Subsidy strategy for reserving flexible capacity of emergency supply production

This paper investigates a government's subsidy strategy for motivating a manufacturer to set up a flexible production line for emergency supplies. Four subsidy strategies are proposed to ensure a desired service level in case of an emergency: zero subsidy, a fixed subsidy, a marginal subsidy, and a hybrid subsidy. We develop a game theoretical model to examine how the government can induce a manufacturer to set up a flexible production line that can respond promptly to an emergency, based on the manufacturer's cost structure (fixed and marginal costs). We find that when the marginal profit of an emergency product is higher than that of the manufacturer's regular product, a fixed (marginal) subsidy is the dominant strategy if the manufacturer's fixed (marginal) cost is high, while a hybrid subsidy strategy is dominant if both costs are high. When the marginal profit of an emergency product is lower than that of the manufacturer's regular product, neither a fixed subsidy nor a zero subsidy will be the dominant strategy. We also find that a marginal subsidy can ensure the effectiveness of the strategy, while a fixed subsidy helps improve strategy efficiency. We use government subsidy strategies implemented for Chinese COVID-19 emergency supplies as examples to demonstrate the effectiveness and efficiency of the subsidy strategies under the proposed framework. We also extend the discussion by considering the manufacturer's social consciousness.

Clinical features of patients with severe acute respiratory syndrome coronavirus 2 Delta variant infection and abnormal liver function in Guangdong Province, China. TT -? ? ? ? ? ?.

Objective To investigate the clinical features of patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta variant infection and abnormal liver function in Guangdong Province, China. Methods The patients with SARS-CoV-2 Delta variant infection who belonged to the same chain of transmission in Guangdong Province (Guangzhou and Foshan) and were admitted to Guangzhou Eighth People's Hospital, Guangzhou Medical University from May 21 to June 18, 2021 were enrolled in this study, and the judgment criteria for liver function were alanine aminotransferase (male/female) > 50/40 U/L, aspartate aminotransferase > 40 U/L, total bilirubin > 26 mumol/L, gamma-glutamyl transpeptidase > 60 U/L, and alkaline phosphatase (ALK) > 125 U/L. Abnormality in any one item of the above criteria was defined as abnormal liver function, and such patients were included in analysis (the patients, aged < 18 years, who had a mild or moderate increase in ALP alone were not included in analysis). Clinical data were compared between the patients with normal liver function and those with abnormal liver function, and the etiology and prognosis of abnormal liver function were analyzed. The Mann-Whitney U test was used for comparison of continuous data between two groups;the chi-square test was used for comparison of categorical data between two groups. Results Among the 166 patients with SARS-CoV-2 Delta variant infection, 32 (19.3%) had abnormal liver function with mild-to-moderate increases in liver function parameters, and compared with the normal liver function group, the abnormal liver function group had a significantly higher proportion of critical patients (chi2=38.689, P < 0.001) and significantly higher age and inflammatory cytokines [C-reactive protein type, serum amyloid A, and interleukin-6 (IL-6)](all P < 0.05). Among the 32 patients with abnormal liver function, 13 patients had abnormal liver function on admission (defined as primary group), while 19 patients had normal liver function on admission but were found to have abnormal liver function by reexamination after treatment (defined as secondary group). For the primary group, the evidence of abnormal liver function was not found for 3 patients (3/13, 23.1%), and the possibility of toxic liver injury directly associated with SARS-CoV-2 infection was considered. Among the 19 patients in the secondary group, 9 (47.4%) had mild/common type and 10 (52.6%) had critical type, and all critical patients had the evidence of liver injury indirectly caused by the significant increases in C-reactive protein type, serum amyloid A, and IL-6 and hypoxemia;the evidence of abnormal liver function was not found for only 1 patient (1/19, 5.3%), and the possibility of toxic liver injury directly associated with SARS-CoV-2 infection was considered. All 32 patients with abnormal liver function had [JP2]significant reductions in liver function parameters after treatment including liver protection. Conclusion As for the patients with SARS-CoV-2 Delta variant infection who belong to the same chain of transmission in Guangdong Province, the critical patients show a significantly higher proportion of patients with abnormal liver function than the patients with other clinical types, and other factors except SARS-CoV-2 infection and indirect injury caused by SARS-CoV-2 infection are the main cause of liver injury.Copyright © 2022 Editorial Board of Jilin University. All rights reserved.

