RESUMO
OBJECTIVE: Prolonged grief disorder (PGD) and major depressive disorder (MDD) are common syndromes shaping bereaved caregivers' quality of life (QOL). However, distinctiveness of these syndromes warrants confirmation, and the temporal relationship of PGD and MDD symptoms has not been established. To fill these knowledge gaps, we conducted this longitudinal study. METHODS: PGD symptoms, depressive symptoms, and psychological QOL were measured over 398 caregivers' first 2 years of bereavement using the Prolonged Grief-13 (PG-13) scale, Center for Epidemiologic Studies-Depression (CES-D) scale, and Short Form-36 Health Survey mental health summary, respectively. To clarify the distinctiveness of PGD and MDD symptoms, we examined their associations with psychological QOL by incremental validity testing. Distinctiveness and temporal relationship of PGD and MDD symptoms were also examined using longitudinal, lower-level mediation analysis with a lagged approach. RESULTS: After the variance in psychological QOL was explained by CES-D scores (pseudo-R2 = 44.19%, P < .001), PG-13 scores significantly, incrementally increased the explained variance in psychological QOL (pseudo-R2 = 0.21%, P < .001), confirming the distinctiveness of PGD and MDD symptoms. CES-D scores mediated 40.7% of the time vs PG-13 score relationship, whereas PG-13 scores mediated 78.2% of the time vs CES-D score relationship with a better model fit, indicating that PG-13 scores assessed earlier mediated caregivers' current depressive status rather than vice versa. CONCLUSIONS: PGD and MDD are distinct constructs, and PGD precedes onset of MDD. Clinicians should distinguish between these two disorders and address bereaved caregivers' PGD to reduce PGD-associated distress and morbidity and to prevent MDD onset, thereby improving their QOL.
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Cuidadores/psicologia , Transtorno Depressivo Maior/psicologia , Pesar , Neoplasias/enfermagem , Qualidade de Vida/psicologia , Doente Terminal/psicologia , Adulto , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-IdadeRESUMO
This study investigates the subjective experiences of terminal cancer patients who expedite their corneal donation decisions. The percentage of cancer patients who donate their corneas postmortem is low in Taiwan. The reasons are complex and needs further exploration. A qualitative design using content analysis was used. A semistructured interview approach was adopted to interview cancer patients recruited from a cancer ward in northern Taiwan. The study findings show that the factors contributing to an aversive preference of cancer patients included the necessity to consider the emotions of family members, traditional perceptions, religious reasons, disease, and no reason at all. Most cancer patients maintain a negative stance toward corneal donation. The results obtained in the present study can be used as a reference for future in-service education and promotional efforts regarding corneal donation. Discussing cornea donation needs to become a routine end-of-life care discussion.
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Córnea , Tomada de Decisões , Neoplasias/psicologia , Obtenção de Tecidos e Órgãos , Feminino , Humanos , Entrevistas como Assunto , Masculino , Pessoa de Meia-IdadeRESUMO
BACKGROUND: Prolonged grief disorder (PGD) and depression are recognized as distinct emotional-distress disorders for bereaved family caregivers. However, this distinction has been mostly validated in cross-sectional studies, neglecting the dynamic characteristics of bereaved caregivers' emotional distress. OBJECTIVE: To validate the distinction between symptoms of PGD and depression across the first bereavement year for family caregivers of terminally ill cancer patients. METHODS: In this descriptive, longitudinal study of 394 bereaved Taiwanese family caregivers, we measured symptoms of PGD and depression by the Prolonged Grief-13 and Center for Epidemiologic Studies Depression (CES-D) scales at 6 and 13 months postloss, respectively. Agreement between cases of PGD and severe depressive symptoms (CES-D score ≥ 16) was analyzed by Cohen's kappa. Structural distinctiveness was longitudinally examined using confirmatory bifactor modeling. RESULTS: Agreement was poor between cases of PGD and severe depressive symptoms at 6 and 13 months postloss (kappa = .16 [confidence interval = .09, .22] and .12 [confidence interval = .03, .19], respectively). Symptoms of PGD and depression shared a general factor, but were distinct as shown by their significant specific factor loadings at 6 and 13 months postloss. Confirmatory bifactor models showed structural invariance (confirmatory fit index difference < .01 and χ2 difference P > .05) between 6 and 13 months postloss. CONCLUSION: Symptoms of PGD and depression were confirmed as distinct across the first year of bereavement. Health care professionals should recognize early in bereavement that symptoms of PGD and depression are distinct, identify high-risk groups, and provide care tailored to caregivers' unique needs to facilitate recovery from bereavement-related emotional-distress disorders.
