Search

A systematic review and meta-analysis on cognitive tests for mild cognitive impairment and Alzheimer's disease in patients with Down syndrome.

Among the hazards posed by volcanoes are the emissions of gases and particles that can affect air quality and damage agriculture and infrastructure. A recent intense episode of volcanic degassing associated with severe impacts on air quality accompanied the 2018 lower East Rift Zone (LERZ) eruption of Kīlauea volcano, Hawai'i. This resulted in a major increase in gas emission rates with respect to usual emission values for this volcano, along with a shift in the source of the dominant plume to a populated area on the lower flank of the volcano. This led to reduced air quality in downwind communities. We analyse open-access data from the permanent air quality monitoring networks operated by the Hawai'i Department of Health (HDOH) and National Park Service (NPS), and report on measurements of atmospheric sulfur dioxide (SO2) between 2007 and 2018 and PM2.5 (aerosol particulate matter with diameter

Volcano monitoring seeks to better understand volcanic systems, in order to be able to predict their activity. The monitoring techniques include seismic, deformation, gas, hydrologic, and visual monitoring, among others. Gas monitoring is important, among other reasons, because it provides information about the dynamics and evolution of magmatic and hydrothermal systems. Measurements can be conducted directly or by remote sensing methods (ground-based or satellite-based). Here we focus on the main ground-based remote sensing methods, which are currently used at volcanoes. These include the correlation spectrometer (COSPEC), the DOAS, the ultraviolet camera, and the Fourier Transform Infrared spectrometer (FTIR). Each technique has its advantages and disadvantages, and to understand them, we describe here the general aspects of each one, including methods to conduct the measurements, the sources of error, and some examples of case studies. El monitoreo volcánico busca entender mejor los sistemas volcánicos, para poder realizar predicciones de su actividad. Las técnicas de monitoreo incluyen el sísmico, de deformación, de gases, hidrológico, y visual, entre otros. El monitoreo de gases es importante, entre otras razones, porque nos provee información sobre la dinámica y evolución de los sistemas magmáticos e hidrotermales. Las medidas se pueden hacer de forma directa o por métodos de percepción remota (en superficie o satelital). Aquí nos enfocamos en los principales métodos de percepción remota en superficie, que se usan actualmente en volcanes. Estos incluyen el espectrómetro de correlación (COSPEC), el DOAS, la cámara ultravioleta y el espectrómetro infrarrojo de transformada de Fourier (FTIR). Cada una de estas técnicas tiene ventajas y desventajas, y para entenderlas, aquí se describen los aspectos generales de cada una, incluyendo métodos para conducir las mediciones, las fuentes de error y algunos ejemplos de estudios hechos.

Recent advances in volcanic gas sensing technology make possible detailed investigations of the behavior of boundary layer gas plumes. An intensive survey of SO2 flux during two month-long campaigns revealed an apparent decrease of 30-50% downwind of Masaya volcano, Nicaragua. Dry deposition of S and aerosol conversion cannot account for such losses. Local topography modifies regional trade winds, causing plume acceleration. The resulting along-axis dilution of the plume leads to underestimates of total SO2 emissions. This apparent depletion can be accounted for by accurate determination of plume speed at the location of each SO2 flux measurement. Interaction of acidic plumes with elevated topography results in widespread vegetation damage downwind, which may be characterized by a multi-parameter approach incorporating ground-based datasets and Landsat NDVIs at Masaya and other volcanic systems. A thorough understanding of plume behavior is essential for accurate evaluation of volcanic SO2 output and resultant environmental impacts.

Long-lived basaltic volcanic eruptions are a globally important source of environmentally reactive, volatile metal pollutant elements such as selenium, cadmium and lead. The 2018 eruption of Kīlauea, Hawai‘i produced exceptionally high discharge of metal pollutants, and was an unprecedented opportunity to track them from vent to deposition. Here we show, through geochemical sampling of the plume that volatile metal pollutants were depleted in the plume up to 100 times faster than refractory species, such as magnesium and iron. We propose that this rapid wet deposition of complexes containing reactive and potentially toxic volatile metal pollutants may disproportionately impact localised areas close to the vent. We infer that the relationship between volatility and solubility is an important control on the atmospheric behaviour of elements. We suggest that assessment of hazards from volcanic emissions should account for heterogeneous plume depletion of metal pollutants.