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A new methodology for source apportionment of gaseous industrial emissions
(2023) Jorquera, Héctor; Villalobos, Ana María; CEDEUS (Chile)
Air quality modeling (AQM) is often used to investigate gaseous pollution around industrial zones. However, this methodology requires accurate emission inventories, unbiased AQM algorithms and realistic boundary conditions. We introduce a new methodology for source apportionment of industrial gaseous emissions, which is based on a fuzzy clustering of ambient concentrations, along with a standard AQM approach. First, by applying fuzzy clustering, ambient concentration is expressed as a sum of non-negative contributions — each corresponding to a specific spatiotemporal pattern (STP); we denote this method as FUSTA (FUzzy SpatioTemporal Apportionment). Second, AQM of the major industrial emissions in the study zone generates another set of STP. By comparing both STP sets, all major source contributions resolved by FUSTA are identified, so a source apportionment is achieved. The uncertainty in FUSTA results may be estimated by comparing results for different numbers of clusters. We have applied FUSTA in an industrial zone in central Chile, obtaining the contributions from major sources of ambient SO2: a thermal power plant complex and a copper smelter, and other contributions from local and regional sources (outside the AQM domain). The methodology also identifies SO2 episodes associated to emissions from the copper smelter.
Air pollution and environmental epidemiological evidence in Chile: alerts for decision-makers and citizens
(2023) Cortés Arancibia, Sandra; CEDEUS (Chile)
Air pollution in Chile presents unique challenges, exacerbated by inequalities and geographical and climatic diversity. Current policies have not succeeded in aligning air quality with international and national standards, nor have they significantly mitigated public health impacts, despite being more advanced than those in other Latin American countries. The evidence on the health damages caused by air pollution is compelling, showing harmful acute and chronic effects across various life stages. Yet, current measures do not effectively reduce exposure to pollutants. The monitoring network, which reports data from stationary and mobile sources, does not always detect early fugitive emissions and is limited to regulated pollutants, leaving areas without adequate monitoring coverage and without management plans for critical episodes outside of autumn and winter and for a reduced number of pollutants. In the context of climate change, which increases the frequency of forest fires, Chile is experiencing a deterioration of air quality, highlighting the need to expand critical episode management beyond the current Air Pollution Prevention and/or Atmospheric Decontamination Plans. Integrated intersectoral plans need to be improved and extended to address the high exposure to pollutants, due to the large number of people exposed, and a broad population health risks, including quality of life. Decarbonisation by 2040 based on the Sustainable Development Goals is an important pillar of the strategy, but a public debate is needed to establish additional actions for addressing environmental injustice, improving equity and reducing current exposure to air pollutants.
Ambient particulate matter in Santiago, Chile : 1989-2018 : A tale of two size fractions
(2020) Jorquera, Héctor; CEDEUS (Chile)
Artificial intelligence in the new forms of environmental governance in the Chilean State: Towards an eco-algorithmic governance
(Wiley, 2023) Tironi, Martin; Lisboa, Diego Ignacio Rivera; CEDEUS (Chile)
One of the most popular fields of experimentation with technological solutions based on Artificial Intelligence (AI) and algorithmic systems is environmental studies, particularly as it relates to climate change. The promise of mitigating the impact of human activity on the environment through the introduction of sensor technologies has given way to a series of narratives around their role and capabilities. Focusing on the case of Environmental Intelligence, an initiative developed by the Chilean government's Superintendency for the Environment that incorporates AI into the monitoring process, we offer arguments regarding the articulation of an eco-algorithmic governmentality in which the environment is desingularized and reduced to a series of metrics associated with regulatory compliance. The operations that serve to prototype and give shape to the initiative created a series of tensions around the possibility of arriving at other forms of involvement in and understanding of the environment. This article shows how this eco-algorithmic governmentality conceptualizes the environment as an entity that can be optimized and rationalized, generating epistemic frictions with other logics of relationality and situated and terrestrial sensibility.
