1.Effects of oral microbiota and immune cells on oral leukoplakia: a Mendelian randomization and mediation analysis
WANG Yongkang ; GUAN Cuiqiang ; GUO Hongbo
Journal of Prevention and Treatment for Stomatological Diseases 2026;34(2):129-138
Objective:
To assess the causal association between specific oral microbiota and the risk of oral leukoplakia (OLK) using a Mendelian randomization (MR) approach, and to elucidate the potential mediating role of immune cells.
Methods:
Summary statistics from genome-wide association studies (GWAS) of the oral microbiome, GWAS data for immune cell phenotypes, and GWAS summary statistics for OLK from FinnGen were used. The inverse variance weighted (IVW) method was adopted as the primary approach, and it was supplemented by MR Egger regression, simple mode, weighted median, and weighted mode methods for additional analyses, to investigate the causal relationship between 3 117 types of tongue coating and salivary microbiota, as well as 731 immune cell traits, and OLK. Furthermore, a two-step MR approach was applied to explore the potential mediating role of immune cells in the association between oral microbiota and OLK.
Results:
IVW analysis revealed causal associations between 15 oral microbial genera and OLK. Among these, Streptococcus, Neisseria, and Catonella were associated with a reduced risk of OLK, with Fusobacterium showing the most significant protective effect (OR = 0.41, P = 0.023). In contrast, genera, including Microbacterium, Campylobacter, and Haemophilus_A, were linked to an increased risk of OLK, with Lancefieldella exhibiting the strongest risk effect (OR = 2.66, P = 0.006). Eleven immune cell phenotypes with potential causal associations with OLK were identified, including four protective and seven risk-increasing factors. Mediation analysis further identified four key mediating pathways: pathogenic genera, particularly Campylobacter_A and Lancefieldella, may promote the development and progression of OLK by upregulating highly activated pro-inflammatory immune subsets such as activated monocytes, B cells, and myeloid cells. Conversely, the potentially protective genus Catonella appeared to exert inhibitory effects on OLK by significantly downregulating dendritic cell subsets.
Conclusion
This study is the first to reveal, at the genetic level, causal pathways through which specific oral microbial genera influence the risk of OLK by mediating immune cell responses. These findings provide novel insights into the immunopathological mechanisms underlying OLK and offer potential targets for intervention strategies aimed at modulating specific microbial genera or immune cell subsets.
2.Expert consensus on the construction of integrated outpatient clinic for cervical cancer prevention and treatment in General Hospitals
Nan YU ; Dongli KONG ; Lei WANG ; Yihan LU ; Hongbo WANG ; Dongru LIU ; Ling PENG
Journal of Public Health and Preventive Medicine 2026;37(2):1-6
Objective To implement the disease prevention and control strategy of being "proactive and grassroots-focused," and to enhance the overall effectiveness of general hospitals in the tertiary prevention of cervical cancer, this consensus aims to provide an actionable guiding framework for the standardized construction of "Integrated Outpatient Clinics for Cervical Cancer Prevention and Control" in general hospitals at all levels. Methods This consensus systematically elaborates on the specific elements for establishing such integrated clinics and formulates the corresponding standards. Results It is anticipated that the consensus will promote the establishment of standardized, homogeneous, and high-efficiency frontline positions for cervical cancer prevention and control within general hospitals, thereby contributing to the strategic vision of accelerating the elimination of cervical cancer. Conclusion The formulation and promotion of the consensus aim to provide robust clinical practice support for accelerating the realization of China's strategic vision of eliminating cervical cancer.
3.Study on microwave radiation aggravating the impairment of cognitive functions in mice with experimental periodontitis
ZHOU Hongjin ; WANG Jianhui ; LIU Lin ; LI Hongbo
Journal of Prevention and Treatment for Stomatological Diseases 2026;34(6):541-545
Objective:
To explore the effects of microwave radiation on cognitive function and neuroinflammation in mice with experimental periodontitis, providing experimental evidence for understanding how environmental exposure may be linked to the risk of neurodegenerative diseases by modulating chronic inflammation as a shared pathological mechanism
Methods:
This study was approved by the Animal Ethics Committee of the Academy of Military Medical Sciences. C57BL/6J mice were randomly divided into a control group (C group, untreated), a microwave radiation group (R group, exposed to microwave radiation only), a periodontitis group (P group, ligation-induced periodontitis only), and a periodontitis + microwave radiation group (PR group, ligation-induced periodontitis plus microwave radiation exposure). A periodontitis model was established using the silk ligation method. Eight weeks after modeling, the R and PR groups were subjected to whole-body microwave radiation at 2 800 MHz and 10 mW/cm2 for 10 h/day for 7 consecutive days. Behavioral tests were conducted: the open field test and elevated plus maze test were used to assess anxiety-like behavior, the Y-maze test to evaluate spatial memory, and the novel object recognition test to assess learning and memory abilities. Micro-CT, hematoxylin & eosin staining (HE), and quantitative real-time polymerase chain reaction (qPCR) were used to analyze periodontal tissue pathology and local inflammation. Serum and brain levels of lipopolysaccharide (LPS), interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were measured using enzyme-linked immunosorbent assay (ELISA). The composition of the oral microbiota was analyzed based on 16S rRNA sequencing.
