A Satellite-based Assessment of Trans-Pacific Transport of Pollution Aerosol

It has been well documented that pollution aerosol and dust from East Asia can transport across the North Pacific basin, reaching North America and beyond. Such intercontinental transport extends the impact of aerosols for climate change, air quality, atmospheric chemistry, and ocean biology from local and regional scales to hemispheric and global scales. Long term, measurement-based studies are necessary to adequately assess the implications of these wider impacts. A satellite-based assessment can augment intensive field campaigns by expanding temporal and spatial scales and also serve as constraints for model simulations. Satellite imagers have been providing a wealth of evidence for the intercontinental transport of aerosols for more than two decades. Quantitative assessments, however, became feasible only recently as a result of the much improved measurement accuracy and enhanced new capabilities of satellite sensors. In this study, we generated a 4-year (2002 to 2005) climatology of optical depth for pollution aerosol (defined as a mixture of aerosols from urbanlindustrial pollution and biomass burning in this study) over the North Pacific from MODerate resolution Imaging Spectro-radiometer (MODIS) observations of fine- and coarse-mode aerosol optical depths. The pollution aerosol mass loading and fluxes were then calculated using measurements of the dependence of aerosol mass extinction efficiency on relative humidity and of aerosol vertical distributions from field campaigns and available satellite observations in the region. We estimated that about 18 Tg/year pollution aerosol is exported from East Asia to the northwestern Pacific Ocean, of which about 25% reaches the west coast of North America. The pollution fluxes are largest in spring and smallest in summer. For the period we have examined the strongest export and import of pollution particulates occurred in 2003, due largely to record intense Eurasia wildfires in spring and summer. The overall uncertainty of pollution fluxes is estimated at about 80%. A reduction of uncertainty can be achieved with a better characterization of pollution aerosol through integrating emerging A-Train measurements. Simulations by the Goddard Chemistry Aerosol Radiation and Transport (GOCART) and Global Modeling Initiative (GMI) models agree quite well with the satellite-based estimates of annual and latitudeintegrated fluxes, with larger model-satellite differences in latitudinal variations of fluxes

Gender Differences in Self-Reported Symptoms of Depression among Patients with Acute Coronary Syndrome

This study examined the prevalence of self-reported depressive symptoms and the self reported somatic depressive symptoms as measured by the Beck Depression Inventory-II (BDI-II) among patients hospitalized for acute coronary syndrome (ACS), and explored the impact of gender on both. A convenience sample of 789 adults (248 women and 541 men) was recruited for the study during hospital admission for ACS and participants were screened for self-reported depressive symptoms. BDI-II scores of ≥14 indicate a moderate level of depressive symptoms and this cut-off score was used to categorize patients into depressed and non-depressed groups. Pearson chi-square tests for independence (categorical variables) and t tests for independent samples (continuous variables) were used for gender comparisons. Results showed that depressive symptoms during ACS episodes were different between women and men. Women reported greater overall depressive symptoms (BDI-II mean = 11.89, S.D. = 9.68) than men (BDI-II mean = 9.00, S.D. = 7.93) (P < 0.000). Significantly more women (7.66%) were identified positive for somatic depressive symptoms (sleep and appetite disturbances and fatigue) than men (2.22%) (P = 0.0003). Findings support that there are gender differences in depressive symptoms experienced by patients hospitalized for ACS. Somatic symptoms of depression may be important indicators of depression especially among female ACS patients

Investigating arsenic contents in surface and drinking water by voltammetry and the method of standard additions

Testing water samples for arsenic (As) contamination has become an important water quality issue worldwide. Arsenic usually occurs in very small concentrations and a sensitive analytical method is needed. We present here a 1-day laboratory module developed to introduce Earth Sciences and/or Chemistry student undergraduates to key aspects of this topical issue. In this practical session, students were first introduced to the worldwide problems of arsenic contamination in groundwaters as a motivation of the experimental work. This latter consisted in the quantification of As levels in surface and drinking water at the trace level (nM - ppb) using the electroanalytical technique of anodic stripping voltammetry and the method of standard addition. Results were then discussed with respect to water quality guidelines and geology. The complexity of data interpretation in this exercise can be tailored to a range of abilities and subject areas suited to the students and the course