Challenges in determining soil moisture and evaporation fluxes using distributed temperature sensing methods
(2020) Lagos, M.; Serna, J. L.; Munoz, J. F.; Suárez Poch, Francisco Ignacio; CEDEUS (Chile)
Chilean institutional policies and multi-level agents: Challenges from the COVID-19 pandemic and carbon footprint
(2023) Bergamini Ladrón de Guevara, Kay Joaquín; Ojeda Leal, Carolina Grace; Gutiérrez, Patricia; Salazar Preece, Gonzalo; Curillán, Christian; CEDEUS (Chile)
As a result of the increasing number of multilateral agreements that Chile has signed, different sectors of consumption have become sources of emissions. In this context attempts to implement guidelines to address this issue have been made. Nevertheless, international policies such as sustainable development goals (SDG) 11–12 often generate dissonance in national and local administrations and have been approached by different instruments to reduce the effects of emissions, mostly focused on the private industrial sector. Methods: This article focuses on four of the most polluted cities in south-central Chile (Coronel, Temuco, Valdivia, and Osorno). Key agents (ministries, regional government, municipalities, and civil society) from three levels of policy development were selected at three scales (national, regional, and local) and interviewed considering three thematic axes: knowledge of carbon footprint areas (housing, heating, food, mobility, and energy), institutional governance, and adaptive changes due to COVID-19. Results: The results show that in Chile, there is a multiscale climate governance led by the Ministry of the Environment (national level), followed by the regional and local levels. Citizens are then left with few capacities, which is negatively viewed. In relation to the carbon footprint and COVID-19, it can be observed that the topic of energy was more addressed at the national and regional levels. Food and energy, followed by heating and then mobility were addressed at the communal level and in civil society. Discussion: Decision-making strategies and policies were discussed in this paper.
Coastal Wetlands: Ecosystems Affected by Urbanization?
(2020) Rojas Quezada, Carolina Alejandra; Novoa, Vanessa; Rojas, Octavio; Ahumada-Rudolph, Ramón; Sáez, Katia; Fierro, Pablo; CEDEUS (Chile)
Coastal wetlands are ecosystems that provide multiple benefits to human settlements; nonetheless, they are seriously threatened due to both a lack of planning instruments and human activities associated mainly with urban growth. An understanding of their functioning and status is crucial for their protection and conservation. Two wetlands with different degrees of urbanization, Rocuant-Andalién (highly urbanized) and Tubul-Raqui (with little urbanization), were analyzed using temperature, salinity, dissolved oxygen, pH, turbidity, granulometry, fecal coliform, and macroinvertebrate assemblage variables in summer and winter. In both wetlands marked seasonality in salinity, temperature and sediment texture classification, regulated by oceanic influence and changes in the freshwater budget, was observed. In the Rocuant-Andalién wetland, the increases in pH, dissolved oxygen, gravel percentage, and coliform concentration were statistically significant. Urbanization generated negative impacts on macroinvertebrate assemblage structure that inhabit the wetlands; greater richness and abundance (8.5 times greater) were recorded in the Tubul-Raqui wetland than in the more urbanized wetland. The multivariate statistical analysis reflects the alteration of these complex systems.
Coping with Natural Disasters and Urban Risk: An Approach to Urban Sustainability from Socio-Environmental Fragmentation and Urban Vulnerability Assessment
(Emerald Group Publishing Limited, 2014) Link, Felipe; Barth, Katrin; Harris, Jordan Michael; Irarrazaval Irarrazaval, Felipe; Valenzuela, Felipe; Welz, Juliane; William G. Holt; CEDEUS (Chile)
Purpose - Cities have been exposed to a variety of natural disasters such as flooding, extreme temperatures, storms, earthquakes, and other natural shocks, and have had to respond and adapt to such pressures over time. In the context of global climate change, natural disasters have increased across the globe. Apart from climate change, many urban environments in Latin America are experiencing significant transformations in land use patterns, socio-demographic change, changing labor markets, and economic growth, resulting from recent decades of globalization. Such transformations have resulted in the internal fragmentation of cities. In this context, the purpose of the present chapter is to demonstrate the importance in both theoretical and methodological terms, of integrating the concept of socio-environmental fragmentation into urban vulnerability research in order to make progress toward higher degrees of local sustainability in those areas of the city that suffer natural disasters and fragmentation. Methodology/approach - A mixed methods approach is used in order to combine different technical issues from urban and climate change studies. Findings - The findings are related to the importance of an integrated approach, regarding the complexity of urban life, and the relationship between the urban, the social, and the environmental phenomenon. Social implications - This chapter relates to the revisit of the current state of preparedness and to determine whether further adaptations are required. The authors understood that these kinds of mixed approaches are necessary in order to understand the new complexity of urban processes.
