Black carbon and particulate matter concentrations amid central Chile's extreme wildfires.

The increase in the frequency and severity of global wildfires has been largely influenced by climate change and land use changes. From February 2 to 6, 2024, central Chile experienced its most devastating wildland-urban interface wildfire in history, severely impacting the Valparaíso region. This catastrophic event, which led to extensive forest destruction, the loss of thousands of homes, and over a hundred human fatalities, directly impacted the area surrounding the campus of Federico Santa María Technical University. In that period, an air quality monitoring campaign was set up on the campus to measure black carbon (BC) and particulate matter (PM) during the wildfire season. The monitoring station was located directly within the smoke plume, allowing for the collection of unprecedented air quality data. Extremely high concentrations of BC at 880 nm were reported during the wildfires, with a daily mean (±σ) of 14.83 ± 19.52 µg m-3. Peak concentrations measured at 880 nm and 375 nm reached 812.89 µg m-3 and 1561.24 µg m-3, respectively. The maximum daily mean BC concentrations at these wavelengths were 55 and 99 times higher, respectively, compared to the pre-event period. The mean Ångström absorbing coefficient during the event was 1.66, indicating biomass burning as the primary BC source, while the maximum BC/PM2.5 ratio (at 375 nm) reached 57 %. From February 2 to 5, 2024, PM concentrations exceeded the Chilean air quality standard by 82 % and 198 % for coarse and fine particles, respectively. These levels are 4.7 and 6.0 times higher than the World Health Organization's recommendations. These elevated concentrations persisted for up to three days after the fire was extinguished. This study provides unique evidence of the rapid deterioration of regional air quality during a wildfire event using in situ measurements, serving as a stark reminder of the far-reaching consequences of a warming climate.

Social determinants of health associated with severity and mortality in patients with COVID-19.

INTRODUCTION: Historically, pandemics have resulted in higher mortality rates in the most vulnerable populations. Social determinants of health (SDH) have been associated with people morbidity and mortality at different levels. OBJECTIVE: To determine the relationship between SDH and COVID-19 severity and mortality. METHODS: Retrospective study, where data from patients with COVID-19 were collected at a public hospital in Chile. Sociodemographic variables related to structural SDH were classified according to the following categories: gender, age (< 65 years, ≥ 65 years), secondary education (completed or not), work status (active, inactive) and income (< USD 320, ≥ USD 320). RESULTS: A total of 1,012 laboratory-confirmed COVID-19 cases were included. Average age was 64.2 ± 17.5 years. Mortality of the entire sample was 14.5 %. Age, level of education, unemployment and income had a strong association with mortality (p < 0.001). CONCLUSIONS: The findings reinforce the idea that SDH should be considered a public health priority, which is why political efforts should focus on reducing health inequalities for future generations.

INTRODUCCIÓN: Históricamente, las pandemias han tenido como resultado tasas de mortalidad más altas en las poblaciones más vulnerables. Los determinantes sociales de la salud (DSS) se han asociado a la morbimortalidad de las personas en diferentes niveles. OBJETIVO: Determinar la relación entre los DSS, la severidad de COVID-19 y la mortalidad por esta enfermedad. MÉTODOS: Estudio retrospectivo en el que se recolectaron datos de pacientes con COVID-19 en un hospital público de Chile. Las variables sociodemográficas relacionadas con los DSS estructurales se clasificaron según las siguientes categorías: sexo, edad (< 65 años, ≥ 65 años), educación secundaria (completada o no), condición de trabajo (activo, inactivo) e ingreso económico (< USD 320, ≥ USD 320). RESULTADOS: Fueron incluidos 1012 casos con COVID-19 confirmados por laboratorio. La edad promedio fue de 64.2 ± 17.5 años. La mortalidad de la muestra total fue de 14.5 %. La edad, nivel educativo, desempleo e ingresos tuvieron fuerte asociación con la mortalidad (p < 0.001). CONCLUSIONES: Los hallazgos refuerzan la idea de que los DSS deben considerarse una prioridad de salud pública, por lo que los esfuerzos políticos deben centrarse en reducir las desigualdades en salud para las generaciones futuras.

