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INTRODUCTION The efficacy and safety of low- and standard-dose alteplase for acute ischemic stroke (AIS) have not been consistently compared in previous studies. Nevertheless, the distinctions in the effects of low- and standard-dose alteplase, particularly within the context of bridging therapy (BT) for large vessel occlusion (LVO), warrant further exploration. This study compared clinical outcomes between BT with low- and standard-dose alteplase in patients with LVO-related AIS. METHODS We performed a search for randomized controlled trials and prospective or retrospective cohort studies investigating the clinical outcomes of BT in AIS in the PubMed, Embase, and Cochrane Library databases from inception to November 2022. The outcomes of interest were 90-day functional independence, successful recanalization, symptomatic intracerebral hemorrhage (sICH) and mortality; these outcomes were compared between patients who received BT with low- (primarily 0.6 mg/kg) and standard-dose alteplase (0.9 mg/kg). We used the standard-dose group as the reference and calculated the odds ratio (OR) and its 95% confidence interval (CI) from the raw numbers. Meta-analysis and ethnicity-based subgroup analysis (Asian and non-Asian) were performed. RESULTS Five observational studies, published after 2017 and including 408 patients, were included. The meta-analysis results demonstrated that compared with BT with standard-dose alteplase, BT with low-dose alteplase did not improve 90-day functional independence (odds ratio, [OR] 1.02; 95% confidence interval [CI], 0.58-1.80). Nevertheless, BT with low-dose alteplase was associated with a comparable successful recanalization rate (OR, 1.35; 95% CI, 0.68-2.67) and similar sICH incidence (OR 0.36; 95% CI, 0.10-1.36), and mortality (OR, 0.64; 95% CI, 0.27-1.54) compared with BT with standard-dose alteplase; however, the above three results were nonsignificant. In the ethnicity-based subgroup analyses, no differences were noted between Asian and non-Asian participants. CONCLUSIONS In patients with LVO-related AIS, BT with low- or standard-dose alteplase may provide similar efficacy, with no significant differences in sICH incidence and mortality. Additional well-designed prospective studies are required to confirm this result.
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We read with interest the review by Chen et al. They intended to examine the diagnostic accuracy of blood-based biomarkers for detecting Alzheimer's disease and amnestic mild cognitive impairment. We believe that there were substantial methodological flaws in their meta-analysis. These methodological flaws included no comprehensive literature search details, neglect of the negative result research, no prespecified cut-off values, erroneous data input in their meta-analysis, and the issue of prevalence determined by the included studies. These factors potentially contributed to overestimation of the discriminative accuracy of blood-based biomarkers. Subsequently, the conclusion that blood-based biomarkers are effective tools for detecting Alzheimer's disease is debatable without correction of these methodological flaws and providing robust and trustworthy estimates.
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Alzheimer Disease , Cognitive Dysfunction , Humans , Alzheimer Disease/diagnosis , Cognitive Dysfunction/diagnosis , Biomarkers , Prevalence , Amyloid beta-Peptides , tau ProteinsABSTRACT
OBJECTIVES: To explore the validity of the Chinese version of the Identification of Seniors at Risk (ISAR) screening tool in emergency rooms (ERs) to identify elderly patients prone to adverse outcomes after being discharged from the ER. METHODS: A prospective single-center observational study design was adopted and included 497 elderly (aged ≥65 years) ER patients of a medical center in northern Taiwan. Before discharge from the ER, baseline sociodemographic and clinic data were collected by researchers and the ISAR was administered. Adverse health outcomes (ER revisits, readmissions, and mortality) at 30 days were evaluated by medical records and follow-up telephone interviews. RESULTS: ISAR screening showed that 334 (67.2%) elderly patients in the ER were at high risk after discharge. Higher-risk patients were older, had had a fall within the previous 6 months, and had complex comorbidities. The ISAR had good sensitivity (0.77â¼1.00) for screening adverse health outcomes in these elderly patients. The discrimination of the ISAR for adverse health outcomes was 0.60â¼0.77, and it increased to 0.64â¼0.80 when the age-adjusted Charlson comorbidity index (ACCI) was simultaneously considered. CONCLUSIONS: The ISAR exhibited good sensitivity for screening adverse outcomes for elderly patients at risk. The ACCI is recommended to simultaneously be considered to improve the prognostic performance of the ISAR.