Environmental health risk perception: Adaptation of a population-based questionnaire from latin america
(MDPI AG, 2021) Cortés Arancibia, Sandra Isabel; Burgos, Soledad; Adaros, Héctor; Lucero, Boris; Quiróz-Alcalá, Lesliam; CEDEUS (Chile)
BACKGROUND: Environmental risk assessments and interventions to mitigate environmental risks are essential to protect public health. While the objective measurement of environmental hazards is important, it is also critical to address the subjective perception of health risks. A population’s perception of environmental health hazards is a powerful driving force for action and engagement in safety and health behaviors and can also inform the development of effective and more sustainable environmental health policies. To date, no instruments are available to assess risk perception of environmental health hazards in South America even though there are many concerning issues in the region, including mining. OBJECTIVE: We aimed to adapt and validate an environmental health risk perception questionnaire in a Chilean population affected by mining activity among other risks frequently reported in Latin American countries and included the collection of information on trust on public information sources. METHODS: We adapted an Australian risk perception questionnaire for validation in an adult population from a Chilean mining community. This adaptation included two blinded translations (direct, inverse), a pre-test study (n = 20) and a review by environmental health experts. Principal Component Analyses (PCA) was used to identify factors within major domains of interest. The Bartlett test of sphericity, Kaiser-Meyer-Olkin (KMO) measure and the Cronbach α test were used to assess the instrument’s validity and reliability. The instrument was pilot tested in 205 adults from a mining community in Chañaral. RESULTS: The final adapted questionnaire proved to be a good instrument to measure risk perception in a community chronically exposed to mining waste. For community risks, four factors explained 59.4% of the variance. “Global Issues” (30.2%) included air pollution, contamination of mining, ozone layer depletion and vector diseases. For personal risks, the first two components explained 59.5% of the variance, the main factor (36.7%) was “unhealthy behaviors within the household”. For trust in information, the first factor (36.2%) included as main sources “Media and authorities”. The Cronbach α ranged between 0.68 and 0.75; and the KMO test between 0.7 to 0.79 for community and personal risks and trust. CONCLUSIONS: The final questionnaire is a simple, reliable and useful instrument that can assist in evaluating environmental health risk perceptions in Latin American countries.
Environmental signature and health risk assessment of polybrominated diphenyl ethers (PBDEs) emitted from a landfill fire in Santiago de Chile
(2023) Pozo, Karla; Oyola, Germán; Jorquera, Hector; Gomez, Victoria; Galbán-Malagón, Cristobal; Mena-Carrasco, Marcelo; Audy, Ondřej; Příbylová, Petra; Guida, Yago; Estellano, Victor Hugo; Lammel, Gerhard; Klánová, Jana; CEDEUS (Chile)
Polybrominated diphenyl ethers (PBDEs) have been used as flame retardants in building materials, electronics, furnishings, vehicles, airplanes, plastics, polyurethane foams, and textiles for many years. Currently, the primary commercial mixtures, penta-, octa-, and deca-BDE, are globally restricted. Still, products containing PBDEs are expected to impact waste management and the environment for many years. In January 2016, an open fire in the Santa Marta landfill close to Santiago de Chile affected the city and surroundings. The fire caused several acute health effects and an increase in emergency hospitalizations. We measured PBDE levels in the areas affected by the fire in the air (gaseous and particulate) and soil, and PBDE emissions were estimated using a dispersion model. The results showed an increase in PBDE concentrations by a factor of 2–4 one day after the start of the fire. However, PBDE concentrations measured after the fire in PM10 and the gas phase were considered low compared to other regions. Interestingly, PBDEs’ patterns differed across the sites; however, BDE209 was the dominant congener for all environmental matrices. A preliminary risk assessment was conducted using the daily exposure dose (DED) by air inhalation estimation. The results showed low DED values for adults and children and suggested no direct health risk due to PBDE exposure. This study brings new data useful for future solid waste management initiatives in the country
Exposición a contaminantes provenientes de termoeléctricas a carbón y salud infantil: ¿cuál es la evidencia internacional y nacional?