Results:
Behavioral tests showed that anxiety-like behavior was significantly exacerbated in the R and PR groups, and spatial and recognition memory impairments in the PR and P groups were more severe compared with the R and C groups, respectively (P < 0.05). Histological and molecular biological analyses revealed that periodontal inflammation infiltration, alveolar bone resorption, and local expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) were further exacerbated in the PR and P groups compared with the R and C groups, respectively (P < 0.05). ELISA results showed that in serum, LPS levels in group P and group PR were increased compared with group C and group R, respectively. The levels of TNF-α, IL-1β, and IL-6 in group PR were significantly higher than those in group P and group R, with a synergistic increase in TNF-α level (P < 0.05). In brain tissue, LPS and TNF-α, IL-1β, IL-6 levels in group P were significantly higher than those in group C; all the above indicators in group PR were significantly higher than those in group P and group R, and LPS and IL-6 levels showed a synergistic increase (P < 0.05). Oral microbiota analysis found that microwave radiation further reduced microbial diversity on the basis of periodontitis, leading to increased relative abundances of Lactobacillus and Enterococcus, and decreased relative abundances of Staphylococcus. Correlation analysis confirmed that these differential bacterial genera were positively correlated with brain inflammation levels and negatively correlated with cognitive function indicators.
Conclusion
Microwave radiation exposure can exacerbate cognitive impairment in mice with experimental periodontitis, and its mechanism may be related to aggravated local periodontal damage, disruption of oral microbiota homeostasis, and subsequent induction of systemic and central neuroinflammatory cascades.
4.The dual regulatory effect of locoregional therapy on the tumor immune microenvironment of hepatocellular carcinoma: Mechanisms and combined treatment strategies
Enyu WANG ; Hongbo WANG ; Liou ZHANG
Journal of Clinical Hepatology 2026;42(5):1198-1203
Locoregional therapy (LRT), including transarterial chemoembolization, transarterial radioembolization, and various ablation techniques, is an important treatment method for hepatocellular carcinoma. Many studies in recent years have confirmed that LRT has a dual regulatory effect on tumor immune microenvironment. While LRT induces immunogenic cell death, activates dendritic cell-mediated and T cell-driven immunity, and triggers systemic antitumor responses, it concomitantly upregulates the adenosine signaling pathway, promotes the accumulation of TREM2+ macrophages, and enhances the expression of immunosuppressive factors, thereby forming an immunosuppressive microenvironment. At present, the combination of LRT and immune checkpoint inhibitors has shown a promising future and has promoted the exploration of novel targets within treatment-associated immunosuppressive pathways, such as adenosine, TREM2⁺ macrophages, and IL-6. This article summarizes the dual regulatory effect of LRT on immune microenvironment and highlights that multi-omics techniques and clinical trials should be used in the future to decipher its dynamic alterations, in order to optimize combination strategies, realize individualized precise treatment, and improve the prognosis of patients.