Determinants of customer loyalty to online food service delivery: evidence from Indonesia, Taiwan, and New Zealand

This study is dedicated to m-commerce and examines the key factors determining loyalty to online food delivery (OFD) services in Indonesia, Taiwan, and New Zealand, as these countries have faced varying degrees of pandemic severity. The data analysis using Partial Least Square Structural Equation Modeling (PLS-SEM) shows that the quality of both food and e-service, satisfaction, perceived value, and trust are significant predictors of loyalty in all countries. Food quality drives consumer loyalty, contentment, and perceived value in Indonesia and Taiwan, but e-service quality is the main determinant in New Zealand. These differences can be attributed to the status quo of the OFD service market in the three countries pre-Covid, cultural factors, the pandemic severity, and consumer access to other distribution channels. Best practice recommendations for marketing managers associated with OFD are presented.

Clinical Efficacy of Modified Sanxiaoyin in Treatment of Mild or Moderate COVID-19 Patients:Based on Retrospective Analysis.

Objective: To retrospectively analyze the clinical data of 52 patients with coronavirus disease-2019 COVID-19 and explore the clinical efficacy of modified Sanxiaoyin on mild/moderate COVID-19 patients. Method(s): The propensity score matching method was used to collect the clinical data of mild or moderate COVID-19 patients enrolled in the designated hospital of the Second Hospital of Jingzhou from December 2019 to May 2020. A total of 26 eligible patients who were treated with modified Sanxiaoyin were included in the observation group,and the 26 patients treated with conventional method were the regarded as the control. The disappearance of clinical symptoms,disappearance time of main symptoms,efficacy on traditional Chinese medicineTCMsymptoms,hospitalization duration,laboratory test indicators,and CT imaging changes in the two groups were compared. Result(s): The general data in the two groups were insignificantly different and thus they were comparable. After 7 days of treatment,the disappearance rate of fever,cough, fatigue,dry throat,anorexia,poor mental state,and poor sleep quality in the observation group was higher than that in the control groupP<0.05,and the difference in the disappearance rate of expectoration and chest distress was insignificant. For the cases with the disappearance of symptoms,the main symptomsfever, cough,fatigue,dry throat,anorexia,chest distressdisappeared earlier in the observation group than in the control groupP<0.01. After 7 days of treatment,the scores of the TCM symptom scale of both groups decreasedP<0.01,and the decrease of the observation group was larger that of the control groupP<0.01. All patients in the two groups were cured and discharged. The average hospitalization duration in the observation group12.79+/-2.68dwas shorter than that in the control group15.27+/-3.11dP<0.01. The effective rate in the observation group92.31%,24/26was higher than that in the control group76.92%,20/26. After 7 days of treatment,the lymphocyteLYMcount increasedP<0.05,and white blood cellWBCcount and neutrophilNEUTcount decreased insignificantly in the two groups. Moreover,levels of C-reactive protein CRP,erythrocyte sedimentation rateESR,and procalcitoninPCTreduced in the two groups after treatmentP<0.01and the reduction in the observation group was larger than that in the control group P<0.01. Through 7 days of treatment,the total effective rate on pulmonary shadow in the observation group 90.00%,18/20was higher than that in the control group77.27%,17/22P>0.05and the improvement of lung shadow in the observation group was better than that in the control groupP<0.01. Conclusion(s):Modified Sanxiaoyin can significantly alleviate fever,cough,fatigue,anorexia,chest distress,poor sleep quality,and other symptoms of patients with mild or moderate COVID-19,improve biochemical indicators,and promote the recovery of lung function. This paper provides clinical evidence for the application of modified Sanxiaoyin in the treatment of mild or moderate COVID-19.Copyright © 2022, China Academy of Chinese Medical Sciences Institute of Chinese Materia Medica. All rights reserved.

