PM2.5 episodes in northern Taiwan under southerly winds in late winter

From April 6 to 9, 2019, during the period between two cold fronts from Asian continent affecting Taiwan, the Pacific high-pressure system extended westward, causing weak southwesterly winds around Taiwan. During that time, PM2.5 event occurred in central Taiwan. We applied the WRF/CMAQ modeling system to explore the PM2.5 event, with a focus on the maximization of local pollution. The Integrated Process Rate (IPR) is employed to explore the contributions of various mechanisms to the PM2.5 concentration. At the north of central Taiwan, the increase in the PM2.5 concentration was caused mainly by horizontal advection (HADV) and to a limited degree by aerosol chemistry (AERO) and vertical diffusion (VDIF). In Taichung City, AERO, VDIF and vertical advection (ZADV) caused the increase in PM2.5 concentration. In the south of central Taiwan, HADV caused the decrease in the PM2.5 concentration. The calculated integrated reaction rate (IRR) indicated that gaseous HNO3 was produced by OH + NO2 during the day, accounting for almost all the HNO3 formed at noon. After sunset, heterogeneous reactions between N2O5 and water vapor dominated. Local pollution accounted for approximately half of the total amount of SO4 2−. The most important way to control local SO4 2− is to reduce the emission of SO2 or H2O2. Organic carbon (OC) reduction depends mainly on controlling OC produced via combustion. Another way is to reduce low-volatility/semivolatile primary organic aerosols (POAs). Additionally, the simulation indicated that the PM2.5 in central Taiwan was acidic, with pH values was below 2 at noon and between 3 and 5 at midnight. Graphical Abstract

BackgroundEvidence from our recent study suggested that the overall trend for cancer incidence in children and adolescents has been increasing in Taiwan.MethodsTo analyze geographic variations in this trend, cancer frequencies and incidence rates of disease groups were quantified according to geographic areas among 12,633 patients aged <20 years during 1995–2009 by using the population-based Taiwan Cancer Registry. Three geographic levels were defined, namely county or city, region (Northern, Central, Southern, and Eastern Taiwan), and local administrative area (special municipality, provincial city, county-administered city, township, and aboriginal area).ResultsOf the regions, Northern Taiwan had the highest incidence rate at 139.6 per million person-years, followed by Central (132.8), Southern (131.8), and Eastern (128.4) Taiwan. Significantly higher standardized rate ratios (SRRs) were observed in Northern Taiwan (SRR = 1.06, 95% confidence interval [CI] = 1.02–1.10) and at the township level (SRR = 1.07, 95% CI = 1.03–1.11). Of the cities or counties, New Taipei City yielded the highest SRR (1.08), followed by Taipei City (SRR = 1.07). A comparison of the rates in the four regions and the remainder of Taiwan according to cancer type revealed that only the rate of neuroblastomas in Eastern Taiwan was significantly low. Trend analysis showed that the most significant increase in incidence rate was observed at the township level, with an annual percent change of 1.8% during the 15-year study period.ConclusionsThe high rate of childhood cancer in Northern Taiwan and at the township level deserves further attention. The potential impacts of environmental factors on the upward trend of childhood cancer incidence rate in townships warrant further investigation.