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Cuidadores/psicologia , Transtorno Depressivo/fisiopatologia , Família/psicologia , Pesar , Neoplasias/enfermagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Cuidadores/estatística & dados numéricos , Transtorno Depressivo/epidemiologia , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Neoplasias/epidemiologia , Taiwan/epidemiologia , Adulto JovemRESUMO
This prospective, longitudinal study explored changes in and modifiable factors associated with high self-perceived burden to others (SPB) among a convenience sample of 276 dyads of terminally ill Taiwanese cancer patients and their family caregivers over patients' last year of life. High SPB was evaluated by scores ≥20 on the Self-Perceived Burden Scale. Modifiable factors of high SPB included factors related to both patients (i.e., symptom distress, functional dependence and coping capacity) and caregivers (i.e., caregiving burden, depressive symptoms and quality of life [QOL]). Modifiable factors of high SPB were identified by multivariate logistic regression modelling with the generalised estimating equation while controlling for demographic factors. We found that patients tended to experience high SPB if they had more symptom distress. In contrast, the likelihood of high SPB was significantly lower if patients had greater coping capacity and their caregivers reported better QOL. High SPB was not associated with patients' functional dependence, caregivers' caregiving burden and depressive-symptom level while providing end-of-life (EOL) care, and time proximity to death. Healthcare professionals may alleviate terminally ill cancer patients' high SPB at EOL through palliative care that adequately manages patients' physical symptom distress, enhances patients' coping capacity and improves family caregivers' QOL.
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Adaptação Psicológica , Cuidadores/psicologia , Depressão/psicologia , Neoplasias/enfermagem , Qualidade de Vida/psicologia , Autoimagem , Estresse Psicológico/psicologia , Assistência Terminal/psicologia , Adulto , Idoso , Feminino , Humanos , Modelos Logísticos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estudos Prospectivos , Taiwan , Doente Terminal/psicologiaRESUMO
BACKGROUND: No systematic meta-analysis is available on the prevalence of cancer patients' accurate prognostic awareness and differences in accurate prognostic awareness by publication year, region, assessment method, and service received. AIM: To examine the prevalence of advanced/terminal cancer patients' accurate prognostic awareness and differences in accurate prognostic awareness by publication year, region, assessment method, and service received. DESIGN: Systematic review and meta-analysis. METHODS: MEDLINE, Embase, The Cochrane Library, CINAHL, and PsycINFO were systematically searched on accurate prognostic awareness in adult patients with advanced/terminal cancer (1990-2014). Pooled prevalences were calculated for accurate prognostic awareness by a random-effects model. Differences in weighted estimates of accurate prognostic awareness were compared by meta-regression. RESULTS: In total, 34 articles were retrieved for systematic review and meta-analysis. At best, only about half of advanced/terminal cancer patients accurately understood their prognosis (49.1%; 95% confidence interval: 42.7%-55.5%; range: 5.4%-85.7%). Accurate prognostic awareness was independent of service received and publication year, but highest in Australia, followed by East Asia, North America, and southern Europe and the United Kingdom (67.7%, 60.7%, 52.8%, and 36.0%, respectively; p = 0.019). Accurate prognostic awareness was higher by clinician assessment than by patient report (63.2% vs 44.5%, p < 0.001). CONCLUSION: Less than half of advanced/terminal cancer patients accurately understood their prognosis, with significant variations by region and assessment method. Healthcare professionals should thoroughly assess advanced/terminal cancer patients' preferences for prognostic information and engage them in prognostic discussion early in the cancer trajectory, thus facilitating their accurate prognostic awareness and the quality of end-of-life care decision-making.