COVID-19 Stay at Home Restrictions and the Interpretation of Emergency Powers: A Comparative Analysis

The COVID-19 pandemic has created immense challenges for governments in their management of the public health response and tested the limits of public law. This article undertakes a comparative analysis of the common law jurisdictions of the United Kingdom, New Zealand, and Australia. It discusses the imposition of 'stay at home' restrictions pursuant to public health legislative frameworks, focusing on judicial scrutiny in the context of statutory interpretation. It examines the appellate cases of R (Dolan) v Secretary of State for Health and Social Care [2021] 1 WLR 2326, Borrowdale v Director-General of Health [2022] 2 NZLR 356, and Kassam v Hazzard (2021) 106 NSWLR 520. Using these case studies, this article seeks to reveal key themes and implications for public law. What approaches have the courts adopted to construe public health emergency powers? How have the courts treated 'rights-based' principles of statutory interpretation? Have the courts approached interpretation in the usual manner or displayed an unorthodox level of deference to other branches of government? The article concludes on what implications the judicial approaches have for the interpretation of emergency powers in the future. © 2022 The Author(s).

Negotiating the temporal and spatial complexities: Chinese international students' learning experience at home during the COVID-19

Many Chinese international students had to or chose to leave their host universities, receiving online international higher education (HE) at ‘homes' during the COVID-19. Inspired by the ‘glonacal' mode of thought, this qualitative study interviewed 16 Chinese international students at ‘homes' to explore the potential complexities of spatiality and temporality regarding their online international HE experiences during COVID-19. Physically separating from host universities, our participants lost the sense of belongingness to the campus and felt disconnected with their academic communities. Their stories revealed a different ‘money' value between gaining and losing regarding online international HE experiences at ‘homes', and the disadvantages they experienced at host countries/universities. Our participants experienced temporal flexibility, temporal conflicts and temporal asymmetry simultaneously. Such spatial and temporal complexities intertwined with each other, making international student experience (ISE) during the COVID-19 unique. This article contributes to understanding of ISE and internationalisation of HE for a post-pandemic era. © 2023 HERDSA.

Simulation of COVID-19 Outbreak in Nanjing Lukou Airport Based on Complex Dynamical Networks

The Corona Virus Disease 2019 (COVID-19) pandemic is still imposing a devastating impact on public health, the economy, and society. Predicting the development of epidemics and exploring the effects of various mitigation strategies have been a research focus in recent years. However, the spread simulation of COVID-19 in the dynamic social system is relatively unexplored. To address this issue, considering the outbreak of COVID-19 at Nanjing Lukou Airport in 2021, we constructed an artificial society of Nanjing Lukou Airport based on the Artificial societies, Computational experiments, and Parallel execution (ACP) approach. Specifically, the artificial society includes an environmental model, population model, contact networks model, disease spread model, and intervention strategy model. To reveal the dynamic variation of individuals in the airport, we first modeled the movement of passengers and designed an algorithm to generate the moving traces. Then, the mobile contact networks were constructed and aggregated with the static networks of staff and passengers. Finally, the complex dynamical network of contacts between individuals was generated. Based on the artificial society, we conducted large-scale computational experiments to study the spread characteristics of COVID-19 in an airport and to investigate the effects of different intervention strategies. Learned from the reproduction of the outbreak, it is found that the increase in cumulative incidence exhibits a linear growth mode, different from that (an exponential growth mode) in a static network. In terms of mitigation measures, promoting unmanned security checks and boarding in an airport is recommended, as to reduce contact behaviors between individuals and staff. © 2021 TUP.