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Emergency Service, Hospital , Geriatric Assessment , Aged , Humans , Prospective Studies , Risk Assessment , Outcome Assessment, Health CareABSTRACT
BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a significant public health concern. The patients with acute exacerbations of COPD (AECOPD) and pneumonia have similar clinical presentations. The use of conventional diagnostic markers, such as complete blood count with differential and C-reactive protein (CRP), is the current mainstream method for differentiating clinically relevant pneumonia from other mimics. However, those conventional methods have suboptimal sensitivity and specificity for patients with a clinical suspicion of infection. The limitations often cause the ambiguity of the initiation of antibiotic treatment. Recently, our pilot study suggested that the patients with pneumonia have significantly higher plasma Sphingosine-1-phosphate (S1P) levels than controls. The initial findings suggest that plasma S1P is a potential biomarker for predicting prognosis in pneumonia. The aim of this study was to evaluate the value of S1P and CRP for discriminating COPD with pneumonia and AECOPD in an Emergency Department (ED) setting. METHODS: Patients diagnosed with AECOPD or COPD with pneumonia were recruited from the Emergency Department of Wan Fang Hospital. The clinical data, demographics, and blood samples were collected upon ED admission. The concentration of plasma S1P was measured by ELISA. RESULTS: Thirty-nine patients with AECOPD and 78 with COPD plus pneumonia were enrolled in this observational study. The levels of blood S1P and CRP were significantly higher in patients with COPD plus CAP compared to those in AE COPD patients. The area under the receiver operator characteristic (ROC) curve for the S1P and CRP for distinguishing between patients with COPD plus CAP and AECOPD is 0.939 (95% CI: 0.894-0.984) and 0.886 (95% CI: 0.826-0.945), whereas the combination of S1P and CRP yielded a value of 0.994 (95% CI: 0.897-1.000). By comparing with CRP or S1P, combining CRP and S1P had significantly higher AUC value for differentiating between the COPD with pneumonia group and the AECOPD group. CONCLUSIONS: Our findings suggest that S1P is a potential diagnostic biomarker in distinguishing COPD with CAP from AECOPD. Additionally, the diagnostic ability of S1P can be improved when used in combination with CRP.
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Community-Acquired Infections/diagnosis , Pneumonia/diagnosis , Pulmonary Disease, Chronic Obstructive/diagnosis , Aged , Biomarkers/blood , C-Reactive Protein/analysis , Diagnosis, Differential , Female , Humans , Lysophospholipids/blood , Male , Prospective Studies , Sphingosine/analogs & derivatives , Sphingosine/bloodSubject(s)
Foreign Bodies , Tomography, X-Ray Computed , Bone and Bones , Foreign Bodies/diagnostic imaging , Habits , Humans , Radiography , X-RaysABSTRACT
ABSTRACT: Return of spontaneous circulation (ROSC) from out-of-hospital cardiac arrest (OHCA) is critical for the Emergency Medical Services System. When compared to other developed countries, Taiwan has lower rate of ROSC in OHCA patients.We conducted a retrospective study of cardiac arrest using The Emergency Medical Service Dispatching Center in Northern Taiwan and The Prehospital Care System of New Taipei City Paramedic Service. Patients suffering from nontraumatic OHCA between August of 2019 to February of 2020 were included. We analyzed the cardiopulmonary resuscitation (CPR) quality parameters such as chest compression interruptions, bystander CPR, shockable rhythm, CPR interruption, chest compression fraction (CCF) average, patient transportation in buildings, and adrenaline injection during CPR. Multivariable logistic regression analysis was performed to assess the relationship between potential independent variables and ROSC.In our study, we involved 1265 subjects suffering from nontraumatic OHCA, among which 587 patients met inclusion criteria. We identified that CCF> 0.8, chest compression interruption greater than 3 times, and patient transportation in the building were the most critical factors influencing ROSC. However, patient transportation in a building was identified as a dependent predictor variable (Pâ=â.4752).We concluded that CCF >â0.8 and chest compression interruption greater than 3 times were essential factors affecting the CPR ROSC rate. The most significant reason for suboptimal CCF and CPR interruption is patient transportation in a building. Improving the latter point could facilitate high-quality CPR.