(Sociedad Chilena de Pediatría, 2019) Cortés Arancibia, Sandra; Yohannessen, Karla V.; Tellerias C., Lidya; Ahumada P., Ericka; CEDEUS (Chile)
Las centrales termoeléctricas (CTE) a carbón representan un riesgo para la salud de las comunidades expuestas. Se realizó una revisión de la literatura científica nacional e internacional enfocada en los efectos en salud de niños y la exposición a emisiones al aire provenientes de CTE a carbón. Se incluyeron 21 artículos para su revisión en texto completo, donde se midieron efectos en salud infantil relacionados a presencia de biomarcadores de exposición y efecto, daños perinatales, neuroconductuales y respiratorios principalmente. La exposición a emisiones de CTE a carbón en el embarazo se asoció a niños con bajo peso y muy bajo peso al nacer, menor talla, menor diámetro de Circunferencia del Cráneo (CC) y prematuridad; el diámetro de CC aumentó en recién nacidos después del cierre de CTE. Se encontraron menor coeficiente de desarrollo (CD) y coeficiente intelectual (CI) en niños expuestos a emisiones de CTE a carbón comparados con no expuestos; CD aumentó cuando la central fue cerrada. Por otro lado, vivir en zonas con fuentes de emisión de mercurio (asociadas a CTE y plantas de cemento que funcionan con carbón) se asoció con mayor riesgo de autismo. En salud respiratoria, los artículos fueron consistentes en reportar menor función pulmonar en niños residentes en zonas expuestas a fuentes de combustión de carbón comparados con grupos de niños no expuestos. Es muy necesario abrir el debate en Chile sobre los riesgos controlables a los que se enfrenta la población infantil a consecuencia de plantas generadoras de energía instaladas en Chile.
Human exposure to polycyclic aromatic hydrocarbons in the atmosphere of an agricultural area of central Chile and inhalation cancer risk assessments
(2023) Pozo, Karla; Cortés Arancibia, Sandra; Gómez, Victoria; Guida, Yago; Torres, Mariett; Carvalho, Gabriel Oliveira de; P?ibylová, Petra; Klánová, Jana; Jorquera, Héctor; CEDEUS (Chile)
Polycyclic aromatic hydrocarbons (PAHs) are persistent toxic substances prone to long-range atmospheric transport. Even in low concentrations, environmental exposure to PAHs can impact human health. In this study we aimed to i) investigate the occurrence of 15 polycyclic aromatic hydrocarbons (?15PAHs), from August 2016 to January 2018, in the atmosphere of Molina, using polyurethane foam disks (PAS-PUF) in central Chile; and ii) perform deterministic and probabilistic (using Monte Carlo simulations) inhalation cancer risk assessments. Gas chromatography and tandem quadrupole mass spectrometry (GC- MS/MS) measured target PAHs. Results showed ?15PAHs ranging from 2 ng m-3 to 108 ng m-3, with four-ring PAHs as the prevalent compounds, including phenanthrene (44%) and fluoranthene (24%). Winter season showed the highest PAH levels (increasing factor up to ?8 times). PAHs diagnostic ratios showed the prevalence of pyrogenic combustion (winter) and petrogenic combustion (summer). Lifetime cancer risk assessments, using BaP-eq values, indicated an increased cancer risk for the exposed population considering different risk assessment approaches. Younger individuals were the most affected by an increased cancer risk at all sampling sites. The Monte Carlo probabilistic assessment indicated that infants and toddlers could be exposed to PAH air concentrations exceeding the cancer risk threshold in over 94% of the simulations. The coldest months in the studied region are critical for human exposure and health risk due to intense wood combustion. Indoor air can be even more relevant due to the chronic inhalation of the smoke and associated chemicals.