A Multi-function Gas Conditioner Used for Public Anti-epidemic Measures and Health in Rural Region

The outbreak of COVID-2019 has revealed significant challenges in the field of public health security worldwide, especially in rural regions where public infrastructure is poor and public health security is insufficient. In this study, a new type of gas conditioner that combines the functions of sterilization, insect repelling, and carbon-rich fertilization is proposed considering the characteristics of rural an-ti-epidemic measures. The conditioner unit is based on gas-solid adsorption and solid chlorine dioxide technology. The unit adopts the method of combining four-bed electric swing adsorption carbon capture combined with a pressure swing adsorption nitrogen generation cycle method to enrich CO2 and N2 . At the same time, solid chlorine dioxide is applied to the adsorbent to achieve sterilization. Based on test data and simulation models, we analyzed the effects of the temperature difference on the adsorption and desorption temperatures in the car-bon capture cycle, and the outlet flow rate. We also analyzed the effects of the adsorption pressure in the nitrogen generation cycle on the separation performance (recovery rate, purity, and productivity) and energy-efficient performance (specific energy consumption, minimum separation work, second-law efficiency) of the gas conditioner. The results show that the CO2 recovery rate, purity, and produc-tivity all increase with temperature difference;the purity of N2 decreases with an increase in outlet flow rate, and increases with the ad-sorption pressure;the N2 recovery rate and productivity improve with an increase in outlet flow rate and adsorption pressure;the specific energy consumption of the system increases with the increase in the adsorption pressure, and decreases with an increase in the temperature difference and the outlet flow rate;the second law efficiency shows the opposite trend to the specific energy consumption. The simulation results show that when the temperature difference is 105 K, the outlet flow rate is 0. 01 m/ s, and the adsorption pressure is 1 MPa, the purity of CO2 and N2 both reach the maximum, which are 80. 6% VOL and 97. 05% VOL, respectively. The specific energy consumption of the system was 2. 13 MJ/ kg, the efficiency of the second law was 4. 71%, and the energy efficiency performance was better. Even under © 2021 The Author(s).

Parenthood and psychological distress among English Millennials during the second wave of the COVID-19 pandemic: evidence from the Next Steps cohort study.

PURPOSE: The COVID-19 pandemic led to disproportionate mental health responses in younger adults and parents. The aim of the study was to investigate how Millennial parents' experiences were associated with psychological distress over the first year of the pandemic. METHODS: We examined data in September 2020 (n men = 994; n women = 1824) and February 2021 (n men = 1054; n women = 1845) from the Next Steps cohort study (started ages 13-14 in 2003-04). In each wave, we examined differences in GHQ-12 scores between parent groups defined by the age and number of children, adjusting for background characteristics at ages 13-14, psychological distress at ages 25-26, and other circumstances during the pandemic. We also examined if differences varied by work status, financial situation before the outbreak and relationship status. RESULTS: Whereas mothers with one or two children and children aged 0-2 reported less distress than non-mothers in September 2020, there were no such differences in February 2021. Fathers with three or more children reported more distress in February 2021. Compared with non-fathers who worked, fathers were also disproportionally distressed if they were working with one child or with children aged 2 or less in September 2020. CONCLUSION: The distribution of psychological distress among Millennial parents and non-parents has varied by age, sex, parenting stage, work status and the timing of the pandemic. Generous family policies are needed, with special attention dedicated to parents combining work and family responsibilities.

