Health benefits from the rapid reduction in ambient exposure to air pollutants after China's clean air actions: progress in efficacy and geographic equality.

Clean air actions (CAAs) in China have been linked to considerable benefits in public health. However, whether the beneficial effects of CAAs are equally distributed geographically is unknown. Using high-resolution maps of the distributions of major air pollutants (fine particulate matter [PM2.5] and ozone [O3]) and population, we aimed to track spatiotemporal changes in health impacts from, and geographic inequality embedded in, the reduced exposures to PM2.5 and O3 from 2013 to 2020. We used a method established by the Global Burden of Diseases Study. By analyzing the changes in loss of life expectancy (LLE) attributable to PM2.5 and O3, we calculated the gain of life expectancy (GLE) to quantify the health benefits of the air-quality improvement. Finally, we assessed the geographic inequality embedded in the GLE using the Gini index (GI). Based on risk assessments of PM2.5 and O3, during the first stage of CAAs (2013 to 2017), the mean GLE was 1.87 months. Half of the sum of the GLE was disproportionally distributed in about one quarter of the population exposed (GI 0.44). During the second stage of CAAs (2017 to 2020), the mean GLE increased to 3.94 months and geographic inequality decreased (GI 0.18). According to our assessments, CAAs were enhanced, from the first to second stages, in terms of not only preventing premature mortality but also ameliorating health inequalities. The enhancements were related to increased sensitivity to the health effects of air pollution and synergic control of PM2.5 and O3 levels. Our findings will contribute to optimizing future CAAs.

Health Impacts of Long-Term NO2 Exposure and Inequalities among the Chinese Population from 2013 to 2020.

Nitrogen dioxide (NO2) is associated with mortality and many other adverse health outcomes. In 2021, the World Health Organization established a new NO2 air quality guideline (AQG) (annual average <10 µg/m3). However, the burden of diseases attributable to long-term NO2 exposure above the AQG is unknown in China. Nitrogen oxide is a major air pollutant in populous cities, which are disproportionately impacted by NO2; this represents a form of environmental inequality. We conducted a nationwide risk assessment of premature deaths attributable to long-term NO2 exposure from 2013 to 2020 based on the exposure-response relationship, high-resolution annual NO2 concentrations, and gridded population data (considering sex, age, and residence [urban vs rural]). We calculated health metrics including attributable deaths, years of life lost (YLL), and loss of life expectancy (LLE). Inequality in the distribution of attributable deaths and YLLs was evaluated by the Lorenz curve and Gini index. According to the health impact assessments, in 2013, long-term NO2 exposure contributed to 315,847 (95% confidence interval [CI]: 306,709-319,269) premature deaths, 7.90 (7.68-7.99) million YLLs, and an LLE of 0.51 (0.50-0.52) years. The high-risk subgroup (top 20%) accounted for 85.7% of all NO2-related deaths and 85.2% of YLLs, resulting in Gini index values of 0.81 and 0.67, respectively. From 2013 to 2020, the estimated health impact from NO2 exposure was significantly reduced, but inequality displayed a slightly increasing trend. Our study revealed a considerable burden of NO2-related deaths in China, which were disproportionally frequent in a small high-risk subgroup. Future clean air initiatives should focus not only on reducing the average level of NO2 exposure but also minimizing inequality.

Evolution in disparity of PM2.5 pollution in China.

The spatial disparity of air pollutants is one of the key influential factors for environmental inequality. We quantitatively evaluated the evolution of PM2.5 spatial disparity in China during 2013-2020, and investigated the associations between PM2.5 spatial disparity and economic indicators. Differences in PM2.5 between more- and less-polluted cities declined over time, suggesting decreased absolute disparity. However, the more polluted cities in 2013 remained so in 2017 and 2020, and vice versa, indicating persistent relative disparity. PM2.5 pollution levels increased with higher GDP per capita in less-developed areas of China, but such negative effects weakened over time, while economic development tended to promote cleaner air in developed areas of China. Therefore, policies to improve air quality and promote economic development simultaneously are needed in China to reduce the disparity of air pollution and promote all people to enjoy environmental equality.