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Tomada de Decisões , Neoplasias/enfermagem , Neoplasias/psicologia , Preferência do Paciente/psicologia , Assistência Terminal/psicologia , Doente Terminal/psicologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Austrália , Europa (Continente) , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Regressão , Reino UnidoRESUMO
AIMS AND OBJECTIVES: To synthesise concepts of distinct depressive-symptom trajectories in published studies by establishing a measurable standard and estimate the prevalence of recategorised trajectories for bereaved families of chronically ill patients. BACKGROUND: Grieving is a dynamic/individualised process. In studies treating depressive-symptom trajectories as heterogeneous, different criteria were used to identify distinct trajectories, resulting in inconsistent findings. DESIGN: A systematic review of research guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. METHODS: Five databases were systematically searched since each one's launch through June 2015. Two reviewers independently extracted data and assessed study quality using the qualsyst evaluation tool. Distinct depressive-symptom trajectories were narratively synthesised based on depressive-symptom level, duration and improvement over time. The prevalence of recategorised depressive-symptom trajectories was recalculated from published data. RESULTS: We identified six studies, published in 1994-2012, that followed 56-301 bereaved families from eight months to five years. We synthesised five new distinct trajectories (prevalence in synthesised sample): 'endurance' (54·2%), 'resilience' (8·8%), 'transient reaction' (7·7%), 'chronic grief' (19·4%) and 'chronic depression' (9·9%). The 'endurance' group experienced low depressive symptoms throughout the bereavement process. The 'resilience' group had severe depressive symptoms when they first transitioned into bereavement, but quickly recovered. The 'transient reaction' group's distress lasted 7-12 months postbereavement, gradually returning to prebereavement levels. After bereavement, the chronic grief and depression groups experienced prolonged periods of depressive symptoms, which improved gradually only in the 'chronic grief' group. CONCLUSIONS: Most bereaved families endured their grief and adjusted, returning to prebereavement depressive-symptom levels within one year postloss (represented by our synthesised 'endurance', 'resilience' and 'transient reaction' groups), with only 9·9% suffering 'chronic depression'. RELEVANCE TO CLINICAL PRACTICE: Guided by the synthesised distinct trajectories of depressive symptoms, clinicians should identify bereaved families' depressive-symptom trajectories and provide suitable interventions to facilitate adjustment of those with chronic depressive symptoms.
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Doença Crônica , Depressão/epidemiologia , Progressão da Doença , Família/psicologia , Pesar , Depressão/diagnóstico , Transtorno Depressivo/diagnóstico , Transtorno Depressivo/epidemiologia , Feminino , Humanos , Masculino , Prevalência , Pesquisa Qualitativa , Resiliência Psicológica , Fatores de TempoRESUMO
BACKGROUND: A significant minority of bereaved caregivers experience prolonged grief. However, few longitudinal studies have examined prolonged grief, especially in an Asian context. AIM: We explored longitudinal changes and factors predicting prolonged grief in bereaved caregivers of terminally ill Taiwanese cancer patients. DESIGN: Observational, prospective, and longitudinal. Prolonged grief symptoms were measured with the PG-13 at 6, 13, 18, and 24 months postloss. SETTING/PARTICIPANTS: A convenience sample of 493 caregivers (83.3% participation rate) of terminally ill cancer patients was recruited from a medical center in Taiwan. RESULTS: The prevalence of prolonged grief decreased significantly over time from the patient's death (7.73%, 1.80%, 2.49%, and 1.85% at 6, 13, 18, and 24 months postloss, respectively, p < 0.05 at all times in reference to 6 months postloss). Caregivers' likelihood of prolonged grief was significantly higher if they had severe preloss depressive symptoms, negatively perceived their relative's dying situation, and were poorly prepared for the patient's death. However, the likelihood of prolonged grief decreased significantly with greater perceived concurrent social support and subjective caregiving burden right before the patient's death. CONCLUSION: Prolonged grief in bereavement diminished over time and was predicted by modifiable factors before, during, and after bereavement. To facilitate bereavement adjustment and avoid prolonged grief, healthcare professionals should develop and provide at-risk caregivers with effective interventions starting when patients are still alive to improve their dying experience, to facilitate preparedness for the patient's forthcoming death, to alleviate caregivers' preloss depressive symptoms, and to enhance their perceived postloss social support.