Integration of a hybrid scan approach and in-house high-resolution MS2 spectral database for charactering the multicomponents of Xuebijing Injection

Xuebijing (XBJ) Injection is a reputable patent Chinese medicine widely used to cure sepsis, among the Chinese ″Three Medicines and Three Prescriptions″ solution to fight against COVID-19. We were aimed to achieve the comprehensive multicomponent characterization from the single drugs to traditional Chinese medicine (TCM) formula, by integrating powerful data acquisition and the in-house MS2 spectral database searching. By ultra-high performance liquid chromatography/ion mobility-quadrupole time-of-flight mass spectrometry (UHPLC/IM-QTOF-MS), a hybrid scan approach (HDMSE-HDDDA) was developed, while the HDMSE data for five component drugs and 56 reference compounds were acquired and processed to establish an in-house MS2 spectral database of XBJ. Good resolution of the XBJ components was accomplished on a Zorbax Eclipse Plus C18 column within 24 min, while a fit-for-purpose HDMSE-HDDDA approach was elaborated in two ionization modes for enhanced MS2 data acquisition. XBJ MS2 spectral library was thus established on the UNIFITM platform involving rich structure-related information for the chemicals from five component drugs. We could identify or tentatively characterize 294 components from XBJ, involving 81 flavonoids, 51 terpenoids, 42 phthalides, 40 organic acids, 13 phenylpropanoids, seven phenanthrenequinones, six alkaloids, and 54 others. In contrast to the application of conventional MS1 library, this newly established strategy could demonstrate superiority in the accuracy of identification results and the characterization of isomers, due to the more restricted filtering/matching criteria. Conclusively, the integration of the HDMSE-HDDDA hybrid scan approach and the in-house MS2 spectral database can favor the efficient and more reliable multicomponent characterization from single drugs to the TCM formula. © 2022 The Author(s)

Key Generation with Ambient Audio

Digital Contact Tracing (DCT) has been proposed to limit the spread of COVID-19, allowing for targeted quarantine of close contacts. The protocol is designed to be lightweight, broad-casting limited-time tokens over Bluetooth Low Energy (BLE) beacons, allowing receivers to record contacts pseudonymously. However, currently proposed protocols have vulnerabilities that permit an adversary to perform massive surveillance or cause significant numbers of false-positive alerts. In this paper, we present AcousticMask, which encrypts broadcast messages using a key derived from the audio signal present at each device with sufficient security levels. Our results show that a receiver sharing the same social space as a sender will hear all of the sender's ephemeral IDs (EphIDs) with Hamming distance at most 3, which can be decrypted at the rate of 10 Hz on a Raspberry Pi 4, while achieving a security factor of over 2108against attackers in our testing set, showing AcousticMask is lightweight for DCT and provides sufficient security levels to protect user's privacy. © 2022 IEEE.

Research on The Index System of Laboratory Assets Digitization

Under the influence of the fifth industrial revolution and the outbreak of COVID-19, the digital transformation of enterprises has entered a new stage of rapid development. Digital transformation has become the trend of enterprise operation in the digital economy era. In this context, enterprise laboratory asset operation has also become an important aspect of enterprise digital operation. It is urgent to build a set of enterprise laboratory asset digital evaluation system to assist the implementation of enterprise digital strategy. Based on the characteristics of laboratory assets and the closed-loop theory of asset operation management, this paper analyzes and studies the laboratory asset management, establishes a targeted evaluation index system of digital asset management, focuses on the composition of the digital operation system of laboratory assets, and constructs a management index evaluation system of assets, efficiency, cost and other dimensions, so as to create a real-time, comprehensive and comprehensive evaluation system The closed-loop and full cycle digital management ecological environment realizes the effective integration of laboratory resource fragmentation information and the complete embodiment of digitization, provides service support for continuously improving asset management performance, and provides support for further improving enterprise economic efficiency and operation level. © 2022 SPIE.