Reduced inequality in ambient and household PM2.5 exposure in China.

The society has high concerns on the inequality that people are disproportionately exposed to ambient air pollution, but with more time spent indoors, the disparity in the total exposure considering both indoor and outdoor exposure has not been explored; and with the socioeconomical development and efforts in fighting against air pollution, it is unknown how the exposure inequality changed over time. Based on the city-level panel data, this study revealed the Concentration Index (C) in ambient PM2.5 exposure inequality was positive, indicating the low-income group exposed to lower ambient PM2.5; however, the total PM2.5 exposure was negatively correlated with the income, showing a negative C value. The low-income population exposed to high PM2.5 associated with larger contributions of indoor exposure from the residential emissions. The total PM2.5 exposure caused 1.13 (0.63-1.73) million premature deaths in 2019, with only 14 % were high-income population. The toughest-ever air pollution countermeasures have reduced ambient PM2.5 exposures effectively that, however, benefited the rich population more than the others. The transition to clean household energy sources significantly affected on indoor air quality improvements, as well as alleviation of ambient air pollution, resulting in notable reductions of the total PM2.5 exposure and especially benefiting the low-income groups. The negative C values decreased from 2000 to 2019, indicating a significantly reducing trend in the total PM2.5 exposure inequality over time.

A Malicious Domain Detection Model Based on Improved Deep Learning.

With the rapid development of the Internet, malicious domain names pose more and more serious threats to many fields, such as network security and social security, and there have been many research results on malicious domain detection. This article proposes a malicious domain name detection model based on improved deep learning, which can combine the advantages of three different network models, convolutional neural network (CNN), temporal convolutional network (TCN), and long short-term memory network (LSTM) in malicious domain name detection, to obtain a better detection effect than that of the original single or two models. Experiments show that the effect of the improved deep learning model proposed in this article is better than that of the combined model of CNN and LSTM or the combined model of CNN and TCN, and the accuracy and regression rates reached 99.76% and 98.81%, respectively.

Gestational exposure to landscape fire increases under-5 child death via reducing birthweight: A risk assessment based on mediation analysis in low- and middle-income countries.

BACKGROUND: Exposure to landscape fire smoke (LFS) is linked to child mortality and birthweight. It is unknown whether gestational exposure to LFS affects child survival rate. We aimed to link under-five death (U5D) to gestational LFS exposure by performing a causal mediation analysis based on birthweight. METHOD: We conducted a sibling-matched case-control study of children under 5 years of age who were affiliated with the same mothers from Demographic and Health Surveys in 54 low- and middle-income countries, during the period from 2000 to 2014. LFS exposure was quantified as the surface concentration of fine particulate matter (PM2.5) attributable to landscape fires, estimated using a global atmospheric model. Three pairwise associations between fire-sourced PM2.5, birthweight, and U5D were assessed using fixed-effects regressions. We used a bootstrap-based mediation test of regression coefficients to examine whether the LFS-birthweight-U5D pathway was statistically significant. We also conducted three pairwise exposure-response functions using nonlinear models and used them to estimate the pathway-specific disease burden from 2000 to 2014. RESULTS: After adjustments for multiple confounders, each 1-µg/m3 increase in gestational exposure to fire-sourced PM2.5 was associated with a reduction of 2.179 (95% confidence interval [CI]: -3.777, -0.580) g in birthweight. Each 1-g birthweight reduction was associated with a 0.072% (95% CI: 0.065%, 0.078%) increase in U5D. Furthermore, each increase in exposure to fire-sourced PM2.5 was associated with a 2.853% (95% CI: 0.835%, 4.911%) increase in U5D; 7.294% (95% CI: 0.710%, 24.254%) of the linkage was explained by LFS-attributable birthweight reduction. Based on the estimated exposure-response functions, from 2000 to 2014, global exposure to fire-sourced PM2.5 contributed a mean birthweight reduction of 10.30 (95% CI: 2.93, 19.47) g, contributing to 60,350 (18,111, 106,619) premature U5Ds annually. CONCLUSION: In low- and middle-income countries, gestational exposure to LFS can increase mortality during infancy; appropriate interventions are needed to promote health in childhood.