5.Semaphorin 3A promotes pathological cardiac hypertrophy: an experimental study
Lifei WU ; Jiaojiao ZHANG ; Xing ZHANG ; Donghang LI ; Hongbo WANG ; Jimin CAO
Acta Universitatis Medicinalis Anhui 2026;61(7):1215-1222
ObjectiveTo investigate the effect of Semaphorin 3A (Sema3A) on the progression of pathological cardiac hypertrophy. MethodsWild-type C57BL 6J mice, Sema3A global overexpressing (Sema3A/Cre-ERTM) mice, and their littermate controls (Cre-ERTM) were used, with 6 mice per group. A pressure-overload induced cardiac hypertrophy model was established via transverse aortic constriction (TAC), with a sham-operated group (Sham) as the control. Cardiac hypertrophy was assessed by gross morphology, heart weight/body weight ratio (HW/BW), heart weight/tibia length ratio (HW/HL), and heart weight/lung weight ratio (HW/PW). Cardiac function was evaluated by measuring ejection fraction (EF) and fractional shortening (FS) via echocardiography. In heart tissues, the mRNA level of atrial natriuretic peptide (ANP) and Sema3A were detected by RT-qPCR, Sema3A protein level was detected by western blot, morphological structure was detected by hematoxylin and eosin (HE) staining, level of fibrosis was detected by Masson’s trichrome staining, and angiogenesis was detected by immunohistochemical detection of CD31. For in vitro experiments, rat H9C2 cardiomyocytes were treated with angiotensin Ⅱ (Ang Ⅱ) to induce hypertrophy, with PBS-treated cells as the control. After 48 hours, the mRNA expression of ANP, B-type natriuretic peptide (BNP) and Sema3A were measured by RT-qPCR, and Sema3A protein level was assessed by western blot. ResultsAt the animal level, compared with the sham group, mice subjected to TAC showed significantly increased mRNA levels of ANP in cardiac tissue, as well as markedly elevated mRNA and protein levels of Sema3A (all P<0.05). Compared with the Cre-ERTM + TAC group, the Sema3A/Cre-ERTM + TAC group exhibited more pronounced cardiac hypertrophy, greater ventricular wall thickening, higher HW/BW, HW/HL, and HW/PW ratios, more significant reductions in EF and FS, more severe cardiac fibrosis, and a significant decrease in cardiac CD31 expression levels (all P<0.05). At the cellular level, compared with the control group, H9C2 cells treated with Ang Ⅱ displayed significantly increased mRNA levels of ANP and BNP, along with markedly elevated mRNA and protein levels of Sema3A (all P<0.05). ConclusionSema3A promotes the progression of pressure overload-induced cardiac hypertrophy by inhibiting angiogenesis.
6.Association Between Vitamin D Status and Insulin Resistance in Adolescents: A Cross-sectional Observational Study
Xiaoyuan GUO ; Yutong WANG ; Zhibo ZHOU ; Shi CHEN ; Mei ZHANG ; Bo BAN ; Ping LI ; Xinran ZHANG ; Qiuping ZHANG ; Kai YANG ; Hongbo YANG ; Hanze DU ; Hui PAN
Medical Journal of Peking Union Medical College Hospital 2025;16(3):577-583
To investigate the correlation between vitamin D nutritional status and insulin resistance in pubertal adolescents. This cross-sectional observational study employed convenience sampling to recruit 2021-grade(8th grade) students from Jining No.7 Middle School in Shandong Province on June 5, 2023. Data collection included questionnaires, physical examinations, and imaging assessments to obtain general information, secondary sexual characteristics development, and bone age. Venous blood samples were collected to measure fasting blood glucose(FBG), fasting insulin(FINS), homeostasis model assessment of insulin resistance(HOMA-IR), and 25-hydroxyvitamin D[25(OH)D] levels. Spearman correlation analysis and multivariate linear regression models were used to examine the associations between serum vitamin D levels and FBG, FINS, and HOMA-IR. The study included 168 pubertal adolescents[69 females(41.1%), 99 males(58.9%); mean age(13.27±0.46) years]. All participants had entered puberty based on sexual development assessment. Vitamin D deficiency was observed in 41 participants(24.4%), insufficiency in 109(64.9%), and sufficiency in 18(10.7%). The median HOMA-IR was 3.49(2.57, 5.14).Significant differences were found across vitamin D status groups for HOMA-IR [4.45(2.54, 6.62) Vitamin D deficiency/insufficiency is prevalent among pubertal adolescents, and serum vitamin D levels show a significant inverse association with insulin resistance. These findings suggest the potential importance of vitamin D status in metabolic health during puberty.