BackgroundPeptic ulcer disease (PUD) is a common and important cause of morbidity worldwide, with a large impact on healthcare costs. Little research has been conducted on the association between wet-bulb globe temperature (WBGT) and PUD. The aim of this study was to explore this association among different geographical regions of Taiwan in a large sample of participants.MethodsThis is a cross-sectional study. The study participants (n = 120,424) were enrolled from the Taiwan Biobank (TWB) and resided across northern, central, southern and eastern Taiwan. Self-reported questionnaires were used to ascertain the occurrence of PUD. Average WBGT values were recorded during working hours (8:00 AM to 5:00 PM) and the noon period (11:00 AM to 2:00 PM) for each participant at 1, 3, and 5 years before the TWB survey year. The association between WBGT and PUD was examined with logistic regression analysis.ResultsThe 1-year and 5-year noon WBGT values per 1℃ increase were significantly associated with a low prevalence of PUD in northern Taiwan (odds ratio [OR], 0.960, 95% confidence interval [CI], 0.925–0.955; OR, 0.962, 95% CI, 0.929–0.997; respectively). In contrast, there were no significant associations between WBGT and PUD in central Taiwan. In southern Taiwan, the 1-, 3-, and 5-year WBGT values per 1℃ increase during the noon period (OR, 0.875, 95% CI, 0.873–0.909; OR, 0.860, 95% CI, 0.825–0.896; OR, 0.848, 95% CI, 0.812–0.885; respectively) and working period (OR, 0.852, 95% CI, 0.825–0.880; OR, 0.845, 95% CI, 0.816–0.876; OR, 0.832, 95% CI, 0.0.801–0.863; respectively) were significantly associated with a low prevalence of PUD. However, in eastern Taiwan, the 1-, 3-, and 5-year WBGT values per 1℃ increase during the noon period (OR, 1.074, 95% CI, 1.022–1.127; OR, 1.058, 95% CI, 1.013–1.104; OR, 1.058, 95% CI, 1.013–1.105; respectively), and the 3- and 5-year WBGT values per 1℃ increase during the working period were significantly associated with a high prevalence of PUD (OR, 1.049, 95% CI, 1.003–1.097; OR, 1.047, 95% CI, 1.001–1.095; respectively). Based on nonlinear trend analysis, WBGT was categorized into three groups for the noon period or work period, and the results were similar to and generally consistent with those in linear models.ConclusionThe associations between WBGT and PUD differed across the geographical regions of Taiwan. In northern and southern Taiwan, increases in average WBGT values were significantly associated with a low prevalence of PUD. In addition, this relationship was much stronger in southern Taiwan than in northern Taiwan. Of note, there was a reverse relationship between WBGT and PUD during the noon and working periods in eastern Taiwan. Further studies are needed to elucidate the effects of WBGT on PUD.

A study of afternoon heavy rainfall in Taiwan during the mei-yu season

Background: The malignant transformation of oral potentially malignant disorders (OPMDs) is a potential cause of oral cancers. However, epidemiological studies on malignant transformation of OPMDs are lacking. The present study is aimed to investigate the percentage of OPMD in the oral mucosal screening database and the malignant transformation (%) across different regions of Taiwan. Methods: We determined the cases of malignant transformation of OPMD to oral cancers during the 2-year follow-up by the oral mucosal screening database and the cancer registry database contained in the National Health Insurance Research Database. Patients with oral cancer history before OPMD diagnosis were excluded from the study. We collected data including clinical diagnosis, biopsy result, follow-up, and place of residence of the patient. The most widely used definition from the Council for Economic Planning and Development in Taiwan was used in this study for the classification into Southern, Northern, Eastern, and Western Taiwan regions. Differences in the malignant transformation (%) and ranking between regions were evaluated using analysis of variance test. Results: Chiayi city located in Southern Taiwan has the highest percentage of OPMD in oral screening citizen. The percentage of OPMD in the oral mucosal screening database was highest in Southern Taiwan and lowest in Eastern Taiwan; however, the malignant transformation (%) was highest in the Eastern Taiwan and lowest in Northern Taiwan. Conclusion: Dentists and otolaryngologists in Southern Taiwan, especially Chiayi city, should be cautious when screening the patient because of the high percentage of OPMD in oral mucosal screening database. The percentage of OPMD in the oral mucosal screening database and the malignant transformation (%) are different among the different regions in Taiwan. Further research is needed to clarify the reasons for the different malignant transformation (%) between regions.

Classification of PM 10 distributions in Taiwan

Multi-year hourly PM 2.5 carbon measurements in New York: Diurnal, day of week and seasonal patterns

Characterizing the spatial distribution of PM2.5 species concentrations is challenging due to the geographic sparsity of the stationary monitoring network. Recent advances have enabled valid estimation of PM2.5 species concentrations using satellite remote sensing data for use in epidemiologic studies. In this study, we used satellite-based estimates of ambient PM2.5 species concentrations to estimate associations with birth weight and preterm birth in California. Daily 24 h averaged ground-level PM2.5 species concentrations of organic carbon, elemental carbon, nitrate, and sulfate were estimated during 2005-2014 in California at 1 km resolution. Birth records were linked to ambient pollutant exposures based on maternal residential zip code. Linear regression and Cox regression were conducted to estimate the effect of 1 µg/m3 increases in PM2.5 species concentrations on birth weight and preterm birth. Analyses included 4.7 million live singleton births having a median 28 days with exposure measurements per pregnancy. In single pollutant models, the observed changes in mean birth weight (per 1 µg/m3 increase in speciated PM2.5 concentrations) were: organic carbon -3.12 g (CI: -4.71, -1.52), elemental carbon -14.20 g (CI: -18.76, -9.63), nitrate -5.51 g (CI: -6.79, -4.23), and sulfate 9.26 g (CI: 7.03, 11.49). Results from multipollutant models were less precise due to high correlation between pollutants. Associations with preterm birth were null, save for a negative association between sulfate and preterm birth (Hazard Ratio per 1 µg/m3 increase: 0.973 CI: 0.958, 0.987).

