Jorge Leiva-González

Hydrothermal carbonization (HTC) is an emerging waste-to-energy technology that offers a sustainable approach to biomass conversion. This research offers a comprehensive assessment of HTC through Life Cycle Assessment (LCA) and multi-objective optimization. Environmental consequences were evaluated using the TRACI 2.1 technique across essential categories: global warming potential (GWP), acidification, eutrophication, smog production, and ecotoxicity. Steam generation was recognized as the principal contributor to environmental burdens. Multi-objective optimization, executed by the Non-dominated Sorting Genetic Algorithm II (NSGA-II) and Pareto curve analysis, aimed to reconcile operational costs with environmental impact. The ideal solution attained a cost of 167.05 USD/h and an environmental impact of 179 kg CO₂-eq./h, exemplifying a proficient balance between economic and ecological objectives. A comparative review of current waste management technologies reveals that HTC produces fewer greenhouse gas emissions, highlighting potential areas for enhancement, particularly in energy efficiency and liquid effluent treatment. The research underscores HTC’s viability as a scalable and pragmatic waste-to-energy technology. This study presents a comprehensive decision-support framework for sustainable process design, integrating Life Cycle Assessment with optimization, specifically tailored to lignocellulosic biomass sources such as Pinus radiata sawdust, rapeseed bran, and olive pomace. These findings enhance the progress of cleaner energy technologies and facilitate informed decision-making in the creation of environmentally and economically sustainable biomass conversion systems.

This study estimated the relative risks (RRs) of respiratory and cardiovascular mortality and morbidity due to short-term ozone exposure in 13 polluted communes across Chile’s Santiago Metropolitan and Valparaíso regions. Data on daily ozone, meteorology, and pollutants were sourced from the National Air Quality Information System (NAQIS), while health outcomes (mortality, hospital admissions, and emergency visits) were obtained from the Department of Health Statistics. A Poisson regression model, adjusted for trends, meteorology, day-of-week effects, and pollutants, quantified RRs for a 10 ppb ozone increase, ranging from 1.004 to 1.198 (95% CI). The highest risks were in Santiago’s Eastern zone (cerebrovascular, RR 1.171, 95% CI: 1.018–1.347), Western zone (cardiovascular, RR 1.198, 95% CI: 1.049–1.369), and Valparaíso’s Viña del Mar (ischemic heart disease, RR 1.127, 95% CI: 1.017–1.248). The 5–64-year age group was most affected, particularly in terms of emergency visits. Reducing ozone to the WHO guideline (100 µg/m³) could avoid 837,498 cases in Santiago and 17,992 in Valparaíso annually, resulting in economic savings of $7,439,930,640 and $1,044,568,800, respectively. These results highlight the need for stricter air quality policies to reduce ozone-related health burdens.

The 2023–2024 blackouts in Quito, Ecuador, led to severe air quality deterioration, primarily driven by diesel generator use and increased vehicular traffic. This study analyzed data from seven urban and peri-urban monitoring stations, applying meteorologically normalized data and machine learning models (Boosted Regression Trees and Random Forests) to isolate the direct impact of blackouts on pollutant concentrations. The results revealed that PM₁₀ increased by up to 45% and PM_2.5 by 30%, frequently exceeding regulatory limits, particularly in industrial and residential zones. SO₂ exhibited the most extreme rise, surging by 390%, with peak values reaching 500 µg/m³ in areas heavily reliant on high-sulfur diesel generators. The NO₂ concentrations exceeded 200 µg/m³ in high-traffic areas, while O₃ showed dual behavior, decreasing in urban cores due to titration effects but increasing by 15% in suburban valleys, driven by photochemical interactions. A comparison between 2023 and 2024 blackouts highlighted worsening pollution trends, with longer (8–12 h) outages in 2024 causing severe environmental impacts. The findings demonstrate that blackouts significantly worsen air quality, posing critical public health risks. This study underscores the urgent need for policy interventions to mitigate the environmental impact of energy disruptions. Key recommendations include stricter fuel quality standards, diesel generator emission controls, and an accelerated transition to renewable energy. These results provide scientific evidence for future environmental regulations, supporting sustainable air quality management strategies to minimize future energy crises’ health and ecological consequences.

Climate change is a global issue with significant implications for ecosystems, societies, and socioeconomic structures. It is primarily caused by increased fossil fuel consumption, leading to rising global temperatures and shifting weather patterns. The Southern Hemisphere is experiencing significant temperature fluctuations and climate-induced changes, affecting regional economies, ecosystems, and communities. This research examines the impact of climate change on the southern hemisphere from 1880 to the present day, focusing on temperature variations and the relationship between temperature changes and carbon dioxide emissions. The data was sourced from NASA's database and the Mauna Loa Observatory in Hawaii. The study used Stata software to analyze the data, revealing significant summertime temperature fluctuations. The results show the seasonal variation of CO₂; the ascending curve indicates that the increase in the concentration of CO₂ in the atmosphere does not stop. The study concluded that there is a constant increase in average temperatures in the southern hemisphere, depending on the increasing CO₂ levels in the atmosphere