee pain for a long time and the ACL partial tear was diagnosed through the magnetic resonance imaging (MRI). After three times of PRP injection through ultrasound guidance, the pain, instability, and enhancements of ACL tear in the postintervention MRI were decreased. This case confirms the effect of PRP combined with conservative treatment under the accuracy procedure and may provide another choice for the treatment of the ACL tear.

Simultaneous recording of ultrasound and polysomnography during natural sleep in patients with obstructive sleep apnea: a pilot study.

Tongue base deformation may play a critical role in the phenomenon of obstructive sleep apnea, but polysomnography provides limited information regarding the effect of tongue motion during natural sleep. We reported on preliminary results of combining a novel ultrasound system and polysomnography for simultaneous recordings during natural sleep in volunteers and patients with obstructive sleep apnea. All participants underwent time-synchronized polysomnography and submental transcutaneous ultrasound examinations. The wearable ultrasound device detected the air-mucosal interface of the tongue surface and automatically determined the maximum tongue base thickness in real time. All participants reported no sensation of heat, no sign of skin allergy, and an average of mild disturbance after the ultrasound recordings. In the individual patient with obstructive sleep apnea, we demonstrated a significant difference (P < 0.001) between the ultrasonic tongue base thickness measured during eupnea and that measured during snoring, hypopnea and apnea. The ultrasonic tongue base thickness increased and remained before the occurrence of obstructive apnea. On average, increased tongue base thicknesses of 2.5 (4.1%), 6.0 (9.8%) and 7.7 mm (12.5%) are associated with snoring, hypopnea and apnea, respectively. Our present data demonstrate that simultaneous examination of ultrasonic tongue base thickness and polysomnography is feasible for prolonged recording during natural sleep. The proposed method also enables the detection of significant differences in ultrasonic tongue base thickness between eupnea and obstructive respiratory events evaluated using polysomnography. This novel technique can be used to generate hypotheses for subsequent investigations of the underlying mechanisms and individualized combined therapy for obstructive sleep apnea. CLINICAL TRIAL REGISTRATION: This study has been registered at the Chinese Clinical Trial Registry website with the registration number of ChiCTR-DDT-13003313. The date of registration was 13 July 2013.

Polybrominated Diphenyl Ethers (PBDEs) in Surface Soils across Five Asian Countries: Levels, Spatial Distribution, and Source Contribution.

A total of 23 polybrominated diphenyl ether (PBDE) congeners were measured in soil samples collected in areas with no known point source [urban/rural/background (U/R/B) sites] and in areas with known point source [brominated flame retardant (BFR)-related industrial sites (F sites) and e-waste recycling sites (E sites)] across five Asian countries. The highest PBDE concentrations were found in BFR-related industrial and e-waste recycling sites. The concentrations of PBDEs in U/R/B sites decreased in the following order: urban > rural > background sites. Total PBDE concentrations were dominated by BDE-209, while BDE-17, -85, -138, -191, -204, and -205 were the least abundant compounds. In both urban sites and rural sites, the mean concentrations of total PBDEs (∑23BDEs) in soils decreased in the following order: Japan > China > South Korea > India > Vietnam. The concentrations of PBDEs in soils were comparable with those reported in other studies. Among the three commercial PBDE mixtures, relatively large contributions of commercial penta-BDE were observed in Vietnam, whereas deca-BDE was the dominant form in mixtures contributing from 55.8 ± 2.5 to 100.0 ± 1.2% of the total PBDEs in soils collected from other four countries. Regression analysis suggested that local population density (PD) is a good indicator of PBDEs in soils of each country. Significant and positive correlation between soil organic content and PBDE level was observed in Chinese soil for most nondeca-BDE homologues with their usage stopped 10 years ago, indicating its important role in controlling the revolatilization of PBDEs from soil and changing the spatial trend of PBDE in soil from the primary distribution pattern to the secondary distribution pattern, especially when primary emission is ceased.

Distribution, Fate, Inhalation Exposure and Lung Cancer Risk of Atmospheric Polycyclic Aromatic Hydrocarbons in Some Asian Countries.

A large-scale monitoring program, the Asia Soil and Air Monitoring Program (Asia-SAMP), was conducted in five Asian countries, including China, Japan, South Korea, Vietnam, and India. Air samples were collected using passive air samplers with polyurethane foam disks over four consecutive 3-month periods from September 2012 to August 2013 to measure the seasonal concentrations of 47 polycyclic aromatic hydrocarbons (PAHs), including 21 parent and 26 alkylated PAHs, at 176 sites (11 background, 83 rural, and 82 urban). The annual concentrations of total 47 PAHs (∑47PAHs) at all sites ranged from 6.29 to 688 ng/m(3) with median of 82.2 ng/m(3). Air concentrations of PAHs in China, Vietnam, and India were greater than those in Japan and South Korea. As expected, the air concentrations (ng/m(3)) were highest at urban sites (143 ± 117) followed by rural (126 ± 147) and background sites (22.4 ± 11.4). Significant positive correlations were found between PAH concentrations and atmosphere aerosol optical depth. The average benzo(a)pyrene equivalent concentration (BaPeq) was 5.61 ng/m(3). It was estimated that the annual BaPeq concentrations at 78.8% of the sampling sites exceeded the WHO guideline level. The mean population attributable fraction (PAF) for lung cancer due to inhalation exposure to outdoor PAHs was on the order 8.8‰ (0.056-52‰) for China, 0.38‰ (0.007-3.2‰) for Japan, 0.85‰ (0.042-4.5‰) for South Korea, 7.5‰ (0.26-27‰) for Vietnam, and 3.2‰ (0.047-20‰) for India. We estimated a number of lifetime excess lung cancer cases caused by exposure to PAHs, which the concentrations ranging from 27.8 to 2200, 1.36 to 108, 2.45 to 194, 21.8 to 1730, and 9.10 to 720 per million people for China, Japan, South Korea, Vietnam, and India, respectively. Overall, the lung cancer risk in China and Vietnam were higher than that in Japan, South Korea, and India.