Research on The Index System of Laboratory Assets Digitization

Under the influence of the fifth industrial revolution and the outbreak of COVID-19, the digital transformation of enterprises has entered a new stage of rapid development. Digital transformation has become the trend of enterprise operation in the digital economy era. In this context, enterprise laboratory asset operation has also become an important aspect of enterprise digital operation. It is urgent to build a set of enterprise laboratory asset digital evaluation system to assist the implementation of enterprise digital strategy. Based on the characteristics of laboratory assets and the closed-loop theory of asset operation management, this paper analyzes and studies the laboratory asset management, establishes a targeted evaluation index system of digital asset management, focuses on the composition of the digital operation system of laboratory assets, and constructs a management index evaluation system of assets, efficiency, cost and other dimensions, so as to create a real-time, comprehensive and comprehensive evaluation system The closed-loop and full cycle digital management ecological environment realizes the effective integration of laboratory resource fragmentation information and the complete embodiment of digitization, provides service support for continuously improving asset management performance, and provides support for further improving enterprise economic efficiency and operation level. © 2022 SPIE.

FlowTele: Remotely Shaping Traffic on Internet-Scale Networks

Internet content providers often deliver content through bandwidth bottlenecks that are out of their control. Thus, despite often having massively over-provisioned upstream servers, the content providers still cannot control the end-to-end user experience. This paper explores remote traffic shaping, allowing the content provider to allocate its share of a remote bottleneck link across its users using a metric other than TCP fairness, while remaining TCP-friendly to cross traffic on the bottleneck link. To evaluate this approach, we designed FlowTele, the first system that shapes outbound traffic on an Internet-scale network to optimize provider-selected metrics, using source control with neither in-network support nor special client support. Our extensive evaluations over the Internet show that by strategically reallocating bandwidth among provider-owned co-bottlenecked flows, FlowTele improves the provider's total revenue by roughly 20% - 30% in various network settings, compared with both (i) status quo TCP fairshare and (ii) recent practice by content providers that proactively throttles video quality during the COVID-19 pandemic, while being TCP-friendly to cross-traffic. Besides revenue, we also study other metrics, such as QoE fairness, that a content provider may wish to optimize using FlowTele. © 2022 Owner/Author.

The impact of VIX on China's financial market: A new perspective based on high-dimensional and time-varying methods

Based on the new perspective of high-dimensional and time-varying methods, this paper analyzes the contagion effects of US financial market volatility on China's nine financial sub-markets. The results show evidence of non-linear Granger causality from the US financial volatility (VIX) to the China's financial markets. Increased US financial volatility has a negative next-day impact on the stock, bond, fund, interest rate, foreign exchange, industrial product and agricultural product markets, and a positive next-day impact on the gold and real estate markets. US financial volatility has the greatest impact on industrial product market, following by stock, agricultural product, fund, real estate, bond, gold, foreign exchange, and interest rates. Major risk events such as the global financial crisis can cause an enhanced contagion effect of US financial volatility to China's financial markets. This paper supports the achievements of China's actions to prevent and resolve major financial risks in the period of the COVID-19 epidemic. © 2022 Elsevier Inc.

COVID-19 and SARS Virus Function Sites Classification with Machine Learning Methods

COVID-19 and SARS virus are two related coronaviruses. In recent years, the increasingly serious epidemic situation has become the focus of all human beings, and has brought a significant impact on daily life. So, we proposed a link analysis of the two viruses. We obtained all the required COVID-19 and SARS virus data from the Uniprot database website, and we preprocessed the data after obtaining the data. In the prediction of the binding site of the COVID-19 and SARS, it is to judge the validity between the two binding sites. In response to this problem, we used Adaboost, voting-classifier and SVM classifier, and compared different classifier strategies through experiments. Among them, Metal binding site can effectively improve the accuracy of protein binding site prediction, and the effect is more obvious. Provide assistance for bioinformatics research. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Green spaces, especially nearby forest, may reduce the SARS-CoV-2 infection rate: A nationwide study in the United States