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Cuidadores/psicologia , Morte , Pesar , Neoplasias , Doente Terminal , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Inquéritos e Questionários , Taiwan , Adulto JovemRESUMO
CONTEXT: Postloss depressive symptom trajectories are heterogeneous and predicted by preloss psychosocial resources, but this evidence was from one old study on caregivers of patients with terminal cancer for whom these issues are highly relevant. OBJECTIVES: To identify depressive symptom trajectories among cancer patients' bereaved caregivers and examine if they are predicted by preloss psychosocial resources while considering caregiving burden. METHODS: Preloss psychosocial resources (sense of coherence and social support) were measured among 282 caregivers. Depressive symptoms were measured by the Center for Epidemiological Studies-Depression scale at one, three, six, 13, 18, and 24 months after loss (Center for Epidemiological Studies-Depression scores ≥16 indicate severe depressive symptoms). Distinct depressive symptom trajectories and their predictors were identified by latent-class growth analysis. RESULTS: We identified five depressive symptom trajectories (prevalence): endurance (47.2%), resilience (16.7%), transient reaction (20.2%), prolonged symptomatic (11.7%), and chronically distressed (4.2%). Over two years after loss, the endurance group never experienced severe depressive symptoms. Severe depressive symptoms lasted six, seven to 12, and 18 months for the resilience, transient-reaction, and prolonged-symptomatic groups, respectively. The chronically distressed group's severe depressive symptoms persisted. The endurance and chronically distressed groups had the best and weakest psychological resources, respectively. Endurance-group caregivers perceived the greatest social support, whereas the resilience and transient-reaction groups had higher social support than the prolonged-symptomatic group. CONCLUSIONS: Most (84.1%) caregivers' depressive symptoms subsided within one year after loss. Preloss psychosocial resources predicted depressive symptom trajectories for bereaved caregivers. Health care professionals can help caregivers adjust their bereavement by providing support to enhance their sense of coherence and encouraging social contacts while they are providing end-of-life care.
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Cuidadores/psicologia , Depressão/psicologia , Doente Terminal , Adulto , Luto , Depressão/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Resiliência Psicológica , Apoio SocialRESUMO
Visibility trends on the island of Taiwan were investigated employing visibility and meteorological (1961-2003), and air pollutant (1994-2003) data from one highly urbanized center (Taipei), one highly industrialized center (Kaohsiung), and two rural centers (Hualien and Taitung). Average annual visibility (1961-2003) was significantly higher at the rural centers. Unlike at the other centers, visibility in Taipei improved between 1992 (6.6 km) and 2003 (9.9 km), and this can be linked to the construction and expansion of a mass transit rail system in Taipei, the use of which has helped reduce emissions of traffic related air pollutants, particles, and NO2. This has left Kaohsiung with the lowest annual visibility since 1994, despite its 1961-2003 average being superior to that of Taipei. Precipitation lowers visibility, as demonstrated by the all-centers correlation coefficient for visibility and precipitation of -0.92. Hence, frequency of precipitation is one of the factors contributing to the average annual visibility number. The poorest air quality category ('episode'), most commonly experienced in Taipei and Kaohsiung, was characterized by relatively high concentrations of PM10 and NOx at those centers, with comparatively high atmospheric pressure and comparatively low visibility and wind speed. Excepting O3, pollutant concentrations were slightly higher during weekdays, although there was no consistent, significant difference in weekday-weekend visibility. Principal component analysis demonstrated that visibility was markedly reduced in Taipei, Kaohsiung, and Hualien by increased vehicular emissions, road traffic dust, and industrial activity, but not in Taitung, where visibility was as a result superior to that at the other centers and degradation in visibility was likely a response to long-range transport of pollutants rather than local sources. Optimal empirical regression models indicated a negative impact on visibility for each of PM10, SO2 and NO2, particularly so for PM10, and validity of these models for Taipei, Kaohsiung, and Hualien was confirmed by correlation coefficients of simulated and observed average visibility of 0.63-0.72 for daily visibility and 0.85-0.88 for monthly visibility. For Taitung these figures were only 0.46 and 0.50, respectively, indicating that simulations for Taitung should include long-range transport as a pollutant source.
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Poluição do Ar/análise , Ar/análise , Cidades , Indústrias , Material Particulado/análise , População Rural , Monitoramento Ambiental , TaiwanRESUMO
The effects of four essential oils (rosemary, ylang, lilacin, and peppermint oils), and three plant oils (jojoba oil, corn germ oil, and olive oil) on the permeation of aminophylline were studied using human skin. The permeation effects of these oils were compared with those of three chemical penetration enhancers. Although all oils enhanced the permeation of aminophylline, their effects were less than that of ethanol. Jojoba oil was found to be the most active, causing about a 32% peak height decrease of N-H bending absorbances in comparison with the control, while peppermint, lilacin, rosemary, and ylang oils caused 28%, 24%, 18%, and 12% peak height decreases, respectively. Microemulsions containing 10% jojoba oil and 30% corn germ oil were found to be superior vehicles for the percutaneous absorption of aminophylline. Comparision with results obtained from high-performance liquid chromatography shows good agreement.