Clean air actions in China, PM2.5 exposure, and household medical expenditures: A quasi-experimental study.

BACKGROUND: Exposure to air pollution, a leading contributor to the global burden of disease, can cause economic losses. Driven by clean air policies, the air quality in China, one of the most polluted countries, has improved rapidly since 2013. This has enabled a unique, quasi-experiment to assess the economic impact of air pollution empirically. METHODS AND FINDINGS: Using a series of nation-scale longitudinal surveys in 2011, 2013, and 2015, we first examined the questionnaire-based medical expenditure changes before and after the policy intervention for air pollution. Using a state-of-the-art estimator of the historical concentration of particulate matters with diameter less than 2.5 µm (particulate matter (PM)2.5), we further quantified the association between household medical expenditure and PM2.5 using mixed-effect models of the repeated measurements from 26,511 households in 126 cities. Regression models suggest a robust linear association between reduced PM2.5 and saved medical expenditures, since the association did not vary significantly across models with different covariate adjustments, subregions, or subpopulations. Each 10 µg/m3 reduction in PM2.5 was associated with a saving of 251.6 (95% CI: 30.8, 472.3; p-value = 0.026) Yuan in per capita annual medical expenditure. However, due to limitations in data quality (e.g., self-reported expenditures), and imperfect control for unmeasured confounders or impact from concurrent healthcare reform in China, the causality underlying our findings should be further confirmed or refuted. CONCLUSION: In this study, we observed that compared with the PM2.5 reduction in 2013, the PM2.5 reduction in 2017 was associated with a saving of 552 (95% CI: 68, 1036) Yuan / (person × year), or approximately 736 billion Yuan (equivalent to 111 billion US dollar) per year nationally, which is equivalent to approximately 1% of the national gross domestic product of China.

High-Resolution Spatiotemporal Modeling for Ambient PM2.5 Exposure Assessment in China from 2013 to 2019.

Exposure to fine particulate matter (PM2.5) has become a major global health concern. Although modeling exposure to PM2.5 has been examined in China, accurate long-term assessment of PM2.5 exposure with high spatiotemporal resolution at the national scale is still challenging. We aimed to establish a hybrid spatiotemporal modeling framework for PM2.5 in China that incorporated extensive predictor variables (satellite, chemical transport model, geographic, and meteorological data) and advanced machine learning methods to support long-term and short-term health studies. The modeling framework included three stages: (1) filling satellite aerosol optical depth (AOD) missing values; (2) modeling 1 km × 1 km daily PM2.5 concentrations at a national scale using extensive covariates; and (3) downscaling daily PM2.5 predictions to 100-m resolution at a city scale. We achieved good model performances with spatial cross-validation (CV) R2 of 0.92 and temporal CV R2 of 0.85 at the air quality sites across the country. We then estimated daily PM2.5 concentrations in China from 2013 to 2019 at 1 km × 1 km grid cells. The downscaled predictions at 100 m resolution greatly improved the spatial variation of PM2.5 concentrations at the city scale. The framework and data set generated in this study could be useful to PM2.5 exposure assessment and epidemiological studies.

Laboratory Selection, Cross-Resistance, Risk Assessment to Lambda-Cyhalothrin Resistance, and Monitoring of Insecticide Resistance for Plant Bug Lygus pratensis (Hemiptera: Miridae) in Farming-Pastoral Ecotones of Northern China.