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Cardiopulmonary Resuscitation/methods , Emergency Medical Services/methods , Out-of-Hospital Cardiac Arrest/epidemiology , Adolescent , Chest Wall Oscillation , Child , Emergency Medical Technicians , Female , Humans , Male , Out-of-Hospital Cardiac Arrest/therapy , Recovery of Function , Retrospective Studies , TaiwanABSTRACT
BACKGROUND: Chlamydia trachomatis infection is the most common sexually transmitted infectious disease and carries a risk of complications. However, the optimal treatment for rectal chlamydial infection remains unclear. OBJECTIVES: To compare the efficacy of doxycycline and azithromycin for the treatment of rectal chlamydia by undertaking a systematic review and meta-analysis of published data. METHODS: We searched PubMed, EMBASE, Cochrane Library, Web of Science and clinicaltrials.gov databases from inception to 7 July 2021 for randomized controlled trials (RCTs) and observational studies that compared the efficacy of doxycycline and single-dose azithromycin on rectal chlamydia cure rates. Data were synthesized using a random-effects model, and subgroup analysis was conducted. RESULTS: All included studies were conducted in developed countries. Two RCTs and nine observational studies, with a total of 2457 patients, were analysed. Doxycycline had a higher microbiological cure rate than azithromycin (risk ratio = 1.21; 95% CI = 1.15-1.28; P < 0.05). Pooled results from two RCTs also revealed a higher microbiological cure rate for doxycycline than azithromycin (risk ratio = 1.27; 95% CI = 1.20-1.35; P < 0.05). The results remained consistent in subgroups of different study designs, countries and sexes. CONCLUSIONS: On the basis of our findings, we recommend doxycycline rather than azithromycin as a first-line treatment for rectal chlamydia in developed countries. More RCTs from developing countries are warranted.
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Azithromycin , Chlamydia Infections , Anti-Bacterial Agents/therapeutic use , Azithromycin/therapeutic use , Chlamydia Infections/drug therapy , Chlamydia trachomatis , Doxycycline/therapeutic use , HumansABSTRACT
BACKGROUND: Although tranexamic acid (TXA), a readily accessible antifibrinolytic agent, is widely adopted in hemorrhage scenarios, its role on mortality in patients with hemoptysis remains uncertain. New evidence is yet to be generated to evaluate the risk of mortality after using TXA in patients with hemoptysis. METHODS: PubMed, EMBASE, Cochrane Library, Web of Science, and Scopus databases were searched from inception to May 2020. Randomized controlled trials and observational studies that evaluated the effect of TXA on patients with hemoptysis were included. Data were independently extracted by 2 reviewers and synthesized using a random-effects model. MAIN RESULTS: Five studies with a total of 20,047 patients were analyzed. When compared with the control, administration of TXA was associated with a reduction in short-term mortality (risk ratio = 0.78, 95% confidence interval [CI] 0.72-0.85; I2 = 0), shorter bleeding time (mean difference =â-â24.61âhours, 95% CIâ-â35.96 to -13.26, I2 = 0), shorter length of hospital stay (mean difference = -1.94âdays, 95% CI -2.48 to -1.40, I2 = 0), and lower need for intervention (risk ratio = 0.38, 95% CI 0.16-0.87, I2 = 0) in patients with hemoptysis. Compared with control, administration of TXA did not cause increased major or minor adverse effects. CONCLUSIONS: TXA provided benefits in terms of a lower short-term mortality rate, less bleeding time, shorter length of hospital stays, and less need for intervention in patients with hemoptysis. Use of TXA was not associated with increased adverse effects.