Assuntos
Aminofilina/farmacologia , Ceratolíticos/farmacologia , Fitoterapia , Óleos de Plantas/farmacologia , Plantas Medicinais , Absorção Cutânea/efeitos dos fármacos , Administração Cutânea , Adulto , Aminofilina/administração & dosagem , Aminofilina/química , Química Farmacêutica , Humanos , Ceratolíticos/administração & dosagem , Ceratolíticos/química , Veículos Farmacêuticos/administração & dosagem , Veículos Farmacêuticos/química , Veículos Farmacêuticos/farmacologia , Óleos de Plantas/administração & dosagem , Óleos de Plantas/química , Ceras/química , Ceras/farmacologiaRESUMO
This study investigated allergenic terpenol compounds in incense powder and smoke. The powder of two Thai brands contained higher concentrations of terpenols up to 6.15 times higher than those of two Taiwanese brands. Consequently, Thai incense makers face a higher potential risk of contact dermatitis than Taiwanese incense makers do. d-Limonene was the primary terpenol compound in the powder of Thai B (64.0%) and Thai Y (31.5%), sold in Thailand. By contrast, anisyl alcohol was the primary terpenol compound in the powder of LST (40.3%) and SC (37.7%), sold in Taiwan. After the four brands of incense were ignited, their mean PM2.5 emission factor was 18.02±6.20mgg-1 incense. The PM2.5 mass emission factors of the Taiwanese brands were far higher than those of the Thai brands, and so were the PM2.5 terpenol emission factors, showing that the smokes of the Taiwanese incense were potentially more allergenic than those of the Thai incense. Geraniol, the most allergenic terpenol compound, was 2.8%-10.7% of total terpenol compounds in the powder of the four brands, yet was the main contributor to PM2.5, constituting 66.3%-83.5% of terpenol compounds in the smokes of the four brands. Furthermore, geraniol exhibited an IP ratio, defined as the incense/powder (IP) ratio of terpenol-related species, >1 in all four brands, and >5 in the Taiwanese brands, suggesting a greater health risk with the smoke from the Taiwanese incense. The IP ratios of other terpenol species were all <1, indicating decomposition through combustion. Additionally, the light/darkroom ratios of the terpenol species were >1, meaning that the generation of PM2.5 terpenol compounds was potentially enhanced by indoor lighting.
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Poluição do Ar em Ambientes Fechados/análise , Alérgenos/análise , Fumaça/análise , Poluentes Atmosféricos , Tamanho da Partícula , Material Particulado/análise , Taiwan , TailândiaRESUMO
BACKGROUND: Bereaved families endure tremendous grief. However, few studies have longitudinally investigated caregivers' bereavement grief for more than one year postloss and none is from family-oriented Asian countries. OBJECTIVES: We explored longitudinal changes in and modifiable predictors of severe depressive symptoms for Taiwanese family caregivers of terminally ill cancer patients over the first two years postloss. DESIGN: For this descriptive, longitudinal study, severe depressive symptoms (Center for Epidemiological Studies Depression Scale score ≥16) were measured 1, 3, 6, 13, 18, and 24 months postloss. To identify modifiable factors (preloss depressive symptom levels, subjective caregiving burden, objective caregiving load, preparedness for patient death, and postloss social support) associated with postloss severe depressive symptoms, we used multivariate logistic regression modeling with the generalized estimating equation. SETTING/PARTICIPANTS: Bereaved caregivers (N = 285) were recruited by convenience from a medical center in northern Taiwan. RESULTS: Bereaved family caregivers' prevalence of severe depressive symptoms peaked one month postloss (73.3%) and significantly decreased to 15.2% 24 months after the patient's death. After adjusting for confounders, bereaved caregivers were more likely to have severe depressive symptoms if they had heavy objective caregiving load and higher preloss depressive symptom levels. However, their likelihood of severe depressive symptoms was buffered by being better prepared for the patients' death and having greater social support. CONCLUSIONS: Bereaved family caregivers' severe depressive symptoms decreased significantly over the first two years postloss. Healthcare professionals should appropriately assess at-risk bereaved caregivers when patients are still alive and provide effective interventions to facilitate caregivers' return to normal life.