Leaf Thermal and Chemical Properties as Natural Drivers of Plant Flammability of Native and Exotic Tree Species of the Valparaíso Region, Chile.

Forest fires are one of the main environmental threats in Chile. Fires in this Mediterranean climate region frequently affect native forests and exotic plantations, including in several cases urban and rural settlements. Considering the scarcity of information regarding the fire response dynamics of tree species that are frequently affected by fires, this study aims to establish a flammability classification according to the evolution of the fire initiation risk presented by the most affected forest species in the Valparaíso region. Three exotic species, Eucalyptus globulus, Pinus radiata, and Acacia dealbata, and two native species, Cryptocarya alba and Quillaja saponaria, were studied. Flammability assays indicate that E. globulus, A. dealbata, and C. alba are extremely flammable, whereas P. radiata and Q. saponaria are flammable. Furthermore, E. globulus and A. dealbata have the highest heating values while Q. saponaria has the lowest values. The extreme flammability of E. globulus, A. dealbata, and C. alba indicates a high susceptibility to ignite. Furthermore, the high heat of combustion of E. globulus and A. dealbata can be associated with a high energy release, increasing the risk of fires spreading. In contrast, Q. saponaria has the lowest predisposition to ignite and capacity to release heat. Accordingly, this work shows that all studied tree species contain organic metabolites that are potentially flammable (sesquiterpenes, aliphatic hydrocarbons, alcohol esters, ketones, diterpenes, and triterpenes) and can be considered as drivers of flammability in vegetation. Finally, these preliminary results will aid in the construction of more resilient landscapes in the near future.

Determinantes sociales de la salud asociados a la severidad y mortalidad en pacientes con COVID-19 / Social determinants of health associated with severity and mortality in patients with COVID-19

Resumen Introducción: Históricamente, las pandemias han tenido como resultado tasas de mortalidad más altas en las poblaciones más vulnerables. Los determinantes sociales de la salud (DSS) se han asociado a la morbimortalidad de las personas en diferentes niveles. Objetivo: Determinar la relación entre los DSS, la severidad de COVID-19 y la mortalidad por esta enfermedad. Métodos: Estudio retrospectivo en el que se recolectaron datos de pacientes con COVID-19 en un hospital público de Chile. Las variables sociodemográficas relacionadas con los DSS estructurales se clasificaron según las siguientes categorías: sexo, edad (< 65 años, ≥ 65 años), educación secundaria (completada o no), condición de trabajo (activo, inactivo) e ingreso económico (< USD 320, ≥ USD 320). Resultados: Fueron incluidos 1012 casos con COVID-19 confirmados por laboratorio. La edad promedio fue de 64.2 ± 17.5 años. La mortalidad de la muestra total fue de 14.5 %. La edad, nivel educativo, desempleo e ingresos tuvieron fuerte asociación con la mortalidad (p < 0.001). Conclusiones: Los hallazgos refuerzan la idea de que los DSS deben considerarse una prioridad de salud pública, por lo que los esfuerzos políticos deben centrarse en reducir las desigualdades en salud para las generaciones futuras.

Abstract Introduction: Historically, pandemics have resulted in higher mortality rates in the most vulnerable populations. Social determinants of health (SDH) have been associated with people morbidity and mortality at different levels. Objective: To determine the relationship between SDH and COVID-19 severity and mortality. Methods: Retrospective study, where data from patients with COVID-19 were collected at a public hospital in Chile. Sociodemographic variables related to structural SDH were classified according to the following categories: gender, age (< 65 years, ≥ 65 years), secondary education (completed or not), work status (active, inactive) and income (< USD 320, ≥ USD 320). Results: A total of 1,012 laboratory-confirmed COVID-19 cases were included. Average age was 64.2 ± 17.5 years. Mortality of the entire sample was 14.5 %. Age, level of education, unemployment and income had a strong association with mortality (p < 0.001). Conclusions: The findings reinforce the idea that SDH should be considered a public health priority, which is why political efforts should focus on reducing health inequalities for future generations.