Subject(s)
Antifibrinolytic Agents/administration & dosage , Hemoptysis/drug therapy , Hospital Mortality , Tranexamic Acid/administration & dosage , Antifibrinolytic Agents/adverse effects , Bleeding Time , Hemoptysis/mortality , Humans , Length of Stay/statistics & numerical data , Meta-Analysis as Topic , Observational Studies as Topic , Randomized Controlled Trials as Topic , Systematic Reviews as Topic , Tranexamic Acid/adverse effects , Treatment OutcomeABSTRACT
Foreign body (FB) ingestion is a common clinical problem in acute settings. Detecting FBs in the upper digestive tract is challenging. The conventional X-ray is usually the first-line imaging tool to detect FBs. However, its diagnostic performance is inconsistent in the literature. In this study, we performed a systematic review and meta-analysis to determine the diagnostic performance of the conventional X-ray for detecting FBs in the upper digestive tract. We conducted a systematic search of PubMed, Embase, Cochrane Library, Web of Science, and Scopus until 1 August 2020. Prospective or retrospective studies investigating the diagnostic accuracy of conventional X-rays for detecting FBs in the upper digestive tract in patients of all ages were included. The Quality Assessment of Studies of Diagnostic Accuracy-2 tool was used to review the quality of included studies. We used a bivariate random-effects model to calculate diagnostic accuracy parameters. Heterogeneity was assessed using I2 statistics. We included 17 studies (n = 4809) in the meta-analysis. Of the 17 studies, most studies were rated as having a high risk of bias. Conventional X-rays had a pooled sensitivity of 0.58 (95% confidence interval [CI] = 0.36-0.77, I2 = 98.52) and a pooled specificity of 0.94 (95% CI = 0.87-0.98, I2 = 94.49) for detecting FBs in the upper digestive tract. The heterogeneity was considerable. The area under the summary receiver operating characteristic curve was 0.91 (95% CI = 0.88-0.93). Deek's funnel plot asymmetry test results revealed no significant publication bias (p = 0.41). The overall sensitivity and specificity of conventional X-rays were low and high, respectively, for detecting FBs in the upper digestive tract. Hence, conventional X-rays to exclude patients without upper FBs in the digestive tract are not recommended. Further imaging or endoscopic examinations should be performed for at-risk patients.
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PURPOSE: Accurate diagnosis of small bowel obstruction (SBO) remains challenging. The evidence of the diagnostic accuracy of ultrasound varies among studies, with reporting sensitivity ranging from 82 % to 100 % and specificity ranging from 54 % to 100 %. The aim of our study is to perform a systematic review and meta-analysis to investigate the accuracy of ultrasound for diagnosing SBO. METHOD: The PubMed, EMBASE, Cochrane Library, Web of Science, and Scopus databases were searched from database inception to March 2020. Randomized controlled trials, quasi randomized studies, and prospective or retrospective cohort studies that evaluated the diagnostic performance of ultrasound for the diagnosis of bowel obstruction in adult patients (age ≥ 16 years) were eligible. The QUADAS-2 tool was used to assess the quality of the included studies. The pooled sensitivities, specificities were analyzed using a bivariate random-effects model. (PROSPERO ID: CRD42020170010). RESULTS: Fifteen studies, with most rating as a moderate risk of bias, met the inclusion criteria. The pooled sensitivity and specificity were 92 % (95 % CI: 89%-95%) and 93 % (95 % CI: 85%-97%), respectively. Subgroup analysis revealed no significant differences in sensitivity when ultrasound was performed on different continents, in different settings, and under different reference standards. However, the specificity was significantly lower when ultrasound was performed in the North America, in the emergency department, and when computed tomography was used as the only reference standard. CONCLUSIONS: Overall, ultrasound is a highly sensitive and specific tool for the diagnosis of SBO. Using ultrasound to rule in patients with SBO should be used with caution, as variations in the specificity were observed in different study setting, operators from different continents and reference standards used.
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Intestinal Obstruction , Adolescent , Adult , Humans , Intestinal Obstruction/diagnostic imaging , North America , Prospective Studies , Randomized Controlled Trials as Topic , Retrospective Studies , Sensitivity and Specificity , UltrasonographyABSTRACT
Scaphoid fractures are the most common carpal fractures. Diagnosing scaphoid fractures is challenging. Recently, cone-beam computed tomography (CBCT) has been shown to be a promising strategy for diagnosing scaphoid fractures. The diagnostic performance of CBCT remains inconclusive in the literature. Through a systematic review and meta-analysis, our study aims to determine the diagnostic performance of CBCT for diagnosing scaphoid fractures. Five databases were searched up to March 25, 2020. We included prospective and retrospective studies describing the diagnostic accuracy of CBCT for scaphoid fractures in adult patients. QUADAS-2 tool was used to assess the quality of the included studies. Four studies (n = 350) were included in the meta-analysis. Three of the four studies had high bias risk. The result showed that CBCT had a pooled sensitivity of 0.88 and a pooled specificity of 0.99 for scaphoid fracture diagnosis. The heterogeneities of sensitivity and specificity were substantial. The area under the summary receiver operating characteristic curve was 0.98. No significant publication bias was observed. The result suggested that the diagnostic performance of CBCT for scaphoid fracture was excellent. The certainty of current evidence is low. Further well-designed studies with large sample sizes are warranted to confirm this finding.