The plant bug Lygus pratensis Linnaeus (Hemiptera: Miridae) is an important insect pest of alfalfa in grassland farming in northern China. A field population of L. pratensis was selected in the laboratory for 14 consecutive generations with lambda-cyhalothrin to generate 42.555-fold resistance. Selection also induced low cross-resistance to imidacloprid and beta-cypermethrin, and medium cross-resistance to deltamethrin. Realized heritability (h2) of lambda-cyhalothrin resistance was 0.339. Susceptible baselines of L. pratensis were established for five insecticides using the glass-vial method, the values of which were 6.849, 3.423, 8.778, 3.559, and 117.553 ng/cm2 for phoxim, methomyl, imidacloprid, lambda-cyhalothrin, and avermectin, respectively, along with the calculated LC99 diagnostic doses. This resistance risk assessment study suggests that a high risk of lambda-cyhalothrin resistance exists in the field. In addition, a 5-year field investigation of resistance monitoring of L. pratensis was conducted in seven alfalfa regions in farming-pastoral ecotones in northern China. The resistance levels of most populations were very low for phoxim, methomyl, and avermectin, with an upward trend for lambda-cyhalothrin resistance in the DK (Dengkou County), TKT (Tuoketuo County), XL (Xilinhot), and LX (Linxi County) populations during 2015-2019, and medium resistance level to imidacloprid in the TKT population in five years we sampled. The study provided information on chemical control, lambda-cyhalothrin resistance development, baseline susceptibility, and the status of resistance to five commonly-used insecticides against L. pratensis. These results could be used to optimize pyrethroid insecticide use as part of a pest integrated resistance management strategy against this key insect pest of alfalfa.

Does asymmetric persistence in convergence of the air quality index (AQI) exist in China?

In recent years, China's air pollution has caused significant concern in the academia. China is the hub of business and financial activities, with the most populous cities. It is important to determine the convergence and asymmetric persistence of air quality index (AQI hereafter) in China to achieve sustainable development goals, especially the ones related to the environment. This paper uses the Fourier quantile unit root test to check for inter-regional convergence of monthly AQI for 74 cities across China from January 2013 to July 2019. For a comparative baseline analysis, five conventional univariate and quantile unit root tests are also conducted. The empirical outcomes show that the Fourier quantile unit test exhibits a significant advantage in detecting smooth breaks and evaluating the asymmetric behavior and mean-reverting properties of AQI. Moreover, the monthly AQI in 70 out of 74 C0hinese cities are stationary processes. These findings not only focus on the appropriate use of relevant modeling techniques of smooth breaks and asymmetries in the AQI series of the 74 Chinese cities but also provide crucial environmental sustainability and economic implications for AQI regulation policies.

Assessment of optic nerve and optic tract alterations in patients with orbital space-occupying lesions using probabilistic diffusion tractography.

AIM: To investigate the diffusion changes in both the optic nerve and optic tract in orbital space-occupying lesion patients with decreased visual acuity, and its clinical significance using probabilistic diffusion tractography (PDT). METHODS: Twenty patients with orbital space-occupying lesions and 25 age- and gender-matched healthy persons were included. All patients and controls underwent routine orbital magnetic resonance imaging and diffusion tensor imaging (DTI), using a 3.0T magnetic resonance scanner (Trio Tim Siemens). After the image data were preprocessed, each DTI parameters of the optic nerve and optic tract was obtained by PDT, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD). The asymmetry index (AI) of each parameter was calculated. Compared the parameters of the affected side optic nerve and ipsilateral optic tract with the contralateral side by paired sample t-test; compared AI of parameters of optic nerve and optic tract between the patient group and the control group by independent sample t-test. Patients were divided into three subgroups according to the low vision grade standard of WHO, compared the FA and AI of FA between the three subgroups by single factor variance analysis. RESULTS: The affected side optic nerve presented significantly decreased FA, increased MD, AD, and RD values compared to the unaffected side (P<0.05). The AI of FA, MD, AD, and RD of optic nerve in the patients was significantly higher than that of the controls (P<0.05). The comparison results of the optic tract showed that there was no significant difference between the patient group and control group in terms of the bilateral optic tracts in patients (P>0.05). The AIs of the FA value of the optic nerve in the eyesight <0.1 subgroup was significantly higher than that in the other groups (P<0.05). CONCLUSION: FA, MD, AD, and RD of the affected side optic nerve of the orbital space-occupying lesions have significantly changed, the FA value is the most sensitive. The PDT could be a useful tool to provide valid quantitative markers of optic nerve injuries and evaluate the severity of orbital diseases, which other examinations cannot be acquired.