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Luto , Cuidadores/psicologia , Transtorno Depressivo/epidemiologia , Família/psicologia , Pesar , Doente Terminal/psicologia , Adulto , Idoso , Povo Asiático/psicologia , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Prevalência , Taiwan , Fatores de Tempo , Adulto JovemRESUMO
The Mid-Autumn Festival (MAF), or Moon Festival, is a harvest festival in Taiwan, celebrated by families across the island with evening barbecues outside. This study investigated the potential impact of these activities on the air quality in Tainan, a city in southern Taiwan. Fine particulate matter (PM2.5) was examined in the period leading up to the MAF (pre-MAF), during the Festival (MAF), after the Festival (post-MAF), and in the period after this (a period of moderate air quality: MAQ). Gaseous pollutants in PM2.5 were, from highest to lowest mean concentration, NH3, SO2, HCl, HNO3, HNO2, and oxalic acid, while inorganic salts were mainly in the form of the photochemical products SO4(2-), NH4(+), and NO3(-). These inorganic salts accounted for 37.6%-44.5% of the PM2.5 mass concentration, while a further 26.3%-42.8% of the PM2.5 mass was total carbon (TC). TC was mostly composed of organic carbon (OC) produced by photochemical reactions. Of this, 9.8%-14.9% was carboxylates, of which oxalate was the most abundant compound, accounting for 22.8%-31.9% of carboxylates. The presence of phthalates in the PM2.5 indicated emissions from the plastics industry. Although a noticeable amount of aerosol was produced by festival activities and burning of softwood and hardwood, onshore air currents during the festival prevented potential high aerosol loading. During the moderate air quality period following post-MAF, the concentration of total carbohydrates was 1.44-2.64 times the amount during the festival. Levoglucosan and myo-inositol accounted for 81.7%-89.6% of the total carbohydrate concentration. The average Levo/Manno ratio was 18.64 ± 5.24. The concentration of levoglucosan was closely related to that of PO4(3-), erythritol, and galactose. Backward trajectories indicated that biomass burning in China affected the air quality of Tainan City.
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Poluentes Atmosféricos/análise , Monitoramento Ambiental , Férias e Feriados , Material Particulado/análise , Cidades , Estações do Ano , TaiwanRESUMO
The purpose of this study was to develop and test a diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) method, a fast and non-destructive method without extraction, and compare it with the standard gas chromatography (GC) method currently used. A micro-orifice uniform deposit impactor (MOUDI) was used to sample all the size distributions of the aerosol particles of essential oils to investigate the relation between size distributions and the indoor concentration distributions of ylang essential oils. Correlation coefficients for DRIFTS and GC were 0.9904, 0.9910, 0.9913, and 0.9983 for eugenol, isoeugenol, methyl ether, and eugenyl acetate, respectively. The results showed that the concentrations of the four eugenol derivatives of smoke were approximately three times higher than those of mist. Additionally, the major size distributions of aerosol were 0.19 microm and 1.8 microm for the smoke and mist methods, respectively. Because these two methods produce similar results, DRIFTS is a practical method for assessing these fragrances in aerosols.
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Aerossóis/química , Cananga/química , Cromatografia Gasosa/métodos , Eugenol/análogos & derivados , Perfumes/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Eugenol/análise , Óleos Voláteis/química , Tamanho da PartículaRESUMO
This paper describes a novel gradient elution ion chromatographic method using a Dionex AS11 system for the determination of low molecular weight dicarboxylic acids (low-M(w) DCAs) in background atmospheric aerosol. Interference with the oxalic acid peak from sulfate in background PM(2.5) aerosol, 15.8 times the oxalic acid concentration, was remedied by removing sulfate using a barium cartridge, whilst interference with the malonic acid peak from carbonate was reduced by using a carbonate removal device. An alternative remedy to sulfate interference was use of an AS14 system using isocratic eluent, and this produced good resolution of oxalic acid from a high sulfate peak. In both the AS11 and the AS14 system, linear correlation coefficients were at all times >0.9990 with excellent linear range, the recoveries ranged from 92.8 to 106%, with relative standard deviation of 3.67-6.30%, whilst method detection limits (MDLs) ranged from 0.36microgL(-1) for malic acid to 3.87microgL(-1) for maleic acid. These data indicate that the analytical methods developed herein produce excellent separation efficiency and good determination of low-M(w) DCAs with satisfactory accuracy, recoveries, and MDLs. Samples left at room temperature (20 degrees C) for 300min in a simulation of the 'waiting time' involved in the proposed IC analysis decayed to between 86% (oxalic acid) and 39% (succinic and malonic acids) of their original concentration, whilst at 4 degrees C concentrations remained at 96-101% of original, indicating that maintaining samples at a low temperature prior to injection into the IC analyzer is vital for obtaining accurate results when analyzing low-M(w) DCAs. Oxalic acid was found to be the most prevalent low-M(w) DCA in background aerosol, comprising 57% of the total low-M(w) DCAs and 0.959% of the PM(2.5) aerosol mass, followed by succinic acid and malonic acid.