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Cone-Beam Computed Tomography/methods , Fractures, Bone/diagnostic imaging , Scaphoid Bone/diagnostic imaging , Humans , Prospective Studies , Retrospective StudiesABSTRACT
There is increasing evidence showing the role of fatty acids and their derived lipid intermediates in the regulation of skeletal muscle mass synthesis and function. However, the role of omega-3 fatty acids remains unclear. Therefore, we conducted a meta-analysis to evaluate the potential effects of omega-3 fatty acids on sarcopenia-related performances among the elderly. Eligible literature and reports of randomized controlled trials were comprehensively searched from the PubMed, Cochrane Library, ClinicalTrials.gov, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases until July 2018. A total of 10 articles were available for the meta-analysis. There were minor benefits for muscle mass gain (0.33 kg; 95% CI: 0.05, 0.62) and timed up and go performance (-0.30 s; 95% CI: -0.43, -0.17). Subgroup analyses regarding muscle mass and walk speed indicated that omega-3 fatty acid supplements at more than 2 g/day may contribute to muscle mass gain (0.67 kg; 95% CI: 0.16, 1.18) and improve walking speed, especially for those receiving more than 6 months of intervention (1.78 m/sec; 95% CI: 1.38, 2.17). Our findings provide some insight into the effects of omega-3 fatty acids on muscle mass, especially for those taking supplements at more than 2 g/day. We also observed that a long period of omega-3 fatty acids supplementation may improve walking speed.
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Fatty Acids, Omega-3/administration & dosage , Muscle Strength/drug effects , Muscle, Skeletal/drug effects , Sarcopenia/prevention & control , Aged , Diet , Dietary Supplements , Docosahexaenoic Acids/administration & dosage , Eicosapentaenoic Acid/administration & dosage , Female , Gait/drug effects , Humans , Male , Middle Aged , Muscle, Skeletal/metabolism , Physical Functional Performance , Randomized Controlled Trials as TopicABSTRACT
BACKGROUND: Magnesium sulfate (MgSO4) is widely used in analgesia for different conditions. Recent randomized controlled trials (RCTs) have evaluated the effects of MgSO4 on renal colic; however, this new evidence has not been synthesized. Thus, we conducted a systematic review and meta-analysis to assess the efficacy and safety of MgSO4 in comparison with control for renal colic. METHODS: PubMed, EMBASE, and Scopus databases were searched from inception to February 2020. We included RCTs that evaluated MgSO4 vs control for patients with renal colic. Data were independently extracted by 2 reviewers and synthesized using a random-effects model. RESULTS: Four studies with a total of 373 patients were analyzed. Intravenous MgSO4 15 to 50âmg/kg did not significantly reduce renal colic pain severity at 15âminutes (mean difference [MD]â=â0.35, 95% confidence interval [CI] -0.51 to 1.21; 2 RCTs), 30âminutes (MDâ=â0.19, 95% CI -0.74 to 1.13; 4 RCTs), and 60âminutes (MDâ=â-0.28, 95% CI -0.72 to 0.16; 3 RCTs) in comparison with controls. In patients who failed to respond to initial analgesics, intravenous MgSO4 15âmg/kg or 2âml of 50% solution provided similar pain relief to ketorolac or morphine at 30âminutes (Pâ=â.90) and 60âminutes (Pâ=â.57). No significant hemodynamic changes were observed with short-term use of MgSO4 in these studies. CONCLUSION: MgSO4 provides no superior therapeutic benefits in comparison with control treatments. MgSO4 may be used as a rescue medication in patients not responding to initial analgesics. The short-term use of MgSO4 did not affect hemodynamic values.