The coronavirus pandemic is an ongoing global crisis that has profoundly harmed public health. Although studies found exposure to green spaces can provide multiple health benefits, the relationship between exposure to green spaces and the SARS-CoV-2 infection rate is unclear. This is a critical knowledge gap for research and practice. In this study, we examined the relationship between total green space, seven types of green space, and a year of SARS-CoV-2 infection data across 3,108 counties in the contiguous United States, after controlling for spatial autocorrelation and multiple types of covariates. First, we examined the association between total green space and SARS-CoV-2 infection rate. Next, we examined the association between different types of green space and SARS-CoV-2 infection rate. Then, we examined forest-infection rate association across five time periods and five urbanicity levels. Lastly, we examined the association between infection rate and population-weighted exposure to forest at varying buffer distances (100 m to 4 km). We found that total green space was negative associated with the SARS-CoV-2 infection rate. Furthermore, two forest variables (forest outside park and forest inside park) had the strongest negative association with the infection rate, while open space variables had mixed associations with the infection rate. Forest outside park was more effective than forest inside park. The optimal buffer dis-tances associated with lowest infection rate are within 1,200 m for forest outside park and within 600 m for forest inside park. Altogether, the findings suggest that green spaces, especially nearby forest, may significantly mitigate risk of SARS-CoV-2 infection.

A Novel Point Process Model for COVID-19: Multivariate Recursive Hawkes Process

This chapter presents a novel point process model for COVID-19 transmission—the multivariate recursive Hawkes process, which is an extension of the recursive Hawkes model to the multivariate case. Equivalently the model can be viewed as an extension of the multivariate Hawkes model to allow for varying productivity as in the recursive model. Several theoretical properties of this process are stated and proved, including the existence of the multivariate recursive counting process and formulas for the mean and variance. EM-based algorithms are explored for estimating parameters of parametric and semi-parametric forms of the model. Additionally, an algorithm is presented to reconstruct the process from imprecise event times. The performance of the algorithms on both synthetic and real COVID-19 data sets is illustrated through several experiments. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Abundance, Source Apportionment and Health Risk Assessment of Polycyclic Aromatic Hydrocarbons and Nitro-Polycyclic Aromatic Hydrocarbons in PM2.5 in the Urban Atmosphere of Singapore

In this study, the levels of fine particulate matter (PM2.5), polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs (NPAHs) in PM2.5 samples were determined from 2020 to 2021 in Singapore. For analysis convenience, the sampling period was classified according to two monsoon periods and the inter-monsoon period. Considering Singapore's typically tropical monsoon climate, the four seasons were divided into the northeast monsoon season (NE), southwest monsoon season (SW), presouthwest monsoon season (PSW) and prenortheast monsoon season (PNE)). The PM2.5 concentration reached 17.1 +/- 8.38 mu g/m(3), which was slightly higher than that in 2015, and the average PAH concentration continuously declined during the sampling period compared to that reported in previous studies in 2006 and 2015. This is the first report of NPAHs in Singapore indicating a concentration of 13.1 +/- 10.7 pg/m(3). The seasonal variation in the PAH and NPAH concentrations in PM2.5 did not obviously differ owing to the unique geographical location and almost uniform climate changes in Singapore. Diagnostic ratios revealed that PAHs and NPAHs mainly originated from local vehicle emissions during all seasons. 2-Nitropyrene (2-NP) and 2-nitrofluoranthene (2-NFR) in Singapore were mainly formed under the daytime OH-initiated reaction pathway. Combined with airmass backward trajectory analysis, the Indonesia air mass could have influenced Singapore's air pollution levels in PSW. However, these survey results showed that no effect was found on the concentrations of PAHs and NPAHs in PM2.5 in Indonesia during SW because of Indonesia's efforts in the environment. It is worth noting that air masses from southern China could impact the PAH and NPAH concentrations according to long-range transportation during the NE. The results of the total incremental lifetime cancer risk (ILCR) via three exposure routes (ingestion, inhalation and dermal absorption) for males and females during the four seasons indicated a low long-term potential carcinogenic risk, with values ranging from 10(-10) to 10(-7). This study systematically explains the latest pollution conditions, sources, and potential health risks in Singapore, and comprehensively analyses the impact of the tropical monsoon system on air pollution in Singapore, providing a new perspective on the transmission mechanism of global air pollution.