Local and NON-LOCAL source apportionment of black carbon and combustion generated PM2.5
(Elsevier Ltd, 2024) Rodríguez Rangel, Jessika Carolina; Villalobos, Ana María; Castro-Molinare J.; Jorquera González, Héctor Iván Joaquin; CEDEUS (Chile)
Current methods for measuring black carbon aerosol (BC) by optical methods apportion BC to fossil fuel and wood combustion. However, these results are aggregated: local and non-local combustion sources are lumped together. The spatial apportioning of carbonaceous aerosol sources is challenging in remote or suburban areas because non-local sources may be significant. Air quality modeling would require highly accurate emission inventories and unbiased dispersion models to quantify such apportionment. We propose FUSTA (FUzzy SpatioTemporal Apportionment) methodology for analyzing aethalometer results for equivalent black carbon coming from fossil fuel (eBCff) and wood combustion (eBCwb). We applied this methodology to ambient measurements at three suburban sites around Santiago, Chile, in the winter season 2021. FUSTA results showed that local sources contributed ∼80% to eBCff and eBCwb in all sites. By using PM2.5 – eBCff and PM2.5 – eBCwb scatterplots for each fuzzy cluster (or source) found by FUSTA, the estimated lower edge lines showed distinctive slopes in each measurement site. These slopes were larger for non-local sources (aged aerosols) than for local ones (fresh emissions) and were used to apportion combustion PM2.5 in each site. In sites Colina, Melipilla and San Jose de Maipo, fossil fuel combustion contributions to PM2.5 were 26 % (15.9 μg m−3), 22 % (9.9 μg m−3), and 22 % (7.8 μg m−3), respectively. Wood burning contributions to PM2.5 were 22 % (13.4 μg m−3), 19 % (8.9 μg m−3) and 22% (7.3 μg m−3), respectively. This methodology generates a joint source apportionment of eBC and PM2.5, which is consistent with available chemical speciation data for PM2.5 in Santiago.
Medium-run local economic effects of a major earthquake
(OXFORD UNIV PRESS, 2022) Aguirre, Paula; Asahi, Kenzo; Diaz-Rioseco, Diego; Riveros, Ignacio; Valdes, Rodrigo O.; CEDEUS (Chile)
Existing research is inconclusive regarding the longer-term economic effects of earthquakes. We examine the medium-run impacts of the 2010 earthquake in Chile, the sixth-largest ever recorded, using value-added tax collection as a proxy for economic activity at the municipal level and a measure of local ground-shaking intensity. We find that the affected municipalities suffered a relevant and persistent drop in their economic activity of about 10%, 8-9 years after the event. We discuss the plausibility of the assumption of conditional parallel trends and show that the overall results are robust to using alternative estimation methods.
Midday Boundary-Layer Collapse in the Altiplano Desert: The Combined Effect of Advection and Subsidence
(2023) Aguirre Correa, Francisca; De Arellano, Jordi Vila-Guerau; Ronda, Reinder; Lobos Roco, Felipe Andrés; Suárez Poch, Francisco Ignacio; Hartogensis, Oscar; CEDEUS (Chile)
Observations in the Altiplano region of the Atacama Desert show that the atmospheric boundary layer (ABL) suddenly collapses at noon. This rapid decrease occurs simultaneously to the entrance of a thermally driven, regional flow that causes a rise in wind speed and a marked temperature decrease. We identify the main drivers that cause the observed ABL collapse by using a land-atmosphere model. The free atmosphere lapse rate and regional forcings, such as advection of mass and cold air as well as subsidence, are first estimated by combining observations from a comprehensive field campaign and a regional model. Then, to disentangle the ABL collapse, we perform a suite of numerical experiments with increasing level of complexity: from only considering local land-atmosphere interactions, to systematically including the regional contributions of mass advection, cold air advection, and subsidence. Our results show that non-local processes related to the arrival of the regional flow are the main factors explaining the boundary-layer collapse. The advection of a shallower boundary layer (approximate to -250 m h(-1) at noon) causes an immediate decrease in the ABL height (h) at midday. This occurs simultaneously with the arrival of a cold air mass, which reaches a strength of approximate to -4 Kh(-1) at 1400 LT. These two external forcings become dominant over entrainment and surface processes that warm the atmosphere and increase h. As a consequence, the ABL growth is capped during the afternoon. Finally, a wind divergence of approximate to 8 x 10(-5) s(-1) contributes to the collapse by causing subsidence motions over the ABL from 1200 LT onward. Our findings show the relevance of treating large and small-scale processes as a continuum to be able to understand the ABL dynamics.