7.Effect of bone marrow-derived mesenchymal stem cell transplantation on mitochondrial autophagy in rats with vascular dementia through ROS/Nrf2 signaling and its mechanism
Lieqian SUN ; Mengyu GU ; Jie YANG ; Kaiyi WANG ; Gaoshuai GUO ; Hongbo ZHANG ; Siyi ZHANG ; Tanglong WANG ; Zhiwei YANG ; Yanni HE ; Chao YANG
Journal of Jilin University(Medicine Edition) 2025;51(3):610-620
Objective:To discuss the effects of bone marrow-derived mesenchymal stem cells(BMSCs)transplantation on mitophagy in the vascular dementia(VaD)rats through reactive oxygen species(ROS)/nuclear factor erythroid 2-related factor 2(Nrf2)signaling,and to clarify its mechanism.Methods:Forty-five male adult SD rats were randomly divided into sham operation group,model group,unloaded group,BMSCs group,and MSCs+ML385(Nrf2 inhibitor)group(combination group),and there were 9 rats in each group.After intraperitoneal anesthesia,the VaD models were established in all groups except sham operation group.Morris water maze test was used to detect the learning and memory abilities of the rats in various groups;HE staining was used to observe the histopathological morphology of brain tissue of the rats in various groups;Nissl staining was used to observe the changes of Nissl bodies in hippocampus region of brain tissue of the rats in various groups;transmission electron microscope was used to observe the ultrastructure of hippocampus region of the rats in various groups;fluorescence probe method was used to detect the ROS levels in hippocampus neurons in various groups;Western blotting method was used to detect the expression levels of Nrf2,heme oxygenase-1(HO-1),PTEN-induced putative kinase 1(PINK1),parkin RBR E3 ubiquitin protein ligase(Parkin),Beclin-1,ubiquitin-binding protein p62(P62),and microtubule-associated protein 1A/1B-light chain 3(LC3-Ⅱ/LC3-Ⅰ)ratio in brain tissue of the rats in various groups.Results:The Morris water maze results showed that compared with sham operation group,the escape latency of the rats in model group was significantly increased(P<0.01),while the number of crossing time and residence time were significantly decreased(P<0.01).Compared with model group,the escape latency of the rats in BMSCs group was significantly decreased(P<0.01),while the number of crossing time and residence time were significantly increased(P<0.01).Compared with BMSCs group,the escape latency of the rats in combination group was significantly increased(P<0.01),while the number of crossing time and residence time were significantly decreased(P<0.01).The HE staining results showed that hippocampus neurons of the rats in sham operation group were normal in quantity and morphology,with uniform staining and clear structure.Compared with sham operation group,the hippocampus tissue of the rats in model group showed sparse arrangement,disordered structure,reduced neuronal quantity,varied morphology,uneven staining,nuclear pyknosis,and partial neuronal necrosis.Compared with model group,the neuronal damage of the rats in hippocampus regio in BMSCs group was alleviated,with restored morphology and improved neuronal loss.Compared with BMSCs group,the neurons of the rats in hippocampus region in combination group showed irregular morphology,disordered structure,unclear cell boundaries,uneven staining,and nuclear pyknosis.The Nissl staining results showed that the hippocampal neurons in sham operation group were tightly arranged with intact morphology,obvious nucleoli,and abundant darkly stained Nissl bodies.Compared with sham operation group,the neurons in hippocampus region of the rats in model group showed pyknosis,vacuolization,and sparse Nissl bodies.Compared with model group,the BMSCs group showed reduced neuronal pyknosis,relatively intact morphology,and increased Nissl bodies.Compared with BMSCs group,the combination group showed neuronal pyknosis,loss of morphological integrity,and fragmented Nissl bodies.The transmission electron microscope results showed that mitochondria in sham operation group exhibited oval shape with intact double-membrane structure and cristae.Compared with sham operation group,the mitochondria in model group showed swelling,disrupted membranes,broken cristae,and numerous autophagosomes.Compared with model group,the BMSCs group showed improved mitochondrial structure and reduced autophagosomes.Compared with BMSCs group,the combination group showed swollen mitochondria,disrupted membranes,broken cristae,and visible autophagosomes.The fluorescence probe results showed that compared with sham operation group,the ROS levels in the hippocampus neurons in brain tissue of the rats in model group were significantly increased(P<0.01);compared with model group,the ROS levels in hippocampus neurons in brain tissue of the rats in BMSCs group were significantly decreased(P<0.01);compared with BMSCs group,the ROS levels in hippocampus neurons in brain tissue of the rats in combination group were significantly increased(P<0.01).The Western blotting results showed that compared with sham operation group,the expression levels of Nrf2 and HO-1 proteins in brain tissue of the rats in model group were significantly decreased(P<0.01);compared with model group,the expression levels of Nrf2 and HO-1 proteins in brain tissue of the rats in BMSCs group were significantly increased(P<0.01);compared with BMSCs group,the expression levels of Nrf2 and HO-1 proteins in brain tissue of the rats in combination group were significantly decreased(P<0.01);compared with sham operation group,the expression levels of Parkin,PINK1,and Beclin-1 proteins,and LC3-Ⅱ/LC3-Ⅰ ratio of the rats in model group were significantly increased(P<0.01),while the expression level of P62 protein was significantly decreased(P<0.01);compared with model group,the expression levels of Parkin,PINK1,and Beclin-1 proteins,as well as the LC3-Ⅱ/LC3-Ⅰ ratio,of the rats in BMSCs group were significantly decreased(P<0.01),while the expression level of P62 protein was significantly increased(P<0.01);compared with BMSCs group,the expression levels of Parkin,PINK1,and Beclin-1 proteins,as well as the LC3-Ⅱ/LC3-Ⅰ ratio,of the rats in combination group were significantly increased(P<0.01),while the expression level of P62 protein was significantly decreased(P<0.01).Conclusion:BMSCs can alleviate the hippocampal neuronal pathological changes and improve cognitive function in the VaD rats,and its mechanism may be related to the regulation of ROS/Nrf2 signaling pathway to inhibit mitophagy.