Change in the number of PM2.5-attributed deaths in China from 2000 to 2010: Comparison between estimations from census-based epidemiology and pre-established exposure-response functions.

Long-term exposure to ambient fine particulate matter (PM2.5) has been identified as a major contributor to disease burden in many countries, including China. The effects of long-term PM2.5 exposure have been evaluated by risk assessment studies, which are based on an exposure-response function (ERF) derived from a specific epidemiological study or multiple studies. To explore whether generalization from the pre-established ERFs (including the integrated exposure-response [IER] model and the global exposure mortality model [GEMM]) introduces biases into risk assessment of a specific local population, we conducted the first census-based epidemiological study of PM2.5, aimed at the entire population of mainland China. Using a difference-in-difference analysis at the county level, we associated mortality changes from 2000 to 2010 to corresponding PM2.5 changes, with adjustments made for multiple socioeconomic factors. Based on the epidemiological linkage between PM2.5 and total mortality, we calculated the change in PM2.5-attributed deaths and compared this value with the results derived from the pre-established models (IER and GEMM). According to the epidemiological model, a 10-µg/m3 increment in PM2.5 was associated with a 4.3% (95% confidence interval [CI]: 1.9%-6.7%) increment in total mortality, and the change in PM2.5-attributed deaths from 2000 to 2010 was estimated as 561,000 (95% CI: 539,000-581,000). The census-based estimation was in better agreement with the GEMM results (545,000-612,000) than was the IER result (354,000 [95% CI: 286,000-421,000]). In sensitivity analyses of the epidemiological model, the association between PM2.5 exposure and mortality was stronger among younger adults, consistent with the pre-established models. Due to the potential limitations of our findings, we cannot conclusively state that GEMM is more reliable than IER in China. Future studies are warranted to confirm or refute our findings.

Associating ambient exposure to fine particles and human fertility rates in China.

BACKGROUND: Adverse effects of ambient fine particles (PM2.5) on sperm quality and oocyte fertilization have been identified by previous research. However, insufficient human studies tested associations between PM2.5 and decreased fertility rates. METHODS: We associated long-term exposure to PM2.5 and county-level fertility rates reported by 2010 census across China. Exposure assessments were based on PM2.5 maps (2009-2010) with a spatial resolution of 0.1° derived from satellite remote sensing data from another published study. We used a Poisson regression to examine the relationship between PM2.5 and fertility rates with adjustment of potential confounders including county-level socioeconomic factors (e.g. sex ratio) and a spatially smoothed trend. RESULTS: We found that fertility rates were significantly decreased by 2.0% (95% confidence interval: 1.8%, 2.1%) per 10 µg/m3 increment of PM2.5. We also found a geographical variation of the associations. CONCLUSIONS: The study add to epidemiological evidences on adverse effects of PM2.5 on fertility rates.

Using spatio-temporal modeling for exposure assessment in an investigation of fine particulate air pollution and cardiovascular mortality.

BACKGROUND: U.S. urban air quality has improved dramatically over the past decades. We evaluated acute effects of fine particulate matter (PM2.5) on cardiovascular (CVD) mortality among residents of Allegheny County in SW Pennsylvania (1999-2011) using spatio-temporal modeling of air pollutants (AP) to reduce misclassification error in exposure assessment. METHODS: Spatio-temporal kriging of daily PM2.5 and ozone (O3) was used to produce daily exposure estimates at the residence ZIP code. Time-stratified case-crossover analysis was conducted to examine short-term effects of PM2.5 on CVD mortality, adjusting for O3 and apparent mean temperature. We studied both single and distributed lags for days 0-5. All CVD mortality and subcategories of ischemic heart disease (IHD), acute myocardial infarction, cerebrovascular disease, peripheral vascular disease (PVD), heart failure and cardiac arrhythmia were examined. RESULTS: A total of 62,135 deaths were identified. We found significant associations of PM2.5 with IHD and PVD mortality at lag day 5: (2.1% (95% CI, 0.2-4.1%) and (7.6%, 95% CI, 0.05-15.7%) per 10µg/m3 increase of PM2.5 in single lag models and for IHD in distributed lag models. There were no statistically significant associations with PM2.5 for any of the other outcomes. CONCLUSIONS: The application of finer scale geographically resolved AP exposures made it possible to study acute effects of PM2.5 on CVD mortality in a large metropolitan area. Our study results demonstrated the continued presence of a dose response relationship of increased risk of CVD mortality within this lower range of PM2.5 exposure.