Multi-objective optimization to balance thermal comfort and energy use in a mining camp located in the Andes Mountains at high altitude
(2020) Dietz, A.; Vera Araya, Sergio Eduardo; Bustamante Gómez, Waldo; Flamant, G.; CEDEUS (Chile)
Multi-scale temporal analysis of evaporation on a saline lake in the Atacama Desert
(2022) Lobos Roco, Felipe Andres; Hartogensis, Oscar; Suarez Poch, Francisco Ignacio; Huerta-Viso, Ariadna; Benedict, Imme; de la Fuente, Alberto; Vila-Guerau de Arellano, Jordi; CEDEUS (Chile)
We investigate how evaporation changes depending on the scales in the Altiplano region of the Atacama Desert. More specifically, we focus on the temporal evolution from the climatological to the sub-diurnal scales on a high-altitude saline lake ecosystem. We analyze the evaporation trends over 70 years (1950–2020) at a high-spatial resolution. The method is based on the downscaling of 30 km ERA5 reanalysis data at hourly resolution to 0.1 km spatial resolution data, using artificial neural networks to analyze the main drivers of evaporation. To this end, we use the Penman open-water evaporation equation, modified to compensate for the energy balance non-closure and the ice cover formation on the lake during the night. Our estimation of the hourly climatology of evaporation shows a consistent agreement with eddy-covariance (EC) measurements and reveals that evaporation is controlled by different drivers depending on the time scale. At the sub-diurnal scale, mechanical turbulence is the primary driver of evaporation, and at this scale, it is not radiation-limited. At the seasonal scale, more than 70 % of the evaporation variability is explained by the radiative contribution term. At the same scale, and using a large-scale moisture tracking model, we identify the main sources of moisture to the Chilean Altiplano. In all cases, our regime of precipitation is controlled by large-scale weather patterns closely linked to climatological fluctuations. Moreover, seasonal evaporation significantly influences the saline lake surface spatial changes. From an interannual scale perspective, evaporation increased by 2.1 mm yr−1 during the entire study period, according to global temperature increases. Finally, we find that yearly evaporation depends on the El Niño–Southern Oscillation (ENSO), where warm and cool ENSO phases are associated with higher evaporation and precipitation rates, respectively. Our results show that warm ENSO phases increase evaporation rates by 15 %, whereas cold phases decrease it by 2 %.
Optimizing and validating the Gravitational Process Path model for regional debris-flow runout modelling
(Copernicus GmbH, 2021) Goetz J.; Kohrs R.; Bustos Morales M.; Henríquez C.; Brenning A.; Parra Hormazábal E.; Araneda Riquelme M.B.; CEDEUS (Chile)
© 2021 The Author(s).Knowing the source and runout of debris flows can help in planning strategies aimed at mitigating these hazards. Our research in this paper focuses on developing a novel approach for optimizing runout models for regional susceptibility modelling, with a case study in the upper Maipo River basin in the Andes of Santiago, Chile. We propose a two-stage optimization approach for automatically selecting parameters for estimating runout path and distance. This approach optimizes the random-walk and Perla et al.'s (PCM) two-parameter friction model components of the open-source Gravitational Process Path (GPP) modelling framework. To validate model performance, we assess the spatial transferability of the optimized runout model using spatial cross-validation, including exploring the model's sensitivity to sample size. We also present diagnostic tools for visualizing uncertainties in parameter selection and model performance. Although there was considerable variation in optimal parameters for individual events, we found our runout modelling approach performed well at regional prediction of potential runout areas. We also found that although a relatively small sample size was sufficient to achieve generally good runout modelling performance, larger samples sizes (i.e. ≥80) had higher model performance and lower uncertainties for estimating runout distances at unknown locations. We anticipate that this automated approach using the open-source R software and the System for Automated Geoscientific Analyses geographic information system (SAGA-GIS) will make process-based debris-flow models more readily accessible and thus enable researchers and spatial planners to improve regional-scale hazard assessments.