8.Strategies for selecting recipient vessels in free flap reconstruction for head and neck defects
Hongbo XU ; Lifeng LI ; Xinmeng QI ; Jing ZHOU ; Zheng YANG ; Qi FU ; Guihua WANG ; Xiaohong CHEN ; Zhigang HUANG
Chinese Archives of Otolaryngology-Head and Neck Surgery 2025;32(7):409-412
OBJECTIVE To investigate the selection strategy for recipient vessels in free flap reconstruction of head and neck defects.METHODS A retrospective analysis was conducted on 96 patients who underwent 99 free flap reconstructions for head and neck defects between January 2020 and December 2024.Recipient vessel selection,flap survival,and postoperative complications were analyzed based on defect location and flap type.RESULTS In 99 cases microvessel anastomosis,the recipient arteries were superior thyroid artery in 49 branches,facial artery in 28 branches,superficial temporal artery in 14 branches,lingual artery in 5 branches.external carotid artery in 1 branch,transverse cervical artery in 1 branch,and superior laryngeal artery in 1 branch.Venous anastomosis was performed in 104 branches,with 94 cases in 1 venous anastomosis and 5 cases in 2 venous anastomoses.The recipient veins selected were facial vein in 62 branches,external jugular vein in 21 branches,superficial temporal vein in 12 branches,retromandibular vein in 3 branches,middle thyroid vein in 2 branches,internal jugular vein in 2 branches,middle temporal vein in 1 branch,and superior thyroid vein in 1 branch.Complete flap necrosis occurred in 5 cases,and partial necrosis occurred in 4 cases.When the recipient vessels were deficient,the lingual artery was chosen in 3 cases,the facial artery in 1 case,the external jugular vein in 3 cases,the internal jugular vein with end-to-side anastomosis in 1 case,and the common facial vein with end-to-side anastomosis in 1 case.CONCLUSION In free flap reconstruction for head and neck defects,the superior thyroid artery,facial artery,and superficial temporal artery are commonly used as recipient arteries,while the facial vein,external jugular vein,and superficial temporal vein are frequently selected as recipient veins.When recipient vessels are scarce,the ipsilateral lingual artery,transverse cervical artery,and main trunk of the internal jugular vein can serve as alternative recipient vessels.