Increase in viral yield in eggs and MDCK cells of reassortant H5N1 vaccine candidate viruses caused by insertion of 38 amino acids into the NA stalk.

BACKGROUND: The H5N1 subtype of highly pathogenic avian influenza viruses has spread to over 63 countries in Asia, Europe, and Africa and has become endemic in poultry. Since 2004, vaccination against H5N1 influenza has become common in domestic poultry operations in China. Most influenza vaccines have been produced in embryonated chicken eggs. High yield is the essential feature of a good vaccine candidate virus. OBJECTIVE: Therefore, the large-scale manufacture of such a vaccine requires that the viral yield of H5N1 reassortant vaccine viruses in eggs and MDCK cells be increased. METHODS: We generated two sets of reassortant H5N1 viruses based on backbone viruses A/Chicken/F/98 (H9N2) and A/Puerto Rico/8/34 (H1N1) using reverse genetics. The HAs and NAs of the reassortants were derived from the three epidemic H5N1 strains found in China. We compared the replication properties of these recombinant H5N1 viruses in embryonated chicken eggs and MDCK cells after inserting either 20 or 38 amino acids into their NA stalks. RESULTS: In this study, we demonstrated that inserting 38 amino acids into the NA stalks can significantly increase the viral yield of H5N1 reassortant viruses in both embryonated chicken eggs and MDCK cells, while inserting only 20 amino acids into the same NA stalks does not. Hemagglutinin inhibition testing and protection assays indicated that recombinant H5N1 viruses with 38 aa inserted into their NA stalks had the same antigenicity as the viruses with wt-NA. CONCLUSION: These results suggest that the generation of an H5N1 recombinant vaccine seed by the insertion of 38 aa into the NA stalk may be a suitable and more economical strategy for the increase in viral yield in both eggs and MDCK cells for the purposes of vaccine production.

Monte Carlo evaluations of the absorbed dose and quality dependence of AL2O3 in radiotherapy photon beams.

PURPOSE: The purpose of this work was to evaluate the absorbed dose to AL2O3 dosimeter at various depths of water phantom in radiotherapy photon beams by Monte Carlo simulation and evaluate the beam quality dependence. METHODS: The simulations were done using EGSnrc. The cylindrical Al2O3 dosimeter (Phi4 mm x 1 mm) was placed at the central axis of the water phantom (Phi16 cm x 16 cm) at depths between 0.5 and 8 cm. The incident beams included monoenergetic photon beams ranging from 1 to 18 MeV, 60Co gamma beams, Varian 6 MV beams using phase space files based on a full simulation of the linac, and Varian beams between 4 and 24 MV using Mohan's spectra. The absorbed dose to the dosimeter and the water at the corresponding position in the absence of the dosimeter, as well as absorbed dose ratio factor fmd, was calculated. RESULTS: The results show that fmd depends obviously on the photon energy at the shallow depths. However, as the depth increases, the change in fmd becomes small, beyond the buildup region, the maximum discrepancy of fmd to the average value is not more than 1%. CONCLUSIONS: These simulation results confirm the use of Al2O3 dosimeter in radiotherapy photon beams and clearly indicate that more attention should be paid when using such a dosimeter in the buildup region of high-energy radiotherapy photon beams.