The effect of mountains on the occurrence of precipitation systems on Taiwan island is very significant, especially as mountain areas occupy about two-thirds of the land-mass. The mountains are, on average, about 3 km high. To investigate the formation of precipitation systems influenced by Pacific high pressure systems, we selected five cases (May 24, 25 and 26, June 19 and 20 in 1987) during a field program, TAMEX (Taiwan Area Mesoscale Experiment, Kuo and Chen, 1990). In all cases most of the rainfall took place in the afternoon when the level of free convection (LFC) was at about the 1 km height. If the average wind (below 3 km in height) was from the south (May 25 and 26), higher amounts of precipitation would be found along the sloped areas of western and eastern Taiwan. Rainfall also occurred in southern and northern Taiwan. If the average wind was from the southwest (May 24), the precipitation pattern was similar to that on May 25, except over the plains area in southwest and northeast Taiwan, where the amount was less. However, if the prevailing wind direction changed little with height and the average wind was from the south-southeast (June 19), higher rainfall amounts occurred from northwestern to central Taiwan. If the average wind was from the south and wind direction changed little with height (June 20), higher rainfall amounts took place in northern and central Taiwan. A nonhydrostatic model was used to simulate the formation of precipitation systems in all five cases. Simulation results indicated that the mixing ratio of rainwater could occur on the upstream side of a mountain slope and in the central mountain areas, where topographic lifting from the environmental wind and an upslope flow due to surface heating were evident. On the downstream side of the mountain, upward motion due to lee-side convergence and upslope motion from surface heating would also help rain form.

The mechanism of the formation of high sulfate concentrations over the Yellow Sea during the KORUS-AQ period: The effect of transport/atmospheric chemistry and ocean emissions

13C signatures of aerosol organic and elemental carbon from major combustion sources in China compared to worldwide estimates

This study examines the utilization patterns of myocardial perfusion imaging (MPI) and cardiac catheterization (CC) under Taiwan's national health insurance program. This study used the longitudinal health insurance database with 1,000,000 people were randomly selected from the national health insurance research database. This study obtained data from these patients with coronary artery disease (CAD) and comparison with the utilization of MPI or CC between 2005 and 2009. The incidence of CAD did not significantly change, while the prevalence of CAD, utilization of MPI, and the utilization of CC for the CAD patients increased annually. There were the most CAD patients in Northern Taiwan (43.5%), followed by Southern, Central, and Eastern Taiwan. The utilizations of both of MPI (12.7 per 100 CAD patients) and CC (10.6 per 100 CAD patients) were most frequent in Northern Taiwan followed by Southern, Central, and Eastern Taiwan. However, the MPI/CC ratio was 1.20 in Northern Taiwan, followed by Southern, Central, and Eastern Taiwan (0.88, 0.64, and 0.52, respectively, P = 0.0008). The use of MPI was higher than CC only in Northern Taiwan. MPI may be underutilized to serve the role of gatekeeper for CC in the other regions.

Emission influences on air pollutant concentrations in New York state: II. PM2.5 organic and elemental carbon constituents

Japanese eel larvae are passively transported to the East Asian Continental Shelf by the North Equatorial Current, Kuroshio and Kuroshio intrusion currents, and coastal currents. Previous studies have investigated the dispersal characteristics and pathways of Japanese glass eels. However, there are still limitations in these studies. According to long-term (2010–2020) catch data from the Fisheries Agency in Taiwan, the distribution and time series of glass eels recruitment to Taiwan are closely related to the surrounding ocean currents. Recruitment begins in eastern Taiwan via the mainstream Kuroshio and in southern Taiwan via the Taiwan Strait Warm Current. In central Taiwan, recruitment occurs from southern Taiwan, as well as from mainland China via the southern branch of the China Coast Current (CCC). The latest recruitment occurred in northern Taiwan and mainly comprised glass eels from mainland China via the northern branch of the CCC. A stronger monsoon during the La Niña phase could affect the recruitment time series in northern and eastern Taiwan. This study suggests that the recruitment directionality of glass eels is an indicator of the flow field of ocean/coastal currents and elucidates the dispersal characteristics of glass eels in the waters around Taiwan.

Epidemiology of and risk factors associated with third-generation cephalosporin-resistant Escherichia coli carriage in children: A comparison between regions in Taiwan