Predictive modeling the effect of Local Climate Zones (LCZ) on the urban meteorology in a tropical andean area
(Springer Heidelberg, 2024) Mancheno Dominguez, Gabriela Alejandra; Castro Molinare, Julio Enrique; Jorquera, Héctor; CEDEUS (Chile)
The Weather Research & Forecasting Model (WRF, Version 4.4) was applied to simulate meteorological conditions in the city of Quito, Ecuador, located in a tropical Andean landscape. These simulations included the urban canopy into WRF, using the Building Environment Parameterization (BEP) scheme combined with Local Climate Zones (LCZ) land use classification; the innermost domain had a horizontal resolution of 2 km. The simulation results showed that using LCZ + BEP options improved the representation of wind speed and planetary boundary layer height (PBLH), in comparison with WRF counter fact simulations which did not use BEP. For temperature and relative humidity, implementation of LCZ did not improve WRF simulations with respect to those counter fact simulations. This may be ascribed to the use of the default LCZ thermophysical parameters, suggesting the need for gathering local built environment features. The best WRF configuration found for wind speed was the one that combined BEP scheme, LCZ land use and the Yonsei University (YSU) PBL model with topographic option activated; this happened for dry and wet seasons and for the unique meteorological conditions in December. Regarding PBLH modeling, the best configurations were YSU-BEP-LCZ (December), MYJ-BEP-LCZ (April, wet season) and YSU (August, dry season). The findings showed the major influence of urban canopy - described by LCZ - on wind circulation and PBLH simulated within the city at high horizontal resolution (2 km). This effect should be considered when modeling atmospheric pollutant dispersion, choosing urban development strategies, and analyzing prospective climate change scenarios, among other goals.
Saharan dust contributions to high hourly PM10 concentrations at a background station in Southwestern Europe
(2023) Rodríguez, Jessika; García, María Ángeles; Pérez, Isidro A.; Jorquera, Héctor; CEDEUS (Chile)
This paper presents a long-term analysis of ambient PM10 concentrations measured at a background station in Spain, using backward trajectories generated with the HYSPLIT model, together with the identification of synoptic patterns and a fuzzy clustering analysis, to identify the sources present and evaluate their relationship with meteorological variables such as wind speed and direction, temperature, and atmospheric pressure. Ambient PM10 presented maximum values during the summer with mean concentrations of approximately 14 µg m−3 for August, and minimum values during the winter with concentrations of 6 µg m−3 for January. The daily cycle presented two peaks—one in the morning and another in the afternoon—with this variability being associated with transport emissions. African air masses reached the study site extending vertically at least up to 2500 m.a.g.l, with a frequency of 43.5%, and are associated to a mean ground PM10 concentration of 41.3 µg m−3. During the episodes of Saharan intrusions, high pressures with unclassified synoptic patterns (U) prevailed over the Iberian Peninsula. Local, European, maritime and intermittent contributions were the four main sources of pollutants identified through fuzzy clustering analysis. These intermittent contributions are associated with Saharan dust intrusions, with a long-term average PM10 concentration of 1.7 µg m−3, which represents an important contribution of 11.2%. These sources affect seasonal variations of PM10 background concentrations, and reach their maximum when the greatest contributions of desert dust occur—mainly during the spring–summer months. These results provide useful information for future comparisons and environmental monitoring of PM10 levels

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