9.Construct a Nomogram prediction model for the short-term prognosis of coronary heart disease patients with hypertension after PCI based on RAAS and Syntax score
Maowen YU ; Zuoli QIN ; Hongbo TANG ; Qingzhong WANG ; Hui TAN
International Journal of Laboratory Medicine 2025;46(6):719-727
Objective To construct a Nomogram prediction model for short-term prognosis of coronary heart disease(CAD)patients with hypertension after percutaneous coronary intervention(PCI)based on re-nin-angiotensin-aldosterone(ALD)system(RAAS)and Syntax score of coronary artery disease,so as to pro-vide a favorable basis for improving the prognosis of patients.Methods A total of 310 CAD patients with hy-pertension admitted to Jintang Hospital of West China Hospital of Sichuan University from June 2019 to April 2023 were selected.According to the ratio of 7:3,310 patients were randomly divided into a training set(217 cases)and a validation set(93 cases).All patients underwent PCI and were followed up for 3 months.The training set was further divided into poor prognosis group(n=68)and good prognosis group(n=148)ac-cording to the incidence of major adverse cardiovascular events(MACE).Multivariate Logistic regression model was used to analyze the risk factors of poor prognosis.The Nomogram prediction model was construc-ted by the R language in the training set,and the calibration curve and receiver operating characteristic(ROC)curve were used to verify the prediction efficiency of the model in the validation set.Results There was no significant difference in the general data between the training set and the validation set(P>0.05).MACE oc-curred in 68 cases(31.34%)in the training set and 28 cases(30.11%)in the validation set.There were sig-nificant differences in age,left ventricular ejection fraction,creatine kinase isoenzyme(CK-MB),number of diseased vessels,renin activity(PRA),angiotensin Ⅱ(ANG Ⅱ),ALD,preoperative Syntax score and N-termi-nal pro-B-type brain natriuretic peptide(NT-proBNP)between the good prognosis group and the poor prog-nosis group(P<0.05).Pearson correlation analysis showed that PRA,ANGⅡ,ALD were positively correla-ted with preoperative Syntax score(r=0.613,0.728,0.695,P<0.05).Lasso regression analysis included age,left ventricular ejection fraction,number of diseased vessels,PRA,ANG Ⅱ,ALD,preoperative Syntax score.Multivariate Logistic regression analysis showed that age,left ventricular ejection fraction,number of diseased vessels,PRA,ANG Ⅱ,ALD and preoperative Syntax score were independent influencing factors for poor short-term prognosis of PCI treatment(OR=4.448,5.153,4.571,3.875,4.914,4.468,5.224,P<0.05).The ROC curve showed that the area under the curve(AUC)of the Nomogram prediction model for poor short-term prognosis of CAD patients with hypertension after PCI in the training set and validation set were 0.884(95%CI 0.837-0.931)and 0.885(95%CI 0.818-0.953),respectively.The calibration curve showed that the prediction probability of poor short-term outcome of PCI in the training set and the validation set was basically consistent with the actual probability.Conclusion The short-term prognosis of CAD patients with hypertension after PCI is affected by age,left ventricular ejection fraction,number of diseased vessels,PRA,ANG Ⅱ,ALD,preoperative Syntax score and other factors.The Nomogram prediction model based on the above factors has high predictive value and good predictive utility.
10.Spatiotemporal characteristics of diesel exhaust particle pollution in confined space and impacts of ventilation and airflow: A laboratory simulation study
Zheyu HUANG ; Jian ZHANG ; Lihua HE ; Wenchu HUANG ; Zihui LI ; Bilige HASEN ; Hongbo WANG ; Yun WANG
Journal of Environmental and Occupational Medicine 2025;42(7):814-821
Background Diesel engines are widely used in transportation, agriculture, construction, industry, and other fields. Diesel exhaust, classified as a Group 1 carcinogen, emits particles (DEP) that can penetrate deep into the respiratory tract, posing significant health risks. DEP pollution is particularly severe in confined environments, necessitating effective control measures. Objective Under laboratory simulation conditions, to explore the spatiotemporal distribution characteristics of the mass and number concentrations of DEP as it diffuses indoors and to reveal the effects of ventilation and additional airflow on indoor DEP pollution levels. Methods A diesel engine was placed in a laboratory (length 3.39 m × width 2.85 m × height 2.4 m) with its exhaust emitted from east to west. An air purifier was installed 1 m south of the engine. Eight measurement points (1 m horizontal distance from the exhaust outlet, height: 1 m/1.5 m) were setup to monitor DEP concentrations using portable laser particle sizers. The effects of engine power (4.05 kW vs. 5.15 kW), ventilation (maximum airflow: 600 m3·h−1), additional airflow intensity (low and high), and direction (forward/reverse) on DEP pollution were analyzed. DEP levels of 5 diesel vehicle models were also compared. Results The mass and number concentrations of DEP indoors increased immediately after the diesel engine started. The peak mass concentration time at the eastern measurement point (−1, 0) m opposite to the exhaust direction (17.70 min) was significantly longer than that at the western (1, 0) m (16.20 min), southern (0, -1) m (14.45 min), and northern (0, 1) m (12.70 min) points (P<0.05), with no significant differences between the other points (western, southern, and northern) (P>0.05). The northern point (0, 1) m exhibited the highest DEP mass and number concentration peaks (174.62 μg·m−3,


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