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Magnesium Sulfate/standards , Pain Management/standards , Renal Colic/drug therapy , Analgesics/pharmacology , Analgesics/standards , Analgesics/therapeutic use , Humans , Magnesium Sulfate/pharmacology , Magnesium Sulfate/therapeutic use , Pain Management/methods , Pain Management/statistics & numerical dataABSTRACT
BACKGROUND: Common complications of pediatric strabismus surgery, including emergence agitation (EA), postoperative nausea and vomiting (PONV), and postoperative pain, may be prevented using dexmedetomidine, which is an anxiolytic and analgesic. This systematic review and meta-analysis assessed the effects of dexmedetomidine in patients who had undergone pediatric strabismus surgery. METHOD: Five databases were searched for randomized controlled trials published from database inception to April 2020 that compared dexmedetomidine use with placebo or active comparator use and evaluated EA, PONV, or postoperative pain incidence (main outcomes) in patients who had undergone pediatric strabismus surgery. Oculocardiac reflex (OCR) incidence and postanesthesia care unit (PACU) stay duration were considered as safety outcomes. All meta-analyses were performed using a random-effects model. RESULTS: In the nine studies meeting our inclusion criteria, compared with placebo use, dexmedetomidine use reduced EA incidence [risk ratio (RR): 0.39; 95% confidence interval (CI): 0.25-0.62, I2 = 66%], severe EA incidence (RR: 0.27, 95% CI: 0.17-0.43, I2 = 0%), PONV incidence (RR: 0.33, 95% CI: 0.21-0.54, I2 = 0%), analgesia requirement (RR: 0.38, 95% CI: 0.25-0.57, I2 = 0%), and pain scores (standardized mean difference: -1.02, 95% CI: -1.44 to -0.61, I2 = 75%). Dexmedetomidine also led to lower EA incidence in the sevoflurane group than in the desflurane group (RR: 0.26 for sevoflurane vs. 0.45 for desflurane). Continuous dexmedetomidine infusion (RR: 0.19) led to better EA incidence reduction than did bolus dexmedetomidine infusion at the end of surgery (RR: 0.26) or during the peri-induction period (RR: 0.36). Compared with placebo use, dexmedetomidine use reduced OCR incidence (RR: 0.63; I2 = 40%). No significant between-group differences were noted for PACU stay duration. CONCLUSION: In patients who have undergone pediatric strabismus surgery, dexmedetomidine use may alleviate EA, PONV, and postoperative pain and reduce OCR incidence. Moreover, dexmedetomidine use does not affect the PACU stay duration.
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Analgesics, Non-Narcotic/therapeutic use , Dexmedetomidine/therapeutic use , Hypnotics and Sedatives/therapeutic use , Postoperative Complications/drug therapy , Strabismus/surgery , Anesthesia Recovery Period , Child , Child, Preschool , Female , Humans , Infant , Male , Randomized Controlled Trials as Topic , Reflex, Oculocardiac/drug effectsABSTRACT
Epidemiological studies have suggested the effects of ambient fine particles (PM2.5) on asthma, but the effects of specific components of PM2.5 on asthma remain to be explored. Here, we studied the effect of PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) on asthma acute exacerbation. The data on daily counts of emergency room visits (ERVs) were obtained from Wan Fang Medical Center, Taipei, Taiwan, from 2012 to 2015. The daily concentrations of PM2.5 and pollutant gases were obtained from a local air quality monitoring station. The levels of PM2.5-bound PAH were estimated by an established grid-scale model. Relative risks for ERVs as the increase in the level of ambient pollutants were calculated by using a generalized additive model of Poisson regression. In the present study, we observed statistically significant positive associations between PM2.5 and asthma ERVs for all age groups. PM2.5-bound PAH was also associated with asthma ERVs for all age groups. In the adult subgroup analysis, there was a significant association between PM2.5-bound PAH and asthma ERVs at lags 1 and 2 (RR 1.289, 95% CI 1.050-1.582 and RR 1.242, 95% CI 1.039-1.485). The impacts of air pollution on the risk of pediatric asthma ERV were found to be significant for PM2.5 at lag day 0 (RR 1.310, 95% CI 1.069-1.606). Moreover, pediatric asthma ERVs were significantly associated with the levels of PM2.5-bound PAH at lag 1 and 2 days (RR 1.576, 95% CI 1.371-1.810 and RR 1.426, 95% CI 1.265-1.607). The study provides evidence that PM2.5-bound PAHs were associated with an increased risk of asthma attacks. Our data further suggested that traffic exhaust is a primary source of PM2.5-bound PAHs.